linux/net/xfrm/xfrm_policy.c

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/*
* xfrm_policy.c
*
* Changes:
* Mitsuru KANDA @USAGI
* Kazunori MIYAZAWA @USAGI
* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
* IPv6 support
* Kazunori MIYAZAWA @USAGI
* YOSHIFUJI Hideaki
* Split up af-specific portion
* Derek Atkins <derek@ihtfp.com> Add the post_input processor
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
*
*/
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/cache.h>
#include <linux/audit.h>
#include <net/dst.h>
#include <net/xfrm.h>
#include <net/ip.h>
#ifdef CONFIG_XFRM_STATISTICS
#include <net/snmp.h>
#endif
#include "xfrm_hash.h"
DEFINE_MUTEX(xfrm_cfg_mutex);
EXPORT_SYMBOL(xfrm_cfg_mutex);
static DEFINE_SPINLOCK(xfrm_policy_sk_bundle_lock);
static struct dst_entry *xfrm_policy_sk_bundles;
static DEFINE_RWLOCK(xfrm_policy_lock);
static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
static struct kmem_cache *xfrm_dst_cache __read_mostly;
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
static void xfrm_init_pmtu(struct dst_entry *dst);
static int stale_bundle(struct dst_entry *dst);
static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
int dir);
static inline int
__xfrm4_selector_match(struct xfrm_selector *sel, struct flowi *fl)
{
return addr_match(&fl->fl4_dst, &sel->daddr, sel->prefixlen_d) &&
addr_match(&fl->fl4_src, &sel->saddr, sel->prefixlen_s) &&
!((xfrm_flowi_dport(fl) ^ sel->dport) & sel->dport_mask) &&
!((xfrm_flowi_sport(fl) ^ sel->sport) & sel->sport_mask) &&
(fl->proto == sel->proto || !sel->proto) &&
(fl->oif == sel->ifindex || !sel->ifindex);
}
static inline int
__xfrm6_selector_match(struct xfrm_selector *sel, struct flowi *fl)
{
return addr_match(&fl->fl6_dst, &sel->daddr, sel->prefixlen_d) &&
addr_match(&fl->fl6_src, &sel->saddr, sel->prefixlen_s) &&
!((xfrm_flowi_dport(fl) ^ sel->dport) & sel->dport_mask) &&
!((xfrm_flowi_sport(fl) ^ sel->sport) & sel->sport_mask) &&
(fl->proto == sel->proto || !sel->proto) &&
(fl->oif == sel->ifindex || !sel->ifindex);
}
int xfrm_selector_match(struct xfrm_selector *sel, struct flowi *fl,
unsigned short family)
{
switch (family) {
case AF_INET:
return __xfrm4_selector_match(sel, fl);
case AF_INET6:
return __xfrm6_selector_match(sel, fl);
}
return 0;
}
static inline struct dst_entry *__xfrm_dst_lookup(struct net *net, int tos,
xfrm_address_t *saddr,
xfrm_address_t *daddr,
int family)
{
struct xfrm_policy_afinfo *afinfo;
struct dst_entry *dst;
afinfo = xfrm_policy_get_afinfo(family);
if (unlikely(afinfo == NULL))
return ERR_PTR(-EAFNOSUPPORT);
dst = afinfo->dst_lookup(net, tos, saddr, daddr);
xfrm_policy_put_afinfo(afinfo);
return dst;
}
static inline struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x, int tos,
xfrm_address_t *prev_saddr,
xfrm_address_t *prev_daddr,
int family)
{
struct net *net = xs_net(x);
xfrm_address_t *saddr = &x->props.saddr;
xfrm_address_t *daddr = &x->id.daddr;
struct dst_entry *dst;
if (x->type->flags & XFRM_TYPE_LOCAL_COADDR) {
saddr = x->coaddr;
daddr = prev_daddr;
}
if (x->type->flags & XFRM_TYPE_REMOTE_COADDR) {
saddr = prev_saddr;
daddr = x->coaddr;
}
dst = __xfrm_dst_lookup(net, tos, saddr, daddr, family);
if (!IS_ERR(dst)) {
if (prev_saddr != saddr)
memcpy(prev_saddr, saddr, sizeof(*prev_saddr));
if (prev_daddr != daddr)
memcpy(prev_daddr, daddr, sizeof(*prev_daddr));
}
return dst;
}
static inline unsigned long make_jiffies(long secs)
{
if (secs >= (MAX_SCHEDULE_TIMEOUT-1)/HZ)
return MAX_SCHEDULE_TIMEOUT-1;
else
return secs*HZ;
}
static void xfrm_policy_timer(unsigned long data)
{
struct xfrm_policy *xp = (struct xfrm_policy*)data;
unsigned long now = get_seconds();
long next = LONG_MAX;
int warn = 0;
int dir;
read_lock(&xp->lock);
if (unlikely(xp->walk.dead))
goto out;
dir = xfrm_policy_id2dir(xp->index);
if (xp->lft.hard_add_expires_seconds) {
long tmo = xp->lft.hard_add_expires_seconds +
xp->curlft.add_time - now;
if (tmo <= 0)
goto expired;
if (tmo < next)
next = tmo;
}
if (xp->lft.hard_use_expires_seconds) {
long tmo = xp->lft.hard_use_expires_seconds +
(xp->curlft.use_time ? : xp->curlft.add_time) - now;
if (tmo <= 0)
goto expired;
if (tmo < next)
next = tmo;
}
if (xp->lft.soft_add_expires_seconds) {
long tmo = xp->lft.soft_add_expires_seconds +
xp->curlft.add_time - now;
if (tmo <= 0) {
warn = 1;
tmo = XFRM_KM_TIMEOUT;
}
if (tmo < next)
next = tmo;
}
if (xp->lft.soft_use_expires_seconds) {
long tmo = xp->lft.soft_use_expires_seconds +
(xp->curlft.use_time ? : xp->curlft.add_time) - now;
if (tmo <= 0) {
warn = 1;
tmo = XFRM_KM_TIMEOUT;
}
if (tmo < next)
next = tmo;
}
if (warn)
km_policy_expired(xp, dir, 0, 0);
if (next != LONG_MAX &&
!mod_timer(&xp->timer, jiffies + make_jiffies(next)))
xfrm_pol_hold(xp);
out:
read_unlock(&xp->lock);
xfrm_pol_put(xp);
return;
expired:
read_unlock(&xp->lock);
if (!xfrm_policy_delete(xp, dir))
km_policy_expired(xp, dir, 1, 0);
xfrm_pol_put(xp);
}
static struct flow_cache_object *xfrm_policy_flo_get(struct flow_cache_object *flo)
{
struct xfrm_policy *pol = container_of(flo, struct xfrm_policy, flo);
if (unlikely(pol->walk.dead))
flo = NULL;
else
xfrm_pol_hold(pol);
return flo;
}
static int xfrm_policy_flo_check(struct flow_cache_object *flo)
{
struct xfrm_policy *pol = container_of(flo, struct xfrm_policy, flo);
return !pol->walk.dead;
}
static void xfrm_policy_flo_delete(struct flow_cache_object *flo)
{
xfrm_pol_put(container_of(flo, struct xfrm_policy, flo));
}
static const struct flow_cache_ops xfrm_policy_fc_ops = {
.get = xfrm_policy_flo_get,
.check = xfrm_policy_flo_check,
.delete = xfrm_policy_flo_delete,
};
/* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
* SPD calls.
*/
struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp)
{
struct xfrm_policy *policy;
policy = kzalloc(sizeof(struct xfrm_policy), gfp);
if (policy) {
write_pnet(&policy->xp_net, net);
INIT_LIST_HEAD(&policy->walk.all);
INIT_HLIST_NODE(&policy->bydst);
INIT_HLIST_NODE(&policy->byidx);
rwlock_init(&policy->lock);
atomic_set(&policy->refcnt, 1);
setup_timer(&policy->timer, xfrm_policy_timer,
(unsigned long)policy);
policy->flo.ops = &xfrm_policy_fc_ops;
}
return policy;
}
EXPORT_SYMBOL(xfrm_policy_alloc);
/* Destroy xfrm_policy: descendant resources must be released to this moment. */
void xfrm_policy_destroy(struct xfrm_policy *policy)
{
BUG_ON(!policy->walk.dead);
if (del_timer(&policy->timer))
BUG();
security_xfrm_policy_free(policy->security);
kfree(policy);
}
EXPORT_SYMBOL(xfrm_policy_destroy);
/* Rule must be locked. Release descentant resources, announce
* entry dead. The rule must be unlinked from lists to the moment.
*/
static void xfrm_policy_kill(struct xfrm_policy *policy)
{
policy->walk.dead = 1;
atomic_inc(&policy->genid);
if (del_timer(&policy->timer))
xfrm_pol_put(policy);
xfrm_pol_put(policy);
}
static unsigned int xfrm_policy_hashmax __read_mostly = 1 * 1024 * 1024;
static inline unsigned int idx_hash(struct net *net, u32 index)
{
return __idx_hash(index, net->xfrm.policy_idx_hmask);
}
static struct hlist_head *policy_hash_bysel(struct net *net, struct xfrm_selector *sel, unsigned short family, int dir)
{
unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;
unsigned int hash = __sel_hash(sel, family, hmask);
return (hash == hmask + 1 ?
&net->xfrm.policy_inexact[dir] :
net->xfrm.policy_bydst[dir].table + hash);
}
static struct hlist_head *policy_hash_direct(struct net *net, xfrm_address_t *daddr, xfrm_address_t *saddr, unsigned short family, int dir)
{
unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;
unsigned int hash = __addr_hash(daddr, saddr, family, hmask);
return net->xfrm.policy_bydst[dir].table + hash;
}
static void xfrm_dst_hash_transfer(struct hlist_head *list,
struct hlist_head *ndsttable,
unsigned int nhashmask)
{
struct hlist_node *entry, *tmp, *entry0 = NULL;
struct xfrm_policy *pol;
unsigned int h0 = 0;
redo:
hlist_for_each_entry_safe(pol, entry, tmp, list, bydst) {
unsigned int h;
h = __addr_hash(&pol->selector.daddr, &pol->selector.saddr,
pol->family, nhashmask);
if (!entry0) {
hlist_del(entry);
hlist_add_head(&pol->bydst, ndsttable+h);
h0 = h;
} else {
if (h != h0)
continue;
hlist_del(entry);
hlist_add_after(entry0, &pol->bydst);
}
entry0 = entry;
}
if (!hlist_empty(list)) {
entry0 = NULL;
goto redo;
}
}
static void xfrm_idx_hash_transfer(struct hlist_head *list,
struct hlist_head *nidxtable,
unsigned int nhashmask)
{
struct hlist_node *entry, *tmp;
struct xfrm_policy *pol;
hlist_for_each_entry_safe(pol, entry, tmp, list, byidx) {
unsigned int h;
h = __idx_hash(pol->index, nhashmask);
hlist_add_head(&pol->byidx, nidxtable+h);
}
}
static unsigned long xfrm_new_hash_mask(unsigned int old_hmask)
{
return ((old_hmask + 1) << 1) - 1;
}
static void xfrm_bydst_resize(struct net *net, int dir)
{
unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;
unsigned int nhashmask = xfrm_new_hash_mask(hmask);
unsigned int nsize = (nhashmask + 1) * sizeof(struct hlist_head);
struct hlist_head *odst = net->xfrm.policy_bydst[dir].table;
struct hlist_head *ndst = xfrm_hash_alloc(nsize);
int i;
if (!ndst)
return;
write_lock_bh(&xfrm_policy_lock);
for (i = hmask; i >= 0; i--)
xfrm_dst_hash_transfer(odst + i, ndst, nhashmask);
net->xfrm.policy_bydst[dir].table = ndst;
net->xfrm.policy_bydst[dir].hmask = nhashmask;
write_unlock_bh(&xfrm_policy_lock);
xfrm_hash_free(odst, (hmask + 1) * sizeof(struct hlist_head));
}
static void xfrm_byidx_resize(struct net *net, int total)
{
unsigned int hmask = net->xfrm.policy_idx_hmask;
unsigned int nhashmask = xfrm_new_hash_mask(hmask);
unsigned int nsize = (nhashmask + 1) * sizeof(struct hlist_head);
struct hlist_head *oidx = net->xfrm.policy_byidx;
struct hlist_head *nidx = xfrm_hash_alloc(nsize);
int i;
if (!nidx)
return;
write_lock_bh(&xfrm_policy_lock);
for (i = hmask; i >= 0; i--)
xfrm_idx_hash_transfer(oidx + i, nidx, nhashmask);
net->xfrm.policy_byidx = nidx;
net->xfrm.policy_idx_hmask = nhashmask;
write_unlock_bh(&xfrm_policy_lock);
xfrm_hash_free(oidx, (hmask + 1) * sizeof(struct hlist_head));
}
static inline int xfrm_bydst_should_resize(struct net *net, int dir, int *total)
{
unsigned int cnt = net->xfrm.policy_count[dir];
unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;
if (total)
*total += cnt;
if ((hmask + 1) < xfrm_policy_hashmax &&
cnt > hmask)
return 1;
return 0;
}
static inline int xfrm_byidx_should_resize(struct net *net, int total)
{
unsigned int hmask = net->xfrm.policy_idx_hmask;
if ((hmask + 1) < xfrm_policy_hashmax &&
total > hmask)
return 1;
return 0;
}
void xfrm_spd_getinfo(struct net *net, struct xfrmk_spdinfo *si)
{
read_lock_bh(&xfrm_policy_lock);
si->incnt = net->xfrm.policy_count[XFRM_POLICY_IN];
si->outcnt = net->xfrm.policy_count[XFRM_POLICY_OUT];
si->fwdcnt = net->xfrm.policy_count[XFRM_POLICY_FWD];
si->inscnt = net->xfrm.policy_count[XFRM_POLICY_IN+XFRM_POLICY_MAX];
si->outscnt = net->xfrm.policy_count[XFRM_POLICY_OUT+XFRM_POLICY_MAX];
si->fwdscnt = net->xfrm.policy_count[XFRM_POLICY_FWD+XFRM_POLICY_MAX];
si->spdhcnt = net->xfrm.policy_idx_hmask;
si->spdhmcnt = xfrm_policy_hashmax;
read_unlock_bh(&xfrm_policy_lock);
}
EXPORT_SYMBOL(xfrm_spd_getinfo);
static DEFINE_MUTEX(hash_resize_mutex);
static void xfrm_hash_resize(struct work_struct *work)
{
struct net *net = container_of(work, struct net, xfrm.policy_hash_work);
int dir, total;
mutex_lock(&hash_resize_mutex);
total = 0;
for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
if (xfrm_bydst_should_resize(net, dir, &total))
xfrm_bydst_resize(net, dir);
}
if (xfrm_byidx_should_resize(net, total))
xfrm_byidx_resize(net, total);
mutex_unlock(&hash_resize_mutex);
}
/* Generate new index... KAME seems to generate them ordered by cost
* of an absolute inpredictability of ordering of rules. This will not pass. */
static u32 xfrm_gen_index(struct net *net, int dir)
{
static u32 idx_generator;
for (;;) {
struct hlist_node *entry;
struct hlist_head *list;
struct xfrm_policy *p;
u32 idx;
int found;
idx = (idx_generator | dir);
idx_generator += 8;
if (idx == 0)
idx = 8;
list = net->xfrm.policy_byidx + idx_hash(net, idx);
found = 0;
hlist_for_each_entry(p, entry, list, byidx) {
if (p->index == idx) {
found = 1;
break;
}
}
if (!found)
return idx;
}
}
static inline int selector_cmp(struct xfrm_selector *s1, struct xfrm_selector *s2)
{
u32 *p1 = (u32 *) s1;
u32 *p2 = (u32 *) s2;
int len = sizeof(struct xfrm_selector) / sizeof(u32);
int i;
for (i = 0; i < len; i++) {
if (p1[i] != p2[i])
return 1;
}
return 0;
}
int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
{
struct net *net = xp_net(policy);
struct xfrm_policy *pol;
struct xfrm_policy *delpol;
struct hlist_head *chain;
struct hlist_node *entry, *newpos;
u32 mark = policy->mark.v & policy->mark.m;
write_lock_bh(&xfrm_policy_lock);
chain = policy_hash_bysel(net, &policy->selector, policy->family, dir);
delpol = NULL;
newpos = NULL;
hlist_for_each_entry(pol, entry, chain, bydst) {
if (pol->type == policy->type &&
!selector_cmp(&pol->selector, &policy->selector) &&
(mark & pol->mark.m) == pol->mark.v &&
xfrm_sec_ctx_match(pol->security, policy->security) &&
!WARN_ON(delpol)) {
if (excl) {
write_unlock_bh(&xfrm_policy_lock);
return -EEXIST;
}
delpol = pol;
if (policy->priority > pol->priority)
continue;
} else if (policy->priority >= pol->priority) {
newpos = &pol->bydst;
continue;
}
if (delpol)
break;
}
if (newpos)
hlist_add_after(newpos, &policy->bydst);
else
hlist_add_head(&policy->bydst, chain);
xfrm_pol_hold(policy);
net->xfrm.policy_count[dir]++;
atomic_inc(&flow_cache_genid);
if (delpol)
__xfrm_policy_unlink(delpol, dir);
policy->index = delpol ? delpol->index : xfrm_gen_index(net, dir);
hlist_add_head(&policy->byidx, net->xfrm.policy_byidx+idx_hash(net, policy->index));
policy->curlft.add_time = get_seconds();
policy->curlft.use_time = 0;
if (!mod_timer(&policy->timer, jiffies + HZ))
xfrm_pol_hold(policy);
list_add(&policy->walk.all, &net->xfrm.policy_all);
write_unlock_bh(&xfrm_policy_lock);
if (delpol)
xfrm_policy_kill(delpol);
else if (xfrm_bydst_should_resize(net, dir, NULL))
schedule_work(&net->xfrm.policy_hash_work);
return 0;
}
EXPORT_SYMBOL(xfrm_policy_insert);
struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u8 type,
int dir, struct xfrm_selector *sel,
struct xfrm_sec_ctx *ctx, int delete,
int *err)
{
struct xfrm_policy *pol, *ret;
struct hlist_head *chain;
struct hlist_node *entry;
*err = 0;
write_lock_bh(&xfrm_policy_lock);
chain = policy_hash_bysel(net, sel, sel->family, dir);
ret = NULL;
hlist_for_each_entry(pol, entry, chain, bydst) {
if (pol->type == type &&
(mark & pol->mark.m) == pol->mark.v &&
!selector_cmp(sel, &pol->selector) &&
xfrm_sec_ctx_match(ctx, pol->security)) {
xfrm_pol_hold(pol);
if (delete) {
*err = security_xfrm_policy_delete(
pol->security);
if (*err) {
write_unlock_bh(&xfrm_policy_lock);
return pol;
}
__xfrm_policy_unlink(pol, dir);
}
ret = pol;
break;
}
}
write_unlock_bh(&xfrm_policy_lock);
if (ret && delete)
xfrm_policy_kill(ret);
return ret;
}
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
EXPORT_SYMBOL(xfrm_policy_bysel_ctx);
struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u8 type,
int dir, u32 id, int delete, int *err)
{
struct xfrm_policy *pol, *ret;
struct hlist_head *chain;
struct hlist_node *entry;
*err = -ENOENT;
if (xfrm_policy_id2dir(id) != dir)
return NULL;
*err = 0;
write_lock_bh(&xfrm_policy_lock);
chain = net->xfrm.policy_byidx + idx_hash(net, id);
ret = NULL;
hlist_for_each_entry(pol, entry, chain, byidx) {
if (pol->type == type && pol->index == id &&
(mark & pol->mark.m) == pol->mark.v) {
xfrm_pol_hold(pol);
if (delete) {
*err = security_xfrm_policy_delete(
pol->security);
if (*err) {
write_unlock_bh(&xfrm_policy_lock);
return pol;
}
__xfrm_policy_unlink(pol, dir);
}
ret = pol;
break;
}
}
write_unlock_bh(&xfrm_policy_lock);
if (ret && delete)
xfrm_policy_kill(ret);
return ret;
}
EXPORT_SYMBOL(xfrm_policy_byid);
#ifdef CONFIG_SECURITY_NETWORK_XFRM
static inline int
xfrm_policy_flush_secctx_check(struct net *net, u8 type, struct xfrm_audit *audit_info)
{
int dir, err = 0;
for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
struct xfrm_policy *pol;
struct hlist_node *entry;
int i;
hlist_for_each_entry(pol, entry,
&net->xfrm.policy_inexact[dir], bydst) {
if (pol->type != type)
continue;
err = security_xfrm_policy_delete(pol->security);
if (err) {
xfrm_audit_policy_delete(pol, 0,
audit_info->loginuid,
audit_info->sessionid,
audit_info->secid);
return err;
}
}
for (i = net->xfrm.policy_bydst[dir].hmask; i >= 0; i--) {
hlist_for_each_entry(pol, entry,
net->xfrm.policy_bydst[dir].table + i,
bydst) {
if (pol->type != type)
continue;
err = security_xfrm_policy_delete(
pol->security);
if (err) {
xfrm_audit_policy_delete(pol, 0,
audit_info->loginuid,
audit_info->sessionid,
audit_info->secid);
return err;
}
}
}
}
return err;
}
#else
static inline int
xfrm_policy_flush_secctx_check(struct net *net, u8 type, struct xfrm_audit *audit_info)
{
return 0;
}
#endif
int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
{
int dir, err = 0, cnt = 0;
write_lock_bh(&xfrm_policy_lock);
err = xfrm_policy_flush_secctx_check(net, type, audit_info);
if (err)
goto out;
for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
struct xfrm_policy *pol;
struct hlist_node *entry;
int i;
again1:
hlist_for_each_entry(pol, entry,
&net->xfrm.policy_inexact[dir], bydst) {
if (pol->type != type)
continue;
__xfrm_policy_unlink(pol, dir);
write_unlock_bh(&xfrm_policy_lock);
cnt++;
xfrm_audit_policy_delete(pol, 1, audit_info->loginuid,
audit_info->sessionid,
audit_info->secid);
xfrm_policy_kill(pol);
write_lock_bh(&xfrm_policy_lock);
goto again1;
}
for (i = net->xfrm.policy_bydst[dir].hmask; i >= 0; i--) {
again2:
hlist_for_each_entry(pol, entry,
net->xfrm.policy_bydst[dir].table + i,
bydst) {
if (pol->type != type)
continue;
__xfrm_policy_unlink(pol, dir);
write_unlock_bh(&xfrm_policy_lock);
cnt++;
xfrm_audit_policy_delete(pol, 1,
audit_info->loginuid,
audit_info->sessionid,
audit_info->secid);
xfrm_policy_kill(pol);
write_lock_bh(&xfrm_policy_lock);
goto again2;
}
}
}
if (!cnt)
err = -ESRCH;
out:
write_unlock_bh(&xfrm_policy_lock);
return err;
}
EXPORT_SYMBOL(xfrm_policy_flush);
int xfrm_policy_walk(struct net *net, struct xfrm_policy_walk *walk,
int (*func)(struct xfrm_policy *, int, int, void*),
void *data)
{
struct xfrm_policy *pol;
struct xfrm_policy_walk_entry *x;
int error = 0;
if (walk->type >= XFRM_POLICY_TYPE_MAX &&
walk->type != XFRM_POLICY_TYPE_ANY)
return -EINVAL;
if (list_empty(&walk->walk.all) && walk->seq != 0)
return 0;
write_lock_bh(&xfrm_policy_lock);
if (list_empty(&walk->walk.all))
x = list_first_entry(&net->xfrm.policy_all, struct xfrm_policy_walk_entry, all);
else
x = list_entry(&walk->walk.all, struct xfrm_policy_walk_entry, all);
list_for_each_entry_from(x, &net->xfrm.policy_all, all) {
if (x->dead)
continue;
pol = container_of(x, struct xfrm_policy, walk);
if (walk->type != XFRM_POLICY_TYPE_ANY &&
walk->type != pol->type)
continue;
error = func(pol, xfrm_policy_id2dir(pol->index),
walk->seq, data);
if (error) {
list_move_tail(&walk->walk.all, &x->all);
goto out;
}
walk->seq++;
}
if (walk->seq == 0) {
error = -ENOENT;
goto out;
}
list_del_init(&walk->walk.all);
out:
write_unlock_bh(&xfrm_policy_lock);
return error;
}
EXPORT_SYMBOL(xfrm_policy_walk);
void xfrm_policy_walk_init(struct xfrm_policy_walk *walk, u8 type)
{
INIT_LIST_HEAD(&walk->walk.all);
walk->walk.dead = 1;
walk->type = type;
walk->seq = 0;
}
EXPORT_SYMBOL(xfrm_policy_walk_init);
void xfrm_policy_walk_done(struct xfrm_policy_walk *walk)
{
if (list_empty(&walk->walk.all))
return;
write_lock_bh(&xfrm_policy_lock);
list_del(&walk->walk.all);
write_unlock_bh(&xfrm_policy_lock);
}
EXPORT_SYMBOL(xfrm_policy_walk_done);
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
/*
* Find policy to apply to this flow.
*
* Returns 0 if policy found, else an -errno.
*/
static int xfrm_policy_match(struct xfrm_policy *pol, struct flowi *fl,
u8 type, u16 family, int dir)
{
struct xfrm_selector *sel = &pol->selector;
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
int match, ret = -ESRCH;
if (pol->family != family ||
(fl->mark & pol->mark.m) != pol->mark.v ||
pol->type != type)
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
return ret;
match = xfrm_selector_match(sel, fl, family);
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
if (match)
ret = security_xfrm_policy_lookup(pol->security, fl->secid,
dir);
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
return ret;
}
static struct xfrm_policy *xfrm_policy_lookup_bytype(struct net *net, u8 type,
struct flowi *fl,
u16 family, u8 dir)
{
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
int err;
struct xfrm_policy *pol, *ret;
xfrm_address_t *daddr, *saddr;
struct hlist_node *entry;
struct hlist_head *chain;
u32 priority = ~0U;
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
daddr = xfrm_flowi_daddr(fl, family);
saddr = xfrm_flowi_saddr(fl, family);
if (unlikely(!daddr || !saddr))
return NULL;
read_lock_bh(&xfrm_policy_lock);
chain = policy_hash_direct(net, daddr, saddr, family, dir);
ret = NULL;
hlist_for_each_entry(pol, entry, chain, bydst) {
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
err = xfrm_policy_match(pol, fl, type, family, dir);
if (err) {
if (err == -ESRCH)
continue;
else {
ret = ERR_PTR(err);
goto fail;
}
} else {
ret = pol;
priority = ret->priority;
break;
}
}
chain = &net->xfrm.policy_inexact[dir];
hlist_for_each_entry(pol, entry, chain, bydst) {
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
err = xfrm_policy_match(pol, fl, type, family, dir);
if (err) {
if (err == -ESRCH)
continue;
else {
ret = ERR_PTR(err);
goto fail;
}
} else if (pol->priority < priority) {
ret = pol;
break;
}
}
if (ret)
xfrm_pol_hold(ret);
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
fail:
read_unlock_bh(&xfrm_policy_lock);
return ret;
}
static struct xfrm_policy *
__xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family, u8 dir)
{
#ifdef CONFIG_XFRM_SUB_POLICY
struct xfrm_policy *pol;
pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_SUB, fl, family, dir);
if (pol != NULL)
return pol;
#endif
return xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN, fl, family, dir);
}
static struct flow_cache_object *
xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family,
u8 dir, struct flow_cache_object *old_obj, void *ctx)
{
struct xfrm_policy *pol;
if (old_obj)
xfrm_pol_put(container_of(old_obj, struct xfrm_policy, flo));
pol = __xfrm_policy_lookup(net, fl, family, dir);
if (IS_ERR_OR_NULL(pol))
return ERR_CAST(pol);
/* Resolver returns two references:
* one for cache and one for caller of flow_cache_lookup() */
xfrm_pol_hold(pol);
return &pol->flo;
}
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
static inline int policy_to_flow_dir(int dir)
{
if (XFRM_POLICY_IN == FLOW_DIR_IN &&
XFRM_POLICY_OUT == FLOW_DIR_OUT &&
XFRM_POLICY_FWD == FLOW_DIR_FWD)
return dir;
switch (dir) {
default:
case XFRM_POLICY_IN:
return FLOW_DIR_IN;
case XFRM_POLICY_OUT:
return FLOW_DIR_OUT;
case XFRM_POLICY_FWD:
return FLOW_DIR_FWD;
}
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
}
static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struct flowi *fl)
{
struct xfrm_policy *pol;
read_lock_bh(&xfrm_policy_lock);
if ((pol = sk->sk_policy[dir]) != NULL) {
int match = xfrm_selector_match(&pol->selector, fl,
sk->sk_family);
int err = 0;
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
if (match) {
if ((sk->sk_mark & pol->mark.m) != pol->mark.v) {
pol = NULL;
goto out;
}
err = security_xfrm_policy_lookup(pol->security,
fl->secid,
policy_to_flow_dir(dir));
if (!err)
xfrm_pol_hold(pol);
else if (err == -ESRCH)
pol = NULL;
else
pol = ERR_PTR(err);
} else
pol = NULL;
}
out:
read_unlock_bh(&xfrm_policy_lock);
return pol;
}
static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
{
struct net *net = xp_net(pol);
struct hlist_head *chain = policy_hash_bysel(net, &pol->selector,
pol->family, dir);
list_add(&pol->walk.all, &net->xfrm.policy_all);
hlist_add_head(&pol->bydst, chain);
hlist_add_head(&pol->byidx, net->xfrm.policy_byidx+idx_hash(net, pol->index));
net->xfrm.policy_count[dir]++;
xfrm_pol_hold(pol);
if (xfrm_bydst_should_resize(net, dir, NULL))
schedule_work(&net->xfrm.policy_hash_work);
}
static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
int dir)
{
struct net *net = xp_net(pol);
if (hlist_unhashed(&pol->bydst))
return NULL;
hlist_del(&pol->bydst);
hlist_del(&pol->byidx);
list_del(&pol->walk.all);
net->xfrm.policy_count[dir]--;
return pol;
}
int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
{
write_lock_bh(&xfrm_policy_lock);
pol = __xfrm_policy_unlink(pol, dir);
write_unlock_bh(&xfrm_policy_lock);
if (pol) {
xfrm_policy_kill(pol);
return 0;
}
return -ENOENT;
}
EXPORT_SYMBOL(xfrm_policy_delete);
int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
{
struct net *net = xp_net(pol);
struct xfrm_policy *old_pol;
#ifdef CONFIG_XFRM_SUB_POLICY
if (pol && pol->type != XFRM_POLICY_TYPE_MAIN)
return -EINVAL;
#endif
write_lock_bh(&xfrm_policy_lock);
old_pol = sk->sk_policy[dir];
sk->sk_policy[dir] = pol;
if (pol) {
pol->curlft.add_time = get_seconds();
pol->index = xfrm_gen_index(net, XFRM_POLICY_MAX+dir);
__xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
}
if (old_pol)
/* Unlinking succeeds always. This is the only function
* allowed to delete or replace socket policy.
*/
__xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
write_unlock_bh(&xfrm_policy_lock);
if (old_pol) {
xfrm_policy_kill(old_pol);
}
return 0;
}
static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
{
struct xfrm_policy *newp = xfrm_policy_alloc(xp_net(old), GFP_ATOMIC);
if (newp) {
newp->selector = old->selector;
if (security_xfrm_policy_clone(old->security,
&newp->security)) {
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
kfree(newp);
return NULL; /* ENOMEM */
}
newp->lft = old->lft;
newp->curlft = old->curlft;
newp->mark = old->mark;
newp->action = old->action;
newp->flags = old->flags;
newp->xfrm_nr = old->xfrm_nr;
newp->index = old->index;
newp->type = old->type;
memcpy(newp->xfrm_vec, old->xfrm_vec,
newp->xfrm_nr*sizeof(struct xfrm_tmpl));
write_lock_bh(&xfrm_policy_lock);
__xfrm_policy_link(newp, XFRM_POLICY_MAX+dir);
write_unlock_bh(&xfrm_policy_lock);
xfrm_pol_put(newp);
}
return newp;
}
int __xfrm_sk_clone_policy(struct sock *sk)
{
struct xfrm_policy *p0 = sk->sk_policy[0],
*p1 = sk->sk_policy[1];
sk->sk_policy[0] = sk->sk_policy[1] = NULL;
if (p0 && (sk->sk_policy[0] = clone_policy(p0, 0)) == NULL)
return -ENOMEM;
if (p1 && (sk->sk_policy[1] = clone_policy(p1, 1)) == NULL)
return -ENOMEM;
return 0;
}
static int
xfrm_get_saddr(struct net *net, xfrm_address_t *local, xfrm_address_t *remote,
unsigned short family)
{
int err;
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
if (unlikely(afinfo == NULL))
return -EINVAL;
err = afinfo->get_saddr(net, local, remote);
xfrm_policy_put_afinfo(afinfo);
return err;
}
/* Resolve list of templates for the flow, given policy. */
static int
xfrm_tmpl_resolve_one(struct xfrm_policy *policy, struct flowi *fl,
struct xfrm_state **xfrm,
unsigned short family)
{
struct net *net = xp_net(policy);
int nx;
int i, error;
xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
xfrm_address_t tmp;
for (nx=0, i = 0; i < policy->xfrm_nr; i++) {
struct xfrm_state *x;
xfrm_address_t *remote = daddr;
xfrm_address_t *local = saddr;
struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
if (tmpl->mode == XFRM_MODE_TUNNEL ||
tmpl->mode == XFRM_MODE_BEET) {
remote = &tmpl->id.daddr;
local = &tmpl->saddr;
family = tmpl->encap_family;
if (xfrm_addr_any(local, family)) {
error = xfrm_get_saddr(net, &tmp, remote, family);
if (error)
goto fail;
local = &tmp;
}
}
x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
if (x && x->km.state == XFRM_STATE_VALID) {
xfrm[nx++] = x;
daddr = remote;
saddr = local;
continue;
}
if (x) {
error = (x->km.state == XFRM_STATE_ERROR ?
-EINVAL : -EAGAIN);
xfrm_state_put(x);
}
else if (error == -ESRCH)
error = -EAGAIN;
if (!tmpl->optional)
goto fail;
}
return nx;
fail:
for (nx--; nx>=0; nx--)
xfrm_state_put(xfrm[nx]);
return error;
}
static int
xfrm_tmpl_resolve(struct xfrm_policy **pols, int npols, struct flowi *fl,
struct xfrm_state **xfrm,
unsigned short family)
{
struct xfrm_state *tp[XFRM_MAX_DEPTH];
struct xfrm_state **tpp = (npols > 1) ? tp : xfrm;
int cnx = 0;
int error;
int ret;
int i;
for (i = 0; i < npols; i++) {
if (cnx + pols[i]->xfrm_nr >= XFRM_MAX_DEPTH) {
error = -ENOBUFS;
goto fail;
}
ret = xfrm_tmpl_resolve_one(pols[i], fl, &tpp[cnx], family);
if (ret < 0) {
error = ret;
goto fail;
} else
cnx += ret;
}
/* found states are sorted for outbound processing */
if (npols > 1)
xfrm_state_sort(xfrm, tpp, cnx, family);
return cnx;
fail:
for (cnx--; cnx>=0; cnx--)
xfrm_state_put(tpp[cnx]);
return error;
}
/* Check that the bundle accepts the flow and its components are
* still valid.
*/
static inline int xfrm_get_tos(struct flowi *fl, int family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
int tos;
if (!afinfo)
return -EINVAL;
tos = afinfo->get_tos(fl);
xfrm_policy_put_afinfo(afinfo);
return tos;
}
static struct flow_cache_object *xfrm_bundle_flo_get(struct flow_cache_object *flo)
{
struct xfrm_dst *xdst = container_of(flo, struct xfrm_dst, flo);
struct dst_entry *dst = &xdst->u.dst;
if (xdst->route == NULL) {
/* Dummy bundle - if it has xfrms we were not
* able to build bundle as template resolution failed.
* It means we need to try again resolving. */
if (xdst->num_xfrms > 0)
return NULL;
} else {
/* Real bundle */
if (stale_bundle(dst))
return NULL;
}
dst_hold(dst);
return flo;
}
static int xfrm_bundle_flo_check(struct flow_cache_object *flo)
{
struct xfrm_dst *xdst = container_of(flo, struct xfrm_dst, flo);
struct dst_entry *dst = &xdst->u.dst;
if (!xdst->route)
return 0;
if (stale_bundle(dst))
return 0;
return 1;
}
static void xfrm_bundle_flo_delete(struct flow_cache_object *flo)
{
struct xfrm_dst *xdst = container_of(flo, struct xfrm_dst, flo);
struct dst_entry *dst = &xdst->u.dst;
dst_free(dst);
}
static const struct flow_cache_ops xfrm_bundle_fc_ops = {
.get = xfrm_bundle_flo_get,
.check = xfrm_bundle_flo_check,
.delete = xfrm_bundle_flo_delete,
};
static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
struct dst_ops *dst_ops;
struct xfrm_dst *xdst;
if (!afinfo)
return ERR_PTR(-EINVAL);
switch (family) {
case AF_INET:
dst_ops = &net->xfrm.xfrm4_dst_ops;
break;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
case AF_INET6:
dst_ops = &net->xfrm.xfrm6_dst_ops;
break;
#endif
default:
BUG();
}
xdst = dst_alloc(dst_ops) ?: ERR_PTR(-ENOBUFS);
xfrm_policy_put_afinfo(afinfo);
xdst->flo.ops = &xfrm_bundle_fc_ops;
return xdst;
}
static inline int xfrm_init_path(struct xfrm_dst *path, struct dst_entry *dst,
int nfheader_len)
{
struct xfrm_policy_afinfo *afinfo =
xfrm_policy_get_afinfo(dst->ops->family);
int err;
if (!afinfo)
return -EINVAL;
err = afinfo->init_path(path, dst, nfheader_len);
xfrm_policy_put_afinfo(afinfo);
return err;
}
static inline int xfrm_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
struct flowi *fl)
{
struct xfrm_policy_afinfo *afinfo =
xfrm_policy_get_afinfo(xdst->u.dst.ops->family);
int err;
if (!afinfo)
return -EINVAL;
err = afinfo->fill_dst(xdst, dev, fl);
xfrm_policy_put_afinfo(afinfo);
return err;
}
/* Allocate chain of dst_entry's, attach known xfrm's, calculate
* all the metrics... Shortly, bundle a bundle.
*/
static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
struct xfrm_state **xfrm, int nx,
struct flowi *fl,
struct dst_entry *dst)
{
struct net *net = xp_net(policy);
unsigned long now = jiffies;
struct net_device *dev;
struct dst_entry *dst_prev = NULL;
struct dst_entry *dst0 = NULL;
int i = 0;
int err;
int header_len = 0;
int nfheader_len = 0;
int trailer_len = 0;
int tos;
int family = policy->selector.family;
xfrm_address_t saddr, daddr;
xfrm_flowi_addr_get(fl, &saddr, &daddr, family);
tos = xfrm_get_tos(fl, family);
err = tos;
if (tos < 0)
goto put_states;
dst_hold(dst);
for (; i < nx; i++) {
struct xfrm_dst *xdst = xfrm_alloc_dst(net, family);
struct dst_entry *dst1 = &xdst->u.dst;
err = PTR_ERR(xdst);
if (IS_ERR(xdst)) {
dst_release(dst);
goto put_states;
}
if (!dst_prev)
dst0 = dst1;
else {
dst_prev->child = dst_clone(dst1);
dst1->flags |= DST_NOHASH;
}
xdst->route = dst;
memcpy(&dst1->metrics, &dst->metrics, sizeof(dst->metrics));
if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
family = xfrm[i]->props.family;
dst = xfrm_dst_lookup(xfrm[i], tos, &saddr, &daddr,
family);
err = PTR_ERR(dst);
if (IS_ERR(dst))
goto put_states;
} else
dst_hold(dst);
dst1->xfrm = xfrm[i];
xdst->xfrm_genid = xfrm[i]->genid;
dst1->obsolete = -1;
dst1->flags |= DST_HOST;
dst1->lastuse = now;
dst1->input = dst_discard;
dst1->output = xfrm[i]->outer_mode->afinfo->output;
dst1->next = dst_prev;
dst_prev = dst1;
header_len += xfrm[i]->props.header_len;
if (xfrm[i]->type->flags & XFRM_TYPE_NON_FRAGMENT)
nfheader_len += xfrm[i]->props.header_len;
trailer_len += xfrm[i]->props.trailer_len;
}
dst_prev->child = dst;
dst0->path = dst;
err = -ENODEV;
dev = dst->dev;
if (!dev)
goto free_dst;
/* Copy neighbour for reachability confirmation */
dst0->neighbour = neigh_clone(dst->neighbour);
xfrm_init_path((struct xfrm_dst *)dst0, dst, nfheader_len);
xfrm_init_pmtu(dst_prev);
for (dst_prev = dst0; dst_prev != dst; dst_prev = dst_prev->child) {
struct xfrm_dst *xdst = (struct xfrm_dst *)dst_prev;
err = xfrm_fill_dst(xdst, dev, fl);
if (err)
goto free_dst;
dst_prev->header_len = header_len;
dst_prev->trailer_len = trailer_len;
header_len -= xdst->u.dst.xfrm->props.header_len;
trailer_len -= xdst->u.dst.xfrm->props.trailer_len;
}
out:
return dst0;
put_states:
for (; i < nx; i++)
xfrm_state_put(xfrm[i]);
free_dst:
if (dst0)
dst_free(dst0);
dst0 = ERR_PTR(err);
goto out;
}
static int inline
xfrm_dst_alloc_copy(void **target, void *src, int size)
{
if (!*target) {
*target = kmalloc(size, GFP_ATOMIC);
if (!*target)
return -ENOMEM;
}
memcpy(*target, src, size);
return 0;
}
static int inline
xfrm_dst_update_parent(struct dst_entry *dst, struct xfrm_selector *sel)
{
#ifdef CONFIG_XFRM_SUB_POLICY
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
return xfrm_dst_alloc_copy((void **)&(xdst->partner),
sel, sizeof(*sel));
#else
return 0;
#endif
}
static int inline
xfrm_dst_update_origin(struct dst_entry *dst, struct flowi *fl)
{
#ifdef CONFIG_XFRM_SUB_POLICY
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
return xfrm_dst_alloc_copy((void **)&(xdst->origin), fl, sizeof(*fl));
#else
return 0;
#endif
}
static int xfrm_expand_policies(struct flowi *fl, u16 family,
struct xfrm_policy **pols,
int *num_pols, int *num_xfrms)
{
int i;
if (*num_pols == 0 || !pols[0]) {
*num_pols = 0;
*num_xfrms = 0;
return 0;
}
if (IS_ERR(pols[0]))
return PTR_ERR(pols[0]);
*num_xfrms = pols[0]->xfrm_nr;
#ifdef CONFIG_XFRM_SUB_POLICY
if (pols[0] && pols[0]->action == XFRM_POLICY_ALLOW &&
pols[0]->type != XFRM_POLICY_TYPE_MAIN) {
pols[1] = xfrm_policy_lookup_bytype(xp_net(pols[0]),
XFRM_POLICY_TYPE_MAIN,
fl, family,
XFRM_POLICY_OUT);
if (pols[1]) {
if (IS_ERR(pols[1])) {
xfrm_pols_put(pols, *num_pols);
return PTR_ERR(pols[1]);
}
(*num_pols) ++;
(*num_xfrms) += pols[1]->xfrm_nr;
}
}
#endif
for (i = 0; i < *num_pols; i++) {
if (pols[i]->action != XFRM_POLICY_ALLOW) {
*num_xfrms = -1;
break;
}
}
return 0;
}
static struct xfrm_dst *
xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols,
struct flowi *fl, u16 family,
struct dst_entry *dst_orig)
{
struct net *net = xp_net(pols[0]);
struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
struct dst_entry *dst;
struct xfrm_dst *xdst;
int err;
/* Try to instantiate a bundle */
err = xfrm_tmpl_resolve(pols, num_pols, fl, xfrm, family);
if (err < 0) {
if (err != -EAGAIN)
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
return ERR_PTR(err);
}
dst = xfrm_bundle_create(pols[0], xfrm, err, fl, dst_orig);
if (IS_ERR(dst)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLEGENERROR);
return ERR_CAST(dst);
}
xdst = (struct xfrm_dst *)dst;
xdst->num_xfrms = err;
if (num_pols > 1)
err = xfrm_dst_update_parent(dst, &pols[1]->selector);
else
err = xfrm_dst_update_origin(dst, fl);
if (unlikely(err)) {
dst_free(dst);
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLECHECKERROR);
return ERR_PTR(err);
}
xdst->num_pols = num_pols;
memcpy(xdst->pols, pols, sizeof(struct xfrm_policy*) * num_pols);
xdst->policy_genid = atomic_read(&pols[0]->genid);
return xdst;
}
static struct flow_cache_object *
xfrm_bundle_lookup(struct net *net, struct flowi *fl, u16 family, u8 dir,
struct flow_cache_object *oldflo, void *ctx)
{
struct dst_entry *dst_orig = (struct dst_entry *)ctx;
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
struct xfrm_dst *xdst, *new_xdst;
int num_pols = 0, num_xfrms = 0, i, err, pol_dead;
/* Check if the policies from old bundle are usable */
xdst = NULL;
if (oldflo) {
xdst = container_of(oldflo, struct xfrm_dst, flo);
num_pols = xdst->num_pols;
num_xfrms = xdst->num_xfrms;
pol_dead = 0;
for (i = 0; i < num_pols; i++) {
pols[i] = xdst->pols[i];
pol_dead |= pols[i]->walk.dead;
}
if (pol_dead) {
dst_free(&xdst->u.dst);
xdst = NULL;
num_pols = 0;
num_xfrms = 0;
oldflo = NULL;
}
}
/* Resolve policies to use if we couldn't get them from
* previous cache entry */
if (xdst == NULL) {
num_pols = 1;
pols[0] = __xfrm_policy_lookup(net, fl, family, dir);
err = xfrm_expand_policies(fl, family, pols,
&num_pols, &num_xfrms);
if (err < 0)
goto inc_error;
if (num_pols == 0)
return NULL;
if (num_xfrms <= 0)
goto make_dummy_bundle;
}
new_xdst = xfrm_resolve_and_create_bundle(pols, num_pols, fl, family, dst_orig);
if (IS_ERR(new_xdst)) {
err = PTR_ERR(new_xdst);
if (err != -EAGAIN)
goto error;
if (oldflo == NULL)
goto make_dummy_bundle;
dst_hold(&xdst->u.dst);
return oldflo;
}
/* Kill the previous bundle */
if (xdst) {
/* The policies were stolen for newly generated bundle */
xdst->num_pols = 0;
dst_free(&xdst->u.dst);
}
/* Flow cache does not have reference, it dst_free()'s,
* but we do need to return one reference for original caller */
dst_hold(&new_xdst->u.dst);
return &new_xdst->flo;
make_dummy_bundle:
/* We found policies, but there's no bundles to instantiate:
* either because the policy blocks, has no transformations or
* we could not build template (no xfrm_states).*/
xdst = xfrm_alloc_dst(net, family);
if (IS_ERR(xdst)) {
xfrm_pols_put(pols, num_pols);
return ERR_CAST(xdst);
}
xdst->num_pols = num_pols;
xdst->num_xfrms = num_xfrms;
memcpy(xdst->pols, pols, sizeof(struct xfrm_policy*) * num_pols);
dst_hold(&xdst->u.dst);
return &xdst->flo;
inc_error:
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
error:
if (xdst != NULL)
dst_free(&xdst->u.dst);
else
xfrm_pols_put(pols, num_pols);
return ERR_PTR(err);
}
/* Main function: finds/creates a bundle for given flow.
*
* At the moment we eat a raw IP route. Mostly to speed up lookups
* on interfaces with disabled IPsec.
*/
int __xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl,
struct sock *sk, int flags)
{
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
struct flow_cache_object *flo;
struct xfrm_dst *xdst;
struct dst_entry *dst, *dst_orig = *dst_p, *route;
u16 family = dst_orig->ops->family;
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 15:12:27 +08:00
u8 dir = policy_to_flow_dir(XFRM_POLICY_OUT);
int i, err, num_pols, num_xfrms = 0, drop_pols = 0;
restart:
dst = NULL;
xdst = NULL;
route = NULL;
if (sk && sk->sk_policy[XFRM_POLICY_OUT]) {
num_pols = 1;
pols[0] = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
err = xfrm_expand_policies(fl, family, pols,
&num_pols, &num_xfrms);
if (err < 0)
goto dropdst;
if (num_pols) {
if (num_xfrms <= 0) {
drop_pols = num_pols;
goto no_transform;
}
xdst = xfrm_resolve_and_create_bundle(
pols, num_pols, fl,
family, dst_orig);
if (IS_ERR(xdst)) {
xfrm_pols_put(pols, num_pols);
err = PTR_ERR(xdst);
goto dropdst;
}
spin_lock_bh(&xfrm_policy_sk_bundle_lock);
xdst->u.dst.next = xfrm_policy_sk_bundles;
xfrm_policy_sk_bundles = &xdst->u.dst;
spin_unlock_bh(&xfrm_policy_sk_bundle_lock);
route = xdst->route;
}
}
if (xdst == NULL) {
/* To accelerate a bit... */
if ((dst_orig->flags & DST_NOXFRM) ||
!net->xfrm.policy_count[XFRM_POLICY_OUT])
goto nopol;
flo = flow_cache_lookup(net, fl, family, dir,
xfrm_bundle_lookup, dst_orig);
if (flo == NULL)
goto nopol;
if (IS_ERR(flo)) {
err = PTR_ERR(flo);
goto dropdst;
}
xdst = container_of(flo, struct xfrm_dst, flo);
num_pols = xdst->num_pols;
num_xfrms = xdst->num_xfrms;
memcpy(pols, xdst->pols, sizeof(struct xfrm_policy*) * num_pols);
route = xdst->route;
}
dst = &xdst->u.dst;
if (route == NULL && num_xfrms > 0) {
/* The only case when xfrm_bundle_lookup() returns a
* bundle with null route, is when the template could
* not be resolved. It means policies are there, but
* bundle could not be created, since we don't yet
* have the xfrm_state's. We need to wait for KM to
* negotiate new SA's or bail out with error.*/
if (net->xfrm.sysctl_larval_drop) {
/* EREMOTE tells the caller to generate
* a one-shot blackhole route. */
dst_release(dst);
xfrm_pols_put(pols, drop_pols);
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
return -EREMOTE;
}
if (flags & XFRM_LOOKUP_WAIT) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(&net->xfrm.km_waitq, &wait);
set_current_state(TASK_INTERRUPTIBLE);
schedule();
set_current_state(TASK_RUNNING);
remove_wait_queue(&net->xfrm.km_waitq, &wait);
if (!signal_pending(current)) {
dst_release(dst);
goto restart;
}
err = -ERESTART;
} else
err = -EAGAIN;
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
goto error;
}
no_transform:
if (num_pols == 0)
goto nopol;
if ((flags & XFRM_LOOKUP_ICMP) &&
!(pols[0]->flags & XFRM_POLICY_ICMP)) {
err = -ENOENT;
goto error;
}
for (i = 0; i < num_pols; i++)
pols[i]->curlft.use_time = get_seconds();
if (num_xfrms < 0) {
/* Prohibit the flow */
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLBLOCK);
err = -EPERM;
goto error;
} else if (num_xfrms > 0) {
/* Flow transformed */
*dst_p = dst;
dst_release(dst_orig);
} else {
/* Flow passes untransformed */
dst_release(dst);
}
ok:
xfrm_pols_put(pols, drop_pols);
return 0;
nopol:
if (!(flags & XFRM_LOOKUP_ICMP))
goto ok;
err = -ENOENT;
error:
dst_release(dst);
dropdst:
dst_release(dst_orig);
*dst_p = NULL;
xfrm_pols_put(pols, drop_pols);
return err;
}
EXPORT_SYMBOL(__xfrm_lookup);
int xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl,
struct sock *sk, int flags)
{
int err = __xfrm_lookup(net, dst_p, fl, sk, flags);
if (err == -EREMOTE) {
dst_release(*dst_p);
*dst_p = NULL;
err = -EAGAIN;
}
return err;
}
EXPORT_SYMBOL(xfrm_lookup);
static inline int
xfrm_secpath_reject(int idx, struct sk_buff *skb, struct flowi *fl)
{
struct xfrm_state *x;
if (!skb->sp || idx < 0 || idx >= skb->sp->len)
return 0;
x = skb->sp->xvec[idx];
if (!x->type->reject)
return 0;
return x->type->reject(x, skb, fl);
}
/* When skb is transformed back to its "native" form, we have to
* check policy restrictions. At the moment we make this in maximally
* stupid way. Shame on me. :-) Of course, connected sockets must
* have policy cached at them.
*/
static inline int
xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x,
unsigned short family)
{
if (xfrm_state_kern(x))
return tmpl->optional && !xfrm_state_addr_cmp(tmpl, x, tmpl->encap_family);
return x->id.proto == tmpl->id.proto &&
(x->id.spi == tmpl->id.spi || !tmpl->id.spi) &&
(x->props.reqid == tmpl->reqid || !tmpl->reqid) &&
x->props.mode == tmpl->mode &&
(tmpl->allalgs || (tmpl->aalgos & (1<<x->props.aalgo)) ||
!(xfrm_id_proto_match(tmpl->id.proto, IPSEC_PROTO_ANY))) &&
!(x->props.mode != XFRM_MODE_TRANSPORT &&
xfrm_state_addr_cmp(tmpl, x, family));
}
/*
* 0 or more than 0 is returned when validation is succeeded (either bypass
* because of optional transport mode, or next index of the mathced secpath
* state with the template.
* -1 is returned when no matching template is found.
* Otherwise "-2 - errored_index" is returned.
*/
static inline int
xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
unsigned short family)
{
int idx = start;
if (tmpl->optional) {
if (tmpl->mode == XFRM_MODE_TRANSPORT)
return start;
} else
start = -1;
for (; idx < sp->len; idx++) {
if (xfrm_state_ok(tmpl, sp->xvec[idx], family))
return ++idx;
if (sp->xvec[idx]->props.mode != XFRM_MODE_TRANSPORT) {
if (start == -1)
start = -2-idx;
break;
}
}
return start;
}
int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
unsigned int family, int reverse)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
int err;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
afinfo->decode_session(skb, fl, reverse);
err = security_xfrm_decode_session(skb, &fl->secid);
xfrm_policy_put_afinfo(afinfo);
return err;
}
EXPORT_SYMBOL(__xfrm_decode_session);
static inline int secpath_has_nontransport(struct sec_path *sp, int k, int *idxp)
{
for (; k < sp->len; k++) {
if (sp->xvec[k]->props.mode != XFRM_MODE_TRANSPORT) {
*idxp = k;
return 1;
}
}
return 0;
}
int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
unsigned short family)
{
struct net *net = dev_net(skb->dev);
struct xfrm_policy *pol;
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
int npols = 0;
int xfrm_nr;
int pi;
int reverse;
struct flowi fl;
u8 fl_dir;
int xerr_idx = -1;
reverse = dir & ~XFRM_POLICY_MASK;
dir &= XFRM_POLICY_MASK;
fl_dir = policy_to_flow_dir(dir);
if (__xfrm_decode_session(skb, &fl, family, reverse) < 0) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
return 0;
}
nf_nat_decode_session(skb, &fl, family);
/* First, check used SA against their selectors. */
if (skb->sp) {
int i;
for (i=skb->sp->len-1; i>=0; i--) {
struct xfrm_state *x = skb->sp->xvec[i];
if (!xfrm_selector_match(&x->sel, &fl, family)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
return 0;
}
}
}
pol = NULL;
if (sk && sk->sk_policy[dir]) {
pol = xfrm_sk_policy_lookup(sk, dir, &fl);
if (IS_ERR(pol)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLERROR);
return 0;
}
}
if (!pol) {
struct flow_cache_object *flo;
flo = flow_cache_lookup(net, &fl, family, fl_dir,
xfrm_policy_lookup, NULL);
if (IS_ERR_OR_NULL(flo))
pol = ERR_CAST(flo);
else
pol = container_of(flo, struct xfrm_policy, flo);
}
if (IS_ERR(pol)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLERROR);
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
return 0;
}
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
if (!pol) {
if (skb->sp && secpath_has_nontransport(skb->sp, 0, &xerr_idx)) {
xfrm_secpath_reject(xerr_idx, skb, &fl);
XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOPOLS);
return 0;
}
return 1;
}
pol->curlft.use_time = get_seconds();
pols[0] = pol;
npols ++;
#ifdef CONFIG_XFRM_SUB_POLICY
if (pols[0]->type != XFRM_POLICY_TYPE_MAIN) {
pols[1] = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN,
&fl, family,
XFRM_POLICY_IN);
if (pols[1]) {
if (IS_ERR(pols[1])) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLERROR);
IPsec: propagate security module errors up from flow_cache_lookup When a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return an access denied permission (or other error). We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The way I was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. The first SYNACK would be blocked, because of an uncached lookup via flow_cache_lookup(), which would fail to resolve an xfrm policy because the SELinux policy is checked at that point via the resolver. However, retransmitted SYNACKs would then find a cached flow entry when calling into flow_cache_lookup() with a null xfrm policy, which is interpreted by xfrm_lookup() as the packet not having any associated policy and similarly to the first case, allowing it to pass without transformation. The solution presented here is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:27 +08:00
return 0;
}
pols[1]->curlft.use_time = get_seconds();
npols ++;
}
}
#endif
if (pol->action == XFRM_POLICY_ALLOW) {
struct sec_path *sp;
static struct sec_path dummy;
struct xfrm_tmpl *tp[XFRM_MAX_DEPTH];
struct xfrm_tmpl *stp[XFRM_MAX_DEPTH];
struct xfrm_tmpl **tpp = tp;
int ti = 0;
int i, k;
if ((sp = skb->sp) == NULL)
sp = &dummy;
for (pi = 0; pi < npols; pi++) {
if (pols[pi] != pol &&
pols[pi]->action != XFRM_POLICY_ALLOW) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLBLOCK);
goto reject;
}
if (ti + pols[pi]->xfrm_nr >= XFRM_MAX_DEPTH) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto reject_error;
}
for (i = 0; i < pols[pi]->xfrm_nr; i++)
tpp[ti++] = &pols[pi]->xfrm_vec[i];
}
xfrm_nr = ti;
if (npols > 1) {
xfrm_tmpl_sort(stp, tpp, xfrm_nr, family);
tpp = stp;
}
/* For each tunnel xfrm, find the first matching tmpl.
* For each tmpl before that, find corresponding xfrm.
* Order is _important_. Later we will implement
* some barriers, but at the moment barriers
* are implied between each two transformations.
*/
for (i = xfrm_nr-1, k = 0; i >= 0; i--) {
k = xfrm_policy_ok(tpp[i], sp, k, family);
if (k < 0) {
if (k < -1)
/* "-2 - errored_index" returned */
xerr_idx = -(2+k);
XFRM_INC_STATS(net, LINUX_MIB_XFRMINTMPLMISMATCH);
goto reject;
}
}
if (secpath_has_nontransport(sp, k, &xerr_idx)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINTMPLMISMATCH);
goto reject;
}
xfrm_pols_put(pols, npols);
return 1;
}
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLBLOCK);
reject:
xfrm_secpath_reject(xerr_idx, skb, &fl);
reject_error:
xfrm_pols_put(pols, npols);
return 0;
}
EXPORT_SYMBOL(__xfrm_policy_check);
int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
{
struct net *net = dev_net(skb->dev);
struct flowi fl;
struct dst_entry *dst;
int res;
if (xfrm_decode_session(skb, &fl, family) < 0) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMFWDHDRERROR);
return 0;
}
dst = skb_dst(skb);
res = xfrm_lookup(net, &dst, &fl, NULL, 0) == 0;
skb_dst_set(skb, dst);
return res;
}
EXPORT_SYMBOL(__xfrm_route_forward);
/* Optimize later using cookies and generation ids. */
static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
{
/* Code (such as __xfrm4_bundle_create()) sets dst->obsolete
* to "-1" to force all XFRM destinations to get validated by
* dst_ops->check on every use. We do this because when a
* normal route referenced by an XFRM dst is obsoleted we do
* not go looking around for all parent referencing XFRM dsts
* so that we can invalidate them. It is just too much work.
* Instead we make the checks here on every use. For example:
*
* XFRM dst A --> IPv4 dst X
*
* X is the "xdst->route" of A (X is also the "dst->path" of A
* in this example). If X is marked obsolete, "A" will not
* notice. That's what we are validating here via the
* stale_bundle() check.
*
* When a policy's bundle is pruned, we dst_free() the XFRM
* dst which causes it's ->obsolete field to be set to a
* positive non-zero integer. If an XFRM dst has been pruned
* like this, we want to force a new route lookup.
*/
if (dst->obsolete < 0 && !stale_bundle(dst))
return dst;
return NULL;
}
static int stale_bundle(struct dst_entry *dst)
{
IPsec: correct semantics for SELinux policy matching Currently when an IPSec policy rule doesn't specify a security context, it is assumed to be "unlabeled" by SELinux, and so the IPSec policy rule fails to match to a flow that it would otherwise match to, unless one has explicitly added an SELinux policy rule allowing the flow to "polmatch" to the "unlabeled" IPSec policy rules. In the absence of such an explicitly added SELinux policy rule, the IPSec policy rule fails to match and so the packet(s) flow in clear text without the otherwise applicable xfrm(s) applied. The above SELinux behavior violates the SELinux security notion of "deny by default" which should actually translate to "encrypt by default" in the above case. This was first reported by Evgeniy Polyakov and the way James Morris was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. With this patch applied, SELinux "polmatching" of flows Vs. IPSec policy rules will only come into play when there's a explicit context specified for the IPSec policy rule (which also means there's corresponding SELinux policy allowing appropriate domains/flows to polmatch to this context). Secondly, when a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return errors other than access denied, such as -EINVAL. We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The solution for this is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). This patch: Fix the selinux side of things. This makes sure SELinux polmatching of flow contexts to IPSec policy rules comes into play only when an explicit context is associated with the IPSec policy rule. Also, this no longer defaults the context of a socket policy to the context of the socket since the "no explicit context" case is now handled properly. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:18 +08:00
return !xfrm_bundle_ok(NULL, (struct xfrm_dst *)dst, NULL, AF_UNSPEC, 0);
}
void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
{
while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
dst->dev = dev_net(dev)->loopback_dev;
dev_hold(dst->dev);
dev_put(dev);
}
}
EXPORT_SYMBOL(xfrm_dst_ifdown);
static void xfrm_link_failure(struct sk_buff *skb)
{
/* Impossible. Such dst must be popped before reaches point of failure. */
}
static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
{
if (dst) {
if (dst->obsolete) {
dst_release(dst);
dst = NULL;
}
}
return dst;
}
static void __xfrm_garbage_collect(struct net *net)
{
struct dst_entry *head, *next;
flow_cache_flush();
spin_lock_bh(&xfrm_policy_sk_bundle_lock);
head = xfrm_policy_sk_bundles;
xfrm_policy_sk_bundles = NULL;
spin_unlock_bh(&xfrm_policy_sk_bundle_lock);
while (head) {
next = head->next;
dst_free(head);
head = next;
}
}
static void xfrm_init_pmtu(struct dst_entry *dst)
{
do {
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
u32 pmtu, route_mtu_cached;
pmtu = dst_mtu(dst->child);
xdst->child_mtu_cached = pmtu;
pmtu = xfrm_state_mtu(dst->xfrm, pmtu);
route_mtu_cached = dst_mtu(xdst->route);
xdst->route_mtu_cached = route_mtu_cached;
if (pmtu > route_mtu_cached)
pmtu = route_mtu_cached;
dst->metrics[RTAX_MTU-1] = pmtu;
} while ((dst = dst->next));
}
/* Check that the bundle accepts the flow and its components are
* still valid.
*/
IPsec: correct semantics for SELinux policy matching Currently when an IPSec policy rule doesn't specify a security context, it is assumed to be "unlabeled" by SELinux, and so the IPSec policy rule fails to match to a flow that it would otherwise match to, unless one has explicitly added an SELinux policy rule allowing the flow to "polmatch" to the "unlabeled" IPSec policy rules. In the absence of such an explicitly added SELinux policy rule, the IPSec policy rule fails to match and so the packet(s) flow in clear text without the otherwise applicable xfrm(s) applied. The above SELinux behavior violates the SELinux security notion of "deny by default" which should actually translate to "encrypt by default" in the above case. This was first reported by Evgeniy Polyakov and the way James Morris was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. With this patch applied, SELinux "polmatching" of flows Vs. IPSec policy rules will only come into play when there's a explicit context specified for the IPSec policy rule (which also means there's corresponding SELinux policy allowing appropriate domains/flows to polmatch to this context). Secondly, when a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return errors other than access denied, such as -EINVAL. We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The solution for this is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). This patch: Fix the selinux side of things. This makes sure SELinux polmatching of flow contexts to IPSec policy rules comes into play only when an explicit context is associated with the IPSec policy rule. Also, this no longer defaults the context of a socket policy to the context of the socket since the "no explicit context" case is now handled properly. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
2006-10-06 04:42:18 +08:00
int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
struct flowi *fl, int family, int strict)
{
struct dst_entry *dst = &first->u.dst;
struct xfrm_dst *last;
u32 mtu;
if (!dst_check(dst->path, ((struct xfrm_dst *)dst)->path_cookie) ||
(dst->dev && !netif_running(dst->dev)))
return 0;
#ifdef CONFIG_XFRM_SUB_POLICY
if (fl) {
if (first->origin && !flow_cache_uli_match(first->origin, fl))
return 0;
if (first->partner &&
!xfrm_selector_match(first->partner, fl, family))
return 0;
}
#endif
last = NULL;
do {
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
return 0;
if (fl && pol &&
!security_xfrm_state_pol_flow_match(dst->xfrm, pol, fl))
return 0;
if (dst->xfrm->km.state != XFRM_STATE_VALID)
return 0;
if (xdst->xfrm_genid != dst->xfrm->genid)
return 0;
if (xdst->policy_genid != atomic_read(&xdst->pols[0]->genid))
return 0;
if (strict && fl &&
!(dst->xfrm->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) &&
!xfrm_state_addr_flow_check(dst->xfrm, fl, family))
return 0;
mtu = dst_mtu(dst->child);
if (xdst->child_mtu_cached != mtu) {
last = xdst;
xdst->child_mtu_cached = mtu;
}
if (!dst_check(xdst->route, xdst->route_cookie))
return 0;
mtu = dst_mtu(xdst->route);
if (xdst->route_mtu_cached != mtu) {
last = xdst;
xdst->route_mtu_cached = mtu;
}
dst = dst->child;
} while (dst->xfrm);
if (likely(!last))
return 1;
mtu = last->child_mtu_cached;
for (;;) {
dst = &last->u.dst;
mtu = xfrm_state_mtu(dst->xfrm, mtu);
if (mtu > last->route_mtu_cached)
mtu = last->route_mtu_cached;
dst->metrics[RTAX_MTU-1] = mtu;
if (last == first)
break;
last = (struct xfrm_dst *)last->u.dst.next;
last->child_mtu_cached = mtu;
}
return 1;
}
EXPORT_SYMBOL(xfrm_bundle_ok);
int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
{
struct net *net;
int err = 0;
if (unlikely(afinfo == NULL))
return -EINVAL;
if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT;
write_lock_bh(&xfrm_policy_afinfo_lock);
if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
err = -ENOBUFS;
else {
struct dst_ops *dst_ops = afinfo->dst_ops;
if (likely(dst_ops->kmem_cachep == NULL))
dst_ops->kmem_cachep = xfrm_dst_cache;
if (likely(dst_ops->check == NULL))
dst_ops->check = xfrm_dst_check;
if (likely(dst_ops->negative_advice == NULL))
dst_ops->negative_advice = xfrm_negative_advice;
if (likely(dst_ops->link_failure == NULL))
dst_ops->link_failure = xfrm_link_failure;
if (likely(afinfo->garbage_collect == NULL))
afinfo->garbage_collect = __xfrm_garbage_collect;
xfrm_policy_afinfo[afinfo->family] = afinfo;
}
write_unlock_bh(&xfrm_policy_afinfo_lock);
rtnl_lock();
for_each_net(net) {
struct dst_ops *xfrm_dst_ops;
switch (afinfo->family) {
case AF_INET:
xfrm_dst_ops = &net->xfrm.xfrm4_dst_ops;
break;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
case AF_INET6:
xfrm_dst_ops = &net->xfrm.xfrm6_dst_ops;
break;
#endif
default:
BUG();
}
*xfrm_dst_ops = *afinfo->dst_ops;
}
rtnl_unlock();
return err;
}
EXPORT_SYMBOL(xfrm_policy_register_afinfo);
int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
{
int err = 0;
if (unlikely(afinfo == NULL))
return -EINVAL;
if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT;
write_lock_bh(&xfrm_policy_afinfo_lock);
if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
err = -EINVAL;
else {
struct dst_ops *dst_ops = afinfo->dst_ops;
xfrm_policy_afinfo[afinfo->family] = NULL;
dst_ops->kmem_cachep = NULL;
dst_ops->check = NULL;
dst_ops->negative_advice = NULL;
dst_ops->link_failure = NULL;
afinfo->garbage_collect = NULL;
}
}
write_unlock_bh(&xfrm_policy_afinfo_lock);
return err;
}
EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
static void __net_init xfrm_dst_ops_init(struct net *net)
{
struct xfrm_policy_afinfo *afinfo;
read_lock_bh(&xfrm_policy_afinfo_lock);
afinfo = xfrm_policy_afinfo[AF_INET];
if (afinfo)
net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
afinfo = xfrm_policy_afinfo[AF_INET6];
if (afinfo)
net->xfrm.xfrm6_dst_ops = *afinfo->dst_ops;
#endif
read_unlock_bh(&xfrm_policy_afinfo_lock);
}
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
{
struct xfrm_policy_afinfo *afinfo;
if (unlikely(family >= NPROTO))
return NULL;
read_lock(&xfrm_policy_afinfo_lock);
afinfo = xfrm_policy_afinfo[family];
if (unlikely(!afinfo))
read_unlock(&xfrm_policy_afinfo_lock);
return afinfo;
}
static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
{
read_unlock(&xfrm_policy_afinfo_lock);
}
static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
switch (event) {
case NETDEV_DOWN:
__xfrm_garbage_collect(dev_net(dev));
}
return NOTIFY_DONE;
}
static struct notifier_block xfrm_dev_notifier = {
.notifier_call = xfrm_dev_event,
};
#ifdef CONFIG_XFRM_STATISTICS
static int __net_init xfrm_statistics_init(struct net *net)
{
int rv;
if (snmp_mib_init((void __percpu **)net->mib.xfrm_statistics,
sizeof(struct linux_xfrm_mib)) < 0)
return -ENOMEM;
rv = xfrm_proc_init(net);
if (rv < 0)
snmp_mib_free((void __percpu **)net->mib.xfrm_statistics);
return rv;
}
static void xfrm_statistics_fini(struct net *net)
{
xfrm_proc_fini(net);
snmp_mib_free((void __percpu **)net->mib.xfrm_statistics);
}
#else
static int __net_init xfrm_statistics_init(struct net *net)
{
return 0;
}
static void xfrm_statistics_fini(struct net *net)
{
}
#endif
static int __net_init xfrm_policy_init(struct net *net)
{
unsigned int hmask, sz;
int dir;
if (net_eq(net, &init_net))
xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
sizeof(struct xfrm_dst),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
NULL);
hmask = 8 - 1;
sz = (hmask+1) * sizeof(struct hlist_head);
net->xfrm.policy_byidx = xfrm_hash_alloc(sz);
if (!net->xfrm.policy_byidx)
goto out_byidx;
net->xfrm.policy_idx_hmask = hmask;
for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
struct xfrm_policy_hash *htab;
net->xfrm.policy_count[dir] = 0;
INIT_HLIST_HEAD(&net->xfrm.policy_inexact[dir]);
htab = &net->xfrm.policy_bydst[dir];
htab->table = xfrm_hash_alloc(sz);
if (!htab->table)
goto out_bydst;
htab->hmask = hmask;
}
INIT_LIST_HEAD(&net->xfrm.policy_all);
INIT_WORK(&net->xfrm.policy_hash_work, xfrm_hash_resize);
if (net_eq(net, &init_net))
register_netdevice_notifier(&xfrm_dev_notifier);
return 0;
out_bydst:
for (dir--; dir >= 0; dir--) {
struct xfrm_policy_hash *htab;
htab = &net->xfrm.policy_bydst[dir];
xfrm_hash_free(htab->table, sz);
}
xfrm_hash_free(net->xfrm.policy_byidx, sz);
out_byidx:
return -ENOMEM;
}
static void xfrm_policy_fini(struct net *net)
{
struct xfrm_audit audit_info;
unsigned int sz;
int dir;
flush_work(&net->xfrm.policy_hash_work);
#ifdef CONFIG_XFRM_SUB_POLICY
audit_info.loginuid = -1;
audit_info.sessionid = -1;
audit_info.secid = 0;
xfrm_policy_flush(net, XFRM_POLICY_TYPE_SUB, &audit_info);
#endif
audit_info.loginuid = -1;
audit_info.sessionid = -1;
audit_info.secid = 0;
xfrm_policy_flush(net, XFRM_POLICY_TYPE_MAIN, &audit_info);
WARN_ON(!list_empty(&net->xfrm.policy_all));
for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
struct xfrm_policy_hash *htab;
WARN_ON(!hlist_empty(&net->xfrm.policy_inexact[dir]));
htab = &net->xfrm.policy_bydst[dir];
sz = (htab->hmask + 1);
WARN_ON(!hlist_empty(htab->table));
xfrm_hash_free(htab->table, sz);
}
sz = (net->xfrm.policy_idx_hmask + 1) * sizeof(struct hlist_head);
WARN_ON(!hlist_empty(net->xfrm.policy_byidx));
xfrm_hash_free(net->xfrm.policy_byidx, sz);
}
static int __net_init xfrm_net_init(struct net *net)
{
int rv;
rv = xfrm_statistics_init(net);
if (rv < 0)
goto out_statistics;
rv = xfrm_state_init(net);
if (rv < 0)
goto out_state;
rv = xfrm_policy_init(net);
if (rv < 0)
goto out_policy;
xfrm_dst_ops_init(net);
rv = xfrm_sysctl_init(net);
if (rv < 0)
goto out_sysctl;
return 0;
out_sysctl:
xfrm_policy_fini(net);
out_policy:
xfrm_state_fini(net);
out_state:
xfrm_statistics_fini(net);
out_statistics:
return rv;
}
static void __net_exit xfrm_net_exit(struct net *net)
{
xfrm_sysctl_fini(net);
xfrm_policy_fini(net);
xfrm_state_fini(net);
xfrm_statistics_fini(net);
}
static struct pernet_operations __net_initdata xfrm_net_ops = {
.init = xfrm_net_init,
.exit = xfrm_net_exit,
};
void __init xfrm_init(void)
{
register_pernet_subsys(&xfrm_net_ops);
xfrm_input_init();
}
#ifdef CONFIG_AUDITSYSCALL
static void xfrm_audit_common_policyinfo(struct xfrm_policy *xp,
struct audit_buffer *audit_buf)
{
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
struct xfrm_sec_ctx *ctx = xp->security;
struct xfrm_selector *sel = &xp->selector;
if (ctx)
audit_log_format(audit_buf, " sec_alg=%u sec_doi=%u sec_obj=%s",
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
ctx->ctx_alg, ctx->ctx_doi, ctx->ctx_str);
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
switch(sel->family) {
case AF_INET:
audit_log_format(audit_buf, " src=%pI4", &sel->saddr.a4);
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
if (sel->prefixlen_s != 32)
audit_log_format(audit_buf, " src_prefixlen=%d",
sel->prefixlen_s);
audit_log_format(audit_buf, " dst=%pI4", &sel->daddr.a4);
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
if (sel->prefixlen_d != 32)
audit_log_format(audit_buf, " dst_prefixlen=%d",
sel->prefixlen_d);
break;
case AF_INET6:
audit_log_format(audit_buf, " src=%pI6", sel->saddr.a6);
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
if (sel->prefixlen_s != 128)
audit_log_format(audit_buf, " src_prefixlen=%d",
sel->prefixlen_s);
audit_log_format(audit_buf, " dst=%pI6", sel->daddr.a6);
[IPSEC]: SPD auditing fix to include the netmask/prefix-length Currently the netmask/prefix-length of an IPsec SPD entry is not included in any of the SPD related audit messages. This can cause a problem when the audit log is examined as the netmask/prefix-length is vital in determining what network traffic is affected by a particular SPD entry. This patch fixes this problem by adding two additional fields, "src_prefixlen" and "dst_prefixlen", to the SPD audit messages to indicate the source and destination netmasks. These new fields are only included in the audit message when the netmask/prefix-length is less than the address length, i.e. the SPD entry applies to a network address and not a host address. Example audit message: type=UNKNOWN[1415] msg=audit(1196105849.752:25): auid=0 \ subj=root:system_r:unconfined_t:s0-s0:c0.c1023 op=SPD-add res=1 \ src=192.168.0.0 src_prefixlen=24 dst=192.168.1.0 dst_prefixlen=24 In addition, this patch also fixes a few other things in the xfrm_audit_common_policyinfo() function. The IPv4 string formatting was converted to use the standard NIPQUAD_FMT constant, the memcpy() was removed from the IPv6 code path and replaced with a typecast (the memcpy() was acting as a slow, implicit typecast anyway), and two local variables were created to make referencing the XFRM security context and selector information cleaner. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-01 20:27:18 +08:00
if (sel->prefixlen_d != 128)
audit_log_format(audit_buf, " dst_prefixlen=%d",
sel->prefixlen_d);
break;
}
}
void xfrm_audit_policy_add(struct xfrm_policy *xp, int result,
uid_t auid, u32 sessionid, u32 secid)
{
struct audit_buffer *audit_buf;
audit_buf = xfrm_audit_start("SPD-add");
if (audit_buf == NULL)
return;
xfrm_audit_helper_usrinfo(auid, sessionid, secid, audit_buf);
audit_log_format(audit_buf, " res=%u", result);
xfrm_audit_common_policyinfo(xp, audit_buf);
audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_policy_add);
void xfrm_audit_policy_delete(struct xfrm_policy *xp, int result,
uid_t auid, u32 sessionid, u32 secid)
{
struct audit_buffer *audit_buf;
audit_buf = xfrm_audit_start("SPD-delete");
if (audit_buf == NULL)
return;
xfrm_audit_helper_usrinfo(auid, sessionid, secid, audit_buf);
audit_log_format(audit_buf, " res=%u", result);
xfrm_audit_common_policyinfo(xp, audit_buf);
audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_policy_delete);
#endif
#ifdef CONFIG_XFRM_MIGRATE
static int xfrm_migrate_selector_match(struct xfrm_selector *sel_cmp,
struct xfrm_selector *sel_tgt)
{
if (sel_cmp->proto == IPSEC_ULPROTO_ANY) {
if (sel_tgt->family == sel_cmp->family &&
xfrm_addr_cmp(&sel_tgt->daddr, &sel_cmp->daddr,
sel_cmp->family) == 0 &&
xfrm_addr_cmp(&sel_tgt->saddr, &sel_cmp->saddr,
sel_cmp->family) == 0 &&
sel_tgt->prefixlen_d == sel_cmp->prefixlen_d &&
sel_tgt->prefixlen_s == sel_cmp->prefixlen_s) {
return 1;
}
} else {
if (memcmp(sel_tgt, sel_cmp, sizeof(*sel_tgt)) == 0) {
return 1;
}
}
return 0;
}
static struct xfrm_policy * xfrm_migrate_policy_find(struct xfrm_selector *sel,
u8 dir, u8 type)
{
struct xfrm_policy *pol, *ret = NULL;
struct hlist_node *entry;
struct hlist_head *chain;
u32 priority = ~0U;
read_lock_bh(&xfrm_policy_lock);
chain = policy_hash_direct(&init_net, &sel->daddr, &sel->saddr, sel->family, dir);
hlist_for_each_entry(pol, entry, chain, bydst) {
if (xfrm_migrate_selector_match(sel, &pol->selector) &&
pol->type == type) {
ret = pol;
priority = ret->priority;
break;
}
}
chain = &init_net.xfrm.policy_inexact[dir];
hlist_for_each_entry(pol, entry, chain, bydst) {
if (xfrm_migrate_selector_match(sel, &pol->selector) &&
pol->type == type &&
pol->priority < priority) {
ret = pol;
break;
}
}
if (ret)
xfrm_pol_hold(ret);
read_unlock_bh(&xfrm_policy_lock);
return ret;
}
static int migrate_tmpl_match(struct xfrm_migrate *m, struct xfrm_tmpl *t)
{
int match = 0;
if (t->mode == m->mode && t->id.proto == m->proto &&
(m->reqid == 0 || t->reqid == m->reqid)) {
switch (t->mode) {
case XFRM_MODE_TUNNEL:
case XFRM_MODE_BEET:
if (xfrm_addr_cmp(&t->id.daddr, &m->old_daddr,
m->old_family) == 0 &&
xfrm_addr_cmp(&t->saddr, &m->old_saddr,
m->old_family) == 0) {
match = 1;
}
break;
case XFRM_MODE_TRANSPORT:
/* in case of transport mode, template does not store
any IP addresses, hence we just compare mode and
protocol */
match = 1;
break;
default:
break;
}
}
return match;
}
/* update endpoint address(es) of template(s) */
static int xfrm_policy_migrate(struct xfrm_policy *pol,
struct xfrm_migrate *m, int num_migrate)
{
struct xfrm_migrate *mp;
int i, j, n = 0;
write_lock_bh(&pol->lock);
if (unlikely(pol->walk.dead)) {
/* target policy has been deleted */
write_unlock_bh(&pol->lock);
return -ENOENT;
}
for (i = 0; i < pol->xfrm_nr; i++) {
for (j = 0, mp = m; j < num_migrate; j++, mp++) {
if (!migrate_tmpl_match(mp, &pol->xfrm_vec[i]))
continue;
n++;
if (pol->xfrm_vec[i].mode != XFRM_MODE_TUNNEL &&
pol->xfrm_vec[i].mode != XFRM_MODE_BEET)
continue;
/* update endpoints */
memcpy(&pol->xfrm_vec[i].id.daddr, &mp->new_daddr,
sizeof(pol->xfrm_vec[i].id.daddr));
memcpy(&pol->xfrm_vec[i].saddr, &mp->new_saddr,
sizeof(pol->xfrm_vec[i].saddr));
pol->xfrm_vec[i].encap_family = mp->new_family;
/* flush bundles */
atomic_inc(&pol->genid);
}
}
write_unlock_bh(&pol->lock);
if (!n)
return -ENODATA;
return 0;
}
static int xfrm_migrate_check(struct xfrm_migrate *m, int num_migrate)
{
int i, j;
if (num_migrate < 1 || num_migrate > XFRM_MAX_DEPTH)
return -EINVAL;
for (i = 0; i < num_migrate; i++) {
if ((xfrm_addr_cmp(&m[i].old_daddr, &m[i].new_daddr,
m[i].old_family) == 0) &&
(xfrm_addr_cmp(&m[i].old_saddr, &m[i].new_saddr,
m[i].old_family) == 0))
return -EINVAL;
if (xfrm_addr_any(&m[i].new_daddr, m[i].new_family) ||
xfrm_addr_any(&m[i].new_saddr, m[i].new_family))
return -EINVAL;
/* check if there is any duplicated entry */
for (j = i + 1; j < num_migrate; j++) {
if (!memcmp(&m[i].old_daddr, &m[j].old_daddr,
sizeof(m[i].old_daddr)) &&
!memcmp(&m[i].old_saddr, &m[j].old_saddr,
sizeof(m[i].old_saddr)) &&
m[i].proto == m[j].proto &&
m[i].mode == m[j].mode &&
m[i].reqid == m[j].reqid &&
m[i].old_family == m[j].old_family)
return -EINVAL;
}
}
return 0;
}
int xfrm_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
struct xfrm_migrate *m, int num_migrate,
struct xfrm_kmaddress *k)
{
int i, err, nx_cur = 0, nx_new = 0;
struct xfrm_policy *pol = NULL;
struct xfrm_state *x, *xc;
struct xfrm_state *x_cur[XFRM_MAX_DEPTH];
struct xfrm_state *x_new[XFRM_MAX_DEPTH];
struct xfrm_migrate *mp;
if ((err = xfrm_migrate_check(m, num_migrate)) < 0)
goto out;
/* Stage 1 - find policy */
if ((pol = xfrm_migrate_policy_find(sel, dir, type)) == NULL) {
err = -ENOENT;
goto out;
}
/* Stage 2 - find and update state(s) */
for (i = 0, mp = m; i < num_migrate; i++, mp++) {
if ((x = xfrm_migrate_state_find(mp))) {
x_cur[nx_cur] = x;
nx_cur++;
if ((xc = xfrm_state_migrate(x, mp))) {
x_new[nx_new] = xc;
nx_new++;
} else {
err = -ENODATA;
goto restore_state;
}
}
}
/* Stage 3 - update policy */
if ((err = xfrm_policy_migrate(pol, m, num_migrate)) < 0)
goto restore_state;
/* Stage 4 - delete old state(s) */
if (nx_cur) {
xfrm_states_put(x_cur, nx_cur);
xfrm_states_delete(x_cur, nx_cur);
}
/* Stage 5 - announce */
km_migrate(sel, dir, type, m, num_migrate, k);
xfrm_pol_put(pol);
return 0;
out:
return err;
restore_state:
if (pol)
xfrm_pol_put(pol);
if (nx_cur)
xfrm_states_put(x_cur, nx_cur);
if (nx_new)
xfrm_states_delete(x_new, nx_new);
return err;
}
EXPORT_SYMBOL(xfrm_migrate);
#endif