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ipv4: Namespaceify tcp_fastopen_key knob 

Different namespace application might require different tcp_fastopen_key
independently of the host.

David Miller pointed out there is a leak without releasing the context
of tcp_fastopen_key during netns teardown. So add the release action in
exit_batch path.

Tested:
1. Container namespace:
# cat /proc/sys/net/ipv4/tcp_fastopen_key:
2817fff2-f803cf97-eadfd1f3-78c0992b

cookie key in tcp syn packets:
Fast Open Cookie
    Kind: TCP Fast Open Cookie (34)
    Length: 10
    Fast Open Cookie: 1e5dd82a8c492ca9

2. Host:
# cat /proc/sys/net/ipv4/tcp_fastopen_key:
107d7c5f-68eb2ac7-02fb06e6-ed341702

cookie key in tcp syn packets:
Fast Open Cookie
    Kind: TCP Fast Open Cookie (34)
    Length: 10
    Fast Open Cookie: e213c02bf0afbc8a

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Haishuang Yan 2017-09-27 11:35:42 +08:00 committed by David S. Miller
parent dd000598a3
commit 4371384856
7 changed files with 70 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/netns/ipv4.h
View File

@ -36,6 +36,8 @@ struct inet_timewait_death_row {
int sysctl_max_tw_buckets;
};
struct tcp_fastopen_context;
struct netns_ipv4 {
#ifdef CONFIG_SYSCTL
struct ctl_table_header *forw_hdr;
@ -129,6 +131,8 @@ struct netns_ipv4 {
struct inet_timewait_death_row tcp_death_row;
int sysctl_max_syn_backlog;
int sysctl_tcp_fastopen;
struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
spinlock_t tcp_fastopen_ctx_lock;
#ifdef CONFIG_NET_L3_MASTER_DEV
int sysctl_udp_l3mdev_accept;

6
include/net/tcp.h
View File

@ -1549,13 +1549,13 @@ struct tcp_fastopen_request {
};
void tcp_free_fastopen_req(struct tcp_sock *tp);
extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
int tcp_fastopen_reset_cipher(void *key, unsigned int len);
void tcp_fastopen_ctx_destroy(struct net *net);
int tcp_fastopen_reset_cipher(struct net *net, void *key, unsigned int len);
void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
struct tcp_fastopen_cookie *foc);
void tcp_fastopen_init_key_once(void);
void tcp_fastopen_init_key_once(struct net *net);
bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss,
struct tcp_fastopen_cookie *cookie);
bool tcp_fastopen_defer_connect(struct sock *sk, int *err);

2
net/ipv4/af_inet.c
View File

@ -222,7 +222,7 @@ int inet_listen(struct socket *sock, int backlog)
(tcp_fastopen & TFO_SERVER_ENABLE) &&
!inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {
fastopen_queue_tune(sk, backlog);
tcp_fastopen_init_key_once();
tcp_fastopen_init_key_once(sock_net(sk));
}
err = inet_csk_listen_start(sk, backlog);

21
net/ipv4/sysctl_net_ipv4.c
View File

@ -251,10 +251,12 @@ static int proc_allowed_congestion_control(struct ctl_table *ctl,
return ret;
}
static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write,
static int proc_tcp_fastopen_key(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
struct net *net = container_of(table->data, struct net,
ipv4.sysctl_tcp_fastopen);
struct ctl_table tbl = { .maxlen = (TCP_FASTOPEN_KEY_LENGTH * 2 + 10) };
struct tcp_fastopen_context *ctxt;
int ret;
@ -265,7 +267,7 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write,
return -ENOMEM;
rcu_read_lock();
ctxt = rcu_dereference(tcp_fastopen_ctx);
ctxt = rcu_dereference(net->ipv4.tcp_fastopen_ctx);
if (ctxt)
memcpy(user_key, ctxt->key, TCP_FASTOPEN_KEY_LENGTH);
else
@ -282,7 +284,7 @@ static int proc_tcp_fastopen_key(struct ctl_table *ctl, int write,
ret = -EINVAL;
goto bad_key;
}
tcp_fastopen_reset_cipher(user_key, TCP_FASTOPEN_KEY_LENGTH);
tcp_fastopen_reset_cipher(net, user_key, TCP_FASTOPEN_KEY_LENGTH);
}
bad_key:
@ -395,12 +397,6 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
{
.procname = "tcp_fastopen_key",
.mode = 0600,
.maxlen = ((TCP_FASTOPEN_KEY_LENGTH * 2) + 10),
.proc_handler = proc_tcp_fastopen_key,
},
{
.procname = "tcp_fastopen_blackhole_timeout_sec",
.data = &sysctl_tcp_fastopen_blackhole_timeout,
@ -1080,6 +1076,13 @@ static struct ctl_table ipv4_net_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "tcp_fastopen_key",
.mode = 0600,
.data = &init_net.ipv4.sysctl_tcp_fastopen,
.maxlen = ((TCP_FASTOPEN_KEY_LENGTH * 2) + 10),
.proc_handler = proc_tcp_fastopen_key,
},
#ifdef CONFIG_IP_ROUTE_MULTIPATH
{
.procname = "fib_multipath_use_neigh",

2
net/ipv4/tcp.c
View File

@ -2749,7 +2749,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
case TCP_FASTOPEN:
if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
TCPF_LISTEN))) {
tcp_fastopen_init_key_once();
tcp_fastopen_init_key_once(net);
fastopen_queue_tune(sk, val);
} else {

64
net/ipv4/tcp_fastopen.c
View File

@ -9,13 +9,18 @@
#include <net/inetpeer.h>
#include <net/tcp.h>
struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
static DEFINE_SPINLOCK(tcp_fastopen_ctx_lock);
void tcp_fastopen_init_key_once(void)
void tcp_fastopen_init_key_once(struct net *net)
{
static u8 key[TCP_FASTOPEN_KEY_LENGTH];
u8 key[TCP_FASTOPEN_KEY_LENGTH];
struct tcp_fastopen_context *ctxt;
rcu_read_lock();
ctxt = rcu_dereference(net->ipv4.tcp_fastopen_ctx);
if (ctxt) {
rcu_read_unlock();
return;
}
rcu_read_unlock();
/* tcp_fastopen_reset_cipher publishes the new context
* atomically, so we allow this race happening here.
@ -23,8 +28,8 @@ void tcp_fastopen_init_key_once(void)
* All call sites of tcp_fastopen_cookie_gen also check
* for a valid cookie, so this is an acceptable risk.
*/
if (net_get_random_once(key, sizeof(key)))
tcp_fastopen_reset_cipher(key, sizeof(key));
get_random_bytes(key, sizeof(key));
tcp_fastopen_reset_cipher(net, key, sizeof(key));
}
static void tcp_fastopen_ctx_free(struct rcu_head *head)
@ -35,7 +40,22 @@ static void tcp_fastopen_ctx_free(struct rcu_head *head)
kfree(ctx);
}
int tcp_fastopen_reset_cipher(void *key, unsigned int len)
void tcp_fastopen_ctx_destroy(struct net *net)
{
struct tcp_fastopen_context *ctxt;
spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
ctxt = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, NULL);
spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
if (ctxt)
call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free);
}
int tcp_fastopen_reset_cipher(struct net *net, void *key, unsigned int len)
{
int err;
struct tcp_fastopen_context *ctx, *octx;
@ -59,26 +79,27 @@ error: kfree(ctx);
}
memcpy(ctx->key, key, len);
spin_lock(&tcp_fastopen_ctx_lock);
spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
octx = rcu_dereference_protected(tcp_fastopen_ctx,
lockdep_is_held(&tcp_fastopen_ctx_lock));
rcu_assign_pointer(tcp_fastopen_ctx, ctx);
spin_unlock(&tcp_fastopen_ctx_lock);
octx = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, ctx);
spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
if (octx)
call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
return err;
}
static bool __tcp_fastopen_cookie_gen(const void *path,
static bool __tcp_fastopen_cookie_gen(struct net *net,
const void *path,
struct tcp_fastopen_cookie *foc)
{
struct tcp_fastopen_context *ctx;
bool ok = false;
rcu_read_lock();
ctx = rcu_dereference(tcp_fastopen_ctx);
ctx = rcu_dereference(net->ipv4.tcp_fastopen_ctx);
if (ctx) {
crypto_cipher_encrypt_one(ctx->tfm, foc->val, path);
foc->len = TCP_FASTOPEN_COOKIE_SIZE;
@ -94,7 +115,8 @@ static bool __tcp_fastopen_cookie_gen(const void *path,
*
* XXX (TFO) - refactor when TCP_FASTOPEN_COOKIE_SIZE != AES_BLOCK_SIZE.
*/
static bool tcp_fastopen_cookie_gen(struct request_sock *req,
static bool tcp_fastopen_cookie_gen(struct net *net,
struct request_sock *req,
struct sk_buff *syn,
struct tcp_fastopen_cookie *foc)
{
@ -102,7 +124,7 @@ static bool tcp_fastopen_cookie_gen(struct request_sock *req,
const struct iphdr *iph = ip_hdr(syn);
__be32 path[4] = { iph->saddr, iph->daddr, 0, 0 };
return __tcp_fastopen_cookie_gen(path, foc);
return __tcp_fastopen_cookie_gen(net, path, foc);
}
#if IS_ENABLED(CONFIG_IPV6)
@ -110,13 +132,13 @@ static bool tcp_fastopen_cookie_gen(struct request_sock *req,
const struct ipv6hdr *ip6h = ipv6_hdr(syn);
struct tcp_fastopen_cookie tmp;
if (__tcp_fastopen_cookie_gen(&ip6h->saddr, &tmp)) {
if (__tcp_fastopen_cookie_gen(net, &ip6h->saddr, &tmp)) {
struct in6_addr *buf = &tmp.addr;
int i;
for (i = 0; i < 4; i++)
buf->s6_addr32[i] ^= ip6h->daddr.s6_addr32[i];
return __tcp_fastopen_cookie_gen(buf, foc);
return __tcp_fastopen_cookie_gen(net, buf, foc);
}
}
#endif
@ -296,7 +318,7 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
goto fastopen;
if (foc->len >= 0 && /* Client presents or requests a cookie */
tcp_fastopen_cookie_gen(req, skb, &valid_foc) &&
tcp_fastopen_cookie_gen(sock_net(sk), req, skb, &valid_foc) &&
foc->len == TCP_FASTOPEN_COOKIE_SIZE &&
foc->len == valid_foc.len &&
!memcmp(foc->val, valid_foc.val, foc->len)) {

6
net/ipv4/tcp_ipv4.c
View File

@ -2473,6 +2473,7 @@ static int __net_init tcp_sk_init(struct net *net)
net->ipv4.sysctl_tcp_timestamps = 1;
net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
return 0;
fail:
@ -2483,7 +2484,12 @@ static int __net_init tcp_sk_init(struct net *net)
static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
{
struct net *net;
inet_twsk_purge(&tcp_hashinfo, AF_INET);
list_for_each_entry(net, net_exit_list, exit_list)
tcp_fastopen_ctx_destroy(net);
}
static struct pernet_operations __net_initdata tcp_sk_ops = {