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netfilter: x_tables: introduce and use xt_copy_counters_from_user 

The three variants use same copy&pasted code, condense this into a
helper and use that.

Make sure info.name is 0-terminated.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2016-04-01 15:37:59 +02:00 committed by Pablo Neira Ayuso
parent aded9f3e9f
commit d7591f0c41
5 changed files with 92 additions and 130 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/netfilter/x_tables.h
View File

@ -251,6 +251,9 @@ int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto,
int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
bool inv_proto);
void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
struct xt_counters_info *info, bool compat);
struct xt_table *xt_register_table(struct net *net,
const struct xt_table *table,
struct xt_table_info *bootstrap,

48
net/ipv4/netfilter/arp_tables.c
View File

@ -1123,55 +1123,17 @@ static int do_add_counters(struct net *net, const void __user *user,
unsigned int i;
struct xt_counters_info tmp;
struct xt_counters *paddc;
unsigned int num_counters;
const char *name;
int size;
void *ptmp;
struct xt_table *t;
const struct xt_table_info *private;
int ret = 0;
struct arpt_entry *iter;
unsigned int addend;
#ifdef CONFIG_COMPAT
struct compat_xt_counters_info compat_tmp;
if (compat) {
ptmp = &compat_tmp;
size = sizeof(struct compat_xt_counters_info);
} else
#endif
{
ptmp = &tmp;
size = sizeof(struct xt_counters_info);
}
paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
if (IS_ERR(paddc))
return PTR_ERR(paddc);
if (copy_from_user(ptmp, user, size) != 0)
return -EFAULT;
#ifdef CONFIG_COMPAT
if (compat) {
num_counters = compat_tmp.num_counters;
name = compat_tmp.name;
} else
#endif
{
num_counters = tmp.num_counters;
name = tmp.name;
}
if (len != size + num_counters * sizeof(struct xt_counters))
return -EINVAL;
paddc = vmalloc(len - size);
if (!paddc)
return -ENOMEM;
if (copy_from_user(paddc, user + size, len - size) != 0) {
ret = -EFAULT;
goto free;
}
t = xt_find_table_lock(net, NFPROTO_ARP, name);
t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free;
@ -1179,7 +1141,7 @@ static int do_add_counters(struct net *net, const void __user *user,
local_bh_disable();
private = t->private;
if (private->number != num_counters) {
if (private->number != tmp.num_counters) {
ret = -EINVAL;
goto unlock_up_free;
}

48
net/ipv4/netfilter/ip_tables.c
View File

@ -1307,55 +1307,17 @@ do_add_counters(struct net *net, const void __user *user,
unsigned int i;
struct xt_counters_info tmp;
struct xt_counters *paddc;
unsigned int num_counters;
const char *name;
int size;
void *ptmp;
struct xt_table *t;
const struct xt_table_info *private;
int ret = 0;
struct ipt_entry *iter;
unsigned int addend;
#ifdef CONFIG_COMPAT
struct compat_xt_counters_info compat_tmp;
if (compat) {
ptmp = &compat_tmp;
size = sizeof(struct compat_xt_counters_info);
} else
#endif
{
ptmp = &tmp;
size = sizeof(struct xt_counters_info);
}
paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
if (IS_ERR(paddc))
return PTR_ERR(paddc);
if (copy_from_user(ptmp, user, size) != 0)
return -EFAULT;
#ifdef CONFIG_COMPAT
if (compat) {
num_counters = compat_tmp.num_counters;
name = compat_tmp.name;
} else
#endif
{
num_counters = tmp.num_counters;
name = tmp.name;
}
if (len != size + num_counters * sizeof(struct xt_counters))
return -EINVAL;
paddc = vmalloc(len - size);
if (!paddc)
return -ENOMEM;
if (copy_from_user(paddc, user + size, len - size) != 0) {
ret = -EFAULT;
goto free;
}
t = xt_find_table_lock(net, AF_INET, name);
t = xt_find_table_lock(net, AF_INET, tmp.name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free;
@ -1363,7 +1325,7 @@ do_add_counters(struct net *net, const void __user *user,
local_bh_disable();
private = t->private;
if (private->number != num_counters) {
if (private->number != tmp.num_counters) {
ret = -EINVAL;
goto unlock_up_free;
}

49
net/ipv6/netfilter/ip6_tables.c
View File

@ -1319,55 +1319,16 @@ do_add_counters(struct net *net, const void __user *user, unsigned int len,
unsigned int i;
struct xt_counters_info tmp;
struct xt_counters *paddc;
unsigned int num_counters;
char *name;
int size;
void *ptmp;
struct xt_table *t;
const struct xt_table_info *private;
int ret = 0;
struct ip6t_entry *iter;
unsigned int addend;
#ifdef CONFIG_COMPAT
struct compat_xt_counters_info compat_tmp;
if (compat) {
ptmp = &compat_tmp;
size = sizeof(struct compat_xt_counters_info);
} else
#endif
{
ptmp = &tmp;
size = sizeof(struct xt_counters_info);
}
if (copy_from_user(ptmp, user, size) != 0)
return -EFAULT;
#ifdef CONFIG_COMPAT
if (compat) {
num_counters = compat_tmp.num_counters;
name = compat_tmp.name;
} else
#endif
{
num_counters = tmp.num_counters;
name = tmp.name;
}
if (len != size + num_counters * sizeof(struct xt_counters))
return -EINVAL;
paddc = vmalloc(len - size);
if (!paddc)
return -ENOMEM;
if (copy_from_user(paddc, user + size, len - size) != 0) {
ret = -EFAULT;
goto free;
}
t = xt_find_table_lock(net, AF_INET6, name);
paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
if (IS_ERR(paddc))
return PTR_ERR(paddc);
t = xt_find_table_lock(net, AF_INET6, tmp.name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free;
@ -1375,7 +1336,7 @@ do_add_counters(struct net *net, const void __user *user, unsigned int len,
local_bh_disable();
private = t->private;
if (private->number != num_counters) {
if (private->number != tmp.num_counters) {
ret = -EINVAL;
goto unlock_up_free;
}

74
net/netfilter/x_tables.c
View File

@ -752,6 +752,80 @@ int xt_check_target(struct xt_tgchk_param *par,
}
EXPORT_SYMBOL_GPL(xt_check_target);
/**
* xt_copy_counters_from_user - copy counters and metadata from userspace
*
* @user: src pointer to userspace memory
* @len: alleged size of userspace memory
* @info: where to store the xt_counters_info metadata
* @compat: true if we setsockopt call is done by 32bit task on 64bit kernel
*
* Copies counter meta data from @user and stores it in @info.
*
* vmallocs memory to hold the counters, then copies the counter data
* from @user to the new memory and returns a pointer to it.
*
* If @compat is true, @info gets converted automatically to the 64bit
* representation.
*
* The metadata associated with the counters is stored in @info.
*
* Return: returns pointer that caller has to test via IS_ERR().
* If IS_ERR is false, caller has to vfree the pointer.
*/
void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
struct xt_counters_info *info, bool compat)
{
void *mem;
u64 size;
#ifdef CONFIG_COMPAT
if (compat) {
/* structures only differ in size due to alignment */
struct compat_xt_counters_info compat_tmp;
if (len <= sizeof(compat_tmp))
return ERR_PTR(-EINVAL);
len -= sizeof(compat_tmp);
if (copy_from_user(&compat_tmp, user, sizeof(compat_tmp)) != 0)
return ERR_PTR(-EFAULT);
strlcpy(info->name, compat_tmp.name, sizeof(info->name));
info->num_counters = compat_tmp.num_counters;
user += sizeof(compat_tmp);
} else
#endif
{
if (len <= sizeof(*info))
return ERR_PTR(-EINVAL);
len -= sizeof(*info);
if (copy_from_user(info, user, sizeof(*info)) != 0)
return ERR_PTR(-EFAULT);
info->name[sizeof(info->name) - 1] = '\0';
user += sizeof(*info);
}
size = sizeof(struct xt_counters);
size *= info->num_counters;
if (size != (u64)len)
return ERR_PTR(-EINVAL);
mem = vmalloc(len);
if (!mem)
return ERR_PTR(-ENOMEM);
if (copy_from_user(mem, user, len) == 0)
return mem;
vfree(mem);
return ERR_PTR(-EFAULT);
}
EXPORT_SYMBOL_GPL(xt_copy_counters_from_user);
#ifdef CONFIG_COMPAT
int xt_compat_target_offset(const struct xt_target *target)
{