netfilter: x_tables: make sure e->next_offset covers remaining blob size

Otherwise this function may read data beyond the ruleset blob.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2016-03-22 18:02:50 +01:00 committed by Pablo Neira Ayuso
parent bdf533de69
commit 6e94e0cfb0
3 changed files with 12 additions and 6 deletions

View File

@ -573,7 +573,8 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e,
int err;
if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
(unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
(unsigned char *)e + sizeof(struct arpt_entry) >= limit ||
(unsigned char *)e + e->next_offset > limit) {
duprintf("Bad offset %p\n", e);
return -EINVAL;
}
@ -1232,7 +1233,8 @@ check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
duprintf("check_compat_entry_size_and_hooks %p\n", e);
if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
(unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
(unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit ||
(unsigned char *)e + e->next_offset > limit) {
duprintf("Bad offset %p, limit = %p\n", e, limit);
return -EINVAL;
}

View File

@ -738,7 +738,8 @@ check_entry_size_and_hooks(struct ipt_entry *e,
int err;
if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 ||
(unsigned char *)e + sizeof(struct ipt_entry) >= limit) {
(unsigned char *)e + sizeof(struct ipt_entry) >= limit ||
(unsigned char *)e + e->next_offset > limit) {
duprintf("Bad offset %p\n", e);
return -EINVAL;
}
@ -1492,7 +1493,8 @@ check_compat_entry_size_and_hooks(struct compat_ipt_entry *e,
duprintf("check_compat_entry_size_and_hooks %p\n", e);
if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 ||
(unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit) {
(unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit ||
(unsigned char *)e + e->next_offset > limit) {
duprintf("Bad offset %p, limit = %p\n", e, limit);
return -EINVAL;
}

View File

@ -750,7 +750,8 @@ check_entry_size_and_hooks(struct ip6t_entry *e,
int err;
if ((unsigned long)e % __alignof__(struct ip6t_entry) != 0 ||
(unsigned char *)e + sizeof(struct ip6t_entry) >= limit) {
(unsigned char *)e + sizeof(struct ip6t_entry) >= limit ||
(unsigned char *)e + e->next_offset > limit) {
duprintf("Bad offset %p\n", e);
return -EINVAL;
}
@ -1504,7 +1505,8 @@ check_compat_entry_size_and_hooks(struct compat_ip6t_entry *e,
duprintf("check_compat_entry_size_and_hooks %p\n", e);
if ((unsigned long)e % __alignof__(struct compat_ip6t_entry) != 0 ||
(unsigned char *)e + sizeof(struct compat_ip6t_entry) >= limit) {
(unsigned char *)e + sizeof(struct compat_ip6t_entry) >= limit ||
(unsigned char *)e + e->next_offset > limit) {
duprintf("Bad offset %p, limit = %p\n", e, limit);
return -EINVAL;
}