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Subject[PATCH 3.10 004/180] netfilter: x_tables: make sure e->next_offset covers remaining blob size
Date
From: Florian Westphal <fw@strlen.de>

commit 6e94e0cfb0887e4013b3b930fa6ab1fe6bb6ba91 upstream.

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>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/ipv4/netfilter/arp_tables.c | 6 ++++--
net/ipv4/netfilter/ip_tables.c | 6 ++++--
net/ipv6/netfilter/ip6_tables.c | 6 ++++--
3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 269759d..ee40bd4 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -558,7 +558,8 @@ 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;
}
@@ -1218,7 +1219,8 @@ 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;
}
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 5ca478f..7cfd566 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -721,7 +721,8 @@ 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;
}
@@ -1484,7 +1485,8 @@ 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;
}
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 597f539..9c6b543 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -732,7 +732,8 @@ 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;
}
@@ -1496,7 +1497,8 @@ 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;
}
--
2.8.0.rc2.1.gbe9624a
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