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

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index a7900b4ecc3a784aef4920113101dce1c33ea560..5f0cb5ffb2353a114c2175b743d236b7adbe2ce3 100644 (file)
--- 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 cfa29526b1646503491b6f4f6b3a7338961c69e8..ac35ae982fe52984446d542ff90ef2dbfd16c6d1 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -722,7 +722,8 @@ 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;
        }
@@ -1485,7 +1486,8 @@ 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 503e614233b938f9f085883a8167b4da421f489f..8d4664374b0f4745b61fd29221f12524acdcd7dd 100644 (file)
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -745,7 +745,8 @@ 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;
        }
@@ -1509,7 +1510,8 @@ 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;
        }