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>
Cc: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 29aa90ea4c8d83df0efe110ba95ee97f568e0133..456fc6efe05d7ed9c18a4d7ca8dd086dc49a2fdd 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 d400a2ad7c563ef901557e3e2ce72f0a158925b7..a5bd3c8eee840163b968329b61a75eb168bdf2a7 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -720,7 +720,8 @@ 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;
        }
@@ -1483,7 +1484,8 @@ 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 e0538df697c84170cfebbaa20931d6d450cfbac6..fb8a146abed8986d15c5165a5812c54eaf0d1f46 100644 (file)
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -731,7 +731,8 @@ 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;
        }
@@ -1495,7 +1496,8 @@ 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;
        }