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

[ Upstream commit 6e94e0cfb0887e4013b3b930fa6ab1fe6bb6ba91 ]

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: Sasha Levin <sasha.levin@oracle.com>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index e500f4fcf868401a7e3d9b5702b5c8c6686b8188..835b768e10e8888a76c5feadc3df3521583b498a 100644 (file)
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -562,7 +562,8 @@ 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;
        }
@@ -1225,7 +1226,8 @@ 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 a75ff8a8420fce74260cf9b9ee38de4af602f8ff..4ad55767569a364ff24bf76f151a694c9dd4573a 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -725,7 +725,8 @@ 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;
        }
@@ -1491,7 +1492,8 @@ 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 ef764a67cc645994f62320a8cda60e6d1415c7af..9a4666be412d468034d68689432e9292dc92b97e 100644 (file)
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -739,7 +739,8 @@ 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;
        }
@@ -1506,7 +1507,8 @@ 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;
        }