[NETFILTER]: Fix possible overflow in netfilters do_replace()

[mirror_ubuntu-bionic-kernel.git] / net / ipv4 / netfilter / ip_tables.c

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 2371b2062c2d812468ad62f4fe19d4360e748f41..16f47c675fefd8304d86174f6d4beeebdec6539b 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -921,6 +921,13 @@ do_replace(void __user *user, unsigned int len)
        if (len != sizeof(tmp) + tmp.size)
                return -ENOPROTOOPT;
 
+       /* overflow check */
+       if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
+                       SMP_CACHE_BYTES)
+               return -ENOMEM;
+       if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
+               return -ENOMEM;
+
        newinfo = xt_alloc_table_info(tmp.size);
        if (!newinfo)
                return -ENOMEM;