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net: ipv6: router advertisement message length should be within limits

The argument len passed to function process_ra is the length of the IPv6
router advertisement message and needs to be between 0 and MTU because
it is assigned to remaining_option_len and used as a loop variable.

Addresses-Coverity-ID: 450971 ("TAINTED_SCALAR")
Signed-off-by: Ehsan Mohandesi <emohandesi@linux.microsoft.com>
Reviewed-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Ehsan Mohandesi 1 year ago
parent
commit
a29df56eab
1 changed files with 2 additions and 0 deletions
  1. 2 0
      net/ndisc.c

+ 2 - 0
net/ndisc.c

@@ -382,6 +382,8 @@ int process_ra(struct ip6_hdr *ip6, int len)
 	unsigned char type = 0;
 	struct icmp6_ra_prefix_info *prefix = NULL;
 
+	if (len > ETH_MAX_MTU)
+		return -EMSGSIZE;
 	/* Ignore the packet if router lifetime is 0. */
 	if (!icmp->icmp6_rt_lifetime)
 		return -EOPNOTSUPP;