mpls: Properly validate RTA_VIA payload length

If the nla length is less than 2 then the nla data could be accessed
beyond the accessible bounds. So ensure that the nla is big enough to
at least read the via_family before doing so. Replace magic value of
2.

Fixes: 03c0566542 ("mpls: Basic support for adding and removing routes")
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Robert Shearman 2015-03-06 10:47:00 +00:00 committed by David S. Miller
parent 5c4b934f89
commit f8d54afc4c

View File

@ -586,8 +586,11 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
case RTA_VIA:
{
struct rtvia *via = nla_data(nla);
if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
goto errout;
cfg->rc_via_family = via->rtvia_family;
cfg->rc_via_alen = nla_len(nla) - 2;
cfg->rc_via_alen = nla_len(nla) -
offsetof(struct rtvia, rtvia_addr);
if (cfg->rc_via_alen > MAX_VIA_ALEN)
goto errout;