s390/qeth: fix L3 next-hop in xmit qeth hdr

On L3, the qeth_hdr struct needs to be filled with the next-hop
IP address.
The current code accesses rtable->rt_gateway without checking that
rtable is a valid address. The accidental access to a lowcore area
results in a random next-hop address in the qeth_hdr.
rtable (or more precisely, skb_dst(skb)) can be NULL in rare cases
(for instance together with AF_PACKET sockets).
This patch adds the missing NULL-ptr checks.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Fixes: 87e7597b5a qeth: Move away from using neighbour entries in qeth_l3_fill_header()
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Julian Wiedmann 2017-08-07 13:28:39 +02:00 committed by David S. Miller
parent c0e0fb8379
commit ec2c672632

View File

@ -2512,7 +2512,7 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
struct rtable *rt = (struct rtable *) dst;
__be32 *pkey = &ip_hdr(skb)->daddr;
if (rt->rt_gateway)
if (rt && rt->rt_gateway)
pkey = &rt->rt_gateway;
/* IPv4 */
@ -2523,7 +2523,7 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
struct rt6_info *rt = (struct rt6_info *) dst;
struct in6_addr *pkey = &ipv6_hdr(skb)->daddr;
if (!ipv6_addr_any(&rt->rt6i_gateway))
if (rt && !ipv6_addr_any(&rt->rt6i_gateway))
pkey = &rt->rt6i_gateway;
/* IPv6 */