pktgen: fix crash when generating IPv6 packets
authorAmerigo Wang <amwang@redhat.com>
Tue, 9 Oct 2012 17:48:16 +0000 (17:48 +0000)
committerDavid S. Miller <davem@davemloft.net>
Thu, 11 Oct 2012 02:33:30 +0000 (22:33 -0400)
commit5aa8b572007c4bca1e6d3dd4c4820f1ae49d6bb2
tree81f64cc4441a8677763b89aff0df1fba8080b184
parent85457685e0e314f6902caaef976b3fd8ef4f51b4
pktgen: fix crash when generating IPv6 packets

For IPv6, sizeof(struct ipv6hdr) = 40, thus the following
expression will result negative:

        datalen = pkt_dev->cur_pkt_size - 14 -
                  sizeof(struct ipv6hdr) - sizeof(struct udphdr) -
                  pkt_dev->pkt_overhead;

And,  the check "if (datalen < sizeof(struct pktgen_hdr))" will be
passed as "datalen" is promoted to unsigned, therefore will cause
a crash later.

This is a quick fix by checking if "datalen" is negative. The following
patch will increase the default value of 'min_pkt_size' for IPv6.

This bug should exist for a long time, so Cc -stable too.

Cc: <stable@vger.kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/pktgen.c