From: Amerigo Wang <amwang@redhat.com>
Date: Tue, 9 Oct 2012 17:48:16 +0000 (+0000)
Subject: pktgen: fix crash when generating IPv6 packets
X-Git-Tag: v3.2.33~66
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe54b1e7efb9b0c4bc0be5202c50639cd7571c8e;p=pandora-kernel.git

pktgen: fix crash when generating IPv6 packets

commit 5aa8b572007c4bca1e6d3dd4c4820f1ae49d6bb2 upstream.

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: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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