Commit 5aa8b572 authored Oct 09, 2012 by Amerigo Wang Committed by David S. Miller Oct 10, 2012

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>

parent 85457685

net/core/pktgen.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -2927,7 +2927,7 @@ static struct sk_buff fill_packet_ipv6(struct net_device odev,
	sizeof(struct ipv6hdr) - sizeof(struct udphdr) -		sizeof(struct ipv6hdr) - sizeof(struct udphdr) -
	pkt_dev->pkt_overhead;		pkt_dev->pkt_overhead;

	if (datalen < sizeof(struct pktgen_hdr)) {		if (datalen < 0 \|\| datalen < sizeof(struct pktgen_hdr)) {
	datalen = sizeof(struct pktgen_hdr);		datalen = sizeof(struct pktgen_hdr);
	net_info_ratelimited("increased datalen to %d\n", datalen);		net_info_ratelimited("increased datalen to %d\n", datalen);
	}		}

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