| From | Herton Ronaldo Krzesinski <> | Subject | [PATCH 068/270] pktgen: fix crash when generating IPv6 packets | Date | Mon, 26 Nov 2012 14:55:58 -0200 |
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3.5.7u1 -stable review patch. If anyone has any objections, please let me know.
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From: Amerigo Wang <amwang@redhat.com>
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: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- net/core/pktgen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/pktgen.c b/net/core/pktgen.c index cce9e53..aa278cd 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2927,7 +2927,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev, sizeof(struct ipv6hdr) - sizeof(struct udphdr) - pkt_dev->pkt_overhead; - if (datalen < sizeof(struct pktgen_hdr)) { + if (datalen < 0 || datalen < sizeof(struct pktgen_hdr)) { datalen = sizeof(struct pktgen_hdr); net_info_ratelimited("increased datalen to %d\n", datalen); } -- 1.7.9.5
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