3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Amerigo Wang <amw...@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.
Signed-off-by: Cong Wang <amw...@redhat.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
net/core/pktgen.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2932,7 +2932,7 @@ static struct sk_buff *fill_packet_ipv6(
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);
if (net_ratelimit())
pr_info("increased datalen to %d\n", datalen);
--
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