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From: Alexis Dambricourt <alexis.dambricourt@gmail.com>
To: qemu-devel@nongnu.org
Cc: jasowang@redhat.com
Subject: [Qemu-devel] [PATCH v2] l2tpv3: fix cookie decoding
Date: Tue,  5 Jan 2016 00:26:07 +0100	[thread overview]
Message-ID: <1451949967-30272-1-git-send-email-alexis.dambricourt@gmail.com> (raw)

If a 32 bits l2tpv3 frame cookie MSB if set to 1, the cast to uint64_t
cookie will spread 1 to the four most significant bytes.
Then the condition (cookie != s->rx_cookie) becomes false.

Signed-off-by: Alexis Dambricourt <alexis.dambricourt@gmail.com>
---
 net/l2tpv3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/l2tpv3.c b/net/l2tpv3.c
index 8e68e54..21d6119 100644
--- a/net/l2tpv3.c
+++ b/net/l2tpv3.c
@@ -325,7 +325,7 @@ static int l2tpv3_verify_header(NetL2TPV3State *s, uint8_t *buf)
         if (s->cookie_is_64) {
             cookie = ldq_be_p(buf + s->cookie_offset);
         } else {
-            cookie = ldl_be_p(buf + s->cookie_offset);
+            cookie = ldl_be_p(buf + s->cookie_offset) & 0xffffffffULL;
         }
         if (cookie != s->rx_cookie) {
             if (!s->header_mismatch) {
-- 
2.6.4

             reply	other threads:[~2016-01-04 23:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-04 23:26 Alexis Dambricourt [this message]
2016-01-06  3:01 ` [Qemu-devel] [PATCH v2] l2tpv3: fix cookie decoding Jason Wang

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