[Qemu-devel] [PULL 23/24] l2tpv3: fix cookie decoding

[Jason Wang]

From: Alexis Dambricourt <address@hidden>

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 <address@hidden>
Signed-off-by: Jason Wang <address@hidden>
---
 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) {
-- 
2.5.0