[Qemu-devel] [PATCH] l2tpv3: fix cookie decoding

[Qemu-devel] [PATCH] l2tpv3: fix cookie decoding

[Alexis D...t]

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) {
-- 
2.6.2

Re: [Qemu-devel] [PATCH] l2tpv3: fix cookie decoding

[Jason Wang]

On 12/31/2015 10:34 PM, Alexis D...t wrote:
> 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) {

Hi:

Patch looks good. But it fails to be applied cleanly:

Applying: l2tpv3: fix cookie decoding
fatal: corrupt patch at line 10
Patch failed at 0001 l2tpv3: fix cookie decoding

It's suggested to use git-foramt-patch(1) and git-send-email(1) to
format and send patches.