Some callers (e.g. sctp_sf_violation_chunk) passes NULL to
asoc argument of sctp_sf_violation. So, it should check it
before calling sctp_vtag_verify().
Probably it could be exploited by a malicious SCTP packet
to cause NULL pointer dereference.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Fixes: aa0f697e4528 ("sctp: add vtag check in sctp_sf_violation")
---
net/sctp/sm_statefuns.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index fb3da4d8f4a3..77f3cd6c516e 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -4669,7 +4669,7 @@ enum sctp_disposition sctp_sf_violation(struct net *net,
{
struct sctp_chunk *chunk = arg;
- if (!sctp_vtag_verify(chunk, asoc))
+ if (asoc && !sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Make sure that the chunk has a valid length. */
--
2.7.4
