sctp: add vtag check in sctp_sf_violation

[ Upstream commit aa0f697e45286a6b5f0ceca9418acf54b9099d99 ]

sctp_sf_violation() is called when processing HEARTBEAT_ACK chunk
in cookie_wait state, and some other places are also using it.

The vtag in the chunk's sctphdr should be verified, otherwise, as
later in chunk length check, it may send abort with the existent
asoc's vtag, which can be exploited by one to cook a malicious
chunk to terminate a SCTP asoc.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 1e3f6be5bab9b45d2b60feb814006ef79be7865f..35701acbed739dcb77ff85e66ff3490c6fabc86a 100644 (file)
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -4549,6 +4549,9 @@ enum sctp_disposition sctp_sf_violation(struct net *net,
 {
        struct sctp_chunk *chunk = arg;
 
+       if (!sctp_vtag_verify(chunk, asoc))
+               return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
        /* Make sure that the chunk has a valid length. */
        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,