sctp: add vtag check in sctp_sf_violation

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 <[email protected]> Acked-by: Marcelo Ricardo Leitner <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
josf · Oct 22, 2021 · aa0f697 · aa0f697
1 parent a64b341
commit aa0f697
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
@@ -4669,6 +4669,9 @@ 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,