sctp: add vtag check in sctp_sf_ootb

sctp_sf_ootb() is called when processing DATA chunk in closed state, and many 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. When fails to verify the vtag from the chunk, this patch sets asoc to NULL, so that the abort will be made with the vtag from the received chunk later. Fixes: 1da177e ("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]>
Brandon-Hurst · Oct 22, 2021 · 9d02831 · 9d02831
1 parent ef16b17
commit 9d02831
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
@@ -3688,6 +3688,9 @@ enum sctp_disposition sctp_sf_ootb(struct net *net,
 
 	SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
 
+	if (asoc && !sctp_vtag_verify(chunk, asoc))
+		asoc = NULL;
+
 	ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
 	do {
 		/* Report violation if the chunk is less then minimal */