From: Qing Luo Date: Tue, 21 Jul 2026 01:55:32 +0000 (+0800) Subject: sctp: auth: verify auth requirement when auth_chunk is NULL X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8e04823c120b376ef7dab14b60ebf6823aa16c14;p=thirdparty%2Fkernel%2Flinux.git sctp: auth: verify auth requirement when auth_chunk is NULL sctp_auth_chunk_verify() returns true unconditionally when chunk->auth_chunk is NULL, silently skipping authentication. This is incorrect when: 1. skb_clone() failed in the BH receive path, leaving auth_chunk NULL. In sctp_endpoint_bh_rcv() asoc is NULL for new connections, so the early sctp_auth_recv_cid() check cannot catch this. 2. No AUTH chunk precedes COOKIE-ECHO, so skb_clone() is never called and auth_chunk remains NULL. Fix by checking sctp_auth_recv_cid() when auth_chunk is NULL: if authentication is required, return false to drop the chunk; otherwise continue normally. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Signed-off-by: Qing Luo Acked-by: Xin Long Link: https://patch.msgid.link/20260721015532.120157-2-l1138897701@163.com Signed-off-by: Jakub Kicinski --- diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 3893b44448b3..708fa07d5fff 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -643,7 +643,7 @@ static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, struct sctp_chunk auth; if (!chunk->auth_chunk) - return true; + return !sctp_auth_recv_cid(chunk->chunk_hdr->type, asoc); /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo * is supposed to be authenticated and we have to do delayed