This is a note to let you know that I've just added the patch titled sctp: fix the processing for COOKIE_ECHO chunk to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sctp-fix-the-processing-for-cookie_echo-chunk.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit cb7de9600b3a64f23f0e851ee878c16e5d5f594c Author: Xin Long <lucien.xin@xxxxxxxxx> Date: Wed Oct 20 07:42:44 2021 -0400 sctp: fix the processing for COOKIE_ECHO chunk [ Upstream commit a64b341b8695e1c744dd972b39868371b4f68f83 ] 1. In closed state: in sctp_sf_do_5_1D_ce(): When asoc is NULL, making packet for abort will use chunk's vtag in sctp_ootb_pkt_new(). But when asoc exists, vtag from the chunk should be verified before using peer.i.init_tag to make packet for abort in sctp_ootb_pkt_new(), and just discard it if vtag is not correct. 2. In the other states: in sctp_sf_do_5_2_4_dupcook(): asoc always exists, but duplicate cookie_echo's vtag will be handled by sctp_tietags_compare() and then take actions, so before that we only verify the vtag for the abort sent for invalid chunk length. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 5063f9884367..0cfbf6046bf8 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -697,6 +697,9 @@ enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, struct sock *sk; int error = 0; + if (asoc && !sctp_vtag_verify(chunk, asoc)) + return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); + /* If the packet is an OOTB packet which is temporarily on the * control endpoint, respond with an ABORT. */ @@ -711,7 +714,8 @@ enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, * in sctp_unpack_cookie(). */ if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) - return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); + return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, + commands); /* If the endpoint is not listening or if the number of associations * on the TCP-style socket exceed the max backlog, respond with an @@ -2141,9 +2145,11 @@ enum sctp_disposition sctp_sf_do_5_2_4_dupcook( * enough for the chunk header. Cookie length verification is * done later. */ - if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) - return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, - commands); + if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) { + if (!sctp_vtag_verify(chunk, asoc)) + asoc = NULL; + return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); + } /* "Decode" the chunk. We have no optional parameters so we * are in good shape.