From: Xin Long lucien.xin@gmail.com
mainline inclusion from mainline-v5.15 commit aa0f697e45286a6b5f0ceca9418acf54b9099d99 category: bugfix bugzilla: NA CVE: CVE-2021-3772
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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: Huang Guobin huangguobin4@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/sctp/sm_statefuns.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index aed5b3e09b68c..1c730a9a55e67 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -4583,6 +4583,9 @@ 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,