From: Matthieu Baerts (NGI0) Date: Mon, 7 Apr 2025 18:26:32 +0000 (+0200) Subject: mptcp: only inc MPJoinAckHMacFailure for HMAC failures X-Git-Tag: v6.15-rc2~22^2~9^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=21c02e8272bc95ba0dd44943665c669029b42760;p=thirdparty%2Flinux.git mptcp: only inc MPJoinAckHMacFailure for HMAC failures Recently, during a debugging session using local MPTCP connections, I noticed MPJoinAckHMacFailure was not zero on the server side. The counter was in fact incremented when the PM rejected new subflows, because the 'subflow' limit was reached. The fix is easy, simply dissociating the two cases: only the HMAC validation check should increase MPTCP_MIB_JOINACKMAC counter. Fixes: 4cf8b7e48a09 ("subflow: introduce and use mptcp_can_accept_new_subflow()") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250407-net-mptcp-hmac-failure-mib-v1-1-3c9ecd0a3a50@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 409bd415ef1d1..24c2de1891bdf 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -899,13 +899,17 @@ create_child: goto dispose_child; } - if (!subflow_hmac_valid(req, &mp_opt) || - !mptcp_can_accept_new_subflow(subflow_req->msk)) { + if (!subflow_hmac_valid(req, &mp_opt)) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT); goto dispose_child; } + if (!mptcp_can_accept_new_subflow(owner)) { + subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT); + goto dispose_child; + } + /* move the msk reference ownership to the subflow */ subflow_req->msk = NULL; ctx->conn = (struct sock *)owner;