From patchwork Fri Mar 28 14:27:16 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthieu Baerts X-Patchwork-Id: 14032085 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69BC51C4609; Fri, 28 Mar 2025 14:28:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743172090; cv=none; b=TTjjOmaPIo9UTHHYERxJfjQhqy7W2SkZZRbUsydLJU0yzC17relSKncRiSZddKupYAtCzoUJMpMR4oNuGTAEu7eCYIDCUWBOKP9nDtAWkjtTkOIac+NxH/GjIXhAjqMBUkloFY8PbUJgG0LdDuy0YQUM6OQwjf1CLlrFq3Qrebw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743172090; c=relaxed/simple; bh=awEuvFGtpL0MNDNIG1y3EbcEixXwlA0kAeb844a7YbY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=YrxanjPBCTMx6ppCzDp189H9UEhePQRojcbzVy/daz+KOxqKdWJKZMwuXDj4bUCiAxmGzCrSijpVIfP0vXOwKrsOk64dDYJxMV1JxFhftSMi/I1Z+ghQ2sHj0fEQLM2BGp8PYvceOzrqEFsCQ3UWZRuljPPFZSJ/cm486X4ZGBw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YTFnvJ1N; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YTFnvJ1N" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C708AC4CEED; Fri, 28 Mar 2025 14:28:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743172089; bh=awEuvFGtpL0MNDNIG1y3EbcEixXwlA0kAeb844a7YbY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=YTFnvJ1N0/b1vAO66PXbpqwCWYd66vqwf8s0Mt/SvS+Vqebc9zeBjcI+mSs5uFXto uUid1PpRifdHp403pB2SmWFVTeSySKXXACRDVctj5slzeRje6MfH5SfhWGbWEKjL7L J6Qjt5AtbNr0DeyD2RM0b+dbsI72SlZbj6XsMBmE+YzJGZHl6sHFG7/hg+ga1DfA06 0niXuXppnAoOBxU/uRBto9yF4Au5Mw6sGmjiOti49SUpKqBuu8fTtSTbtB+M4L7eLM iU4EV+dEJBiKEfGtyobhVJ/2gEiqKOcA+fOXznZMkX25xTmpVBh4fnwcb/5WiYui0W suYJ0Gq2w6CXg== From: "Matthieu Baerts (NGI0)" Date: Fri, 28 Mar 2025 15:27:16 +0100 Subject: [PATCH net 1/4] mptcp: fix NULL pointer in can_accept_new_subflow Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250328-net-mptcp-misc-fixes-6-15-v1-1-34161a482a7f@kernel.org> References: <20250328-net-mptcp-misc-fixes-6-15-v1-0-34161a482a7f@kernel.org> In-Reply-To: <20250328-net-mptcp-misc-fixes-6-15-v1-0-34161a482a7f@kernel.org> To: mptcp@lists.linux.dev, Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Florian Westphal , Shuah Khan , Dmytro Shytyi , Gang Yan Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, "Matthieu Baerts (NGI0)" , stable@vger.kernel.org X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3226; i=matttbe@kernel.org; h=from:subject:message-id; bh=vzugoolZfElAHOE2QlY156jFm2862QpuAvKqHC67q0k=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBn5rHs0x3onJRwijrAj23vtbDAMHIUqriAsYEgS 047nkrOm2yJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZ+ax7AAKCRD2t4JPQmmg cxXZD/9XVTwvr6jRlUHzXWoJXNFpjEmFoAmYtzGVtbJ/teyt5CkFX2DforBfX0FrLHRqqVGc6OO CqNKRSfHryPlAB+yHLlHp9rySZNpP7w5cxUdrTADFMc13pScKaDxXsEijArr8KtHZ6r0h6f4Cze TqEWXuHx7TbEj19yn/p51N2dL35akIBpay+ivcUe/C8qpLGYdedJvQKMHl2Mv3/IMaxAlsr38Kh AY/aLIr9HskeG0JMrdYRX2nhqATa+IjeLn4924XtQ1TZ0VnoP1E6ZJQiaNK8aLcouafchJ6ZpvC SMbMEO5nFR2fOFNTWoT5WLMC7+Oe/sUa6H8Og1nqcHg3QyUwMn/oNKb0BqEka5rowQ4bK31AH07 YDF++JUatOPc0Rlde9Uh2WGUTtYey/Oht6CMpUZeBa8p08qZ8Dr9iQFQU2NS4+8hvp2B2BZ5ar5 ghw5A65UaUWfK/7V6nB4a8Pk+CzUm48yQKPhIdEEAFG8UxmAAerOoApQzuBJow9v+1IqgeyIV/2 sX8bhfTY3Dw5a1OFSPAEK8tuECV6BMFmSoxDZYD3g0o9F9BXRd5ypHobX1Ru4fkGJ5/ZsRe7zH0 6tuWlRBfntB2u7uxxwNPNjfbHM6spiEZcb4eEpRyC+SQLfW35rTyspN8Hs7V2vIf1RMxsuRMRPo ORLlN7MWf6aFboA== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Gang Yan When testing valkey benchmark tool with MPTCP, the kernel panics in 'mptcp_can_accept_new_subflow' because subflow_req->msk is NULL. Call trace: mptcp_can_accept_new_subflow (./net/mptcp/subflow.c:63 (discriminator 4)) (P) subflow_syn_recv_sock (./net/mptcp/subflow.c:854) tcp_check_req (./net/ipv4/tcp_minisocks.c:863) tcp_v4_rcv (./net/ipv4/tcp_ipv4.c:2268) ip_protocol_deliver_rcu (./net/ipv4/ip_input.c:207) ip_local_deliver_finish (./net/ipv4/ip_input.c:234) ip_local_deliver (./net/ipv4/ip_input.c:254) ip_rcv_finish (./net/ipv4/ip_input.c:449) ... According to the debug log, the same req received two SYN-ACK in a very short time, very likely because the client retransmits the syn ack due to multiple reasons. Even if the packets are transmitted with a relevant time interval, they can be processed by the server on different CPUs concurrently). The 'subflow_req->msk' ownership is transferred to the subflow the first, and there will be a risk of a null pointer dereference here. This patch fixes this issue by moving the 'subflow_req->msk' under the `own_req == true` conditional. Note that the !msk check in subflow_hmac_valid() can be dropped, because the same check already exists under the own_req mpj branch where the code has been moved to. Fixes: 9466a1ccebbe ("mptcp: enable JOIN requests even if cookies are in use") Cc: stable@vger.kernel.org Suggested-by: Paolo Abeni Signed-off-by: Gang Yan Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/subflow.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index efe8d86496dbd06a3c4cae6ffc6462e43e42c959..409bd415ef1d190d5599658d01323ad8c8a9be93 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -754,8 +754,6 @@ static bool subflow_hmac_valid(const struct request_sock *req, subflow_req = mptcp_subflow_rsk(req); msk = subflow_req->msk; - if (!msk) - return false; subflow_generate_hmac(READ_ONCE(msk->remote_key), READ_ONCE(msk->local_key), @@ -850,12 +848,8 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, } else if (subflow_req->mp_join) { mptcp_get_options(skb, &mp_opt); - if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK) || - !subflow_hmac_valid(req, &mp_opt) || - !mptcp_can_accept_new_subflow(subflow_req->msk)) { - SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); + if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK)) fallback = true; - } } create_child: @@ -905,6 +899,13 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, goto dispose_child; } + if (!subflow_hmac_valid(req, &mp_opt) || + !mptcp_can_accept_new_subflow(subflow_req->msk)) { + SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); + 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;