From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 29E58352029 for ; Thu, 2 Jul 2026 08:35:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782981302; cv=none; b=JSCMkviZ/NwlvWsxxaKrBVJeYhuguVPgkZoqqeVD5Bn0XwTCVc135k4zMd4F9V/kcRYiXOVeSBYeizsptO6jSCwWX4951W2FGI4J03PpUgyvi/IjQzYzKjMmbVvwoYwIK/u68/iZRzqOlB64a69gEZXDDSr7/BH/o37AlxpTeNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782981302; c=relaxed/simple; bh=EA7Tom8SoGg1n3XNsZQPZJLW3bdmbpmhf4XwzXb6wH0=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=W0465r7YHWbqHaXEETTd27eATzznqkrX3lCEjepRz5Xw2oix/pius2YXravjBxh/q/QzUoA5MkU/rUNi76+GE/Hw1IhrvNTnyeE31uUXgx03LwVYAopeZTenh8m4svkoL7U8w8EZ8rcKZw6pvJErHeSS6ldDQg9SBK/UKV1XVbA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=c8+CQpWd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="c8+CQpWd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40F301F00A3A; Thu, 2 Jul 2026 08:34:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782981301; bh=DmJhohYzYN3VzA5wtXbtjUh7COTErXPLLtyWyRqnfFw=; h=Subject:To:Cc:From:Date; b=c8+CQpWdMlW3s9A3vvmA0R+9eK4cDQP0VPY7ye0Gdv3uWj1zH+GHncE2o0iJsPC6Q yqC+27Ub0NdXsegcncb0J7wvS2RwPd+nGgIuwE8bEcZQ184LDNbjfcsxdxY2466zyw UcktIpV8k9ymMtu26v7tQN3q9vv1AoqQkY5JUIG0= Subject: FAILED: patch "[PATCH] apparmor: mediate the implicit connect of TCP fast open" failed to apply to 5.15-stable tree To: hexlabsecurity@proton.me,john.johansen@canonical.com Cc: From: Date: Thu, 02 Jul 2026 10:34:41 +0200 Message-ID: <2026070241-upper-credible-fb47@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 4d587cd8a72155089a627130bbd4716ec0856e21 # git commit -s git send-email --to '' --in-reply-to '2026070241-upper-credible-fb47@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 4d587cd8a72155089a627130bbd4716ec0856e21 Mon Sep 17 00:00:00 2001 From: Bryam Vargas Date: Mon, 22 Jun 2026 15:57:38 -0500 Subject: [PATCH] apparmor: mediate the implicit connect of TCP fast open sendmsg sendmsg()/sendto() with MSG_FASTOPEN is a combination of connect(2) and write(2): it opens the connection in the SYN. apparmor_socket_sendmsg() only checks AA_MAY_SEND, so a profile that grants send but denies connect lets a confined task open an outbound TCP/MPTCP connection that connect(2) would have refused, bypassing connect mediation. Mediate the implicit connect when MSG_FASTOPEN is set and a destination is supplied. Add it to apparmor_socket_sendmsg() (not the shared aa_sock_msg_perm() helper, which recvmsg also uses) and call aa_sk_perm() directly, mirroring the selinux and tomoyo fixes. sk_is_tcp() does not cover MPTCP fast open, so the SOCK_STREAM/IPPROTO_MPTCP arm is explicit. Fixes: cf60af03ca4e ("net-tcp: Fast Open client - sendmsg(MSG_FASTOPEN)") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Signed-off-by: John Johansen diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 7457067e8192..88d12e89d115 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1422,7 +1422,21 @@ static int aa_sock_msg_perm(const char *op, u32 request, struct socket *sock, static int apparmor_socket_sendmsg(struct socket *sock, struct msghdr *msg, int size) { - return aa_sock_msg_perm(OP_SENDMSG, AA_MAY_SEND, sock, msg, size); + int error = aa_sock_msg_perm(OP_SENDMSG, AA_MAY_SEND, sock, msg, size); + + if (error) + return error; + + /* TCP fast open carries connect() semantics in sendmsg(); mediate + * the implicit connect so it cannot bypass the connect permission. + */ + if ((msg->msg_flags & MSG_FASTOPEN) && msg->msg_name && + (sk_is_tcp(sock->sk) || + (sk_is_inet(sock->sk) && sock->sk->sk_type == SOCK_STREAM && + sock->sk->sk_protocol == IPPROTO_MPTCP))) + error = aa_sk_perm(OP_CONNECT, AA_MAY_CONNECT, sock->sk); + + return error; } static int apparmor_socket_recvmsg(struct socket *sock,