From nobody Fri Apr 26 03:18:21 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 1507D1FAF for ; Tue, 17 Jan 2023 07:37:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673941035; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XcPA4sXVHI6jTcEXVxRdebV8orFAjwvdL7prR34Xm/0=; b=iR9wFx/4zOsKI9bDbvgQZWaUm4UkiJFFeKUfoEy2DOOEq4R/THuiaoaSd35AKAfJIuDu9e VFRNcvTKSdZxX3fW7UcZ3fBs21KJlJC7eh1Qy2bytSQNSZ+h9cxTMkhVSJEJAM5b5+3QtV Mqfhcnicg+78FRid8K4RBcXT6QlFJNg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-6-sR345FC0Mf-QlRfH1CE85g-1; Tue, 17 Jan 2023 02:37:13 -0500 X-MC-Unique: sR345FC0Mf-QlRfH1CE85g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4067D85C6E0 for ; Tue, 17 Jan 2023 07:37:13 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.192.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id C35E040C2064 for ; Tue, 17 Jan 2023 07:37:12 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH mptcp-next v2 01/13] mptcp: fix locking for setsockopt corner-case Date: Tue, 17 Jan 2023 08:36:21 +0100 Message-Id: In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" We need to call the __mptcp_nmpc_socket(), and later subflow socket access under the msk socket lock, or e.g. a racing connect() could change the socket status under the wood, with unexpected results. Fixes: 54635bd04701 ("mptcp: add TCP_FASTOPEN_CONNECT socket option") Signed-off-by: Paolo Abeni --- this and the next patch are new v2. In both case the addressed issue is almost irrelevant until patch 8/12, but will cause lockdep splat after such change --- net/mptcp/sockopt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 9986681aaf40..8a9656248b0f 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -760,14 +760,21 @@ static int mptcp_setsockopt_v4(struct mptcp_sock *msk= , int optname, static int mptcp_setsockopt_first_sf_only(struct mptcp_sock *msk, int leve= l, int optname, sockptr_t optval, unsigned int optlen) { + struct sock *sk =3D (struct sock *)msk; struct socket *sock; + int ret =3D -EINVAL; =20 /* Limit to first subflow, before the connection establishment */ + lock_sock(sk); sock =3D __mptcp_nmpc_socket(msk); if (!sock) - return -EINVAL; + goto unlock; =20 - return tcp_setsockopt(sock->sk, level, optname, optval, optlen); + ret =3D tcp_setsockopt(sock->sk, level, optname, optval, optlen); + +unlock: + release_sock(sk); + return ret; } =20 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname, --=20 2.39.0