From mboxrd@z Thu Jan 1 00:00:00 1970 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 55E47172BCD; Wed, 3 Jul 2024 10:42:50 +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=1720003370; cv=none; b=W2i1KBY8AXOWNnT5+eDkT+VMej6KI90NVBUVwoIZ3hhXQSTSw4/lfKV/GKdmZyjLIffDfXg+NVzExweoW4+NiUt8ClxVV2v3dQ4/nwL2mQgdwBiY+NRDtkJejskKEKEz/jW8LEKvd+83oLcpwWueF9vfIzssqCbO7mPmuTMLTfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720003370; c=relaxed/simple; bh=7NL08pdKXtxhYmrrOqodX67E2h2Y2OSPmafi9mdLpQ4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hE3MB3mVXd48s5RxDcIXcig+jfApQNna1PcKktImy4uoqNLaRkbUHL3fMjdyYA4CVa7FM53EwZ4ep9I0EK2C2EWHvM3+K8Jk38/vhBkm4cgDTDiZiRoVyA5E37yLPlat9qhUqgVrG/lHOAQMawlDthzUOv1PBpRGMr7gIQRxcVE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CYqSCLQv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CYqSCLQv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D17D5C2BD10; Wed, 3 Jul 2024 10:42:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720003370; bh=7NL08pdKXtxhYmrrOqodX67E2h2Y2OSPmafi9mdLpQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CYqSCLQvNw10JBpaRzzsbi164/I2EiJdgGvDT1DPO95qLDofPm84VtUVyMDCVirKf QahXFcnEWz93vn75p3PHctU6SjZ4TtQ2ddoqNngokLxkysFIVDya8v7NL0QUFOSGEe AvE9sqzkibf1g1t/iIUXT3dZ3GozS9rZXi8lhY4g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Paolo Abeni , Sasha Levin Subject: [PATCH 4.19 009/139] af_unix: Annotate data-race of sk->sk_state in unix_inq_len(). Date: Wed, 3 Jul 2024 12:38:26 +0200 Message-ID: <20240703102830.788948230@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240703102830.432293640@linuxfoundation.org> References: <20240703102830.432293640@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuniyuki Iwashima [ Upstream commit 3a0f38eb285c8c2eead4b3230c7ac2983707599d ] ioctl(SIOCINQ) calls unix_inq_len() that checks sk->sk_state first and returns -EINVAL if it's TCP_LISTEN. Then, for SOCK_STREAM sockets, unix_inq_len() returns the number of bytes in recvq. However, unix_inq_len() does not hold unix_state_lock(), and the concurrent listen() might change the state after checking sk->sk_state. If the race occurs, 0 is returned for the listener, instead of -EINVAL, because the length of skb with embryo is 0. We could hold unix_state_lock() in unix_inq_len(), but it's overkill given the result is true for pre-listen() TCP_CLOSE state. So, let's use READ_ONCE() for sk->sk_state in unix_inq_len(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/unix/af_unix.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 02100e62bf608..d363a268f272e 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2584,7 +2584,7 @@ long unix_inq_len(struct sock *sk) struct sk_buff *skb; long amount = 0; - if (sk->sk_state == TCP_LISTEN) + if (READ_ONCE(sk->sk_state) == TCP_LISTEN) return -EINVAL; spin_lock(&sk->sk_receive_queue.lock); -- 2.43.0