From patchwork Wed Apr 10 17:10:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 13624863 X-Patchwork-Delegate: kuba@kernel.org Received: from smtp-fw-9102.amazon.com (smtp-fw-9102.amazon.com [207.171.184.29]) (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 3806017BB0F for ; Wed, 10 Apr 2024 17:11:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.171.184.29 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712769086; cv=none; b=g3Zssb2Mdz39taYG+V4M0vhrDBVD9wspKgsT6kmnxeH+eBxTLpSfBcW3BFaJKV4qWJe5V6Fc7bswrBO14QeS0NOr0UZJZyJ+mvIrz/GkdKrT+pGbZxrUcVkHb3awu+pxFgew2MCwyUW2UYIPfu9I8PiX84Y3gSAuZ5b+WefcBXM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712769086; c=relaxed/simple; bh=/mFzy0/wXcNdV8jrPyJzMG4utX210cUFx+M2IVusYww=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UNo2D9xQZqW0nG+h0010oOJsOzo4dYFcP49RROyNJ9bBz0Zhj3PDDxstWJ5VVbpL+8WzU3IZYC033Caj9BUdYQ52ofja+t1edr4Mc8qh0vWyek3vJFvnZpabBp1GtkQonAQoFW1OSiOsg4SdWODrU3rI5miYuKL7wPaZrlk3QMg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.jp; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=nu/3Vm9O; arc=none smtp.client-ip=207.171.184.29 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.jp Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="nu/3Vm9O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1712769086; x=1744305086; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=PVdZPzfe9EF/CBelLXYDz0AmXvtZb+wa+Sc+QCYcmCs=; b=nu/3Vm9OI+SBe/FR0NjdhaqJ/BiWJDE2w0WGyN/IVgCr4pNJDaanSOlj ImCE1zyPCz7W9mQUQIwwB0AAOJ0RcGqfiSPcznsbygFP77951Zsomhy99 Gn93kkBM6X0aLVZadlScZQ58fTxeL3RmZL7OOQCfwiHEolflraXsMyaFv 8=; X-IronPort-AV: E=Sophos;i="6.07,190,1708387200"; d="scan'208";a="410588411" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.214]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Apr 2024 17:11:19 +0000 Received: from EX19MTAUWB001.ant.amazon.com [10.0.7.35:50874] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.36.40:2525] with esmtp (Farcaster) id 461b574c-ef01-4988-b614-f0cfd7e36fee; Wed, 10 Apr 2024 17:11:18 +0000 (UTC) X-Farcaster-Flow-ID: 461b574c-ef01-4988-b614-f0cfd7e36fee Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWB001.ant.amazon.com (10.250.64.248) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.28; Wed, 10 Apr 2024 17:11:17 +0000 Received: from 88665a182662.ant.amazon.com (10.187.170.44) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.28; Wed, 10 Apr 2024 17:11:15 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni CC: Rao shoaib , Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v2 net 2/2] af_unix: Don't peek OOB data without MSG_OOB. Date: Wed, 10 Apr 2024 10:10:16 -0700 Message-ID: <20240410171016.7621-3-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240410171016.7621-1-kuniyu@amazon.com> References: <20240410171016.7621-1-kuniyu@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D038UWB002.ant.amazon.com (10.13.139.185) To EX19D004ANA001.ant.amazon.com (10.37.240.138) X-Patchwork-Delegate: kuba@kernel.org Currently, we can read OOB data without MSG_OOB by using MSG_PEEK when OOB data is sitting on the front row, which is apparently wrong. >>> from socket import * >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM) >>> c1.send(b'a', MSG_OOB) 1 >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT) b'a' If manage_oob() is called when no data has been copied, we only check if the socket enables SO_OOBINLINE or MSG_PEEK is not used. Otherwise, the skb is returned as is. However, here we should return NULL if MSG_PEEK is set and no data has been copied. Also, in such a case, we should not jump to the redo label because we will be caught in the loop and hog the CPU until normal data comes in. Then, we need to handle skb == NULL case with the if-clause below the manage_oob() block. With this patch: >>> from socket import * >>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM) >>> c1.send(b'a', MSG_OOB) 1 >>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT) Traceback (most recent call last): File "", line 1, in BlockingIOError: [Errno 11] Resource temporarily unavailable Fixes: 314001f0bf92 ("af_unix: Add OOB support") Signed-off-by: Kuniyuki Iwashima --- net/unix/af_unix.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index f297320438bf..9a6ad5974dff 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2663,7 +2663,9 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk, WRITE_ONCE(u->oob_skb, NULL); consume_skb(skb); } - } else if (!(flags & MSG_PEEK)) { + } else if (flags & MSG_PEEK) { + skb = NULL; + } else { skb_unlink(skb, &sk->sk_receive_queue); WRITE_ONCE(u->oob_skb, NULL); if (!WARN_ON_ONCE(skb_unref(skb))) @@ -2745,11 +2747,9 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (skb) { skb = manage_oob(skb, sk, flags, copied); - if (!skb) { + if (!skb && copied) { unix_state_unlock(sk); - if (copied) - break; - goto redo; + break; } } #endif