From patchwork Tue Feb 2 18:14:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 577407 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3B9E0140C57; Wed, 3 Feb 2016 05:18:30 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aQfX0-0000bC-Br; Tue, 02 Feb 2016 18:18:26 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aQfW5-0008TJ-Kr for kernel-team@lists.ubuntu.com; Tue, 02 Feb 2016 18:17:29 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aQfW4-0000V5-QB; Tue, 02 Feb 2016 18:17:28 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1aQfW2-0005yb-1p; Tue, 02 Feb 2016 10:17:26 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.13.y-ckt 055/136] uml: fix hostfs mknod() Date: Tue, 2 Feb 2016 10:14:10 -0800 Message-Id: <1454436931-22481-56-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1454436931-22481-1-git-send-email-kamal@canonical.com> References: <1454436931-22481-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Cc: Richard Weinberger , Jeff Dike , Vegard Nossum , Kamal Mostafa , Al Viro X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.13.11-ckt34 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Vegard Nossum commit 9f2dfda2f2f1c6181c3732c16b85c59ab2d195e0 upstream. An inverted return value check in hostfs_mknod() caused the function to return success after handling it as an error (and cleaning up). It resulted in the following segfault when trying to bind() a named unix socket: Pid: 198, comm: a.out Not tainted 4.4.0-rc4 RIP: 0033:[<0000000061077df6>] RSP: 00000000daae5d60 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000006092a460 RCX: 00000000dfc54208 RDX: 0000000061073ef1 RSI: 0000000000000070 RDI: 00000000e027d600 RBP: 00000000daae5de0 R08: 00000000da980ac0 R09: 0000000000000000 R10: 0000000000000003 R11: 00007fb1ae08f72a R12: 0000000000000000 R13: 000000006092a460 R14: 00000000daaa97c0 R15: 00000000daaa9a88 Kernel panic - not syncing: Kernel mode fault at addr 0x40, ip 0x61077df6 CPU: 0 PID: 198 Comm: a.out Not tainted 4.4.0-rc4 #1 Stack: e027d620 dfc54208 0000006f da981398 61bee000 0000c1ed daae5de0 0000006e e027d620 dfcd4208 00000005 6092a460 Call Trace: [<60dedc67>] SyS_bind+0xf7/0x110 [<600587be>] handle_syscall+0x7e/0x80 [<60066ad7>] userspace+0x3e7/0x4e0 [<6006321f>] ? save_registers+0x1f/0x40 [<6006c88e>] ? arch_prctl+0x1be/0x1f0 [<60054985>] fork_handler+0x85/0x90 Let's also get rid of the "cosmic ray protection" while we're at it. Fixes: e9193059b1b3 "hostfs: fix races in dentry_name() and inode_name()" Signed-off-by: Vegard Nossum Cc: Jeff Dike Cc: Al Viro Signed-off-by: Richard Weinberger Signed-off-by: Kamal Mostafa --- fs/hostfs/hostfs_kern.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index 5d2585a..a39807c 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -717,15 +717,13 @@ static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, init_special_inode(inode, mode, dev); err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); - if (!err) + if (err) goto out_free; err = read_name(inode, name); __putname(name); if (err) goto out_put; - if (err) - goto out_put; d_instantiate(dentry, inode); return 0;