Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753515AbdHOBsk (ORCPT ); Mon, 14 Aug 2017 21:48:40 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56692 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753361AbdHOBTN (ORCPT ); Mon, 14 Aug 2017 21:19:13 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mateusz Jurczyk , Miklos Szeredi Subject: [PATCH 4.9 11/41] fuse: initialize the flock flag in fuse_file on allocation Date: Mon, 14 Aug 2017 18:18:21 -0700 Message-Id: <20170815011809.400731932@linuxfoundation.org> X-Mailer: git-send-email 2.14.0 In-Reply-To: <20170815011808.667221255@linuxfoundation.org> References: <20170815011808.667221255@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1200 Lines: 38 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mateusz Jurczyk commit 68227c03cba84a24faf8a7277d2b1a03c8959c2c upstream. Before the patch, the flock flag could remain uninitialized for the lifespan of the fuse_file allocation. Unless set to true in fuse_file_flock(), it would remain in an indeterminate state until read in an if statement in fuse_release_common(). This could consequently lead to taking an unexpected branch in the code. The bug was discovered by a runtime instrumentation designed to detect use of uninitialized memory in the kernel. Signed-off-by: Mateusz Jurczyk Fixes: 37fb3a30b462 ("fuse: fix flock") Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/fuse/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -46,7 +46,7 @@ struct fuse_file *fuse_file_alloc(struct { struct fuse_file *ff; - ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL); + ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL); if (unlikely(!ff)) return NULL;