Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932612AbdDPK4n (ORCPT ); Sun, 16 Apr 2017 06:56:43 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59880 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932474AbdDPK4k (ORCPT ); Sun, 16 Apr 2017 06:56:40 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, OGAWA Hirofumi , Moreno Bartalucci , Andrew Morton , Linus Torvalds Subject: [PATCH 3.18 079/145] fat: fix using uninitialized fields of fat_inode/fsinfo_inode Date: Sun, 16 Apr 2017 12:49:32 +0200 Message-Id: <20170416080204.786255981@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170416080200.205458595@linuxfoundation.org> References: <20170416080200.205458595@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: 1929 Lines: 63 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: OGAWA Hirofumi commit c0d0e351285161a515396b7b1ee53ec9ffd97e3c upstream. Recently fallocate patch was merged and it uses MSDOS_I(inode)->mmu_private at fat_evict_inode(). However, fat_inode/fsinfo_inode that was introduced in past didn't initialize MSDOS_I(inode) properly. With those combinations, it became the cause of accessing random entry in FAT area. Link: http://lkml.kernel.org/r/87pohrj4i8.fsf@mail.parknet.co.jp Signed-off-by: OGAWA Hirofumi Reported-by: Moreno Bartalucci Tested-by: Moreno Bartalucci Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/fat/inode.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -1266,6 +1266,16 @@ out: return 0; } +static void fat_dummy_inode_init(struct inode *inode) +{ + /* Initialize this dummy inode to work as no-op. */ + MSDOS_I(inode)->mmu_private = 0; + MSDOS_I(inode)->i_start = 0; + MSDOS_I(inode)->i_logstart = 0; + MSDOS_I(inode)->i_attrs = 0; + MSDOS_I(inode)->i_pos = 0; +} + static int fat_read_root(struct inode *inode) { struct super_block *sb = inode->i_sb; @@ -1711,12 +1721,13 @@ int fat_fill_super(struct super_block *s fat_inode = new_inode(sb); if (!fat_inode) goto out_fail; - MSDOS_I(fat_inode)->i_pos = 0; + fat_dummy_inode_init(fat_inode); sbi->fat_inode = fat_inode; fsinfo_inode = new_inode(sb); if (!fsinfo_inode) goto out_fail; + fat_dummy_inode_init(fsinfo_inode); fsinfo_inode->i_ino = MSDOS_FSINFO_INO; sbi->fsinfo_inode = fsinfo_inode; insert_inode_hash(fsinfo_inode);