From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 128C4ECAAD2 for ; Sat, 27 Aug 2022 14:09:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233363AbiH0OJu (ORCPT ); Sat, 27 Aug 2022 10:09:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233346AbiH0OJs (ORCPT ); Sat, 27 Aug 2022 10:09:48 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F7764D173; Sat, 27 Aug 2022 07:09:43 -0700 (PDT) Received: from hednb3.intra.ispras.ru (unknown [109.252.119.247]) by mail.ispras.ru (Postfix) with ESMTPSA id B6E7B40737C1; Sat, 27 Aug 2022 14:09:39 +0000 (UTC) From: Alexey Khoroshilov To: Alexander Viro Cc: Rustam Subkhankulov , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexey Khoroshilov , ldv-project@linuxtesting.org Subject: [PATCH] fs/inode.c: change the order of initialization in inode_init_always() Date: Sat, 27 Aug 2022 17:09:26 +0300 Message-Id: <1661609366-26144-1-git-send-email-khoroshilov@ispras.ru> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rustam Subkhankulov If function 'security_inode_alloc()' returns a nonzero value at [fs/inode.c: 195] due to an error (e.g. fail to allocate memory), then some of the fields, including 'i_private', will not be initialized. After that, if the fs-specfic free_inode function is called in 'i_callback', the nonzero value of 'i_private' field can be interpreted as initialized. As a result, this can cause dereferencing of random value pointer (e.g. nilfs2). In earlier versions, a similar situation could occur with the 'u' union in 'inode' structure. Found by Linux Verification Center (linuxtesting.org) with syzkaller. Signed-off-by: Rustam Subkhankulov Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") --- fs/inode.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index bd4da9c5207e..08d093737e8c 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -192,8 +192,6 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_wb_frn_history = 0; #endif - if (security_inode_alloc(inode)) - goto out; spin_lock_init(&inode->i_lock); lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); @@ -230,9 +228,10 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_flctx = NULL; this_cpu_inc(nr_inodes); + if (security_inode_alloc(inode)) + return -ENOMEM; + return 0; -out: - return -ENOMEM; } EXPORT_SYMBOL(inode_init_always); -- 2.34.1