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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C4A4C33C99 for ; Mon, 2 Dec 2019 17:02:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BDF920881 for ; Mon, 2 Dec 2019 17:02:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727706AbfLBRCR (ORCPT ); Mon, 2 Dec 2019 12:02:17 -0500 Received: from mx2.suse.de ([195.135.220.15]:53814 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727460AbfLBRCR (ORCPT ); Mon, 2 Dec 2019 12:02:17 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7F94FBD29; Mon, 2 Dec 2019 17:02:15 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 498241E0B7E; Mon, 2 Dec 2019 18:02:15 +0100 (CET) From: Jan Kara To: Ted Tso Cc: , Jan Kara , stable@vger.kernel.org Subject: [PATCH 2/2] ext4: Check for directory entries too close to block end Date: Mon, 2 Dec 2019 18:02:13 +0100 Message-Id: <20191202170213.4761-3-jack@suse.cz> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20191202170213.4761-1-jack@suse.cz> References: <20191202170213.4761-1-jack@suse.cz> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org ext4_check_dir_entry() currently does not catch a case when a directory entry ends so close to the block end that the header of the next directory entry would not fit in the remaining space. This can lead to directory iteration code trying to access address beyond end of current buffer head leading to oops. CC: stable@vger.kernel.org Signed-off-by: Jan Kara --- fs/ext4/dir.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index 9fdd2b269d61..6305d5ec25af 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -81,6 +81,11 @@ int __ext4_check_dir_entry(const char *function, unsigned int line, error_msg = "rec_len is too small for name_len"; else if (unlikely(((char *) de - buf) + rlen > size)) error_msg = "directory entry overrun"; + else if (unlikely(((char *) de - buf) + rlen > + size - EXT4_DIR_REC_LEN(1) && + ((char *) de - buf) + rlen != size)) { + error_msg = "directory entry too close to block end"; + } else if (unlikely(le32_to_cpu(de->inode) > le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))) error_msg = "inode out of bounds"; -- 2.16.4