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 A3836C43217 for ; Tue, 8 Nov 2022 13:50:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234656AbiKHNuq (ORCPT ); Tue, 8 Nov 2022 08:50:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234661AbiKHNup (ORCPT ); Tue, 8 Nov 2022 08:50:45 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5910C1BEA4 for ; Tue, 8 Nov 2022 05:50:44 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 18B3EB81AF7 for ; Tue, 8 Nov 2022 13:50:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 231F4C433D6; Tue, 8 Nov 2022 13:50:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667915441; bh=PDreTqukr3x3dAhFef1QS0svsQxz1l5sFVYNKoVT3sM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tpjbo3mnFqOgVVrHwJuYv7iMaWImvnZy0KEF1PkZSV6JOAS82zHoYXg/QzWYzI627 Bujyva4yhq8MfLebJTK5V5HhPHLoX7sKQiqX9LesHC0qyFJL8p5ine9yGbIbVHu+Zc Xu/31xz1jNy61MxHLF0/Nv+GmhLHu4FmoIVKNRJo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, =?UTF-8?q?Lu=C3=ADs=20Henriques?= , Theodore Tso Subject: [PATCH 5.4 63/74] ext4: fix BUG_ON() when directory entry has invalid rec_len Date: Tue, 8 Nov 2022 14:39:31 +0100 Message-Id: <20221108133336.344562559@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221108133333.659601604@linuxfoundation.org> References: <20221108133333.659601604@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Luís Henriques commit 17a0bc9bd697f75cfdf9b378d5eb2d7409c91340 upstream. The rec_len field in the directory entry has to be a multiple of 4. A corrupted filesystem image can be used to hit a BUG() in ext4_rec_len_to_disk(), called from make_indexed_dir(). ------------[ cut here ]------------ kernel BUG at fs/ext4/ext4.h:2413! ... RIP: 0010:make_indexed_dir+0x53f/0x5f0 ... Call Trace: ? add_dirent_to_buf+0x1b2/0x200 ext4_add_entry+0x36e/0x480 ext4_add_nondir+0x2b/0xc0 ext4_create+0x163/0x200 path_openat+0x635/0xe90 do_filp_open+0xb4/0x160 ? __create_object.isra.0+0x1de/0x3b0 ? _raw_spin_unlock+0x12/0x30 do_sys_openat2+0x91/0x150 __x64_sys_open+0x6c/0xa0 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 The fix simply adds a call to ext4_check_dir_entry() to validate the directory entry, returning -EFSCORRUPTED if the entry is invalid. CC: stable@kernel.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=216540 Signed-off-by: Luís Henriques Link: https://lore.kernel.org/r/20221012131330.32456-1-lhenriques@suse.de Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/namei.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2141,8 +2141,16 @@ static int make_indexed_dir(handle_t *ha memcpy(data2, de, len); de = (struct ext4_dir_entry_2 *) data2; top = data2 + len; - while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) + while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) { + if (ext4_check_dir_entry(dir, NULL, de, bh2, data2, len, + (data2 + (blocksize - csum_size) - + (char *) de))) { + brelse(bh2); + brelse(bh); + return -EFSCORRUPTED; + } de = de2; + } de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) - (char *) de, blocksize);