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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT autolearn=unavailable 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 91986C28EBD for ; Sun, 9 Jun 2019 16:56:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C485206BB for ; Sun, 9 Jun 2019 16:56:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099411; bh=ISzGiHCBv8wniRLyahJSfJFScHVAsSJgClPxPxkgjSg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z4q3L1pk8jXxfVQy5tSZ+jL/bYrTeL/bPwgz2USu7SWyJvzg3DWeEpc21Bn56KibF ObYqqaOUyEkyUiOs7WqOk7YKxfUW/xLvVoMUfOlqWUopC3Gp81ciq16hF7FnEsQXQY HGpj1CIF+2HPtZPDklUQsCvE4Vk2JU9U+Vryu8JQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733038AbfFIQ4p (ORCPT ); Sun, 9 Jun 2019 12:56:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:59376 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732675AbfFIQ4n (ORCPT ); Sun, 9 Jun 2019 12:56:43 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1FFC1204EC; Sun, 9 Jun 2019 16:56:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099402; bh=ISzGiHCBv8wniRLyahJSfJFScHVAsSJgClPxPxkgjSg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M6AwRXqVpyDAzu9SvnYWqfe3MfnPTI05du+j8eKO4Z80qmDmJfW1FMQvn2VqTzSFc mt8DYcjKAIlOWtCmrNJWy2lOIW/AYHS/G1yJhVFgmKNPjYnIV5bd3Wu7Ap0QAgv4HU qJ12ox04WpQaT5OotZvEjHwu1KWM9bhk0SLXrSRs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sriram Rajagopalan , Theodore Tso , stable@kernel.org Subject: [PATCH 4.4 029/241] ext4: zero out the unused memory region in the extent tree block Date: Sun, 9 Jun 2019 18:39:31 +0200 Message-Id: <20190609164148.621401348@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190609164147.729157653@linuxfoundation.org> References: <20190609164147.729157653@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sriram Rajagopalan commit 592acbf16821288ecdc4192c47e3774a4c48bb64 upstream. This commit zeroes out the unused memory region in the buffer_head corresponding to the extent metablock after writing the extent header and the corresponding extent node entries. This is done to prevent random uninitialized data from getting into the filesystem when the extent block is synced. This fixes CVE-2019-11833. Signed-off-by: Sriram Rajagopalan Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/extents.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1049,6 +1049,7 @@ static int ext4_ext_split(handle_t *hand __le32 border; ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ int err = 0; + size_t ext_size = 0; /* make decision: where to split? */ /* FIXME: now decision is simplest: at current extent */ @@ -1140,6 +1141,10 @@ static int ext4_ext_split(handle_t *hand le16_add_cpu(&neh->eh_entries, m); } + /* zero out unused area in the extent block */ + ext_size = sizeof(struct ext4_extent_header) + + sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries); + memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size); ext4_extent_block_csum_set(inode, neh); set_buffer_uptodate(bh); unlock_buffer(bh); @@ -1219,6 +1224,11 @@ static int ext4_ext_split(handle_t *hand sizeof(struct ext4_extent_idx) * m); le16_add_cpu(&neh->eh_entries, m); } + /* zero out unused area in the extent block */ + ext_size = sizeof(struct ext4_extent_header) + + (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries)); + memset(bh->b_data + ext_size, 0, + inode->i_sb->s_blocksize - ext_size); ext4_extent_block_csum_set(inode, neh); set_buffer_uptodate(bh); unlock_buffer(bh); @@ -1284,6 +1294,7 @@ static int ext4_ext_grow_indepth(handle_ ext4_fsblk_t newblock, goal = 0; struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es; int err = 0; + size_t ext_size = 0; /* Try to prepend new index to old one */ if (ext_depth(inode)) @@ -1309,9 +1320,11 @@ static int ext4_ext_grow_indepth(handle_ goto out; } + ext_size = sizeof(EXT4_I(inode)->i_data); /* move top-level index/leaf into new block */ - memmove(bh->b_data, EXT4_I(inode)->i_data, - sizeof(EXT4_I(inode)->i_data)); + memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size); + /* zero out unused area in the extent block */ + memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size); /* set size of new block */ neh = ext_block_hdr(bh);