From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx492BMGrEK4YangJCU82XbfF7SRB6ekyF237k2/q52AhCNguvO4O0mmMYifb9+tLs63LeNlO ARC-Seal: i=1; a=rsa-sha256; t=1524405502; cv=none; d=google.com; s=arc-20160816; b=K7mJPxQNLcmS6cB5BNVRlLDgBrEMoMF21THcemUaY84IUT3ub/o+8plpTzuAe7AUND wwuxTgdYc3rmMvxl6h5cJVa+e7Hjq+3JvkSvjDYW4t8D0mck1LNxPBty67qV3mIMKMP2 Kxpxyw/mmHpufTI5sKz4jnM6VfmJanEQJHp25VJt4B5QZ2SLnb/2P/PsoDvaf1XvLhGr E/27gf2k+ltoK4ucy/QTZVtbk8GprJ/lpY96SLxlyRKNEKy4L4LpaWi9uNYIbmNdO28/ 3S2vNvRephLLvFAG0RyMkb64eZjZp60rqe21zgbaYkm2w60tQd8NchJE3Ab3tgiPHqtE mRmQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=V2l2lUj1r96wwcj12PPFGyALQZDFuAu4a+R+EwjNiTs=; b=scP7D4IIgR5lTjBrJRH+JRMoLS6bw8wcIxPBalNdcXWZe5HLRgWU8AM8UCw2mtyfi7 GjaN9Pry4yYj/oIwiZFDB99XoOtI04gIGkPyBye+z+gEQZ8IthE0IR/KQnGYv554ojur HI7p6wfV1fg9cfbsh/X4869Ukov6b6ywcV8wQbCX7eTa1wIga/8PBx5rIeM++0I5Y9Yh Ay26uqift53nP4tUvcF6qoy4CrP4vQHmwOApejyWG700m4R7gqp7+Fh9sPUvKiMxZCOn tfCt8wxXhL8tUbpKknmQ7dvMoF5wfNnnsblGMIG1cQJFOWXZVNoCYXqD8AzlK2wcI0mX vNTg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wen Xu , Theodore Tso Subject: [PATCH 4.16 091/196] ext4: add validity checks for bitmap block numbers Date: Sun, 22 Apr 2018 15:51:51 +0200 Message-Id: <20180422135109.001540448@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135104.278511750@linuxfoundation.org> References: <20180422135104.278511750@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598455024318699724?= X-GMAIL-MSGID: =?utf-8?q?1598455024318699724?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 7dac4a1726a9c64a517d595c40e95e2d0d135f6f upstream. An privileged attacker can cause a crash by mounting a crafted ext4 image which triggers a out-of-bounds read in the function ext4_valid_block_bitmap() in fs/ext4/balloc.c. This issue has been assigned CVE-2018-1093. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199181 BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1560782 Reported-by: Wen Xu Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/balloc.c | 16 ++++++++++++++-- fs/ext4/ialloc.c | 7 +++++++ 2 files changed, 21 insertions(+), 2 deletions(-) --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -338,20 +338,25 @@ static ext4_fsblk_t ext4_valid_block_bit /* check whether block bitmap block number is set */ blk = ext4_block_bitmap(sb, desc); offset = blk - group_first_block; - if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) + if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || + !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) /* bad block bitmap */ return blk; /* check whether the inode bitmap block number is set */ blk = ext4_inode_bitmap(sb, desc); offset = blk - group_first_block; - if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) + if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || + !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) /* bad block bitmap */ return blk; /* check whether the inode table block number is set */ blk = ext4_inode_table(sb, desc); offset = blk - group_first_block; + if (offset < 0 || EXT4_B2C(sbi, offset) >= sb->s_blocksize || + EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= sb->s_blocksize) + return blk; next_zero_bit = ext4_find_next_zero_bit(bh->b_data, EXT4_B2C(sbi, offset + sbi->s_itb_per_group), EXT4_B2C(sbi, offset)); @@ -417,6 +422,7 @@ struct buffer_head * ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) { struct ext4_group_desc *desc; + struct ext4_sb_info *sbi = EXT4_SB(sb); struct buffer_head *bh; ext4_fsblk_t bitmap_blk; int err; @@ -425,6 +431,12 @@ ext4_read_block_bitmap_nowait(struct sup if (!desc) return ERR_PTR(-EFSCORRUPTED); bitmap_blk = ext4_block_bitmap(sb, desc); + if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || + (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { + ext4_error(sb, "Invalid block bitmap block %llu in " + "block_group %u", bitmap_blk, block_group); + return ERR_PTR(-EFSCORRUPTED); + } bh = sb_getblk(sb, bitmap_blk); if (unlikely(!bh)) { ext4_error(sb, "Cannot get buffer for block bitmap - " --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -122,6 +122,7 @@ static struct buffer_head * ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) { struct ext4_group_desc *desc; + struct ext4_sb_info *sbi = EXT4_SB(sb); struct buffer_head *bh = NULL; ext4_fsblk_t bitmap_blk; int err; @@ -131,6 +132,12 @@ ext4_read_inode_bitmap(struct super_bloc return ERR_PTR(-EFSCORRUPTED); bitmap_blk = ext4_inode_bitmap(sb, desc); + if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || + (bitmap_blk >= ext4_blocks_count(sbi->s_es))) { + ext4_error(sb, "Invalid inode bitmap blk %llu in " + "block_group %u", bitmap_blk, block_group); + return ERR_PTR(-EFSCORRUPTED); + } bh = sb_getblk(sb, bitmap_blk); if (unlikely(!bh)) { ext4_error(sb, "Cannot read inode bitmap - "