From: Greg Kroah-Hartman Date: Sun, 29 Apr 2018 10:24:16 +0000 (+0200) Subject: 4.9-stable patches X-Git-Tag: v4.16.7~52 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bc8e57fd025e7cda7ef9966b0a56a1b9ad12d1f3;p=thirdparty%2Fkernel%2Fstable-queue.git 4.9-stable patches added patches: ext4-add-validity-checks-for-bitmap-block-numbers.patch --- diff --git a/queue-4.9/ext4-add-validity-checks-for-bitmap-block-numbers.patch b/queue-4.9/ext4-add-validity-checks-for-bitmap-block-numbers.patch new file mode 100644 index 00000000000..eea464cec02 --- /dev/null +++ b/queue-4.9/ext4-add-validity-checks-for-bitmap-block-numbers.patch @@ -0,0 +1,101 @@ +From 7dac4a1726a9c64a517d595c40e95e2d0d135f6f Mon Sep 17 00:00:00 2001 +From: Theodore Ts'o +Date: Mon, 26 Mar 2018 23:54:10 -0400 +Subject: ext4: add validity checks for bitmap block numbers + +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 +@@ -337,20 +337,25 @@ 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 + EXT4_SB(sb)->s_itb_per_group), + EXT4_B2C(sbi, offset)); +@@ -416,6 +421,7 @@ 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; +@@ -424,6 +430,12 @@ 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 +@@ -119,6 +119,7 @@ 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; +@@ -128,6 +129,12 @@ 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 - " diff --git a/queue-4.9/series b/queue-4.9/series index 20861aca094..f342b5a96c0 100644 --- a/queue-4.9/series +++ b/queue-4.9/series @@ -1,2 +1,3 @@ ext4-prevent-right-shifting-extents-beyond-ext_max_blocks.patch ext4-set-h_journal-if-there-is-a-failure-starting-a-reserved-handle.patch +ext4-add-validity-checks-for-bitmap-block-numbers.patch