5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara <jack@xxxxxxx> commit 322a6aff03937aa1ece33b4e46c298eafaf9ac41 upstream. Verify bitmap block numbers and inode table blocks are sane before using them for checking bits in the block bitmap. CC: stable@xxxxxxxxxxxxxxx Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext2/balloc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/ext2/balloc.c +++ b/fs/ext2/balloc.c @@ -79,26 +79,33 @@ static int ext2_valid_block_bitmap(struc ext2_grpblk_t next_zero_bit; ext2_fsblk_t bitmap_blk; ext2_fsblk_t group_first_block; + ext2_grpblk_t max_bit; group_first_block = ext2_group_first_block_no(sb, block_group); + max_bit = ext2_group_last_block_no(sb, block_group) - group_first_block; /* check whether block bitmap block number is set */ bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); offset = bitmap_blk - group_first_block; - if (!ext2_test_bit(offset, bh->b_data)) + if (offset < 0 || offset > max_bit || + !ext2_test_bit(offset, bh->b_data)) /* bad block bitmap */ goto err_out; /* check whether the inode bitmap block number is set */ bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap); offset = bitmap_blk - group_first_block; - if (!ext2_test_bit(offset, bh->b_data)) + if (offset < 0 || offset > max_bit || + !ext2_test_bit(offset, bh->b_data)) /* bad block bitmap */ goto err_out; /* check whether the inode table block number is set */ bitmap_blk = le32_to_cpu(desc->bg_inode_table); offset = bitmap_blk - group_first_block; + if (offset < 0 || offset > max_bit || + offset + EXT2_SB(sb)->s_itb_per_group - 1 > max_bit) + goto err_out; next_zero_bit = ext2_find_next_zero_bit(bh->b_data, offset + EXT2_SB(sb)->s_itb_per_group, offset);
