ext4: add validity checks for bitmap block numbers

[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / ialloc.c

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 6e0804d7863394df4447df46b2d3e5a214678b74..b5e2cc28af4707eb884a93b76fb92b0377868143 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -125,6 +125,7 @@ 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;
@@ -134,6 +135,12 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
                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 - "