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| author | Theodore Ts'o <tytso@mit.edu> | 2018-03-26 23:54:10 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-03-26 23:54:10 -0400 |
| commit | 7dac4a1726a9c64a517d595c40e95e2d0d135f6f (patch) | |
| tree | c750d6e29407cc63499a6659abc2c45635a4bf28 /fs/ext4/ialloc.c | |
| parent | dcae058a8da9c3cfc0055c7937ccd1a3dd0382a8 (diff) | |
| download | linux-7dac4a1726a9c64a517d595c40e95e2d0d135f6f.tar.gz | |
ext4: add validity checks for bitmap block numbers
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 <wen.xu@gatech.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/ialloc.c')
| -rw-r--r-- | fs/ext4/ialloc.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 3fa93665b4a339..df92e3ec9913d8 100644 --- 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_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 - " |