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| author | Lukas Czerner <lczerner@redhat.com> | 2022-07-04 16:27:20 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2022-08-02 23:56:17 -0400 |
| commit | 65f8ea4cd57dbd46ea13b41dc8bac03176b04233 (patch) | |
| tree | aead1ed770aa09c0145987b78e0845a1418c270d | |
| parent | 3fa5d23e68a34dae9df2be168750dc5e03e0e40d (diff) | |
| download | linux-65f8ea4cd57dbd46ea13b41dc8bac03176b04233.tar.gz linux-65f8ea4cd57dbd46ea13b41dc8bac03176b04233.tar.bz2 linux-65f8ea4cd57dbd46ea13b41dc8bac03176b04233.zip | |
ext4: check if directory block is within i_size
Currently ext4 directory handling code implicitly assumes that the
directory blocks are always within the i_size. In fact ext4_append()
will attempt to allocate next directory block based solely on i_size and
the i_size is then appropriately increased after a successful
allocation.
However, for this to work it requires i_size to be correct. If, for any
reason, the directory inode i_size is corrupted in a way that the
directory tree refers to a valid directory block past i_size, we could
end up corrupting parts of the directory tree structure by overwriting
already used directory blocks when modifying the directory.
Fix it by catching the corruption early in __ext4_read_dirblock().
Addresses Red-Hat-Bugzilla: #2070205
CVE: CVE-2022-1184
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20220704142721.157985-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/namei.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 1c6725ecca1a..7fced54e2891 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -110,6 +110,13 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode, struct ext4_dir_entry *dirent; int is_dx_block = 0; + if (block >= inode->i_size) { + ext4_error_inode(inode, func, line, block, + "Attempting to read directory block (%u) that is past i_size (%llu)", + block, inode->i_size); + return ERR_PTR(-EFSCORRUPTED); + } + if (ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_EIO)) bh = ERR_PTR(-EIO); else |