diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2018-06-14 12:55:10 -0400 |
|---|---|---|
| committer | Todd Kjos <tkjos@google.com> | 2019-01-04 09:56:03 -0800 |
| commit | 4edc2edea575902da97e2171842be6a9e07411cf (patch) | |
| tree | ee0e8f5d8f37c074173f36926d26a3bd4a1bec3e | |
| parent | c8853895280faa3907c91c65af6d1e9a547f56a4 (diff) | |
ext4: verify the depth of extent tree in ext4_find_extent()ASB-2019-01-05_4.4-o-mr1
commit bc890a60247171294acc0bd67d211fa4b88d40ba upstream.
If there is a corupted file system where the claimed depth of the
extent tree is -1, this can cause a massive buffer overrun leading to
sadness.
This addresses CVE-2018-10877.
https://bugzilla.kernel.org/show_bug.cgi?id=199417
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/ext4/ext4_extents.h | 1 | ||||
| -rw-r--r-- | fs/ext4/extents.c | 6 |
2 files changed, 7 insertions, 0 deletions
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h index 3c9381547094..2d8e73793512 100644 --- a/fs/ext4/ext4_extents.h +++ b/fs/ext4/ext4_extents.h @@ -103,6 +103,7 @@ struct ext4_extent_header { }; #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) +#define EXT4_MAX_EXTENT_DEPTH 5 #define EXT4_EXTENT_TAIL_OFFSET(hdr) \ (sizeof(struct ext4_extent_header) + \ diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 61d5bfc7318c..53be2f4910b5 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -876,6 +876,12 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, eh = ext_inode_hdr(inode); depth = ext_depth(inode); + if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) { + EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d", + depth); + ret = -EFSCORRUPTED; + goto err; + } if (path) { ext4_ext_drop_refs(path); |