diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2009-01-16 11:13:47 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-02-02 08:28:13 -0800 |
| commit | 6d3910dec56c78543e35550fad433366047e6878 (patch) | |
| tree | 9078546be66f3fc3433aa739895c39457003602c | |
| parent | a0aec447b8076f10f0f46433f20ad3fa32e2c500 (diff) | |
| download | lwn-6d3910dec56c78543e35550fad433366047e6878.tar.gz lwn-6d3910dec56c78543e35550fad433366047e6878.zip | |
ext3: Add sanity check to make_indexed_dir
commit a21102b55c4f8dfd3adb4a15a34cd62237b46039 upstream.
Make sure the rec_len field in the '..' entry is sane, lest we overrun
the directory block and cause a kernel oops on a purposefully
corrupted filesystem.
This fixes a bug related to a bug originally reported by Sami Liedes
for ext4 at:
http://bugzilla.kernel.org/show_bug.cgi?id=12430
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/ext3/namei.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c index 1f5538263b62..89b1c93c56b9 100644 --- a/fs/ext3/namei.c +++ b/fs/ext3/namei.c @@ -1374,7 +1374,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, struct fake_dirent *fde; blocksize = dir->i_sb->s_blocksize; - dxtrace(printk("Creating index\n")); + dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino)); retval = ext3_journal_get_write_access(handle, bh); if (retval) { ext3_std_error(dir->i_sb, retval); @@ -1383,6 +1383,19 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, } root = (struct dx_root *) bh->b_data; + /* The 0th block becomes the root, move the dirents out */ + fde = &root->dotdot; + de = (struct ext3_dir_entry_2 *)((char *)fde + + ext3_rec_len_from_disk(fde->rec_len)); + if ((char *) de >= (((char *) root) + blocksize)) { + ext3_error(dir->i_sb, __func__, + "invalid rec_len for '..' in inode %lu", + dir->i_ino); + brelse(bh); + return -EIO; + } + len = ((char *) root) + blocksize - (char *) de; + bh2 = ext3_append (handle, dir, &block, &retval); if (!(bh2)) { brelse(bh); @@ -1391,11 +1404,6 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, EXT3_I(dir)->i_flags |= EXT3_INDEX_FL; data1 = bh2->b_data; - /* The 0th block becomes the root, move the dirents out */ - fde = &root->dotdot; - de = (struct ext3_dir_entry_2 *)((char *)fde + - ext3_rec_len_from_disk(fde->rec_len)); - len = ((char *) root) + blocksize - (char *) de; memcpy (data1, de, len); de = (struct ext3_dir_entry_2 *) data1; top = data1 + len; |