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| author | Theodore Ts'o <tytso@mit.edu> | 2009-01-16 11:13:47 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2009-01-16 11:13:47 -0500 |
| commit | a21102b55c4f8dfd3adb4a15a34cd62237b46039 (patch) | |
| tree | 270f663b46460ee6055073fe862b4ec68ee47bbd /fs/ext3 | |
| parent | e6b8bc09ba2075cd91fbffefcd2778b1a00bd76f (diff) | |
| download | linux-a21102b55c4f8dfd3adb4a15a34cd62237b46039.tar.gz linux-a21102b55c4f8dfd3adb4a15a34cd62237b46039.tar.bz2 linux-a21102b55c4f8dfd3adb4a15a34cd62237b46039.zip | |
ext3: Add sanity check to make_indexed_dir
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>
Cc: stable@kernel.org
Diffstat (limited to 'fs/ext3')
| -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 69a3d19ca9fd..4db4ffa1edad 100644 --- a/fs/ext3/namei.c +++ b/fs/ext3/namei.c @@ -1358,7 +1358,7 @@ 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); @@ -1367,6 +1367,19 @@ 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); @@ -1375,11 +1388,6 @@ 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; |