forked from luck/tmp_suning_uos_patched
ext4: 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. Thanks to Sami Liedes for reporting this bug. http://bugzilla.kernel.org/show_bug.cgi?id=12430 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@kernel.org
This commit is contained in:
parent
06a279d636
commit
e6b8bc09ba
|
@ -1368,7 +1368,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
|
|||
struct fake_dirent *fde;
|
||||
|
||||
blocksize = dir->i_sb->s_blocksize;
|
||||
dxtrace(printk(KERN_DEBUG "Creating index\n"));
|
||||
dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
|
||||
retval = ext4_journal_get_write_access(handle, bh);
|
||||
if (retval) {
|
||||
ext4_std_error(dir->i_sb, retval);
|
||||
|
@ -1377,6 +1377,20 @@ 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 ext4_dir_entry_2 *)((char *)fde +
|
||||
ext4_rec_len_from_disk(fde->rec_len));
|
||||
if ((char *) de >= (((char *) root) + blocksize)) {
|
||||
ext4_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;
|
||||
|
||||
/* Allocate new block for the 0th block's dirents */
|
||||
bh2 = ext4_append(handle, dir, &block, &retval);
|
||||
if (!(bh2)) {
|
||||
brelse(bh);
|
||||
|
@ -1385,11 +1399,6 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
|
|||
EXT4_I(dir)->i_flags |= EXT4_INDEX_FL;
|
||||
data1 = bh2->b_data;
|
||||
|
||||
/* The 0th block becomes the root, move the dirents out */
|
||||
fde = &root->dotdot;
|
||||
de = (struct ext4_dir_entry_2 *)((char *)fde +
|
||||
ext4_rec_len_from_disk(fde->rec_len));
|
||||
len = ((char *) root) + blocksize - (char *) de;
|
||||
memcpy (data1, de, len);
|
||||
de = (struct ext4_dir_entry_2 *) data1;
|
||||
top = data1 + len;
|
||||
|
|
Loading…
Reference in New Issue
Block a user