ntfs: don't allow compression on volumes with clusters larger than 4K

On a volume made with "mkntfs -c 8192", a user can set
FILE_ATTR_COMPRESSED on an empty file through system.ntfs_attrib.
Writing to the file and reading it back after dropping the page cache
then crashes:

  BUG: KASAN: slab-out-of-bounds in ntfs_read_compressed_block+0xa2c/0x2040
  Read of size 8192 at addr ffff88804355a000 by task dd/106

The read path only handles clusters up to 4K. It copies each cluster
out of a single page, and a compression block of 16 8K clusters does
not fit in the 64K ntfs_compression_buffer. Loading an inode already
rejects compressed data on such volumes.

Reject the flag change the same way.

Fixes: fc053f05ca28 ("ntfs: add reparse and ea operations")
Cc: stable@vger.kernel.org
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Reviewed-by: Baolin Liu <liubaolin@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions