[PATCH v5] ntfs : fix shift-out-of-bounds in ntfs_iget

[Manas Ghandat <ghandatmanas@gmail.com>]

Currently there is not check for ni->itype.compressed.block_size when
a->data.non_resident.compression_unit is present and NInoSparse(ni) is
true. Added the correct check to the compression unit.

Signed-off-by: Manas Ghandat <ghandatmanas@gmail.com>
Reported-by: syzbot+4768a8f039aa677897d0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=4768a8f039aa677897d0
Fix-commit-ID: upstream f40ddce88593482919761f74910f42f4b84c004b
---
V4 -> V5: Add recommended check to compression_unit
V3 -> V4: Fix description
V2 -> V3: Fix patching issue.
V1 -> V2: Cleaned up coding style.

 fs/ntfs/inode.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 6c3f38d66579..d8ac221f212b 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1076,6 +1076,16 @@ static int ntfs_read_locked_inode(struct inode *vi)
 					err = -EOPNOTSUPP;
 					goto unm_err_out;
 				}
+				if (NInoSparse(ni) && a->data.non_resident.compression_unit &&
+				a->data.non_resident.compression_unit !=
+				vol->sparse_compression_unit) {
+					ntfs_error(vi->i_sb,
+					"Found non-standard compression unit (%u instead of 0 or %d).  Cannot handle this.",
+					a->data.non_resident.compression_unit,
+					vol->sparse_compression_unit);
+					err = -EOPNOTSUPP;
+					goto unm_err_out;
+				}
 				if (a->data.non_resident.compression_unit) {
 					ni->itype.compressed.block_size = 1U <<
 							(a->data.non_resident.
-- 
2.37.2