[PATCH v4] 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 required check to calculation of block size.

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
---
V3 -> V4: Fix description
V2 -> V3: Fix patching issue.
V1 -> V2: Cleaned up coding style.

 fs/ntfs/inode.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 6c3f38d66579..a657322874ed 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1077,6 +1077,15 @@ static int ntfs_read_locked_inode(struct inode *vi)
 					goto unm_err_out;
 				}
 				if (a->data.non_resident.compression_unit) {
+					if (a->data.non_resident.compression_unit +
+					vol->cluster_size_bits > 32) {
+						ntfs_error(vi->i_sb,
+						"Found non-standard compression unit (%u).   Cannot handle this.",
+						a->data.non_resident.compression_unit
+						);
+						err = -EOPNOTSUPP;
+						goto unm_err_out;
+					}
 					ni->itype.compressed.block_size = 1U <<
 							(a->data.non_resident.
 							compression_unit +
-- 
2.37.2