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From:   Manas Ghandat <ghandatmanas@gmail.com>
To:     gregkh@linuxfoundation.org
Cc:     Manas Ghandat <ghandatmanas@gmail.com>,
        Linux-kernel-mentees@lists.linuxfoundation.org, anton@tuxera.com,
        linkinjeon@kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net,
        syzbot+4768a8f039aa677897d0@syzkaller.appspotmail.com
Subject: [PATCH v3] ntfs : fix shift-out-of-bounds in ntfs_iget
Date:   Thu, 10 Aug 2023 21:43:08 +0530
Message-Id: <20230810161308.8577-1-ghandatmanas@gmail.com>
In-Reply-To: <2023080811-populace-raven-96d2@gregkh>
References: <2023080811-populace-raven-96d2@gregkh>
MIME-Version: 1.0
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Added a check to the compression_unit so that out of bound doesn't occur.

Signed-off-by: Manas Ghandat <ghandatmanas@gmail.com>
Reported-by: syzbot+4768a8f039aa677897d0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=4768a8f039aa677897d0
---
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