[PATCH ntfs3] fs/ntfs3: zero frame pages on read error

[Weiming Shi <bestswngs@gmail.com>]

ni_read_frame() marks every frame page uptodate at the 'out:' label
regardless of the return value. The pages come from ntfs_lock_new_page()
and are not zeroed, and several error paths reach 'out:' before anything
is written to them (e.g. a failed decompress_lznt()/decompress_lzx_xpress()
on a corrupted chunk, or an allocation failure).

A page marked uptodate is served directly from the page cache, so a later
read() of the file returns the uninitialized page contents to userspace.
On a crafted compressed image this leaks kernel memory, including pointers.

Zero each page on the error path before marking it uptodate. The success
path is unchanged.

Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation")
Reported-by: Xiang Mei <xmei5@asu.edu>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
---
 fs/ntfs3/frecord.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/ntfs3/frecord.c b/fs/ntfs3/frecord.c
index 2b49bc077558..ca3b46a2c9c5 100644
--- a/fs/ntfs3/frecord.c
+++ b/fs/ntfs3/frecord.c
@@ -2469,6 +2469,8 @@ int ni_read_frame(struct ntfs_inode *ni, u64 frame_vbo, struct page **pages,
 out:
 	for (i = 0; i < pages_per_frame; i++) {
 		pg = pages[i];
+		if (err)
+			clear_highpage(pg);
 		SetPageUptodate(pg);
 	}
 
-- 
2.43.0