linux-kernel - [PATCH] fs/ntfs3: fix uninitialized memory in ni_create_attr

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Message-ID: <20251007134008.144590-1-swarajgaikwad1925@gmail.com>
Date: Tue,  7 Oct 2025 13:40:07 +0000
From: Swaraj Gaikwad <swarajgaikwad1925@...il.com>
To: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
	ntfs3@...ts.linux.dev (open list:NTFS3 FILESYSTEM),
	linux-kernel@...r.kernel.org (open list)
Cc: skhan@...uxfoundation.org,
	david.hunter.linux@...il.com,
	Swaraj Gaikwad <swarajgaikwad1925@...il.com>,
	syzbot+83c9dd5c0dcf6184fdbf@...kaller.appspotmail.com
Subject: [PATCH] fs/ntfs3: fix uninitialized memory in ni_create_attr_list()

KMSAN reported an "uninit-value" warning in attr_set_size(), which
occurs when the NTFS attribute list buffer contains uninitialized
trailing bytes.

In ni_create_attr_list(q), kmalloc() is used to allocate a buffer of
size al_aligned(rs). However, the amount of data actually written into
this buffer can be smaller than the allocated size, leaving the
remaining bytes uninitialized. If those bytes are later accessed,
KMSAN reports a read of uninitialized memory.

Replace kmalloc() with kzalloc() to ensure the entire buffer is
zero-initialized, preventing future uninitialized memory accesses.

This issue was reproduced and verified using the syzkaller-provided
reproducer. The patch was tested by:
  - Building the kernel to ensure the change does not affect the build
    process.
  - Running the provided repro to confirm that the
    uninit-value warning no longer appears.

Based on commit: 9b0d551bcc05
Reported-by: syzbot+83c9dd5c0dcf6184fdbf@...kaller.appspotmail.com
Tested-by: Swaraj Gaikwad <swarajgaikwad1925@...il.com>

Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@...il.com>
---
 fs/ntfs3/frecord.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ntfs3/frecord.c b/fs/ntfs3/frecord.c
index 8f9fe1d7a690..4fe8da7fc034 100644
--- a/fs/ntfs3/frecord.c
+++ b/fs/ntfs3/frecord.c
@@ -767,7 +767,7 @@ int ni_create_attr_list(struct ntfs_inode *ni)
 	 * Skip estimating exact memory requirement.
 	 * Looks like one record_size is always enough.
 	 */
-	le = kmalloc(al_aligned(rs), GFP_NOFS);
+	le = kzalloc(al_aligned(rs), GFP_NOFS);
 	if (!le)
 		return -ENOMEM;
 
-- 
2.51.0