From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	syzbot+23aee7afc440fe803545@syzkaller.appspotmail.com,
	Baokun Li <libaokun1@huawei.com>,
	Konstantin Komarov <almaz.alexandrovich@paragon-software.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.19 616/781] fs/ntfs3: fix ntfs_mount_options leak in ntfs_fill_super()
Date: Tue, 24 Feb 2026 17:22:05 -0800
Message-ID: <20260225012414.910464549@linuxfoundation.org>
In-Reply-To: <20260225012359.695468795@linuxfoundation.org>
References: <20260225012359.695468795@linuxfoundation.org>
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6.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Baokun Li <libaokun1@huawei.com>

[ Upstream commit f7edab0cee03a1cbe0e55a7bcab8d2d8b6b74278 ]

In ntfs_fill_super(), the fc->fs_private pointer is set to NULL without
first freeing the memory it points to. This causes the subsequent call to
ntfs_fs_free() to skip freeing the ntfs_mount_options structure.

This results in a kmemleak report:

  unreferenced object 0xff1100015378b800 (size 32):
    comm "mount", pid 582, jiffies 4294890685
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 ed ff ed ff 00 04 00 00  ................
    backtrace (crc ed541d8c):
      __kmalloc_cache_noprof+0x424/0x5a0
      __ntfs_init_fs_context+0x47/0x590
      alloc_fs_context+0x5d8/0x960
      __x64_sys_fsopen+0xb1/0x190
      do_syscall_64+0x50/0x1f0
      entry_SYSCALL_64_after_hwframe+0x76/0x7e

This issue can be reproduced using the following commands:
        fallocate -l 100M test.file
        mount test.file /tmp/test

Since sbi->options is duplicated from fc->fs_private and does not
directly use the memory allocated for fs_private, it is unnecessary to
set fc->fs_private to NULL.

Additionally, this patch simplifies the code by utilizing the helper
function put_mount_options() instead of open-coding the cleanup logic.

Reported-by: syzbot+23aee7afc440fe803545@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=23aee7afc440fe803545
Fixes: aee4d5a521e9 ("ntfs3: fix double free of sbi->options->nls and clarify ownership of fc->fs_private")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ntfs3/super.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 8b0cf0ed4f72c..0567a3b224ed3 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -705,9 +705,7 @@ static void ntfs_put_super(struct super_block *sb)
 	ntfs_set_state(sbi, NTFS_DIRTY_CLEAR);
 
 	if (sbi->options) {
-		unload_nls(sbi->options->nls);
-		kfree(sbi->options->nls_name);
-		kfree(sbi->options);
+		put_mount_options(sbi->options);
 		sbi->options = NULL;
 	}
 
@@ -1253,7 +1251,6 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 		}
 	}
 	sbi->options = options;
-	fc->fs_private = NULL;
 	sb->s_flags |= SB_NODIRATIME;
 	sb->s_magic = 0x7366746e; // "ntfs"
 	sb->s_op = &ntfs_sops;
@@ -1679,9 +1676,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 out:
 	/* sbi->options == options */
 	if (options) {
-		unload_nls(options->nls);
-		kfree(options->nls_name);
-		kfree(options);
+		put_mount_options(sbi->options);
 		sbi->options = NULL;
 	}
 
-- 
2.51.0