[PATCH 6.18.y 2/4] ntfs3: fix double free of sbi->options->nls and clarify ownership of fc->fs_private

[Sasha Levin <sashal@kernel.org>]

From: YangWen <anmuxixixi@gmail.com>

[ Upstream commit aee4d5a521e94f658e46c904e08a473daa9c8fc0 ]

commit 02f312754c87 ("ntfs3: fix use-after-free of sbi->options in cmp_fnames") introduced a use-after-free bug
due to improper handling of sbi->options in error paths. This resulted in crashes when superblock cleanup
is performed in ntfs_put_super.

This patch ensures that the options structure and its subfields are properly freed, preventing the memory
corruption and use-after-free errors.

Fixes: 02f312754c87 ("ntfs3: fix use-after-free of sbi->options in cmp_fnames")
Reported-by: syzbot+cc433e4cd6d54736bf80@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=cc433e4cd6d54736bf80
Signed-off-by: YangWen <anmuxixixi@gmail.com>
[almaz.alexandrovich@paragon-software.com: added fixes and closes tags]
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Stable-dep-of: c01b091b0641 ("ntfs3: free the sbi after a grace period")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ntfs3/super.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index ec4bdaae14114..791d3cc489a42 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -706,7 +706,7 @@ static void ntfs_put_super(struct super_block *sb)
 
 	if (sbi->options) {
 		unload_nls(sbi->options->nls);
-		kfree(sbi->options->nls);
+		kfree(sbi->options->nls_name);
 		kfree(sbi->options);
 		sbi->options = NULL;
 	}
@@ -1264,6 +1264,7 @@ 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;
@@ -1694,7 +1695,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
 out:
 	if (sbi && sbi->options) {
 		unload_nls(sbi->options->nls);
-		kfree(sbi->options->nls);
+		kfree(sbi->options->nls_name);
 		kfree(sbi->options);
 		sbi->options = NULL;
 	}
-- 
2.53.0