[PATCH] hfsplus: set attributes inode dirty at correct position

Edward Adam Davis
2026-04-15T08:45:15Z

Syzbot reported a null-ptr-deref in [1].
If the attributes file is not loaded during system mount, a trigger
occurs [1] when setxattr is executed in userspace.

Move the mark inode dirty operation to a point after the attr_tree has
been successfully acquired.

[1]
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
Call Trace:
hfsplus_setxattr+0x124/0x340 fs/hfsplus/xattr.c:555
hfsplus_trusted_setxattr+0x40/0x60 fs/hfsplus/xattr_trusted.c:30
__vfs_setxattr+0x43c/0x480 fs/xattr.c:218
__vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:252
vfs_setxattr+0x163/0x360 fs/xattr.c:339
do_setxattr fs/xattr.c:654 [inline]

Reported-by: syzbot+bc70a12e438dadba4fb4@syzkaller.appspotmail.com
Fixes: ee8422d00b7c ("hfsplus: fix potential Allocation File corruption after fsync")
Closes: https://syzkaller.appspot.com/bug?extid=bc70a12e438dadba4fb4
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
fs/hfsplus/xattr.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index 452a1f9becb2..3e6f45b3259d 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -317,12 +317,14 @@ static int hfsplus_create_attributes_file(struct super_block *sb)
next_node++;
}

- hfsplus_mark_inode_dirty(HFSPLUS_ATTR_TREE_I(sb), HFSPLUS_I_ATTR_DIRTY);
hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY);

sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
if (!sbi->attr_tree)
pr_err("failed to load attributes file\n");
+ else
+ hfsplus_mark_inode_dirty(HFSPLUS_ATTR_TREE_I(sb),
+ HFSPLUS_I_ATTR_DIRTY);

failed_header_node_init:
kfree(buf);
--
2.43.0