fs: hfsplus: fix UAF issue in hfsplus_put_super

commit 07db5e247ab5858439b14dd7cc1fe538b9efcf32 upstream.

The current hfsplus_put_super first calls hfs_btree_close on
sbi->ext_tree, then invokes iput on sbi->hidden_dir, resulting in an
use-after-free issue in hfsplus_release_folio.

As shown in hfsplus_fill_super, the error handling code also calls iput
before hfs_btree_close.

To fix this error, we move all iput calls before hfsplus_btree_close.

Note that this patch is tested on Syzbot.

Link: https://lkml.kernel.org/r/[email protected]
Reported-by: [email protected]
Tested-by: Dongliang Mu <[email protected]>
Signed-off-by: Dongliang Mu <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

fs/hfsplus/super.c

@@ -295,11 +295,11 @@ static void hfsplus_put_super(struct super_block *sb)
 		hfsplus_sync_fs(sb, 1);
 	}
 
+	iput(sbi->alloc_file);
+	iput(sbi->hidden_dir);
 	hfs_btree_close(sbi->attr_tree);
 	hfs_btree_close(sbi->cat_tree);
 	hfs_btree_close(sbi->ext_tree);
-	iput(sbi->alloc_file);
-	iput(sbi->hidden_dir);
 	kfree(sbi->s_vhdr_buf);
 	kfree(sbi->s_backup_vhdr_buf);
 	unload_nls(sbi->nls);