Re: [syzbot] Re: [syzbot] [ntfs3?] KASAN: slab-out-of-bounds Read in mi_enum_attr

[syzbot <syzbot+a426cde6dee8c2884b0b@syzkaller.appspotmail.com>]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: Re: [syzbot] [ntfs3?] KASAN: slab-out-of-bounds Read in mi_enum_attr
Author: lizhi.xu@windriver.com

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index 53629b1f65e9..a435df98c2b1 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -243,14 +243,14 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
 		off += asize;
 	}
 
-	asize = le32_to_cpu(attr->size);
-
 	/* Can we use the first field (attr->type). */
 	if (off + 8 > used) {
 		static_assert(ALIGN(sizeof(enum ATTR_TYPE), 8) == 8);
 		return NULL;
 	}
 
+	asize = le32_to_cpu(attr->size);
+
 	if (attr->type == ATTR_END) {
 		/* End of enumeration. */
 		return NULL;