[PATCH] jfs : fix array-index-out-of-bounds in diWrite

[Manas Ghandat]

Currently while copying dtree root from inode to dnode in the xp slot
there is a out of bound memcpy. Added a bound check to the memcpy.

Reported-by: syzbot+c1056fdfe414463fdb33@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: https://syzkaller.appspot.com/bug?extid=c1056fdfe414463fdb33
Signed-off-by: Manas Ghandat <ghandatmanas@xxxxxxxxx>
---
 fs/jfs/jfs_imap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 799d3837e7c2..d1f897848be0 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -746,7 +746,8 @@ int diWrite(tid_t tid, struct inode *ip)
 		xp = (dtpage_t *) & dp->di_dtroot;
 		lv = ilinelock->lv;
 		for (n = 0; n < ilinelock->index; n++, lv++) {
-			memcpy(&xp->slot[lv->offset], &p->slot[lv->offset],
+			if (lv->offset < 128)
+				memcpy(&xp->slot[lv->offset], &p->slot[lv->offset],
 			       lv->length << L2DTSLOTSIZE);
 		}
 	} else {
-- 
2.37.2