From fc961522ddbdf00254dd03b677627139cc1f68bc Mon Sep 17 00:00:00 2001

From: Dan Carpenter <dan.carpenter@oracle.com>

Date: Mon, 8 Jun 2020 17:16:29 +0300

Subject: [Backport fc961522ddbd] exfat: Fix potential use after free in

 exfat_load_upcase_table()

This code calls brelse(bh) and then dereferences "bh" on the next line

resulting in a possible use after free.  The brelse() should just be

moved down a line.

Fixes: b676fdbcf4c8 ("exfat: standardize checksum calculation")

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

---

 src/nls.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/nls.c b/src/nls.c

index c1ec05695497445934ac8f2d537ccd131e5d7f5c..57b5a7a4d1f7a18b1854348bd6841ea7bc9c466a 100644

--- a/src/nls.c

+++ b/src/nls.c

@@ -692,8 +692,8 @@ static int exfat_load_upcase_table(struct super_block *sb,

 				index++;

 			}

 		}

-		brelse(bh);

 		chksum = exfat_calc_chksum32(bh->b_data, i, chksum, CS_DEFAULT);

+		brelse(bh);

 	}

 	if (index >= 0xFFFF && utbl_checksum == chksum)

-- 

2.31.1