From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Mon, 8 Jun 2020 14:16:29 +0000 (+0300)
Subject: exfat: Fix potential use after free in exfat_load_upcase_table()
X-Git-Tag: v5.10.7~2382^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fc961522ddbdf00254dd03b677627139cc1f68bc;p=platform%2Fkernel%2Flinux-rpi.git

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>
---

diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
index c1ec05695497..57b5a7a4d1f7 100644
--- a/fs/exfat/nls.c
+++ b/fs/exfat/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)