linux-kernel - [PATCH v2] exfat: add missing brelse() calls on error paths

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Date:   Wed, 10 Jun 2020 20:22:13 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Markus Elfring <Markus.Elfring@....de>
Cc:     linux-fsdevel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Namjae Jeon <namjae.jeon@...sung.com>,
        Sungjong Seo <sj1557.seo@...sung.com>,
        Pali Rohár <pali@...nel.org>,
        Tetsuhiro Kohada <kohada.t2@...il.com>,
        Wei Yongjun <weiyongjun1@...wei.com>
Subject: [PATCH v2] exfat: add missing brelse() calls on error paths

If the second exfat_get_dentry() call fails then we need to release
"old_bh" before returning.  There is a similar bug in exfat_move_file().

Fixes: 5f2aa075070c ("exfat: add inode operations")
Reported-by: Markus Elfring <Markus.Elfring@....de>
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
v2: fix exfat_move_file() as well.  Also add a Fixes tag.

 fs/exfat/namei.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 5b0f35329d63e..edd8023865a0e 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -1077,10 +1077,14 @@ static int exfat_rename_file(struct inode *inode, struct exfat_chain *p_dir,
 
 		epold = exfat_get_dentry(sb, p_dir, oldentry + 1, &old_bh,
 			&sector_old);
+		if (!epold)
+			return -EIO;
 		epnew = exfat_get_dentry(sb, p_dir, newentry + 1, &new_bh,
 			&sector_new);
-		if (!epold || !epnew)
+		if (!epnew) {
+			brelse(old_bh);
 			return -EIO;
+		}
 
 		memcpy(epnew, epold, DENTRY_SIZE);
 		exfat_update_bh(sb, new_bh, sync);
@@ -1161,10 +1165,14 @@ static int exfat_move_file(struct inode *inode, struct exfat_chain *p_olddir,
 
 	epmov = exfat_get_dentry(sb, p_olddir, oldentry + 1, &mov_bh,
 		&sector_mov);
+	if (!epmov)
+		return -EIO;
 	epnew = exfat_get_dentry(sb, p_newdir, newentry + 1, &new_bh,
 		&sector_new);
-	if (!epmov || !epnew)
+	if (!epnew) {
+		brelse(mov_bh);
 		return -EIO;
+	}
 
 	memcpy(epnew, epmov, DENTRY_SIZE);
 	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
-- 
2.26.2