Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
From:   Eric Biggers <ebiggers@kernel.org>
To:     linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Cc:     Jeff Layton <jlayton@kernel.org>,
        Lukas Czerner <lczerner@redhat.com>,
        Theodore Ts'o <tytso@mit.edu>,
        Jaegeuk Kim <jaegeuk@kernel.org>, stable@vger.kernel.org
Subject: [PATCH v3 1/5] ext4: fix memory leak in parse_apply_sb_mount_options()
Date:   Fri, 13 May 2022 16:16:01 -0700
Message-Id: <20220513231605.175121-2-ebiggers@kernel.org>
In-Reply-To: <20220513231605.175121-1-ebiggers@kernel.org>
References: <20220513231605.175121-1-ebiggers@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Eric Biggers <ebiggers@google.com>

If processing the on-disk mount options fails after any memory was
allocated in the ext4_fs_context, e.g. s_qf_names, then this memory is
leaked.  Fix this by calling ext4_fc_free() instead of kfree() directly.

Reproducer:

    mkfs.ext4 -F /dev/vdc
    tune2fs /dev/vdc -E mount_opts=usrjquota=file
    echo clear > /sys/kernel/debug/kmemleak
    mount /dev/vdc /vdc
    echo scan > /sys/kernel/debug/kmemleak
    sleep 5
    echo scan > /sys/kernel/debug/kmemleak
    cat /sys/kernel/debug/kmemleak

Fixes: 7edfd85b1ffd ("ext4: Completely separate options parsing and sb setup")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/ext4/super.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1466fbdbc8e34..60fa2f2623e07 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2625,8 +2625,10 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
 	ret = ext4_apply_options(fc, sb);
 
 out_free:
-	kfree(s_ctx);
-	kfree(fc);
+	if (fc) {
+		ext4_fc_free(fc);
+		kfree(fc);
+	}
 	kfree(s_mount_opts);
 	return ret;
 }
-- 
2.36.1