linux-kernel - [PATCH 5.13 020/175] ext4: fix potential uninitialized access to retval in kmmpd

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Date:   Tue, 10 Aug 2021 19:28:48 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ye Bin <yebin10@...wei.com>,
        Theodore Tso <tytso@....edu>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.13 020/175] ext4: fix potential uninitialized access to retval in kmmpd

From: Ye Bin <yebin10@...wei.com>

[ Upstream commit b66541422824cf6cf20e9a35112e9cb5d82cdf62 ]

if (!ext4_has_feature_mmp(sb)) then retval can be unitialized before
we jump to the wait_to_exit label.

Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system")
Signed-off-by: Ye Bin <yebin10@...wei.com>
Link: https://lore.kernel.org/r/20210713022728.2533770-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/ext4/mmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index bc364c119af6..cebea4270817 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -138,7 +138,7 @@ static int kmmpd(void *data)
 	unsigned mmp_check_interval;
 	unsigned long last_update_time;
 	unsigned long diff;
-	int retval;
+	int retval = 0;
 
 	mmp_block = le64_to_cpu(es->s_mmp_block);
 	mmp = (struct mmp_struct *)(bh->b_data);
-- 
2.30.2