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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 224/639] fs/nfs: Fix nfs_parse_devname to not modify its argument
Date:   Fri, 24 Jan 2020 10:26:34 +0100
Message-Id: <20200124093114.967613031@linuxfoundation.org>
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From: Eric W. Biederman <ebiederm@xmission.com>

[ Upstream commit 40cc394be1aa18848b8757e03bd8ed23281f572e ]

In the rare and unsupported case of a hostname list nfs_parse_devname
will modify dev_name.  There is no need to modify dev_name as the all
that is being computed is the length of the hostname, so the computed
length can just be shorted.

Fixes: dc04589827f7 ("NFS: Use common device name parsing logic for NFSv4 and NFSv2/v3")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index d90efdea9fbd6..5db7aceb41907 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1930,7 +1930,7 @@ static int nfs_parse_devname(const char *dev_name,
 		/* kill possible hostname list: not supported */
 		comma = strchr(dev_name, ',');
 		if (comma != NULL && comma < end)
-			*comma = 0;
+			len = comma - dev_name;
 	}
 
 	if (len > maxnamlen)
-- 
2.20.1