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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Julien Gomes" <julien@arista.com>,
        "Cong Wang" <xiyou.wangcong@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.590744536@decadent.org.uk>
Subject: [PATCH 3.16 002/410] tun: allow positive return values on
 dev_get_valid_name() call
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Julien Gomes <julien@arista.com>

commit 5c25f65fd1e42685f7ccd80e0621829c105785d9 upstream.

If the name argument of dev_get_valid_name() contains "%d", it will try
to assign it a unit number in __dev__alloc_name() and return either the
unit number (>= 0) or an error code (< 0).
Considering positive values as error values prevent tun device creations
relying this mechanism, therefor we should only consider negative values
as errors here.

Signed-off-by: Julien Gomes <julien@arista.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/net/tun.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1648,7 +1648,7 @@ static int tun_set_iff(struct net *net,
 		if (!dev)
 			return -ENOMEM;
 		err = dev_get_valid_name(net, dev, name);
-		if (err)
+		if (err < 0)
 			goto err_free_dev;
 
 		dev_net_set(dev, net);