From d2f459e3feb0f73d2e95ab7892adcf22f21fe9ef Mon Sep 17 00:00:00 2001
From: Alexander Potapenko <glider@google.com>
Date: Tue, 6 Jun 2017 15:56:54 +0200
Subject: net: don't call strlen on non-terminated string in dev_set_alias()

[ Upstream commit c28294b941232931fbd714099798eb7aa7e865d7 ]

KMSAN reported a use of uninitialized memory in dev_set_alias(),
which was caused by calling strlcpy() (which in turn called strlen())
on the user-supplied non-terminated string.

Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index 2e04fd1..97f8061 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1250,8 +1250,9 @@ int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
 	if (!new_ifalias)
 		return -ENOMEM;
 	dev->ifalias = new_ifalias;
+	memcpy(dev->ifalias, alias, len);
+	dev->ifalias[len] = 0;
 
-	strlcpy(dev->ifalias, alias, len+1);
 	return len;
 }
 
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