From: Alexander Potapenko <glider@google.com>
Date: Tue, 6 Jun 2017 13:56:54 +0000 (+0200)
Subject: net: don't call strlen on non-terminated string in dev_set_alias()
X-Git-Tag: release-20171130_firefly~4^2~100^2^2~2^2~98
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e79948e2d90bfe19267b35850c83c7cd98a78a60;p=firefly-linux-kernel-4.4.55.git

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 87b8754f34ac..524d8b28e690 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1246,8 +1246,9 @@ 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;
 }