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: v4.11.9~86
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3227b51e72f4d8e33cd6274e471c08b2fbec6e2e;p=linux

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 9b5875388c23..85c626bfed33 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1251,8 +1251,9 @@ 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;
 }