releases/4.4.81/rtnetlink-allocate-more-memory-for-dev_set_mac_address.patch

From foo@baz Tue Aug  8 16:51:58 PDT 2017
From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Thu, 20 Jul 2017 11:27:57 -0700
Subject: rtnetlink: allocate more memory for dev_set_mac_address()

From: WANG Cong <xiyou.wangcong@gmail.com>


[ Upstream commit 153711f9421be5dbc973dc57a4109dc9d54c89b1 ]

virtnet_set_mac_address() interprets mac address as struct
sockaddr, but upper layer only allocates dev->addr_len
which is ETH_ALEN + sizeof(sa_family_t) in this case.

We lack a unified definition for mac address, so just fix
the upper layer, this also allows drivers to interpret it
to struct sockaddr freely.

Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/core/rtnetlink.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1742,7 +1742,8 @@ static int do_setlink(const struct sk_bu
 		struct sockaddr *sa;
 		int len;
 
-		len = sizeof(sa_family_t) + dev->addr_len;
+		len = sizeof(sa_family_t) + max_t(size_t, dev->addr_len,
+						  sizeof(*sa));
 		sa = kmalloc(len, GFP_KERNEL);
 		if (!sa) {
 			err = -ENOMEM;