From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Thu, 20 Jul 2017 18:27:57 +0000 (-0700)
Subject: rtnetlink: allocate more memory for dev_set_mac_address()
X-Git-Tag: v4.9.42~49
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cda2bc91baf7b6849733145331726a1364f20512;p=linux

rtnetlink: allocate more memory for dev_set_mac_address()


[ 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>
---

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 9c6fd7f83a4a..4d2629781e8b 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1965,7 +1965,8 @@ static int do_setlink(const struct sk_buff *skb,
 		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;