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: v4.13-rc2~26^2~4
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=153711f9421be5dbc973dc57a4109dc9d54c89b1;p=karo-tx-linux.git

rtnetlink: allocate more memory for dev_set_mac_address()

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>
---

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 11b25fbf3dd2..9201e3621351 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2031,7 +2031,8 @@ 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;