netdev - [Patch net] rtnetlink: allocate more memory for dev_set_mac

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Message-Id: <20170720182758.20204-1-xiyou.wangcong@gmail.com>
Date:   Thu, 20 Jul 2017 11:27:57 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     netdev@...r.kernel.org
Cc:     dsahern@...il.com, Cong Wang <xiyou.wangcong@...il.com>
Subject: [Patch net] 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@...il.com>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
 net/core/rtnetlink.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d1ba90980be1..ebaa26cf777f 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;
-- 
2.13.0