On 7/19/17 12:23 PM, Cong Wang wrote:
> On Wed, Jul 19, 2017 at 9:59 AM, David Ahern <dsah...@gmail.com> wrote:
>> Changing the mac address on a virtio-net based nic is triggering an
>> out-of-bounds access. Nothing fancy with the command:
>>
>> ip li set dev eth2 addr 01:02:34:56:78:9a
>>
>> virtnet_set_mac_address is calling kmemdup for sizeof sockaddr, yet only
>> ETH_ALEN + sizeof(sa_family_t) bytes were malloc'ed.
>
> Previously we have a dev->addr_len longer than sizeof sockaddr,
> now we a shorter one... This mac addr thing is really a mess currently.
>
>
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index d1ba90980be1..d13bebdf6465 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -2031,7 +2031,7 @@ 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(dev->addr_len, sizeof(*sa));
> sa = kmalloc(len, GFP_KERNEL);
> if (!sa) {
> err = -ENOMEM;
>
seems reasonable. I am heading to the mountains in a few hours; won't
have time to test until Friday. Please submit formally; no need to wait
for me.
