On 6/23/20 3:11 PM, Eric Dumazet wrote:
On 6/23/20 10:03 AM, Yonghong Song wrote:
On 6/23/20 9:27 AM, Eric Dumazet wrote:
On 6/22/20 7:22 PM, Yonghong Song wrote:
On 6/22/20 6:47 PM, Eric Dumazet wrote:
&
Why is the sk_fullsock(sk) needed ?
The parameter 'sk' could be a sock_common. That is why the
helper name bpf_skc_to_udp6_sock implies. The sock_common cannot
access sk_protocol, hence we requires sk_fullsock(sk) here.
Did I miss anything?
OK, if arbitrary sockets can land here, you need also to check sk_type
The current check is:
if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_UDP &&
sk->sk_family == AF_INET6)
return (unsigned long)sk;
it checks to ensure it is full socket, it is a ipv6 socket and then check protocol.
Are you suggesting to add the following check?
sk->sk_type == SOCK_DGRAM
Not a networking expert. Maybe you can explain when we could have
protocol is IPPROTO_UDP and sk_type not SOCK_DGRAM?
RAW sockets for instance.
Look at :
commit 940ba14986657a50c15f694efca1beba31fa568f
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Tue Jan 21 23:17:14 2020 -0800
gtp: make sure only SOCK_DGRAM UDP sockets are accepted
A malicious user could use RAW sockets and fool
GTP using them as standard SOCK_DGRAM UDP sockets.
Thanks for the pointer! Will fix it in the next revision.
