Re: [PATCH v7 04/11] net/socket: Break down __sys_getsockopt

[Martin KaFai Lau]

On 10/19/23 1:04 PM, Jens Axboe wrote:
> On 10/19/23 1:12 PM, Martin KaFai Lau wrote:
> > On 10/16/23 6:47?AM, Breno Leitao wrote:
> > > diff --git a/net/socket.c b/net/socket.c
> > > index 0087f8c071e7..f4c156a1987e 100644
> > > --- a/net/socket.c
> > > +++ b/net/socket.c
> > > @@ -2350,6 +2350,42 @@ SYSCALL_DEFINE5(setsockopt, int, fd, int, level, int, optname,
> > >    INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level,
> > >                                 int optname));
> > >    +int do_sock_getsockopt(struct socket *sock, bool compat, int level,
> > > +               int optname, sockptr_t optval, sockptr_t optlen)
> > > +{
> > > +    int max_optlen __maybe_unused;
> > > +    const struct proto_ops *ops;
> > > +    int err;
> > > +
> > > +    err = security_socket_getsockopt(sock, level, optname);
> > > +    if (err)
> > > +        return err;
> > > +
> > > +    ops = READ_ONCE(sock->ops);
> > > +    if (level == SOL_SOCKET) {
> > > +        err = sk_getsockopt(sock->sk, level, optname, optval, optlen);
> > > +    } else if (unlikely(!ops->getsockopt)) {
> > > +        err = -EOPNOTSUPP;
> > > +    } else {
> > > +        if (WARN_ONCE(optval.is_kernel || optlen.is_kernel,
> > > +                  "Invalid argument type"))
> > > +            return -EOPNOTSUPP;
> > > +
> > > +        err = ops->getsockopt(sock, level, optname, optval.user,
> > > +                      optlen.user);
> > > +    }
> > > +
> > > +    if (!compat) {
> > > +        max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
> >
> > The max_optlen was done before the above sk_getsockopt. The bpf CI cannot catch it because it cannot apply patch 5 cleanly. I ran the following out of the linux-block tree:
> >
> > $> ./test_progs -t sockopt_sk
> > test_sockopt_sk:PASS:join_cgroup /sockopt_sk 0 nsec
> > run_test:PASS:skel_load 0 nsec
> > run_test:PASS:setsockopt_link 0 nsec
> > run_test:PASS:getsockopt_link 0 nsec
> > (/data/users/kafai/fb-kernel/linux/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c:111: errno: Operation not permitted) Failed to call getsockopt, ret=-1
> > run_test:FAIL:getsetsockopt unexpected error: -1 (errno 1)
> > #217     sockopt_sk:FAIL
>
> Does it work with this incremental? I can fold that in, will rebase
> anyway to collect acks.

Yes, that should work.

Acked-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>

> diff --git a/net/socket.c b/net/socket.c
> index bccd257e13fe..eb6960958026 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -2344,6 +2344,9 @@ int do_sock_getsockopt(struct socket *sock, bool compat, int level,
>   	if (err)
>   		return err;
>   
> +	if (!compat)
> +		max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
> +
>   	ops = READ_ONCE(sock->ops);
>   	if (level == SOL_SOCKET) {
>   		err = sk_getsockopt(sock->sk, level, optname, optval, optlen);
> @@ -2358,12 +2361,10 @@ int do_sock_getsockopt(struct socket *sock, bool compat, int level,
>   				      optlen.user);
>   	}
>   
> -	if (!compat) {
> -		max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
> +	if (!compat)
>   		err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname,
>   						     optval, optlen, max_optlen,
>   						     err);
> -	}
>   
>   	return err;
>   }