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Message-ID: <1074c1f1-e676-fbe6-04bc-783821d746a1@linux.dev>
Date: Thu, 19 Oct 2023 12:12:03 -0700
From: Martin KaFai Lau <martin.lau@...ux.dev>
To: Breno Leitao <leitao@...ian.org>
Cc: bpf@...r.kernel.org, linux-kernel@...r.kernel.org,
netdev@...r.kernel.org, io-uring@...r.kernel.org,
Kuniyuki Iwashima <kuniyu@...zon.com>,
Alexander Mikhalitsyn <alexander@...alicyn.com>,
David Howells <dhowells@...hat.com>, sdf@...gle.com,
axboe@...nel.dk, asml.silence@...il.com,
willemdebruijn.kernel@...il.com, kuba@...nel.org,
pabeni@...hat.com, krisman@...e.de,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
John Fastabend <john.fastabend@...il.com>,
Andrii Nakryiko <andrii@...nel.org>,
Song Liu <song@...nel.org>,
Yonghong Song <yonghong.song@...ux.dev>,
KP Singh <kpsingh@...nel.org>, Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH v7 04/11] net/socket: Break down __sys_getsockopt
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
> + err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname,
> + optval, optlen, max_optlen,
> + err);
> + }
> +
> + return err;
> +}
> +EXPORT_SYMBOL(do_sock_getsockopt);
> +
> /*
> * Get a socket option. Because we don't know the option lengths we have
> * to pass a user mode parameter for the protocols to sort out.
> @@ -2357,37 +2393,18 @@ INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level,
> int __sys_getsockopt(int fd, int level, int optname, char __user *optval,
> int __user *optlen)
> {
> - int max_optlen __maybe_unused;
> - const struct proto_ops *ops;
> int err, fput_needed;
> struct socket *sock;
> + bool compat;
>
> sock = sockfd_lookup_light(fd, &err, &fput_needed);
> if (!sock)
> return err;
>
> - err = security_socket_getsockopt(sock, level, optname);
> - if (err)
> - goto out_put;
> -
> - if (!in_compat_syscall())
> - max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen);
The old max_optlen was done here.
> + compat = in_compat_syscall();
> + err = do_sock_getsockopt(sock, compat, level, optname,
> + USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
>
> - ops = READ_ONCE(sock->ops);
> - if (level == SOL_SOCKET)
> - err = sock_getsockopt(sock, level, optname, optval, optlen);
> - else if (unlikely(!ops->getsockopt))
> - err = -EOPNOTSUPP;
> - else
> - err = ops->getsockopt(sock, level, optname, optval,
> - optlen);
> -
> - if (!in_compat_syscall())
> - err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname,
> - USER_SOCKPTR(optval),
> - USER_SOCKPTR(optlen),
> - max_optlen, err);
> -out_put:
> fput_light(sock->file, fput_needed);
> return err;
> }
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