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Message-ID: <e1920ac4-18ad-4b97-a3a3-9604724937d6@kernel.dk>
Date:   Thu, 19 Oct 2023 14:04:43 -0600
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Subject: Re: [PATCH v7 04/11] net/socket: Break down __sys_getsockopt
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To:     Martin KaFai Lau <martin.lau@linux.dev>,
        Breno Leitao <leitao@debian.org>
Cc:     bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, io-uring@vger.kernel.org,
        Kuniyuki Iwashima <kuniyu@amazon.com>,
        Alexander Mikhalitsyn <alexander@mihalicyn.com>,
        David Howells <dhowells@redhat.com>, sdf@google.com,
        asml.silence@gmail.com, willemdebruijn.kernel@gmail.com,
        kuba@kernel.org, pabeni@redhat.com, krisman@suse.de,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Song Liu <song@kernel.org>,
        Yonghong Song <yonghong.song@linux.dev>,
        KP Singh <kpsingh@kernel.org>, Hao Luo <haoluo@google.com>,
        Jiri Olsa <jolsa@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>
References: <20231016134750.1381153-1-leitao@debian.org>
 <20231016134750.1381153-5-leitao@debian.org>
 <1074c1f1-e676-fbe6-04bc-783821d746a1@linux.dev>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <1074c1f1-e676-fbe6-04bc-783821d746a1@linux.dev>
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Precedence: bulk

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.


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;
 }

-- 
Jens Axboe