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Date: Fri, 21 Aug 2020 09:13:01 -0700
From: Yonghong Song <yhs@...com>
To: Lorenz Bauer <lmb@...udflare.com>, <jakub@...udflare.com>,
<john.fastabend@...il.com>, Shuah Khan <shuah@...nel.org>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>
CC: <kernel-team@...udflare.com>, <linux-kernel@...r.kernel.org>,
<linux-kselftest@...r.kernel.org>, <netdev@...r.kernel.org>,
<bpf@...r.kernel.org>
Subject: Re: [PATCH bpf-next v3 6/6] selftests: bpf: test sockmap update from
BPF
On 8/21/20 3:29 AM, Lorenz Bauer wrote:
> Add a test which copies a socket from a sockmap into another sockmap
> or sockhash. This excercises bpf_map_update_elem support from BPF
> context. Compare the socket cookies from source and destination to
> ensure that the copy succeeded.
>
> Also check that the verifier rejects map_update from unsafe contexts.
>
> Signed-off-by: Lorenz Bauer <lmb@...udflare.com>
A few nits below.
Acked-by: Yonghong Song <yhs@...com>
> ---
> .../selftests/bpf/prog_tests/sockmap_basic.c | 78 +++++++++++++++++++
> .../bpf/progs/test_sockmap_invalid_update.c | 23 ++++++
> .../selftests/bpf/progs/test_sockmap_update.c | 48 ++++++++++++
> 3 files changed, 149 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_invalid_update.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_update.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> index 96e7b7f84c65..65ce7c289534 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> @@ -4,6 +4,8 @@
>
> #include "test_progs.h"
> #include "test_skmsg_load_helpers.skel.h"
> +#include "test_sockmap_update.skel.h"
> +#include "test_sockmap_invalid_update.skel.h"
>
> #define TCP_REPAIR 19 /* TCP sock is under repair right now */
>
> @@ -101,6 +103,76 @@ static void test_skmsg_helpers(enum bpf_map_type map_type)
> test_skmsg_load_helpers__destroy(skel);
> }
>
> +static void test_sockmap_update(enum bpf_map_type map_type)
> +{
> + struct bpf_prog_test_run_attr tattr;
> + int err, prog, src, dst, duration = 0;
> + struct test_sockmap_update *skel;
> + __u64 src_cookie, dst_cookie;
> + const __u32 zero = 0;
> + char dummy[14] = {0};
> + __s64 sk;
> +
> + sk = connected_socket_v4();
> + if (CHECK(sk == -1, "connected_socket_v4", "cannot connect\n"))
> + return;
> +
> + skel = test_sockmap_update__open_and_load();
> + if (CHECK(!skel, "open_and_load", "cannot load skeleton\n")) {
> + close(sk);
> + return;
> + }
> +
> + prog = bpf_program__fd(skel->progs.copy_sock_map);
> + src = bpf_map__fd(skel->maps.src);
> + if (map_type == BPF_MAP_TYPE_SOCKMAP)
> + dst = bpf_map__fd(skel->maps.dst_sock_map);
> + else
> + dst = bpf_map__fd(skel->maps.dst_sock_hash);
> +
> + err = bpf_map_update_elem(src, &zero, &sk, BPF_NOEXIST);
> + if (CHECK(err, "update_elem(src)", "errno=%u\n", errno))
> + goto out;
> +
> + err = bpf_map_lookup_elem(src, &zero, &src_cookie);
> + if (CHECK(err, "lookup_elem(src, cookie)", "errno=%u\n", errno))
> + goto out;
> +
> + tattr = (struct bpf_prog_test_run_attr){
> + .prog_fd = prog,
> + .repeat = 1,
> + .data_in = dummy,
> + .data_size_in = sizeof(dummy),
> + };
> +
> + err = bpf_prog_test_run_xattr(&tattr);
> + if (CHECK_ATTR(err || !tattr.retval, "bpf_prog_test_run",
> + "errno=%u retval=%u\n", errno, tattr.retval))
> + goto out;
> +
> + err = bpf_map_lookup_elem(dst, &zero, &dst_cookie);
> + if (CHECK(err, "lookup_elem(dst, cookie)", "errno=%u\n", errno))
> + goto out;
> +
> + CHECK(dst_cookie != src_cookie, "cookie mismatch", "%llu != %llu\n",
> + dst_cookie, src_cookie);
> +
> +out:
> + close(sk);
> + test_sockmap_update__destroy(skel);
nit. In the beginning of the function, 'sk' is available and then skel
is opened and loaded. You can have
out:
test_sockmap_update__destroy(skel);
close_sk:
close(sk);
this probably more conforms to linux coding style.
Then you can have
if (CHECK(!skel, "open_and_load", "cannot load skeleton\n"))
goto close_sk;
> +}
> +
> +static void test_sockmap_invalid_update(void)
> +{
> + struct test_sockmap_invalid_update *skel;
> + int duration = 0;
> +
> + skel = test_sockmap_invalid_update__open_and_load();
> + CHECK(skel, "open_and_load", "verifier accepted map_update\n");
> + if (skel)
> + test_sockmap_invalid_update__destroy(skel);
nit, you can just have
if (CHECK(skel, "open_and_load", "verifier accepted map_update\n"))
test_sockmap_invalid_update__destroy(skel);
> +}
> +
> void test_sockmap_basic(void)
> {
> if (test__start_subtest("sockmap create_update_free"))
> @@ -111,4 +183,10 @@ void test_sockmap_basic(void)
> test_skmsg_helpers(BPF_MAP_TYPE_SOCKMAP);
> if (test__start_subtest("sockhash sk_msg load helpers"))
> test_skmsg_helpers(BPF_MAP_TYPE_SOCKHASH);
> + if (test__start_subtest("sockmap update"))
> + test_sockmap_update(BPF_MAP_TYPE_SOCKMAP);
> + if (test__start_subtest("sockhash update"))
> + test_sockmap_update(BPF_MAP_TYPE_SOCKHASH);
> + if (test__start_subtest("sockmap update in unsafe context"))
> + test_sockmap_invalid_update();
> }
> diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_invalid_update.c b/tools/testing/selftests/bpf/progs/test_sockmap_invalid_update.c
> new file mode 100644
> index 000000000000..02a59e220cbc
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_sockmap_invalid_update.c
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2020 Cloudflare
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKMAP);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u64);
> +} map SEC(".maps");
> +
> +SEC("sockops")
> +int bpf_sockmap(struct bpf_sock_ops *skops)
> +{
> + __u32 key = 0;
> +
> + if (skops->sk)
> + bpf_map_update_elem(&map, &key, skops->sk, 0);
> + return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_update.c b/tools/testing/selftests/bpf/progs/test_sockmap_update.c
> new file mode 100644
> index 000000000000..9d0c9f28cab2
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_sockmap_update.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2020 Cloudflare
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKMAP);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u64);
> +} src SEC(".maps");
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKMAP);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u64);
> +} dst_sock_map SEC(".maps");
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_SOCKHASH);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u64);
> +} dst_sock_hash SEC(".maps");
> +
> +SEC("classifier/copy_sock_map")
> +int copy_sock_map(void *ctx)
> +{
> + struct bpf_sock *sk;
> + bool failed = false;
> + __u32 key = 0;
> +
> + sk = bpf_map_lookup_elem(&src, &key);
> + if (!sk)
> + return SK_DROP;
> +
> + if (bpf_map_update_elem(&dst_sock_map, &key, sk, 0))
> + failed = true;
> +
> + if (bpf_map_update_elem(&dst_sock_hash, &key, sk, 0))
> + failed = true;
> +
> + bpf_sk_release(sk);
> + return failed ? SK_DROP : SK_PASS;
> +}
> +
> +char _license[] SEC("license") = "GPL";
>
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