Re: [PATCH bpf-next v3 6/6] selftests: bpf: test sockmap update from BPF
From: Yonghong Song
Date: Fri Aug 21 2020 - 12:13:29 EST
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@xxxxxxxxxxxxxx>
A few nits below.
Acked-by: Yonghong Song <yhs@xxxxxx>
---
.../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";