selftests: bpf: Test sockmap update from BPF

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@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-7-lmb@cloudflare.com

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index 96e7b7f..65ce7c2 100644 (file)
--- 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 @@ out:
        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);
+}
+
+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);
+}
+
 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 (file)
index 0000000..02a59e2
--- /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 (file)
index 0000000..9d0c9f2
--- /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";