tests load/attach bpf prog with maps, perfbuf and ringbuf, pinning
them. Then effective caps are dropped and we verify we can
- pick up the pin
- create ringbuf/perfbuf
- get ringbuf/perfbuf events, carry out map update, lookup and delete
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/testing/selftests/bpf/config | 1 +
.../bpf/prog_tests/unpriv_map_access.c | 194 ++++++++++++++++++
.../bpf/progs/test_unpriv_map_access.c | 81 ++++++++
3 files changed, 276 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/unpriv_map_access.c
create mode 100644 tools/testing/selftests/bpf/progs/test_unpriv_map_access.c
diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 763db63a3890..f9570f93ba29 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -36,6 +36,7 @@ CONFIG_MPLS_ROUTING=m
CONFIG_MPLS_IPTUNNEL=m
CONFIG_IPV6_SIT=m
CONFIG_BPF_JIT=y
+CONFIG_BPF_UNPRIV_MAP_ACCESS=y
CONFIG_BPF_LSM=y
CONFIG_SECURITY=y
CONFIG_RC_CORE=y
diff --git a/tools/testing/selftests/bpf/prog_tests/unpriv_map_access.c b/tools/testing/selftests/bpf/prog_tests/unpriv_map_access.c
new file mode 100644
index 000000000000..cd64a38ee075
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/unpriv_map_access.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022, Oracle and/or its affiliates. */
+
+#include <test_progs.h>
+#include "test_unpriv_map_access.skel.h"
+
+#include "cap_helpers.h"
+
+/* need CAP_BPF, CAP_NET_ADMIN, CAP_PERFMON to load progs */
+#define ADMIN_CAPS (1ULL << CAP_SYS_ADMIN | \
+ 1ULL << CAP_PERFMON | \
+ 1ULL << CAP_BPF)
+
+#define PINPATH "/sys/fs/bpf/unpriv_map_access_"
+
+static __u32 got_perfbuf_val;
+static __u32 got_ringbuf_val;
+
+static int process_ringbuf(void *ctx, void *data, size_t len)
+{
+ if (len == sizeof(__u32))
+ got_ringbuf_val = *(__u32 *)data;
+ return 0;
+}
+
+static void process_perfbuf(void *ctx, int cpu, void *data, __u32 len)
+{
+ if (len == sizeof(__u32))
+ got_perfbuf_val = *(__u32 *)data;
+}
+
+static int sysctl_set(const char *sysctl_path, char *old_val, const char *new_val)
+{
+ int ret = 0;
+ FILE *fp;
+
+ fp = fopen(sysctl_path, "r+");
+ if (!fp)
+ return -errno;
+ if (old_val && fscanf(fp, "%s", old_val) <= 0) {
+ ret = -ENOENT;
+ } else if (!old_val || strcmp(old_val, new_val) != 0) {
+ fseek(fp, 0, SEEK_SET);
+ if (fprintf(fp, "%s", new_val) < 0)
+ ret = -errno;
+ }
+ fclose(fp);
+
+ return ret;
+}
+
+void test_unpriv_map_access(void)
+{
+ struct test_unpriv_map_access *skel;
+ struct perf_buffer *perfbuf = NULL;
+ struct ring_buffer *ringbuf = NULL;
+ __u64 save_caps = 0;
+ int i, ret, nr_cpus, map_fds[7];
+ char *map_paths[7] = { PINPATH "array",
+ PINPATH "percpu_array",
+ PINPATH "hash",
+ PINPATH "percpu_hash",
+ PINPATH "perfbuf",
+ PINPATH "ringbuf",
+ PINPATH "prog_array" };
+ char unprivileged_bpf_disabled_orig[32] = {};
+ char perf_event_paranoid_orig[32] = {};
+
+ nr_cpus = bpf_num_possible_cpus();
+
+ skel = test_unpriv_map_access__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ if (!ASSERT_OK_PTR(skel->kconfig, "skel_kconfig"))
+ goto cleanup;
+
+ if (!skel->kconfig->CONFIG_BPF_UNPRIV_MAP_ACCESS) {
+ printf("%s:SKIP:CONFIG_BPF_UNPRIV_MAP_ACCESS is not set", __func__);
+ test__skip();
+ goto cleanup;
+ }
+
+ skel->bss->perfbuf_val = 1;
+ skel->bss->ringbuf_val = 2;
+ skel->bss->test_pid = getpid();
+
+ if (!ASSERT_OK(test_unpriv_map_access__attach(skel), "skel_attach"))
+ goto cleanup;
+
+ map_fds[0] = bpf_map__fd(skel->maps.array);
+ map_fds[1] = bpf_map__fd(skel->maps.percpu_array);
+ map_fds[2] = bpf_map__fd(skel->maps.hash);
+ map_fds[3] = bpf_map__fd(skel->maps.percpu_hash);
+ map_fds[4] = bpf_map__fd(skel->maps.perfbuf);
+ map_fds[5] = bpf_map__fd(skel->maps.ringbuf);
+ map_fds[6] = bpf_map__fd(skel->maps.prog_array);
+
+ for (i = 0; i < ARRAY_SIZE(map_fds); i++)
+ ASSERT_OK(bpf_obj_pin(map_fds[i], map_paths[i]), "pin map_fd");
+
+ /* allow user without caps to use perf events */
+ if (!ASSERT_OK(sysctl_set("/proc/sys/kernel/perf_event_paranoid", perf_event_paranoid_orig,
+ "-1"),
+ "set_perf_event_paranoid"))
+ goto cleanup;
+ /* ensure unprivileged bpf id disabled */
+ ret = sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled",
+ unprivileged_bpf_disabled_orig, "2");
+ if (ret == -EPERM) {
+ /* if unprivileged_bpf_disabled=1, we get -EPERM back; that's okay. */
+ if (!ASSERT_OK(strcmp(unprivileged_bpf_disabled_orig, "1"),
+ "unpriviliged_bpf_disabled_on"))
+ goto cleanup;
+ } else {
+ if (!ASSERT_OK(ret, "set unpriviliged_bpf_disabled"))
+ goto cleanup;
+ }
+
+ if (!ASSERT_OK(cap_disable_effective(ADMIN_CAPS, &save_caps), "disable caps"))
+ goto cleanup;
+
+ perfbuf = perf_buffer__new(bpf_map__fd(skel->maps.perfbuf), 8, process_perfbuf, NULL, NULL,
+ NULL);
+ if (!ASSERT_OK_PTR(perfbuf, "perf_buffer__new"))
+ goto cleanup;
+
+ ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf), process_ringbuf, NULL, NULL);
+ if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new"))
+ goto cleanup;
+
+ /* trigger & validate perf event, ringbuf output */
+ usleep(1);
+
+ ASSERT_GT(perf_buffer__poll(perfbuf, 100), -1, "perf_buffer__poll");
+
+ ASSERT_EQ(got_perfbuf_val, skel->bss->perfbuf_val, "check_perfbuf_val");
+
+ ASSERT_EQ(ring_buffer__consume(ringbuf), 1, "ring_buffer__consume");
+
+ ASSERT_EQ(got_ringbuf_val, skel->bss->ringbuf_val, "check_ringbuf_val");
+
+ for (i = 0; i < ARRAY_SIZE(map_fds); i++) {
+ map_fds[i] = bpf_obj_get(map_paths[i]);
+ if (!ASSERT_GT(map_fds[i], -1, "bpf_obj_get"))
+ goto cleanup;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(map_fds); i++) {
+ bool prog_array = strstr(map_paths[i], "prog_array") != NULL;
+ bool array = strstr(map_paths[i], "array") != NULL;
+ bool buf = strstr(map_paths[i], "buf") != NULL;
+ __u32 key = 0, vals[nr_cpus], lookup_vals[nr_cpus];
+ int j;
+
+ /* skip ringbuf, perfbuf */
+ if (buf)
+ continue;
+
+ for (j = 0; j < nr_cpus; j++)
+ vals[j] = 1;
+
+ if (prog_array) {
+ ASSERT_EQ(bpf_map_update_elem(map_fds[i], &key, vals, 0), -EPERM,
+ "bpf_map_update_elem_fail");
+ ASSERT_EQ(bpf_map_lookup_elem(map_fds[i], &key, &lookup_vals), -EPERM,
+ "bpf_map_lookup_elem_fail");
+ } else {
+ ASSERT_OK(bpf_map_update_elem(map_fds[i], &key, vals, 0),
+ "bpf_map_update_elem");
+ ASSERT_OK(bpf_map_lookup_elem(map_fds[i], &key, &lookup_vals),
+ "bpf_map_lookup_elem");
+ ASSERT_EQ(lookup_vals[0], 1, "bpf_map_lookup_elem_values");
+ if (!array)
+ ASSERT_OK(bpf_map_delete_elem(map_fds[i], &key),
+ "bpf_map_delete_elem");
+ }
+ }
+cleanup:
+ if (save_caps)
+ cap_enable_effective(save_caps, NULL);
+ if (strlen(perf_event_paranoid_orig) > 0)
+ sysctl_set("/proc/sys/kernel/perf_event_paranoid", NULL, perf_event_paranoid_orig);
+ if (strlen(unprivileged_bpf_disabled_orig) > 0)
+ sysctl_set("/proc/sys/kernel/unprivileged_bpf_disabled", NULL,
+ unprivileged_bpf_disabled_orig);
+ if (perfbuf)
+ perf_buffer__free(perfbuf);
+ if (ringbuf)
+ ring_buffer__free(ringbuf);
+ for (i = 0; i < ARRAY_SIZE(map_paths); i++)
+ unlink(map_paths[i]);
+ test_unpriv_map_access__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_unpriv_map_access.c b/tools/testing/selftests/bpf/progs/test_unpriv_map_access.c
new file mode 100644
index 000000000000..a215e2f1fa16
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_unpriv_map_access.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022, Oracle and/or its affiliates. */
+
+#include "vmlinux.h"
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+
+extern bool CONFIG_BPF_UNPRIV_MAP_ACCESS __kconfig;
+bool unpriv_map_access = 0;
+__u32 perfbuf_val = 0;
+__u32 ringbuf_val = 0;
+
+int test_pid;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} array SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} percpu_array SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} hash SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} percpu_hash SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __type(key, __u32);
+ __type(value, __u32);
+} perfbuf SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_RINGBUF);
+ __uint(max_entries, 1 << 12);
+} ringbuf SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+ __uint(max_entries, 1);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u32));
+} prog_array SEC(".maps");
+
+SEC("fentry/" SYS_PREFIX "sys_nanosleep")
+int sys_enter(void *ctx)
+{
+ int cur_pid;
+
+ cur_pid = bpf_get_current_pid_tgid() >> 32;
+
+ if (cur_pid != test_pid)
+ return 0;
+
+ unpriv_map_access = CONFIG_BPF_UNPRIV_MAP_ACCESS;
+
+ bpf_perf_event_output(ctx, &perfbuf, BPF_F_CURRENT_CPU, &perfbuf_val, sizeof(perfbuf_val));
+ bpf_ringbuf_output(&ringbuf, &ringbuf_val, sizeof(ringbuf_val), 0);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.27.0
