[PATCH bpf-next 3/4] selftests/bpf: add bpftool map manipulations tests

Alexis Lothoré (eBPF Foundation)
2026-01-14T08:59:43Z

The test_bpftool_map.sh script tests that maps read/write accesses
are being properly allowed/refused by the kernel depending on a specific
fmod_ret program being attached on security_bpf_map function.

Rewrite this test to integrate it in the new test_bpftool runner. The
new test spawns a few subtests:

#1/1 maps_access/unprotected_unpinned: OK
#1/2 maps_access/unprotected_pinned: OK
#1/3 maps_access/protected_unpinned: OK
#1/4 maps_access/protected_pinned: OK
#1/5 maps_access/nested_maps: OK
#1/6 maps_access/btf_list: OK
#1 maps_access: OK
#2/1 metadata/metadata_unused: OK
#2/2 metadata/metadata_used: OK
#2 metadata: OK
Summary: 2 PASSED, 0 FAILED

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
.../bpf/bpftool_tests/bpftool_maps_access.c | 370 +++++++++++++++++++++
1 file changed, 370 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpftool_tests/bpftool_maps_access.c b/tools/testing/selftests/bpf/bpftool_tests/bpftool_maps_access.c
new file mode 100644
index 000000000000..da4277c79e22
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpftool_tests/bpftool_maps_access.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <bpf/libbpf.h>
+#include <bpftool_helpers.h>
+#include <stdlib.h>
+#include <test_bpftool.h>
+#include <assert_helpers.h>
+#include <linux/bpf.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <sys/stat.h>
+#include <stdbool.h>
+#include <bpf/bpf.h>
+#include "security_bpf_map.skel.h"
+
+#define PROTECTED_MAP_NAME "prot_map"
+#define UNPROTECTED_MAP_NAME "not_prot_map"
+#define BPF_ITER_FILE "bpf_iter_map_elem.bpf.o"
+#define BPFFS_PIN_DIR "/sys/fs/bpf/test_bpftool_map"
+#define INNER_MAP_NAME "inner_map_tt"
+#define OUTER_MAP_NAME "outer_map_tt"
+
+#define MAP_NAME_MAX_LEN 64
+#define PATH_MAX_LEN 128
+
+enum map_protection {
+ PROTECTED,
+ UNPROTECTED
+};
+
+struct test_desc {
+ char *name;
+ enum map_protection protection;
+ struct bpf_map *map;
+ char *map_name;
+ bool pinned;
+ char pin_path[PATH_MAX_LEN];
+ bool write_must_fail;
+};
+
+static struct security_bpf_map *general_setup(void)
+{
+ struct security_bpf_map *skel;
+ uint32_t key, value;
+ int ret, i;
+
+ skel = security_bpf_map__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "open and load skeleton"))
+ goto end;
+
+ struct bpf_map *maps[] = {skel->maps.prot_map, skel->maps.not_prot_map};
+
+ ret = security_bpf_map__attach(skel);
+ if (!ASSERT_OK(ret, "attach maps security programs"))
+ goto end_destroy;
+
+ for (i = 0; i < sizeof(maps)/sizeof(struct bpf_map *); i++) {
+ for (key = 0; key < 2; key++) {
+ int ret = bpf_map__update_elem(maps[i], &key,
+ sizeof(key), &key, sizeof(key),
+ 0);
+ if (!ASSERT_OK(ret, "set initial map value"))
+ goto end_destroy;
+ }
+ }
+
+ key = 0;
+ value = 1;
+ ret = bpf_map__update_elem(skel->maps.prot_status_map, &key,
+ sizeof(key), &value, sizeof(value), 0);
+ if (!ASSERT_OK(ret, "configure map protection"))
+ goto end_destroy;
+
+ if (!ASSERT_OK(mkdir(BPFFS_PIN_DIR, S_IFDIR), "create bpffs pin dir"))
+ goto end_destroy;
+
+ return skel;
+end_destroy:
+ security_bpf_map__destroy(skel);
+end:
+ return NULL;
+}
+
+static void general_cleanup(struct security_bpf_map *skel)
+{
+ rmdir(BPFFS_PIN_DIR);
+ security_bpf_map__destroy(skel);
+}
+
+static void update_test_desc(struct security_bpf_map *skel,
+ struct test_desc *test)
+{
+ /* Now that the skeleton is loaded, update all missing fields to
+ * have the subtest properly configured
+ */
+ if (test->protection == PROTECTED) {
+ test->map = skel->maps.prot_map;
+ test->map_name = PROTECTED_MAP_NAME;
+ } else {
+ test->map = skel->maps.not_prot_map;
+ test->map_name = UNPROTECTED_MAP_NAME;
+ }
+}
+
+static int test_setup(struct security_bpf_map *skel, struct test_desc *desc)
+{
+ int ret;
+
+ update_test_desc(skel, desc);
+
+ if (desc->pinned) {
+ ret = snprintf(desc->pin_path, PATH_MAX_LEN, "%s/%s", BPFFS_PIN_DIR,
+ desc->name);
+ if (!ASSERT_GT(ret, 0, "format pin path"))
+ return 1;
+ ret = bpf_map__pin(desc->map, desc->pin_path);
+ if (!ASSERT_OK(ret, "pin map"))
+ return 1;
+ }
+
+ return 0;
+}
+
+static void test_cleanup(struct test_desc *desc)
+{
+ if (desc->pinned)
+ bpf_map__unpin(desc->map, NULL);
+}
+
+static int lookup_map_value(char *map_handle)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN, "map lookup %s key 0 0 0 0",
+ map_handle);
+ if (!ASSERT_GT(ret, 0, "format map lookup cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static int read_map_btf_data(char *map_handle)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN, "btf dump map %s",
+ map_handle);
+ if (!ASSERT_GT(ret, 0, "format map btf dump cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static int write_map_value(char *map_handle)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN,
+ "map update %s key 0 0 0 0 value 1 1 1 1", map_handle);
+ if (!ASSERT_GT(ret, 0, "format value write cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static int delete_map_value(char *map_handle)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN,
+ "map delete %s key 0 0 0 0", map_handle);
+ if (!ASSERT_GT(ret, 0, "format value deletion cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static int iterate_on_map_values(char *map_handle, char *iter_pin_path)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+
+ ret = snprintf(cmd, MAX_BPFTOOL_CMD_LEN, "iter pin %s %s map %s",
+ BPF_ITER_FILE, iter_pin_path, map_handle);
+ if (!ASSERT_GT(ret, 0, "format iterator cration cmd"))
+ return 1;
+ ret = run_bpftool_command(cmd);
+ if (ret)
+ return ret;
+ ret = snprintf(cmd, MAP_NAME_MAX_LEN, "cat %s", iter_pin_path);
+ if (ret < 0)
+ goto cleanup;
+ ret = system(cmd);
+
+cleanup:
+ unlink(iter_pin_path);
+ return ret;
+}
+
+static int create_inner_map(void)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(
+ cmd, MAX_BPFTOOL_CMD_LEN,
+ "map create %s/%s type array key 4 value 4 entries 4 name %s",
+ BPFFS_PIN_DIR, INNER_MAP_NAME, INNER_MAP_NAME);
+ if (!ASSERT_GT(ret, 0, "format inner map create cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static int create_outer_map(void)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(
+ cmd, MAX_BPFTOOL_CMD_LEN,
+ "map create %s/%s type hash_of_maps key 4 value 4 entries 2 name %s inner_map name %s",
+ BPFFS_PIN_DIR, OUTER_MAP_NAME, OUTER_MAP_NAME, INNER_MAP_NAME);
+ if (!ASSERT_GT(ret, 0, "format outer map create cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static void delete_pinned_map(char *map_name)
+{
+ char pin_path[PATH_MAX_LEN];
+ int ret;
+
+ ret = snprintf(pin_path, PATH_MAX_LEN, "%s/%s", BPFFS_PIN_DIR,
+ map_name);
+ if (ret >= 0)
+ unlink(pin_path);
+}
+
+static int add_outer_map_entry(int key)
+{
+ char cmd[MAX_BPFTOOL_CMD_LEN];
+ int ret = 0;
+
+ ret = snprintf(
+ cmd, MAX_BPFTOOL_CMD_LEN,
+ "map update pinned %s/%s key %d 0 0 0 value name %s",
+ BPFFS_PIN_DIR, OUTER_MAP_NAME, key, INNER_MAP_NAME);
+ if (!ASSERT_GT(ret, 0, "format outer map value addition cmd"))
+ return 1;
+ return run_bpftool_command(cmd);
+}
+
+static void test_basic_access(struct test_desc *desc)
+{
+ char map_handle[MAP_NAME_MAX_LEN];
+ char iter_pin_path[PATH_MAX_LEN];
+ int ret;
+
+ if (desc->pinned)
+ ret = snprintf(map_handle, MAP_NAME_MAX_LEN, "pinned %s",
+ desc->pin_path);
+ else
+ ret = snprintf(map_handle, MAP_NAME_MAX_LEN, "name %s",
+ desc->map_name);
+ if (!ASSERT_GT(ret, 0, "format map handle"))
+ return;
+
+ ret = lookup_map_value(map_handle);
+ ASSERT_OK(ret, "read map value");
+
+ ret = read_map_btf_data(map_handle);
+ ASSERT_OK(ret, "read map btf data");
+
+ ret = write_map_value(map_handle);
+ ASSERT_OK(desc->write_must_fail ? !ret : ret, "write map value");
+
+ ret = delete_map_value(map_handle);
+ ASSERT_OK(desc->write_must_fail ? !ret : ret, "delete map value");
+ /* Restore deleted value */
+ if (!ret)
+ write_map_value(map_handle);
+
+ ret = snprintf(iter_pin_path, PATH_MAX_LEN, "%s/iter", BPFFS_PIN_DIR);
+ if (ASSERT_GT(ret, 0, "format iter pin path")) {
+ ret = iterate_on_map_values(map_handle, iter_pin_path);
+ ASSERT_OK(ret, "iterate on map values");
+ }
+}
+
+static void test_create_nested_maps(void)
+{
+ if (!ASSERT_OK(create_inner_map(), "create inner map"))
+ return;
+ if (!ASSERT_OK(create_outer_map(), "create outer map"))
+ goto end_cleanup_inner;
+ ASSERT_OK(add_outer_map_entry(0), "add a first entry in outer map");
+ ASSERT_OK(add_outer_map_entry(1), "add a second entry in outer map");
+ ASSERT_NEQ(add_outer_map_entry(2), 0, "add a third entry in outer map");
+
+ delete_pinned_map(OUTER_MAP_NAME);
+end_cleanup_inner:
+ delete_pinned_map(INNER_MAP_NAME);
+}
+
+static void test_btf_list(void)
+{
+ ASSERT_OK(run_bpftool_command("btf list"), "list btf data");
+}
+
+static struct test_desc tests[] = {
+ {
+ .name = "unprotected_unpinned",
+ .protection = UNPROTECTED,
+ .map_name = UNPROTECTED_MAP_NAME,
+ .pinned = false,
+ .write_must_fail = false,
+ },
+ {
+ .name = "unprotected_pinned",
+ .protection = UNPROTECTED,
+ .map_name = UNPROTECTED_MAP_NAME,
+ .pinned = true,
+ .write_must_fail = false,
+ },
+ {
+ .name = "protected_unpinned",
+ .protection = PROTECTED,
+ .map_name = UNPROTECTED_MAP_NAME,
+ .pinned = false,
+ .write_must_fail = true,
+ },
+ {
+ .name = "protected_pinned",
+ .protection = PROTECTED,
+ .map_name = UNPROTECTED_MAP_NAME,
+ .pinned = true,
+ .write_must_fail = true,
+ }
+};
+
+static const size_t tests_count = ARRAY_SIZE(tests);
+
+void test_maps_access(void)
+{
+ struct security_bpf_map *skel;
+ struct test_desc *current;
+ int i;
+
+ skel = general_setup();
+ if (!ASSERT_OK_PTR(skel, "prepare programs"))
+ goto cleanup;
+
+ for (i = 0; i < tests_count; i++) {
+ current = &tests[i];
+ test__start_subtest(current->name);
+ if (ASSERT_OK(test_setup(skel, current), "subtest setup"))
+ test_basic_access(current);
+ test_cleanup(current);
+ }
+ test__start_subtest("nested_maps");
+ test_create_nested_maps();
+ test__start_subtest("btf_list");
+ test_btf_list();
+
+cleanup:
+ general_cleanup(skel);
+}
+

--
2.52.0