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Date: Wed, 10 Apr 2019 13:36:31 -0700
From: Javier Honduvilla Coto <javierhonduco@...com>
To: <netdev@...r.kernel.org>
CC: <yhs@...com>, <kernel-team@...com>
Subject: [PATCH v5 bpf-next 3/3] bpf: add tests for bpf_descendant_of
Adding the following test cases:
- bpf_descendant_of(current->pid) == 1
- bpf_descendant_of(current->real_parent->pid) == 1
- bpf_descendant_of(1) == 1
- bpf_descendant_of(0) == 1
- bpf_descendant_of(-1) == 0
- bpf_descendant_of(current->children[0]->pid) == 0
Signed-off-by: Javier Honduvilla Coto <javierhonduco@...com>
---
tools/testing/selftests/bpf/.gitignore | 1 +
tools/testing/selftests/bpf/Makefile | 2 +-
tools/testing/selftests/bpf/bpf_helpers.h | 3 +
.../bpf/progs/test_descendant_of_kern.c | 46 +++
.../selftests/bpf/test_descendant_of_user.c | 268 ++++++++++++++++++
5 files changed, 319 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/progs/test_descendant_of_kern.c
create mode 100644 tools/testing/selftests/bpf/test_descendant_of_user.c
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 41e8a689aa77..ab8adac4bcb6 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -32,3 +32,4 @@ test_tcpnotify_user
test_libbpf
test_tcp_check_syncookie_user
alu32
+test_descendant_of_user
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 078283d073b0..dbe65853e8ca 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -23,7 +23,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user \
test_socket_cookie test_cgroup_storage test_select_reuseport test_section_names \
- test_netcnt test_tcpnotify_user test_sock_fields
+ test_netcnt test_tcpnotify_user test_sock_fields test_descendant_of_user
BPF_OBJ_FILES = $(patsubst %.c,%.o, $(notdir $(wildcard progs/*.c)))
TEST_GEN_FILES = $(BPF_OBJ_FILES)
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index e85d62cb53d0..c7ec64515373 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -1,4 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
+#include <sys/types.h>
+
#ifndef __BPF_HELPERS_H
#define __BPF_HELPERS_H
@@ -192,6 +194,7 @@ static int (*bpf_skb_ecn_set_ce)(void *ctx) =
static int (*bpf_tcp_check_syncookie)(struct bpf_sock *sk,
void *ip, int ip_len, void *tcp, int tcp_len) =
(void *) BPF_FUNC_tcp_check_syncookie;
+static int (*bpf_descendant_of)(pid_t pid) = (void *) BPF_FUNC_descendant_of;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
diff --git a/tools/testing/selftests/bpf/progs/test_descendant_of_kern.c b/tools/testing/selftests/bpf/progs/test_descendant_of_kern.c
new file mode 100644
index 000000000000..e7d3f02355a7
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_descendant_of_kern.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") pidmap = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(__u32),
+ .max_entries = 2,
+};
+
+struct bpf_map_def SEC("maps") resultmap = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(__u32),
+ .max_entries = 1,
+};
+
+SEC("tracepoint/syscalls/sys_enter_open")
+int trace(void *ctx)
+{
+ __u32 pid = bpf_get_current_pid_tgid();
+ __u32 current_key = 0, ancestor_key = 1, *expected_pid, *ancestor_pid;
+ __u32 *val;
+
+ expected_pid = bpf_map_lookup_elem(&pidmap, ¤t_key);
+ if (!expected_pid || *expected_pid != pid)
+ return 0;
+
+ ancestor_pid = bpf_map_lookup_elem(&pidmap, &ancestor_key);
+ if (!ancestor_pid)
+ return 0;
+
+ if (!bpf_descendant_of(*ancestor_pid))
+ return 0;
+
+ val = bpf_map_lookup_elem(&resultmap, ¤t_key);
+ if (val)
+ *val = *ancestor_pid;
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1;
diff --git a/tools/testing/selftests/bpf/test_descendant_of_user.c b/tools/testing/selftests/bpf/test_descendant_of_user.c
new file mode 100644
index 000000000000..cfcd6f9fb99a
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_descendant_of_user.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <syscall.h>
+#include <unistd.h>
+#include <linux/perf_event.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#define CHECK(condition, tag, format...) \
+ ({ \
+ int __ret = !!(condition); \
+ if (__ret) { \
+ printf("%s:FAIL:%s ", __func__, tag); \
+ printf(format); \
+ } else { \
+ printf("%s:PASS:%s\n", __func__, tag); \
+ } \
+ __ret; \
+ })
+
+static int bpf_find_map(const char *test, struct bpf_object *obj,
+ const char *name)
+{
+ struct bpf_map *map;
+
+ map = bpf_object__find_map_by_name(obj, name);
+ if (!map)
+ return -1;
+ return bpf_map__fd(map);
+}
+
+int main(int argc, char **argv)
+{
+ const char *probe_name = "syscalls/sys_enter_open";
+ const char *file = "test_descendant_of_kern.o";
+ int err, bytes, efd, prog_fd, pmu_fd;
+ int resultmap_fd, pidmap_fd;
+ struct perf_event_attr attr = {};
+ struct bpf_object *obj;
+ __u32 retrieved_ancestor_pid = 0;
+ __u32 key = 0, pid;
+ int exit_code = EXIT_FAILURE;
+ char buf[256];
+
+ int child_pid, ancestor_pid, root_fd, nonexistant = -42;
+ __u32 ancestor_key = 1;
+ int pipefd[2];
+ char marker[1];
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
+ if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno))
+ goto fail;
+
+ resultmap_fd = bpf_find_map(__func__, obj, "resultmap");
+ if (CHECK(resultmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
+ resultmap_fd, errno))
+ goto close_prog;
+
+ pidmap_fd = bpf_find_map(__func__, obj, "pidmap");
+ if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", pidmap_fd,
+ errno))
+ goto close_prog;
+
+ pid = getpid();
+ bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &pid, 0);
+
+ snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%s/id",
+ probe_name);
+ efd = open(buf, O_RDONLY, 0);
+ if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
+ goto close_prog;
+ bytes = read(efd, buf, sizeof(buf));
+ close(efd);
+ if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
+ "bytes %d errno %d\n", bytes, errno))
+ goto close_prog;
+
+ attr.config = strtol(buf, NULL, 0);
+ attr.type = PERF_TYPE_TRACEPOINT;
+ attr.sample_type = PERF_SAMPLE_RAW;
+ attr.sample_period = 1;
+ attr.wakeup_events = 1;
+
+ pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
+ if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
+ errno))
+ goto close_prog;
+
+ err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
+ if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
+ errno))
+ goto close_pmu;
+
+ err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
+ if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
+ errno))
+ goto close_pmu;
+
+ // Test on ourselve: descendant_of(current->pid) is true
+ bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &pid, 0);
+ bpf_map_update_elem(resultmap_fd, &key, &nonexistant, 0);
+
+ root_fd = open("/", O_RDONLY);
+ if (CHECK(efd < 0, "open", "errno %d\n", errno))
+ goto close_prog;
+ close(root_fd);
+
+ err = bpf_map_lookup_elem(resultmap_fd, &key, &retrieved_ancestor_pid);
+ if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
+ goto close_pmu;
+ if (CHECK(retrieved_ancestor_pid != pid,
+ "descendant_of is true with same pid", "%d == %d\n",
+ retrieved_ancestor_pid, pid))
+ goto close_pmu;
+
+ // Test that PID 1 an ancestor
+ bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
+ ancestor_pid = 1;
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &ancestor_pid, 0);
+ bpf_map_update_elem(resultmap_fd, &key, &nonexistant, 0);
+
+ root_fd = open("/", O_RDONLY);
+ if (CHECK(efd < 0, "open", "errno %d\n", errno))
+ goto close_prog;
+ close(root_fd);
+
+ err = bpf_map_lookup_elem(resultmap_fd, &key, &retrieved_ancestor_pid);
+ if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
+ goto close_pmu;
+ if (CHECK(retrieved_ancestor_pid != ancestor_pid,
+ "descendant_of reaches init", "%d == %d\n",
+ retrieved_ancestor_pid, ancestor_pid))
+ goto close_pmu;
+
+ // Test that PID 0 is an ancestor
+ bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
+ ancestor_pid = 0;
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &ancestor_pid, 0);
+ bpf_map_update_elem(resultmap_fd, &key, &nonexistant, 0);
+
+ root_fd = open("/", O_RDONLY);
+ if (CHECK(efd < 0, "open", "errno %d\n", errno))
+ goto close_prog;
+ close(root_fd);
+
+ err = bpf_map_lookup_elem(resultmap_fd, &key, &retrieved_ancestor_pid);
+ if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
+ goto close_pmu;
+ if (CHECK(retrieved_ancestor_pid != ancestor_pid,
+ "descendant_of does not go over init", "%d == %d\n",
+ retrieved_ancestor_pid, ancestor_pid))
+ goto close_pmu;
+
+ // Test that we don't go over PID 0
+ bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
+ ancestor_pid = -1;
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &ancestor_pid, 0);
+ bpf_map_update_elem(resultmap_fd, &key, &nonexistant, 0);
+
+ root_fd = open("/", O_RDONLY);
+ if (CHECK(efd < 0, "open", "errno %d\n", errno))
+ goto close_prog;
+ close(root_fd);
+
+ err = bpf_map_lookup_elem(resultmap_fd, &key, &retrieved_ancestor_pid);
+ if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
+ goto close_pmu;
+ if (CHECK(retrieved_ancestor_pid != nonexistant,
+ "descendant_of does not go over init", "%d == %d\n",
+ retrieved_ancestor_pid, nonexistant))
+ goto close_pmu;
+
+ // Test that we are an ancestor of our child
+ pipe(pipefd);
+ child_pid = fork();
+ if (child_pid == -1) {
+ printf("fork failed\n");
+ goto close_pmu;
+ } else if (child_pid == 0) {
+ close(pipefd[1]);
+ read(pipefd[0], &marker, 1);
+
+ root_fd = open("/", O_RDONLY);
+ if (CHECK(efd < 0, "open", "errno %d\n", errno))
+ goto close_prog;
+ close(root_fd);
+
+ close(pipefd[0]);
+ _exit(EXIT_SUCCESS);
+ } else {
+ close(pipefd[0]);
+ bpf_map_update_elem(resultmap_fd, &key, &nonexistant, 0);
+ bpf_map_update_elem(pidmap_fd, &key, &child_pid, 0);
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &pid, 0);
+
+ write(pipefd[1], &marker, 1);
+ wait(NULL);
+ close(pipefd[1]);
+
+ err = bpf_map_lookup_elem(resultmap_fd, &key,
+ &retrieved_ancestor_pid);
+ if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err,
+ errno))
+ goto close_pmu;
+ if (CHECK(retrieved_ancestor_pid != pid, "descendant_of of parent",
+ "%d == %d\n", retrieved_ancestor_pid, pid))
+ goto close_pmu;
+ }
+
+ // Test that a child of ours doesn't belong to our ancestors
+ bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
+ bpf_map_update_elem(resultmap_fd, &key, &nonexistant, 0);
+
+ pipe(pipefd);
+ child_pid = fork();
+ if (child_pid == -1) {
+ printf("fork failed\n");
+ goto close_pmu;
+ } else if (child_pid == 0) {
+ close(pipefd[1]);
+ read(pipefd[0], marker, 1);
+ close(pipefd[0]);
+ _exit(EXIT_SUCCESS);
+ } else {
+ close(pipefd[0]);
+
+ bpf_map_update_elem(pidmap_fd, &ancestor_key, &child_pid, 0);
+
+ root_fd = open("/", O_RDONLY);
+ if (CHECK(efd < 0, "open", "errno %d\n", errno))
+ goto close_prog;
+ close(root_fd);
+
+ write(pipefd[1], marker, 1);
+ wait(NULL);
+ close(pipefd[1]);
+
+ err = bpf_map_lookup_elem(resultmap_fd, &key,
+ &retrieved_ancestor_pid);
+ if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err,
+ errno))
+ goto close_pmu;
+ if (CHECK(retrieved_ancestor_pid != nonexistant, "descendant_of of child",
+ "%d == %d\n", retrieved_ancestor_pid, 0))
+ goto close_pmu;
+ }
+
+ exit_code = EXIT_SUCCESS;
+ printf("%s:PASS\n", argv[0]);
+
+close_pmu:
+ close(pmu_fd);
+close_prog:
+ bpf_object__close(obj);
+fail:
+ return exit_code;
+}
--
2.17.1
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