From: Dmitrii Banshchikov <me@ubique.spb.ru>
Date: Sat, 13 Nov 2021 18:22:27 +0400
Subject: selftests/bpf: Add tests for restricted helpers
Patch-mainline: v5.16-rc2
Git-commit: e60e6962c503f337531f80e2752423b5bd885443
References: jsc#PED-1377
This patch adds tests that bpf_ktime_get_coarse_ns(), bpf_timer_* and
bpf_spin_lock()/bpf_spin_unlock() helpers are forbidden in tracing progs
as their use there may result in various locking issues.
Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211113142227.566439-3-me@ubique.spb.ru
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/testing/selftests/bpf/prog_tests/helper_restricted.c | 33 ++
tools/testing/selftests/bpf/progs/test_helper_restricted.c | 123 ++++++++
tools/testing/selftests/bpf/test_verifier.c | 46 ++-
tools/testing/selftests/bpf/verifier/helper_restricted.c | 196 +++++++++++++
4 files changed, 397 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/helper_restricted.c
create mode 100644 tools/testing/selftests/bpf/progs/test_helper_restricted.c
create mode 100644 tools/testing/selftests/bpf/verifier/helper_restricted.c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/helper_restricted.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include "test_helper_restricted.skel.h"
+
+void test_helper_restricted(void)
+{
+ int prog_i = 0, prog_cnt;
+ int duration = 0;
+
+ do {
+ struct test_helper_restricted *test;
+ int maybeOK;
+
+ test = test_helper_restricted__open();
+ if (!ASSERT_OK_PTR(test, "open"))
+ return;
+
+ prog_cnt = test->skeleton->prog_cnt;
+
+ for (int j = 0; j < prog_cnt; ++j) {
+ struct bpf_program *prog = *test->skeleton->progs[j].prog;
+
+ maybeOK = bpf_program__set_autoload(prog, prog_i == j);
+ ASSERT_OK(maybeOK, "set autoload");
+ }
+
+ maybeOK = test_helper_restricted__load(test);
+ CHECK(!maybeOK, test->skeleton->progs[prog_i].name, "helper isn't restricted");
+
+ test_helper_restricted__destroy(test);
+ } while (++prog_i < prog_cnt);
+}
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_helper_restricted.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <time.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct timer {
+ struct bpf_timer t;
+};
+
+struct lock {
+ struct bpf_spin_lock l;
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, struct timer);
+} timers SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, struct lock);
+} locks SEC(".maps");
+
+static int timer_cb(void *map, int *key, struct timer *timer)
+{
+ return 0;
+}
+
+static void timer_work(void)
+{
+ struct timer *timer;
+ const int key = 0;
+
+ timer = bpf_map_lookup_elem(&timers, &key);
+ if (timer) {
+ bpf_timer_init(&timer->t, &timers, CLOCK_MONOTONIC);
+ bpf_timer_set_callback(&timer->t, timer_cb);
+ bpf_timer_start(&timer->t, 10E9, 0);
+ bpf_timer_cancel(&timer->t);
+ }
+}
+
+static void spin_lock_work(void)
+{
+ const int key = 0;
+ struct lock *lock;
+
+ lock = bpf_map_lookup_elem(&locks, &key);
+ if (lock) {
+ bpf_spin_lock(&lock->l);
+ bpf_spin_unlock(&lock->l);
+ }
+}
+
+SEC("raw_tp/sys_enter")
+int raw_tp_timer(void *ctx)
+{
+ timer_work();
+
+ return 0;
+}
+
+SEC("tp/syscalls/sys_enter_nanosleep")
+int tp_timer(void *ctx)
+{
+ timer_work();
+
+ return 0;
+}
+
+SEC("kprobe/sys_nanosleep")
+int kprobe_timer(void *ctx)
+{
+ timer_work();
+
+ return 0;
+}
+
+SEC("perf_event")
+int perf_event_timer(void *ctx)
+{
+ timer_work();
+
+ return 0;
+}
+
+SEC("raw_tp/sys_enter")
+int raw_tp_spin_lock(void *ctx)
+{
+ spin_lock_work();
+
+ return 0;
+}
+
+SEC("tp/syscalls/sys_enter_nanosleep")
+int tp_spin_lock(void *ctx)
+{
+ spin_lock_work();
+
+ return 0;
+}
+
+SEC("kprobe/sys_nanosleep")
+int kprobe_spin_lock(void *ctx)
+{
+ spin_lock_work();
+
+ return 0;
+}
+
+SEC("perf_event")
+int perf_event_spin_lock(void *ctx)
+{
+ spin_lock_work();
+
+ return 0;
+}
+
+const char LICENSE[] SEC("license") = "GPL";
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -88,6 +88,7 @@ struct bpf_test {
int fixup_map_event_output[MAX_FIXUPS];
int fixup_map_reuseport_array[MAX_FIXUPS];
int fixup_map_ringbuf[MAX_FIXUPS];
+ int fixup_map_timer[MAX_FIXUPS];
/* Expected verifier log output for result REJECT or VERBOSE_ACCEPT.
* Can be a tab-separated sequence of expected strings. An empty string
* means no log verification.
@@ -600,8 +601,15 @@ static int create_cgroup_storage(bool pe
* int cnt;
* struct bpf_spin_lock l;
* };
+ * struct bpf_timer {
+ * __u64 :64;
+ * __u64 :64;
+ * } __attribute__((aligned(8)));
+ * struct timer {
+ * struct bpf_timer t;
+ * };
*/
-static const char btf_str_sec[] = "\0bpf_spin_lock\0val\0cnt\0l";
+static const char btf_str_sec[] = "\0bpf_spin_lock\0val\0cnt\0l\0bpf_timer\0timer\0t";
static __u32 btf_raw_types[] = {
/* int */
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
@@ -612,6 +620,11 @@ static __u32 btf_raw_types[] = {
BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
+ /* struct bpf_timer */ /* [4] */
+ BTF_TYPE_ENC(25, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0), 16),
+ /* struct timer */ /* [5] */
+ BTF_TYPE_ENC(35, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 16),
+ BTF_MEMBER_ENC(41, 4, 0), /* struct bpf_timer t; */
};
static int load_btf(void)
@@ -692,6 +705,29 @@ static int create_sk_storage_map(void)
return fd;
}
+static int create_map_timer(void)
+{
+ struct bpf_create_map_attr attr = {
+ .name = "test_map",
+ .map_type = BPF_MAP_TYPE_ARRAY,
+ .key_size = 4,
+ .value_size = 16,
+ .max_entries = 1,
+ .btf_key_type_id = 1,
+ .btf_value_type_id = 5,
+ };
+ int fd, btf_fd;
+
+ btf_fd = load_btf();
+ if (btf_fd < 0)
+ return -1;
+ attr.btf_fd = btf_fd;
+ fd = bpf_create_map_xattr(&attr);
+ if (fd < 0)
+ printf("Failed to create map with timer\n");
+ return fd;
+}
+
static char bpf_vlog[UINT_MAX >> 8];
static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
@@ -718,6 +754,7 @@ static void do_test_fixup(struct bpf_tes
int *fixup_map_event_output = test->fixup_map_event_output;
int *fixup_map_reuseport_array = test->fixup_map_reuseport_array;
int *fixup_map_ringbuf = test->fixup_map_ringbuf;
+ int *fixup_map_timer = test->fixup_map_timer;
if (test->fill_helper) {
test->fill_insns = calloc(MAX_TEST_INSNS, sizeof(struct bpf_insn));
@@ -903,6 +940,13 @@ static void do_test_fixup(struct bpf_tes
fixup_map_ringbuf++;
} while (*fixup_map_ringbuf);
}
+ if (*fixup_map_timer) {
+ map_fds[21] = create_map_timer();
+ do {
+ prog[*fixup_map_timer].imm = map_fds[21];
+ fixup_map_timer++;
+ } while (*fixup_map_timer);
+ }
}
struct libcap {
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/helper_restricted.c
@@ -0,0 +1,196 @@
+{
+ "bpf_ktime_get_coarse_ns is forbidden in BPF_PROG_TYPE_KPROBE",
+ .insns = {
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ktime_get_coarse_ns),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "unknown func bpf_ktime_get_coarse_ns",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_KPROBE,
+},
+{
+ "bpf_ktime_get_coarse_ns is forbidden in BPF_PROG_TYPE_TRACEPOINT",
+ .insns = {
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ktime_get_coarse_ns),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "unknown func bpf_ktime_get_coarse_ns",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+},
+{
+ "bpf_ktime_get_coarse_ns is forbidden in BPF_PROG_TYPE_PERF_EVENT",
+ .insns = {
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ktime_get_coarse_ns),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "unknown func bpf_ktime_get_coarse_ns",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+},
+{
+ "bpf_ktime_get_coarse_ns is forbidden in BPF_PROG_TYPE_RAW_TRACEPOINT",
+ .insns = {
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ktime_get_coarse_ns),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "unknown func bpf_ktime_get_coarse_ns",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT,
+},
+{
+ "bpf_timer_init isn restricted in BPF_PROG_TYPE_KPROBE",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 1),
+ BPF_EMIT_CALL(BPF_FUNC_timer_init),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_timer = { 3, 8 },
+ .errstr = "tracing progs cannot use bpf_timer yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_KPROBE,
+},
+{
+ "bpf_timer_init is forbidden in BPF_PROG_TYPE_PERF_EVENT",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 1),
+ BPF_EMIT_CALL(BPF_FUNC_timer_init),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_timer = { 3, 8 },
+ .errstr = "tracing progs cannot use bpf_timer yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+},
+{
+ "bpf_timer_init is forbidden in BPF_PROG_TYPE_TRACEPOINT",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 1),
+ BPF_EMIT_CALL(BPF_FUNC_timer_init),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_timer = { 3, 8 },
+ .errstr = "tracing progs cannot use bpf_timer yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+},
+{
+ "bpf_timer_init is forbidden in BPF_PROG_TYPE_RAW_TRACEPOINT",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 1),
+ BPF_EMIT_CALL(BPF_FUNC_timer_init),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_timer = { 3, 8 },
+ .errstr = "tracing progs cannot use bpf_timer yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT,
+},
+{
+ "bpf_spin_lock is forbidden in BPF_PROG_TYPE_KPROBE",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_spin_lock),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_spin_lock = { 3 },
+ .errstr = "tracing progs cannot use bpf_spin_lock yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_KPROBE,
+},
+{
+ "bpf_spin_lock is forbidden in BPF_PROG_TYPE_TRACEPOINT",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_spin_lock),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_spin_lock = { 3 },
+ .errstr = "tracing progs cannot use bpf_spin_lock yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+},
+{
+ "bpf_spin_lock is forbidden in BPF_PROG_TYPE_PERF_EVENT",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_spin_lock),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_spin_lock = { 3 },
+ .errstr = "tracing progs cannot use bpf_spin_lock yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_PERF_EVENT,
+},
+{
+ "bpf_spin_lock is forbidden in BPF_PROG_TYPE_RAW_TRACEPOINT",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_spin_lock),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_spin_lock = { 3 },
+ .errstr = "tracing progs cannot use bpf_spin_lock yet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT,
+},