From e60e6962c503f337531f80e2752423b5bd885443 Mon Sep 17 00:00:00 2001 From: Dmitrii Banshchikov Date: Sat, 13 Nov 2021 18:22:27 +0400 Subject: [PATCH] selftests/bpf: Add tests for restricted helpers 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 Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211113142227.566439-3-me@ubique.spb.ru --- .../selftests/bpf/prog_tests/helper_restricted.c | 33 ++++ .../selftests/bpf/progs/test_helper_restricted.c | 123 +++++++++++++ tools/testing/selftests/bpf/test_verifier.c | 46 ++++- .../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 diff --git a/tools/testing/selftests/bpf/prog_tests/helper_restricted.c b/tools/testing/selftests/bpf/prog_tests/helper_restricted.c new file mode 100644 index 0000000..e1de5f8 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/helper_restricted.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#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); +} diff --git a/tools/testing/selftests/bpf/progs/test_helper_restricted.c b/tools/testing/selftests/bpf/progs/test_helper_restricted.c new file mode 100644 index 0000000..68d64c3 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_helper_restricted.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include + +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"; diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 25afe42..465ef3f 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -92,6 +92,7 @@ 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. @@ -604,8 +605,15 @@ static int create_cgroup_storage(bool percpu) * 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] */ @@ -616,6 +624,11 @@ 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) @@ -696,6 +709,29 @@ 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, @@ -722,6 +758,7 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type, 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)); @@ -907,6 +944,13 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type, 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 { diff --git a/tools/testing/selftests/bpf/verifier/helper_restricted.c b/tools/testing/selftests/bpf/verifier/helper_restricted.c new file mode 100644 index 0000000..a067b70 --- /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, +}, -- 2.7.4