This adds two tests for vgetrandom. The first one, vdso_test_chacha, simply checks that the assembly implementation of chacha20 matches that of libsodium, a basic sanity check that should catch most errors. The second, vdso_test_getrandom, is a full "libc-like" implementation of the userspace side of vgetrandom() support. It's meant to be used also as example code for libcs that might be integrating this.

Cc: linux-kselftest@vger.kernel.org Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com --- tools/include/asm/rwonce.h | 0 tools/testing/selftests/vDSO/.gitignore | 2 + tools/testing/selftests/vDSO/Makefile | 18 ++ .../testing/selftests/vDSO/vdso_test_chacha.c | 43 +++ .../selftests/vDSO/vdso_test_getrandom.c | 288 ++++++++++++++++++ 5 files changed, 351 insertions(+) create mode 100644 tools/include/asm/rwonce.h create mode 100644 tools/testing/selftests/vDSO/vdso_test_chacha.c create mode 100644 tools/testing/selftests/vDSO/vdso_test_getrandom.c

diff --git a/tools/include/asm/rwonce.h b/tools/include/asm/rwonce.h new file mode 100644 index 000000000000..e69de29bb2d1 diff --git a/tools/testing/selftests/vDSO/.gitignore b/tools/testing/selftests/vDSO/.gitignore index a8dc51af5a9c..30d5c8f0e5c7 100644 --- a/tools/testing/selftests/vDSO/.gitignore +++ b/tools/testing/selftests/vDSO/.gitignore @@ -6,3 +6,5 @@ vdso_test_correctness vdso_test_gettimeofday vdso_test_getcpu vdso_standalone_test_x86 +vdso_test_getrandom +vdso_test_chacha diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile index 98d8ba2afa00..3de8e7e052ae 100644 --- a/tools/testing/selftests/vDSO/Makefile +++ b/tools/testing/selftests/vDSO/Makefile @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 uname_M := $(shell uname -m 2>/dev/null || echo not) ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/) +SODIUM := $(shell pkg-config --libs libsodium 2>/dev/null)

TEST_GEN_PROGS := vdso_test_gettimeofday TEST_GEN_PROGS += vdso_test_getcpu @@ -10,6 +11,12 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64)) TEST_GEN_PROGS += vdso_standalone_test_x86 endif TEST_GEN_PROGS += vdso_test_correctness +ifeq ($(uname_M),x86_64) +TEST_GEN_PROGS += vdso_test_getrandom +ifneq ($(SODIUM),) +TEST_GEN_PROGS += vdso_test_chacha +endif +endif

CFLAGS := -std=gnu99

@@ -28,3 +35,14 @@ $(OUTPUT)/vdso_standalone_test_x86: CFLAGS +=-nostdlib -fno-asynchronous-unwind-

$(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c $(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl + +$(OUTPUT)/vdso_test_getrandom: parse_vdso.c +$(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \ + -isystem $(top_srcdir)/include/uapi + +$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/arch/$(ARCH)/entry/vdso/vgetrandom-chacha.S +$(OUTPUT)/vdso_test_chacha: CFLAGS += -idirafter $(top_srcdir)/tools/include \ + -isystem $(top_srcdir)/arch/$(ARCH)/include \ + -isystem $(top_srcdir)/include \ + -D__ASSEMBLY__ -DBULID_VDSO -DCONFIG_FUNCTION_ALIGNMENT=0 \ + -Wa,--noexecstack $(SODIUM) diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c new file mode 100644 index 000000000000..e38f44e5f803 --- /dev/null +++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022-2024 Jason A. Donenfeld Jason@zx2c4.com. All Rights Reserved. + */ + +#include <sodium/crypto_stream_chacha20.h> +#include <sys/random.h> +#include <string.h> +#include <stdint.h> +#include "../kselftest.h" + +extern void __arch_chacha20_blocks_nostack(uint8_t *dst_bytes, const uint8_t *key, uint32_t *counter, size_t nblocks); + +int main(int argc, char *argv[]) +{ + enum { TRIALS = 1000, BLOCKS = 128, BLOCK_SIZE = 64 }; + static const uint8_t nonce[8] = { 0 }; + uint32_t counter[2]; + uint8_t key[32]; + uint8_t output1[BLOCK_SIZE * BLOCKS], output2[BLOCK_SIZE * BLOCKS]; + + ksft_print_header(); + ksft_set_plan(1); + + for (unsigned int trial = 0; trial < TRIALS; ++trial) { + if (getrandom(key, sizeof(key), 0) != sizeof(key)) { + printf("getrandom() failed!\n"); + return KSFT_SKIP; + } + crypto_stream_chacha20(output1, sizeof(output1), nonce, key); + for (unsigned int split = 0; split < BLOCKS; ++split) { + memset(output2, 'X', sizeof(output2)); + memset(counter, 0, sizeof(counter)); + if (split) + __arch_chacha20_blocks_nostack(output2, key, counter, split); + __arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter, BLOCKS - split); + if (memcmp(output1, output2, sizeof(output1))) + return KSFT_FAIL; + } + } + ksft_test_result_pass("chacha: PASS\n"); + return KSFT_PASS; +} diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c new file mode 100644 index 000000000000..05122425a873 --- /dev/null +++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c @@ -0,0 +1,288 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022-2024 Jason A. Donenfeld Jason@zx2c4.com. All Rights Reserved. + */ + +#include <assert.h> +#include <pthread.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.h> +#include <signal.h> +#include <sys/auxv.h> +#include <sys/mman.h> +#include <sys/random.h> +#include <sys/syscall.h> +#include <sys/types.h> +#include <linux/random.h> + +#include "../kselftest.h" +#include "parse_vdso.h" + +#ifndef timespecsub +#define timespecsub(tsp, usp, vsp) \ + do { \ + (vsp)->tv_sec = (tsp)->tv_sec - (usp)->tv_sec; \ + (vsp)->tv_nsec = (tsp)->tv_nsec - (usp)->tv_nsec; \ + if ((vsp)->tv_nsec < 0) { \ + (vsp)->tv_sec--; \ + (vsp)->tv_nsec += 1000000000L; \ + } \ + } while (0) +#endif + +static struct { + pthread_mutex_t lock; + void **states; + size_t len, cap; +} grnd_allocator = { + .lock = PTHREAD_MUTEX_INITIALIZER +}; + +static struct { + ssize_t(*fn)(void *, size_t, unsigned long, void *, size_t); + pthread_key_t key; + pthread_once_t initialized; + struct vgetrandom_opaque_params params; +} grnd_ctx = { + .initialized = PTHREAD_ONCE_INIT +}; + +static void *vgetrandom_get_state(void) +{ + void *state = NULL; + + pthread_mutex_lock(&grnd_allocator.lock); + if (!grnd_allocator.len) { + size_t page_size = getpagesize(); + size_t new_cap; + size_t alloc_size, num = sysconf(_SC_NPROCESSORS_ONLN); /* Just a decent heuristic. */ + void *new_block, *new_states; + + alloc_size = (num * grnd_ctx.params.size_of_opaque_state + page_size - 1) & (~(page_size - 1)); + num = (page_size / grnd_ctx.params.size_of_opaque_state) * (alloc_size / page_size); + new_block = mmap(0, alloc_size, grnd_ctx.params.mmap_prot, grnd_ctx.params.mmap_flags, -1, 0); + if (new_block == MAP_FAILED) + goto out; + + new_cap = grnd_allocator.cap + num; + new_states = reallocarray(grnd_allocator.states, new_cap, sizeof(*grnd_allocator.states)); + if (!new_states) + goto unmap; + grnd_allocator.cap = new_cap; + grnd_allocator.states = new_states; + + for (size_t i = 0; i < num; ++i) { + if (((uintptr_t)new_block & (page_size - 1)) + grnd_ctx.params.size_of_opaque_state > page_size) + new_block = (void *)(((uintptr_t)new_block + page_size - 1) & (~(page_size - 1))); + grnd_allocator.states[i] = new_block; + new_block += grnd_ctx.params.size_of_opaque_state; + } + grnd_allocator.len = num; + goto success; + + unmap: + munmap(new_block, alloc_size); + goto out; + } +success: + state = grnd_allocator.states[--grnd_allocator.len]; + +out: + pthread_mutex_unlock(&grnd_allocator.lock); + return state; +} + +static void vgetrandom_put_state(void *state) +{ + if (!state) + return; + pthread_mutex_lock(&grnd_allocator.lock); + grnd_allocator.states[grnd_allocator.len++] = state; + pthread_mutex_unlock(&grnd_allocator.lock); +} + +static void vgetrandom_init(void) +{ + if (pthread_key_create(&grnd_ctx.key, vgetrandom_put_state) != 0) + return; + unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR); + if (!sysinfo_ehdr) { + printf("AT_SYSINFO_EHDR is not present!\n"); + exit(KSFT_SKIP); + } + vdso_init_from_sysinfo_ehdr(sysinfo_ehdr); + grnd_ctx.fn = (__typeof__(grnd_ctx.fn))vdso_sym("LINUX_2.6", "__vdso_getrandom"); + if (!grnd_ctx.fn) { + printf("__vdso_getrandom is missing!\n"); + exit(KSFT_FAIL); + } + if (grnd_ctx.fn(NULL, 0, 0, &grnd_ctx.params, ~0UL) != 0) { + printf("failed to fetch vgetrandom params!\n"); + exit(KSFT_FAIL); + } +} + +static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags) +{ + void *state; + + pthread_once(&grnd_ctx.initialized, vgetrandom_init); + state = pthread_getspecific(grnd_ctx.key); + if (!state) { + state = vgetrandom_get_state(); + if (pthread_setspecific(grnd_ctx.key, state) != 0) { + vgetrandom_put_state(state); + state = NULL; + } + if (!state) { + printf("vgetrandom_get_state failed!\n"); + exit(KSFT_FAIL); + } + } + return grnd_ctx.fn(buf, len, flags, state, grnd_ctx.params.size_of_opaque_state); +} + +enum { TRIALS = 25000000, THREADS = 256 }; + +static void *test_vdso_getrandom(void *) +{ + for (size_t i = 0; i < TRIALS; ++i) { + unsigned int val; + ssize_t ret = vgetrandom(&val, sizeof(val), 0); + assert(ret == sizeof(val)); + } + return NULL; +} + +static void *test_libc_getrandom(void *) +{ + for (size_t i = 0; i < TRIALS; ++i) { + unsigned int val; + ssize_t ret = getrandom(&val, sizeof(val), 0); + assert(ret == sizeof(val)); + } + return NULL; +} + +static void *test_syscall_getrandom(void *) +{ + for (size_t i = 0; i < TRIALS; ++i) { + unsigned int val; + ssize_t ret = syscall(__NR_getrandom, &val, sizeof(val), 0); + assert(ret == sizeof(val)); + } + return NULL; +} + +static void bench_single(void) +{ + struct timespec start, end, diff; + + clock_gettime(CLOCK_MONOTONIC, &start); + test_vdso_getrandom(NULL); + clock_gettime(CLOCK_MONOTONIC, &end); + timespecsub(&end, &start, &diff); + printf(" vdso: %u times in %lu.%09lu seconds\n", TRIALS, diff.tv_sec, diff.tv_nsec); + + clock_gettime(CLOCK_MONOTONIC, &start); + test_libc_getrandom(NULL); + clock_gettime(CLOCK_MONOTONIC, &end); + timespecsub(&end, &start, &diff); + printf(" libc: %u times in %lu.%09lu seconds\n", TRIALS, diff.tv_sec, diff.tv_nsec); + + clock_gettime(CLOCK_MONOTONIC, &start); + test_syscall_getrandom(NULL); + clock_gettime(CLOCK_MONOTONIC, &end); + timespecsub(&end, &start, &diff); + printf("syscall: %u times in %lu.%09lu seconds\n", TRIALS, diff.tv_sec, diff.tv_nsec); +} + +static void bench_multi(void) +{ + struct timespec start, end, diff; + pthread_t threads[THREADS]; + + clock_gettime(CLOCK_MONOTONIC, &start); + for (size_t i = 0; i < THREADS; ++i) + assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0); + for (size_t i = 0; i < THREADS; ++i) + pthread_join(threads[i], NULL); + clock_gettime(CLOCK_MONOTONIC, &end); + timespecsub(&end, &start, &diff); + printf(" vdso: %u x %u times in %lu.%09lu seconds\n", TRIALS, THREADS, diff.tv_sec, diff.tv_nsec); + + clock_gettime(CLOCK_MONOTONIC, &start); + for (size_t i = 0; i < THREADS; ++i) + assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0); + for (size_t i = 0; i < THREADS; ++i) + pthread_join(threads[i], NULL); + clock_gettime(CLOCK_MONOTONIC, &end); + timespecsub(&end, &start, &diff); + printf(" libc: %u x %u times in %lu.%09lu seconds\n", TRIALS, THREADS, diff.tv_sec, diff.tv_nsec); + + clock_gettime(CLOCK_MONOTONIC, &start); + for (size_t i = 0; i < THREADS; ++i) + assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0); + for (size_t i = 0; i < THREADS; ++i) + pthread_join(threads[i], NULL); + clock_gettime(CLOCK_MONOTONIC, &end); + timespecsub(&end, &start, &diff); + printf(" syscall: %u x %u times in %lu.%09lu seconds\n", TRIALS, THREADS, diff.tv_sec, diff.tv_nsec); +} + +static void fill(void) +{ + uint8_t weird_size[323929]; + for (;;) + vgetrandom(weird_size, sizeof(weird_size), 0); +} + +static void kselftest(void) +{ + uint8_t weird_size[1263]; + + ksft_print_header(); + ksft_set_plan(1); + + for (size_t i = 0; i < 1000; ++i) { + ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0); + if (ret != sizeof(weird_size)) + exit(KSFT_FAIL); + } + + ksft_test_result_pass("getrandom: PASS\n"); + exit(KSFT_PASS); +} + +static void usage(const char *argv0) +{ + fprintf(stderr, "Usage: %s [bench-single|bench-multi|fill]\n", argv0); +} + +int main(int argc, char *argv[]) +{ + if (argc == 1) { + kselftest(); + return 0; + } + + if (argc != 2) { + usage(argv[0]); + return 1; + } + if (!strcmp(argv[1], "bench-single")) + bench_single(); + else if (!strcmp(argv[1], "bench-multi")) + bench_multi(); + else if (!strcmp(argv[1], "fill")) + fill(); + else { + usage(argv[0]); + return 1; + } + return 0; +}