diff options
Diffstat (limited to 'tools/testing/selftests/bpf/test_verifier_log.c')
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier_log.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_verifier_log.c b/tools/testing/selftests/bpf/test_verifier_log.c new file mode 100644 index 000000000000..3cc0b561489e --- /dev/null +++ b/tools/testing/selftests/bpf/test_verifier_log.c @@ -0,0 +1,171 @@ +#include <errno.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +#include <linux/bpf.h> +#include <linux/filter.h> +#include <linux/unistd.h> + +#include <bpf/bpf.h> + +#define LOG_SIZE (1 << 20) + +#define err(str...) printf("ERROR: " str) + +static const struct bpf_insn code_sample[] = { + /* We need a few instructions to pass the min log length */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_map_lookup_elem), + BPF_EXIT_INSN(), +}; + +static inline __u64 ptr_to_u64(const void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + +static int load(char *log, size_t log_len, int log_level) +{ + union bpf_attr attr; + + bzero(&attr, sizeof(attr)); + attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; + attr.insn_cnt = (__u32)(sizeof(code_sample) / sizeof(struct bpf_insn)); + attr.insns = ptr_to_u64(code_sample); + attr.license = ptr_to_u64("GPL"); + attr.log_buf = ptr_to_u64(log); + attr.log_size = log_len; + attr.log_level = log_level; + + return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr)); +} + +static void check_ret(int ret, int exp_errno) +{ + if (ret > 0) { + close(ret); + err("broken sample loaded successfully!?\n"); + exit(1); + } + + if (!ret || errno != exp_errno) { + err("Program load returned: ret:%d/errno:%d, expected ret:%d/errno:%d\n", + ret, errno, -1, exp_errno); + exit(1); + } +} + +static void check_ones(const char *buf, size_t len, const char *msg) +{ + while (len--) + if (buf[len] != 1) { + err("%s", msg); + exit(1); + } +} + +static void test_log_good(char *log, size_t buf_len, size_t log_len, + size_t exp_len, int exp_errno, const char *full_log) +{ + size_t len; + int ret; + + memset(log, 1, buf_len); + + ret = load(log, log_len, 1); + check_ret(ret, exp_errno); + + len = strnlen(log, buf_len); + if (len == buf_len) { + err("verifier did not NULL terminate the log\n"); + exit(1); + } + if (exp_len && len != exp_len) { + err("incorrect log length expected:%zd have:%zd\n", + exp_len, len); + exit(1); + } + + if (strchr(log, 1)) { + err("verifier leaked a byte through\n"); + exit(1); + } + + check_ones(log + len + 1, buf_len - len - 1, + "verifier wrote bytes past NULL termination\n"); + + if (memcmp(full_log, log, LOG_SIZE)) { + err("log did not match expected output\n"); + exit(1); + } +} + +static void test_log_bad(char *log, size_t log_len, int log_level) +{ + int ret; + + ret = load(log, log_len, log_level); + check_ret(ret, EINVAL); + if (log) + check_ones(log, LOG_SIZE, + "verifier touched log with bad parameters\n"); +} + +int main(int argc, char **argv) +{ + char full_log[LOG_SIZE]; + char log[LOG_SIZE]; + size_t want_len; + int i; + + memset(log, 1, LOG_SIZE); + + /* Test incorrect attr */ + printf("Test log_level 0...\n"); + test_log_bad(log, LOG_SIZE, 0); + + printf("Test log_size < 128...\n"); + test_log_bad(log, 15, 1); + + printf("Test log_buff = NULL...\n"); + test_log_bad(NULL, LOG_SIZE, 1); + + /* Test with log big enough */ + printf("Test oversized buffer...\n"); + test_log_good(full_log, LOG_SIZE, LOG_SIZE, 0, EACCES, full_log); + + want_len = strlen(full_log); + + printf("Test exact buffer...\n"); + test_log_good(log, LOG_SIZE, want_len + 2, want_len, EACCES, full_log); + + printf("Test undersized buffers...\n"); + for (i = 0; i < 64; i++) { + full_log[want_len - i + 1] = 1; + full_log[want_len - i] = 0; + + test_log_good(log, LOG_SIZE, want_len + 1 - i, want_len - i, + ENOSPC, full_log); + } + + printf("test_verifier_log: OK\n"); + return 0; +} |