forked from Minki/linux
selftests/bpf: add a test for verifier logs
Add a test for verifier log handling. Check bad attr combinations but focus on cases when log is truncated. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski
David S. Miller
parent
442d713baa
commit
a99ca6dbf4
@ -12,7 +12,7 @@ CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) -I../../../i
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LDLIBS += -lcap -lelf
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TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
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test_align
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test_align test_verifier_log
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TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
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test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
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171
tools/testing/selftests/bpf/test_verifier_log.c
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171
tools/testing/selftests/bpf/test_verifier_log.c
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@ -0,0 +1,171 @@
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#include <errno.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <linux/bpf.h>
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#include <linux/filter.h>
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#include <linux/unistd.h>
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#include <bpf/bpf.h>
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#define LOG_SIZE (1 << 20)
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#define err(str...) printf("ERROR: " str)
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static const struct bpf_insn code_sample[] = {
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/* We need a few instructions to pass the min log length */
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
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BPF_FUNC_map_lookup_elem),
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BPF_EXIT_INSN(),
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};
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static inline __u64 ptr_to_u64(const void *ptr)
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{
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return (__u64) (unsigned long) ptr;
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}
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static int load(char *log, size_t log_len, int log_level)
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{
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union bpf_attr attr;
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bzero(&attr, sizeof(attr));
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attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
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attr.insn_cnt = (__u32)(sizeof(code_sample) / sizeof(struct bpf_insn));
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attr.insns = ptr_to_u64(code_sample);
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attr.license = ptr_to_u64("GPL");
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attr.log_buf = ptr_to_u64(log);
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attr.log_size = log_len;
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attr.log_level = log_level;
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return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
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}
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static void check_ret(int ret, int exp_errno)
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{
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if (ret > 0) {
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close(ret);
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err("broken sample loaded successfully!?\n");
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exit(1);
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}
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if (!ret || errno != exp_errno) {
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err("Program load returned: ret:%d/errno:%d, expected ret:%d/errno:%d\n",
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ret, errno, -1, exp_errno);
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exit(1);
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}
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}
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static void check_ones(const char *buf, size_t len, const char *msg)
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{
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while (len--)
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if (buf[len] != 1) {
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err("%s", msg);
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exit(1);
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}
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}
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static void test_log_good(char *log, size_t buf_len, size_t log_len,
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size_t exp_len, int exp_errno, const char *full_log)
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{
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size_t len;
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int ret;
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memset(log, 1, buf_len);
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ret = load(log, log_len, 1);
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check_ret(ret, exp_errno);
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len = strnlen(log, buf_len);
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if (len == buf_len) {
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err("verifier did not NULL terminate the log\n");
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exit(1);
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}
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if (exp_len && len != exp_len) {
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err("incorrect log length expected:%zd have:%zd\n",
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exp_len, len);
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exit(1);
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}
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if (strchr(log, 1)) {
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err("verifier leaked a byte through\n");
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exit(1);
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}
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check_ones(log + len + 1, buf_len - len - 1,
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"verifier wrote bytes past NULL termination\n");
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if (memcmp(full_log, log, LOG_SIZE)) {
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err("log did not match expected output\n");
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exit(1);
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}
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}
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static void test_log_bad(char *log, size_t log_len, int log_level)
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{
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int ret;
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ret = load(log, log_len, log_level);
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check_ret(ret, EINVAL);
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if (log)
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check_ones(log, LOG_SIZE,
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"verifier touched log with bad parameters\n");
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}
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int main(int argc, char **argv)
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{
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char full_log[LOG_SIZE];
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char log[LOG_SIZE];
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size_t want_len;
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int i;
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memset(log, 1, LOG_SIZE);
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/* Test incorrect attr */
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printf("Test log_level 0...\n");
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test_log_bad(log, LOG_SIZE, 0);
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printf("Test log_size < 128...\n");
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test_log_bad(log, 15, 1);
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printf("Test log_buff = NULL...\n");
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test_log_bad(NULL, LOG_SIZE, 1);
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/* Test with log big enough */
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printf("Test oversized buffer...\n");
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test_log_good(full_log, LOG_SIZE, LOG_SIZE, 0, EACCES, full_log);
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want_len = strlen(full_log);
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printf("Test exact buffer...\n");
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test_log_good(log, LOG_SIZE, want_len + 2, want_len, EACCES, full_log);
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printf("Test undersized buffers...\n");
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for (i = 0; i < 64; i++) {
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full_log[want_len - i + 1] = 1;
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full_log[want_len - i] = 0;
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test_log_good(log, LOG_SIZE, want_len + 1 - i, want_len - i,
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ENOSPC, full_log);
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}
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printf("test_verifier_log: OK\n");
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return 0;
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}
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