path: root/samples/bpf/test_verifier.c

/*
 * Testsuite for eBPF verifier
 *
 * Copyright (c) 2014 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include <stdio.h>
#include <unistd.h>
#include <linux/bpf.h>
#include <errno.h>
#include <linux/unistd.h>
#include <string.h>
#include <linux/filter.h>
#include "libbpf.h"

#define MAX_INSNS 512
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))

struct bpf_test {
	const char *descr;
	struct bpf_insn	insns[MAX_INSNS];
	int fixup[32];
	const char *errstr;
	enum {
		ACCEPT,
		REJECT
	} result;
};

static struct bpf_test tests[] = {
	{
		"add+sub+mul",
		.insns = {
			BPF_MOV64_IMM(BPF_REG_1, 1),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 2),
			BPF_MOV64_IMM(BPF_REG_2, 3),
			BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_2),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -1),
			BPF_ALU64_IMM(BPF_MUL, BPF_REG_1, 3),
			BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
			BPF_EXIT_INSN(),
		},
		.result = ACCEPT,
	},
	{
		"unreachable",
		.insns = {
			BPF_EXIT_INSN(),
			BPF_EXIT_INSN(),
		},
		.errstr = "unreachable",
		.result = REJECT,
	},
	{
		"unreachable2",
		.insns = {
			BPF_JMP_IMM(BPF_JA, 0, 0, 1),
			BPF_JMP_IMM(BPF_JA, 0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "unreachable",
		.result = REJECT,
	},
	{
		"out of range jump",
		.insns = {
			BPF_JMP_IMM(BPF_JA, 0, 0, 1),
			BPF_EXIT_INSN(),
		},
		.errstr = "jump out of range",
		.result = REJECT,
	},
	{
		"out of range jump2",
		.insns = {
			BPF_JMP_IMM(BPF_JA, 0, 0, -2),
			BPF_EXIT_INSN(),
		},
		.errstr = "jump out of range",
		.result = REJECT,
	},
	{
		"test1 ld_imm64",
		.insns = {
			BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
			BPF_LD_IMM64(BPF_REG_0, 0),
			BPF_LD_IMM64(BPF_REG_0, 0),
			BPF_LD_IMM64(BPF_REG_0, 1),
			BPF_LD_IMM64(BPF_REG_0, 1),
			BPF_MOV64_IMM(BPF_REG_0, 2),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid BPF_LD_IMM insn",
		.result = REJECT,
	},
	{
		"test2 ld_imm64",
		.insns = {
			BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
			BPF_LD_IMM64(BPF_REG_0, 0),
			BPF_LD_IMM64(BPF_REG_0, 0),
			BPF_LD_IMM64(BPF_REG_0, 1),
			BPF_LD_IMM64(BPF_REG_0, 1),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid BPF_LD_IMM insn",
		.result = REJECT,
	},
	{
		"test3 ld_imm64",
		.insns = {
			BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
			BPF_RAW_INSN(BPF_LD | BPF_IMM | BPF_DW, 0, 0, 0, 0),
			BPF_LD_IMM64(BPF_REG_0, 0),
			BPF_LD_IMM64(BPF_REG_0, 0),
			BPF_LD_IMM64(BPF_REG_0, 1),
			BPF_LD_IMM64(BPF_REG_0, 1),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid bpf_ld_imm64 insn",
		.result = REJECT,
	},
	{
		"test4 ld_imm64",
		.insns = {
			BPF_RAW_INSN(BPF_LD | BPF_IMM | BPF_DW, 0, 0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid bpf_ld_imm64 insn",
		.result = REJECT,
	},
	{
		"test5 ld_imm64",
		.insns = {
			BPF_RAW_INSN(BPF_LD | BPF_IMM | BPF_DW, 0, 0, 0, 0),
		},
		.errstr = "invalid bpf_ld_imm64 insn",
		.result = REJECT,
	},
	{
		"no bpf_exit",
		.insns = {
			BPF_ALU64_REG(BPF_MOV, BPF_REG_0, BPF_REG_2),
		},
		.errstr = "jump out of range",
		.result = REJECT,
	},
	{
		"loop (back-edge)",
		.insns = {
			BPF_JMP_IMM(BPF_JA, 0, 0, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "back-edge",
		.result = REJECT,
	},
	{
		"loop2 (back-edge)",
		.insns = {
			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
			BPF_MOV64_REG(BPF_REG_3, BPF_REG_0),
			BPF_JMP_IMM(BPF_JA, 0, 0, -4),
			BPF_EXIT_INSN(),
		},
		.errstr = "back-edge",
		.result = REJECT,
	},
	{
		"conditional loop",
		.insns = {
			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
			BPF_MOV64_REG(BPF_REG_3, BPF_REG_0),
			BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, -3),
			BPF_EXIT_INSN(),
		},
		.errstr = "back-edge",
		.result = REJECT,
	},
	{
		"read uninitialized register",
		.insns = {
			BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
			BPF_EXIT_INSN(),
		},
		.errstr = "R2 !read_ok",
		.result = REJECT,
	},
	{
		"read invalid register",
		.insns = {
			BPF_MOV64_REG(BPF_REG_0, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "R15 is invalid",
		.result = REJECT,
	},
	{
		"program doesn't init R0 before exit",
		.insns = {
			BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_1),
			BPF_EXIT_INSN(),
		},
		.errstr = "R0 !read_ok",
		.result = REJECT,
	},
	{
		"stack out of bounds",
		.insns = {
			BPF_ST_MEM(BPF_DW, BPF_REG_10, 8, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid stack",
		.result = REJECT,
	},
	{
		"invalid call insn1",
		.insns = {
			BPF_RAW_INSN(BPF_JMP | BPF_CALL | BPF_X, 0, 0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "BPF_CALL uses reserved",
		.result = REJECT,
	},
	{
		"invalid call insn2",
		.insns = {
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 1, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "BPF_CALL uses reserved",
		.result = REJECT,
	},
	{
		"invalid function call",
		.insns = {
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, 1234567),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid func 1234567",
		.result = REJECT,
	},
	{
		"uninitialized stack1",
		.insns = {
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
			BPF_LD_MAP_FD(BPF_REG_1, 0),
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_unspec),
			BPF_EXIT_INSN(),
		},
		.fixup = {2},
		.errstr = "invalid indirect read from stack",
		.result = REJECT,
	},
	{
		"uninitialized stack2",
		.insns = {
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, -8),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid read from stack",
		.result = REJECT,
	},
	{
		"check valid spill/fill",
		.insns = {
			/* spill R1(ctx) into stack */
			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8),

			/* fill it back into R2 */
			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -8),

			/* should be able to access R0 = *(R2 + 8) */
			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 8),
			BPF_EXIT_INSN(),
		},
		.result = ACCEPT,
	},
	{
		"check corrupted spill/fill",
		.insns = {
			/* spill R1(ctx) into stack */
			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8),

			/* mess up with R1 pointer on stack */
			BPF_ST_MEM(BPF_B, BPF_REG_10, -7, 0x23),

			/* fill back into R0 should fail */
			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),

			BPF_EXIT_INSN(),
		},
		.errstr = "corrupted spill",
		.result = REJECT,
	},
	{
		"invalid src register in STX",
		.insns = {
			BPF_STX_MEM(BPF_B, BPF_REG_10, -1, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "R15 is invalid",
		.result = REJECT,
	},
	{
		"invalid dst register in STX",
		.insns = {
			BPF_STX_MEM(BPF_B, 14, BPF_REG_10, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "R14 is invalid",
		.result = REJECT,
	},
	{
		"invalid dst register in ST",
		.insns = {
			BPF_ST_MEM(BPF_B, 14, -1, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "R14 is invalid",
		.result = REJECT,
	},
	{
		"invalid src register in LDX",
		.insns = {
			BPF_LDX_MEM(BPF_B, BPF_REG_0, 12, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "R12 is invalid",
		.result = REJECT,
	},
	{
		"invalid dst register in LDX",
		.insns = {
			BPF_LDX_MEM(BPF_B, 11, BPF_REG_1, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "R11 is invalid",
		.result = REJECT,
	},
	{
		"junk insn",
		.insns = {
			BPF_RAW_INSN(0, 0, 0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid BPF_LD_IMM",
		.result = REJECT,
	},
	{
		"junk insn2",
		.insns = {
			BPF_RAW_INSN(1, 0, 0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "BPF_LDX uses reserved fields",
		.result = REJECT,
	},
	{
		"junk insn3",
		.insns = {
			BPF_RAW_INSN(-1, 0, 0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid BPF_ALU opcode f0",
		.result = REJECT,
	},
	{
		"junk insn4",
		.insns = {
			BPF_RAW_INSN(-1, -1, -1, -1, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "invalid BPF_ALU opcode f0",
		.result = REJECT,
	},
	{
		"junk insn5",
		.insns = {
			BPF_RAW_INSN(0x7f, -1, -1, -1, -1),
			BPF_EXIT_INSN(),
		},
		.errstr = "BPF_ALU uses reserved fields",
		.result = REJECT,
	},
	{
		"misaligned read from stack",
		.insns = {
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, -4),
			BPF_EXIT_INSN(),
		},
		.errstr = "misaligned access",
		.result = REJECT,
	},
	{
		"invalid map_fd for function call",
		.insns = {
			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
			BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_10),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
			BPF_LD_MAP_FD(BPF_REG_1, 0),
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_unspec),
			BPF_EXIT_INSN(),
		},
		.errstr = "fd 0 is not pointing to valid bpf_map",
		.result = REJECT,
	},
	{
		"don't check return value before access",
		.insns = {
			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
			BPF_LD_MAP_FD(BPF_REG_1, 0),
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_unspec),
			BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
			BPF_EXIT_INSN(),
		},
		.fixup = {3},
		.errstr = "R0 invalid mem access 'map_value_or_null'",
		.result = REJECT,
	},
	{
		"access memory with incorrect alignment",
		.insns = {
			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
			BPF_LD_MAP_FD(BPF_REG_1, 0),
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_unspec),
			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
			BPF_ST_MEM(BPF_DW, BPF_REG_0, 4, 0),
			BPF_EXIT_INSN(),
		},
		.fixup = {3},
		.errstr = "misaligned access",
		.result = REJECT,
	},
	{
		"sometimes access memory with incorrect alignment",
		.insns = {
			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
			BPF_LD_MAP_FD(BPF_REG_1, 0),
			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_unspec),
			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
			BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
			BPF_EXIT_INSN(),
			BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 1),
			BPF_EXIT_INSN(),
		},
		.fixup = {3},
		.errstr = "R0 invalid mem access",
		.result = REJECT,
	},
};

static int probe_filter_length(struct bpf_insn *fp)
{
	int len = 0;

	for (len = MAX_INSNS - 1; len > 0; --len)
		if (fp[len].code != 0 || fp[len].imm != 0)
			break;

	return len + 1;
}

static int create_map(void)
{
	long long key, value = 0;
	int map_fd;

	map_fd = bpf_create_map(BPF_MAP_TYPE_UNSPEC, sizeof(key), sizeof(value), 1024);
	if (map_fd < 0) {
		printf("failed to create map '%s'\n", strerror(errno));
	}

	return map_fd;
}

static int test(void)
{
	int prog_fd, i;

	for (i = 0; i < ARRAY_SIZE(tests); i++) {
		struct bpf_insn *prog = tests[i].insns;
		int prog_len = probe_filter_length(prog);
		int *fixup = tests[i].fixup;
		int map_fd = -1;

		if (*fixup) {
			map_fd = create_map();

			do {
				prog[*fixup].imm = map_fd;
				fixup++;
			} while (*fixup);
		}
		printf("#%d %s ", i, tests[i].descr);

		prog_fd = bpf_prog_load(BPF_PROG_TYPE_UNSPEC, prog,
					prog_len * sizeof(struct bpf_insn),
					"GPL");

		if (tests[i].result == ACCEPT) {
			if (prog_fd < 0) {
				printf("FAIL\nfailed to load prog '%s'\n",
				       strerror(errno));
				printf("%s", bpf_log_buf);
				goto fail;
			}
		} else {
			if (prog_fd >= 0) {
				printf("FAIL\nunexpected success to load\n");
				printf("%s", bpf_log_buf);
				goto fail;
			}
			if (strstr(bpf_log_buf, tests[i].errstr) == 0) {
				printf("FAIL\nunexpected error message: %s",
				       bpf_log_buf);
				goto fail;
			}
		}

		printf("OK\n");
fail:
		if (map_fd >= 0)
			close(map_fd);
		close(prog_fd);

	}

	return 0;
}

int main(void)
{
	return test();
}