Commit 218edd6d authored by Anton Protopopov's avatar Anton Protopopov Committed by Alexei Starovoitov
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selftests/bpf: add selftests for new insn_array map 



Add the following selftests for new insn_array map:

  * Incorrect instruction indexes are rejected
  * Two programs can't use the same map
  * BPF progs can't operate the map
  * no changes to code => map is the same
  * expected changes when instructions are added
  * expected changes when instructions are deleted
  * expected changes when multiple functions are present

Signed-off-by: default avatarAnton Protopopov <a.s.protopopov@gmail.com>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-5-a.s.protopopov@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent cbef91de

tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c

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// SPDX-License-Identifier: GPL-2.0



#include <bpf/bpf.h>

#include <test_progs.h>



#ifdef __x86_64__

static int map_create(__u32 map_type, __u32 max_entries)

{

	const char *map_name = "insn_array";

	__u32 key_size = 4;

	__u32 value_size = sizeof(struct bpf_insn_array_value);



	return bpf_map_create(map_type, map_name, key_size, value_size, max_entries, NULL);

}



static int prog_load(struct bpf_insn *insns, __u32 insn_cnt, int *fd_array, __u32 fd_array_cnt)

{

	LIBBPF_OPTS(bpf_prog_load_opts, opts);



	opts.fd_array = fd_array;

	opts.fd_array_cnt = fd_array_cnt;



	return bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, &opts);

}



static void __check_success(struct bpf_insn *insns, __u32 insn_cnt, __u32 *map_in, __u32 *map_out)

{

	struct bpf_insn_array_value val = {};

	int prog_fd = -1, map_fd, i;



	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, insn_cnt);

	if (!ASSERT_GE(map_fd, 0, "map_create"))

		return;



	for (i = 0; i < insn_cnt; i++) {

		val.orig_off = map_in[i];

		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))

			goto cleanup;

	}



	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))

		goto cleanup;



	prog_fd = prog_load(insns, insn_cnt, &map_fd, 1);

	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))

		goto cleanup;



	for (i = 0; i < insn_cnt; i++) {

		char buf[64];



		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))

			goto cleanup;



		snprintf(buf, sizeof(buf), "val.xlated_off should be equal map_out[%d]", i);

		ASSERT_EQ(val.xlated_off, map_out[i], buf);

	}



cleanup:

	close(prog_fd);

	close(map_fd);

}



/*

 * Load a program, which will not be anyhow mangled by the verifier.  Add an

 * insn_array map pointing to every instruction. Check that it hasn't changed

 * after the program load.

 */

static void check_one_to_one_mapping(void)

{

	struct bpf_insn insns[] = {

		BPF_MOV64_IMM(BPF_REG_0, 4),

		BPF_MOV64_IMM(BPF_REG_0, 3),

		BPF_MOV64_IMM(BPF_REG_0, 2),

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	__u32 map_in[] = {0, 1, 2, 3, 4, 5};

	__u32 map_out[] = {0, 1, 2, 3, 4, 5};



	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);

}



/*

 * Load a program with two patches (get jiffies, for simplicity). Add an

 * insn_array map pointing to every instruction. Check how it was changed

 * after the program load.

 */

static void check_simple(void)

{

	struct bpf_insn insns[] = {

		BPF_MOV64_IMM(BPF_REG_0, 2),

		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	__u32 map_in[] = {0, 1, 2, 3, 4, 5};

	__u32 map_out[] = {0, 1, 4, 5, 8, 9};



	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);

}



/*

 * Verifier can delete code in two cases: nops & dead code. From insn

 * array's point of view, the two cases are the same, so test using

 * the simplest method: by loading some nops

 */

static void check_deletions(void)

{

	struct bpf_insn insns[] = {

		BPF_MOV64_IMM(BPF_REG_0, 2),

		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	__u32 map_in[] = {0, 1, 2, 3, 4, 5};

	__u32 map_out[] = {0, -1, 1, -1, 2, 3};



	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);

}



/*

 * Same test as check_deletions, but also add code which adds instructions

 */

static void check_deletions_with_functions(void)

{

	struct bpf_insn insns[] = {

		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */

		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),

		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */

		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_EXIT_INSN(),

		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */

		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),

		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */

		BPF_MOV64_IMM(BPF_REG_0, 2),

		BPF_EXIT_INSN(),

	};

	__u32 map_in[] =  { 0, 1,  2, 3, 4, 5, /* func */  6, 7,  8, 9, 10};

	__u32 map_out[] = {-1, 0, -1, 3, 4, 5, /* func */ -1, 6, -1, 9, 10};



	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);

}



/*

 * Try to load a program with a map which points to outside of the program

 */

static void check_out_of_bounds_index(void)

{

	struct bpf_insn insns[] = {

		BPF_MOV64_IMM(BPF_REG_0, 4),

		BPF_MOV64_IMM(BPF_REG_0, 3),

		BPF_MOV64_IMM(BPF_REG_0, 2),

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	int prog_fd, map_fd;

	struct bpf_insn_array_value val = {};

	int key;



	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1);

	if (!ASSERT_GE(map_fd, 0, "map_create"))

		return;



	key = 0;

	val.orig_off = ARRAY_SIZE(insns); /* too big */

	if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &key, &val, 0), 0, "bpf_map_update_elem"))

		goto cleanup;



	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))

		goto cleanup;



	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);

	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) {

		close(prog_fd);

		goto cleanup;

	}



cleanup:

	close(map_fd);

}



/*

 * Try to load a program with a map which points to the middle of 16-bit insn

 */

static void check_mid_insn_index(void)

{

	struct bpf_insn insns[] = {

		BPF_LD_IMM64(BPF_REG_0, 0), /* 2 x 8 */

		BPF_EXIT_INSN(),

	};

	int prog_fd, map_fd;

	struct bpf_insn_array_value val = {};

	int key;



	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1);

	if (!ASSERT_GE(map_fd, 0, "map_create"))

		return;



	key = 0;

	val.orig_off = 1; /* middle of 16-byte instruction */

	if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &key, &val, 0), 0, "bpf_map_update_elem"))

		goto cleanup;



	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))

		goto cleanup;



	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);

	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) {

		close(prog_fd);

		goto cleanup;

	}



cleanup:

	close(map_fd);

}



static void check_incorrect_index(void)

{

	check_out_of_bounds_index();

	check_mid_insn_index();

}



/* Once map was initialized, it should be frozen */

static void check_load_unfrozen_map(void)

{

	struct bpf_insn insns[] = {

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	int prog_fd = -1, map_fd;

	struct bpf_insn_array_value val = {};

	int i;



	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns));

	if (!ASSERT_GE(map_fd, 0, "map_create"))

		return;



	for (i = 0; i < ARRAY_SIZE(insns); i++) {

		val.orig_off = i;

		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))

			goto cleanup;

	}



	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);

	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)"))

		goto cleanup;



	/* correctness: now freeze the map, the program should load fine */



	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))

		goto cleanup;



	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);

	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))

		goto cleanup;



	for (i = 0; i < ARRAY_SIZE(insns); i++) {

		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))

			goto cleanup;



		ASSERT_EQ(val.xlated_off, i, "val should be equal i");

	}



cleanup:

	close(prog_fd);

	close(map_fd);

}



/* Map can be used only by one BPF program */

static void check_no_map_reuse(void)

{

	struct bpf_insn insns[] = {

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	int prog_fd = -1, map_fd, extra_fd = -1;

	struct bpf_insn_array_value val = {};

	int i;



	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns));

	if (!ASSERT_GE(map_fd, 0, "map_create"))

		return;



	for (i = 0; i < ARRAY_SIZE(insns); i++) {

		val.orig_off = i;

		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))

			goto cleanup;

	}



	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))

		goto cleanup;



	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);

	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))

		goto cleanup;



	for (i = 0; i < ARRAY_SIZE(insns); i++) {

		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))

			goto cleanup;



		ASSERT_EQ(val.xlated_off, i, "val should be equal i");

	}



	extra_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);

	if (!ASSERT_EQ(extra_fd, -EBUSY, "program should have been rejected (extra_fd != -EBUSY)"))

		goto cleanup;



	/* correctness: check that prog is still loadable without fd_array */

	extra_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0);

	if (!ASSERT_GE(extra_fd, 0, "bpf(BPF_PROG_LOAD): expected no error"))

		goto cleanup;



cleanup:

	close(extra_fd);

	close(prog_fd);

	close(map_fd);

}



static void check_bpf_no_lookup(void)

{

	struct bpf_insn insns[] = {

		BPF_LD_MAP_FD(BPF_REG_1, 0),

		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_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),

		BPF_EXIT_INSN(),

	};

	int prog_fd = -1, map_fd;



	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1);

	if (!ASSERT_GE(map_fd, 0, "map_create"))

		return;



	insns[0].imm = map_fd;



	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))

		goto cleanup;



	prog_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0);

	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)"))

		goto cleanup;



	/* correctness: check that prog is still loadable with normal map */

	close(map_fd);

	map_fd = map_create(BPF_MAP_TYPE_ARRAY, 1);

	insns[0].imm = map_fd;

	prog_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0);

	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))

		goto cleanup;



cleanup:

	close(prog_fd);

	close(map_fd);

}



static void check_bpf_side(void)

{

	check_bpf_no_lookup();

}



static void __test_bpf_insn_array(void)

{

	/* Test if offsets are adjusted properly */



	if (test__start_subtest("one2one"))

		check_one_to_one_mapping();



	if (test__start_subtest("simple"))

		check_simple();



	if (test__start_subtest("deletions"))

		check_deletions();



	if (test__start_subtest("deletions-with-functions"))

		check_deletions_with_functions();



	/* Check all kinds of operations and related restrictions */



	if (test__start_subtest("incorrect-index"))

		check_incorrect_index();



	if (test__start_subtest("load-unfrozen-map"))

		check_load_unfrozen_map();



	if (test__start_subtest("no-map-reuse"))

		check_no_map_reuse();



	if (test__start_subtest("bpf-side-ops"))

		check_bpf_side();

}

#else

static void __test_bpf_insn_array(void)

{

	test__skip();

}

#endif



void test_bpf_insn_array(void)

{

	__test_bpf_insn_array();

}