Commit ae48162a authored by Anton Protopopov's avatar Anton Protopopov Committed by Alexei Starovoitov
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selftests/bpf: test instructions arrays with blinding 



Add a specific test for instructions arrays with blinding enabled.

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/20251105090410.1250500-7-a.s.protopopov@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 30ec0ec0

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

+95 −0
Original line number Diff line number Diff line
@@ -227,6 +227,98 @@ static void check_incorrect_index(void) 
	check_mid_insn_index();

}



static int set_bpf_jit_harden(char *level)

{

	char old_level;

	int err = -1;

	int fd = -1;



	fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR | O_NONBLOCK);

	if (fd < 0) {

		ASSERT_FAIL("open .../bpf_jit_harden returned %d (errno=%d)", fd, errno);

		return -1;

	}



	err = read(fd, &old_level, 1);

	if (err != 1) {

		ASSERT_FAIL("read from .../bpf_jit_harden returned %d (errno=%d)", err, errno);

		err = -1;

		goto end;

	}



	lseek(fd, 0, SEEK_SET);



	err = write(fd, level, 1);

	if (err != 1) {

		ASSERT_FAIL("write to .../bpf_jit_harden returned %d (errno=%d)", err, errno);

		err = -1;

		goto end;

	}



	err = 0;

	*level = old_level;

end:

	if (fd >= 0)

		close(fd);

	return err;

}



static void check_blindness(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_EXIT_INSN(),

	};

	int prog_fd = -1, map_fd;

	struct bpf_insn_array_value val = {};

	char bpf_jit_harden = '@'; /* non-exizsting value */

	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;



	bpf_jit_harden = '2';

	if (set_bpf_jit_harden(&bpf_jit_harden)) {

		bpf_jit_harden = '@'; /* open, read or write failed => no write was done */

		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++) {

		char fmt[32];



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

			goto cleanup;



		snprintf(fmt, sizeof(fmt), "val should be equal 3*%d", i);

		ASSERT_EQ(val.xlated_off, i * 3, fmt);

	}



cleanup:

	/* restore the old one */

	if (bpf_jit_harden != '@')

		set_bpf_jit_harden(&bpf_jit_harden);



	close(prog_fd);

	close(map_fd);

}



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

static void check_load_unfrozen_map(void)

{
@@ -382,6 +474,9 @@ static void __test_bpf_insn_array(void) 
	if (test__start_subtest("deletions-with-functions"))

		check_deletions_with_functions();



	if (test__start_subtest("blindness"))

		check_blindness();



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



	if (test__start_subtest("incorrect-index"))