Commit f0a50562 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

selftests/bpf: add freplace of BTF-unreliable main prog test 



Add a test validating that freplace'ing another main (entry) BPF program
fails if the target BPF program doesn't have valid/expected func proto BTF.

We extend fexit_bpf2bpf test to allow to specify expected log message
for negative test cases (where freplace program is expected to fail to
load).

Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231215011334.2307144-11-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 0a0ffcac

tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c

+27 −3
Original line number Diff line number Diff line
@@ -348,7 +348,8 @@ static void test_func_sockmap_update(void) 
}



static void test_obj_load_failure_common(const char *obj_file,

					 const char *target_obj_file)

					 const char *target_obj_file,

					 const char *exp_msg)

{

	/*

	 * standalone test that asserts failure to load freplace prog
@@ -356,6 +357,7 @@ static void test_obj_load_failure_common(const char *obj_file, 
	 */

	struct bpf_object *obj = NULL, *pkt_obj;

	struct bpf_program *prog;

	char log_buf[64 * 1024];

	int err, pkt_fd;

	__u32 duration = 0;
@@ -374,11 +376,21 @@ static void test_obj_load_failure_common(const char *obj_file, 
	err = bpf_program__set_attach_target(prog, pkt_fd, NULL);

	ASSERT_OK(err, "set_attach_target");



	log_buf[0] = '\0';

	if (exp_msg)

		bpf_program__set_log_buf(prog, log_buf, sizeof(log_buf));

	if (env.verbosity > VERBOSE_NONE)

		bpf_program__set_log_level(prog, 2);



	/* It should fail to load the program */

	err = bpf_object__load(obj);

	if (env.verbosity > VERBOSE_NONE && exp_msg) /* we overtook log */

		printf("VERIFIER LOG:\n================\n%s\n================\n", log_buf);

	if (CHECK(!err, "bpf_obj_load should fail", "err %d\n", err))

		goto close_prog;



	if (exp_msg)

		ASSERT_HAS_SUBSTR(log_buf, exp_msg, "fail_msg");

close_prog:

	bpf_object__close(obj);

	bpf_object__close(pkt_obj);
@@ -388,14 +400,24 @@ static void test_func_replace_return_code(void) 
{

	/* test invalid return code in the replaced program */

	test_obj_load_failure_common("./freplace_connect_v4_prog.bpf.o",

				     "./connect4_prog.bpf.o");

				     "./connect4_prog.bpf.o", NULL);

}



static void test_func_map_prog_compatibility(void)

{

	/* test with spin lock map value in the replaced program */

	test_obj_load_failure_common("./freplace_attach_probe.bpf.o",

				     "./test_attach_probe.bpf.o");

				     "./test_attach_probe.bpf.o", NULL);

}



static void test_func_replace_unreliable(void)

{

	/* freplace'ing unreliable main prog should fail with error

	 * "Cannot replace static functions"

	 */

	test_obj_load_failure_common("freplace_unreliable_prog.bpf.o",

				     "./verifier_btf_unreliable_prog.bpf.o",

				     "Cannot replace static functions");

}



static void test_func_replace_global_func(void)
@@ -563,6 +585,8 @@ void serial_test_fexit_bpf2bpf(void) 
		test_func_replace_return_code();

	if (test__start_subtest("func_map_prog_compatibility"))

		test_func_map_prog_compatibility();

	if (test__start_subtest("func_replace_unreliable"))

		test_func_replace_unreliable();

	if (test__start_subtest("func_replace_multi"))

		test_func_replace_multi();

	if (test__start_subtest("fmod_ret_freplace"))

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

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include "verifier_bpf_get_stack.skel.h"

#include "verifier_bswap.skel.h"

#include "verifier_btf_ctx_access.skel.h"

#include "verifier_btf_unreliable_prog.skel.h"

#include "verifier_cfg.skel.h"

#include "verifier_cgroup_inv_retcode.skel.h"

#include "verifier_cgroup_skb.skel.h"
@@ -125,6 +126,7 @@ void test_verifier_bounds_mix_sign_unsign(void) { RUN(verifier_bounds_mix_sign_u 
void test_verifier_bpf_get_stack(void)        { RUN(verifier_bpf_get_stack); }

void test_verifier_bswap(void)                { RUN(verifier_bswap); }

void test_verifier_btf_ctx_access(void)       { RUN(verifier_btf_ctx_access); }

void test_verifier_btf_unreliable_prog(void)  { RUN(verifier_btf_unreliable_prog); }

void test_verifier_cfg(void)                  { RUN(verifier_cfg); }

void test_verifier_cgroup_inv_retcode(void)   { RUN(verifier_cgroup_inv_retcode); }

void test_verifier_cgroup_skb(void)           { RUN(verifier_cgroup_skb); }

tools/testing/selftests/bpf/progs/freplace_unreliable_prog.c

0 → 100644
+20 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2020 Facebook



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



SEC("freplace/btf_unreliable_kprobe")

/* context type is what BPF verifier expects for kprobe context, but target

 * program has `stuct whatever *ctx` argument, so freplace operation will be

 * rejected with the following message:

 *

 * arg0 replace_btf_unreliable_kprobe(struct pt_regs *) doesn't match btf_unreliable_kprobe(struct whatever *)

 */

int replace_btf_unreliable_kprobe(bpf_user_pt_regs_t *ctx)

{

	return 0;

}



char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/verifier_btf_unreliable_prog.c

0 → 100644
+20 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2017 Facebook



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_core_read.h>

#include "bpf_misc.h"



struct whatever {};



SEC("kprobe")

__success __log_level(2)

/* context type is wrong, making it impossible to freplace this program */

int btf_unreliable_kprobe(struct whatever *ctx)

{

	return 0;

}



char _license[] SEC("license") = "GPL";