Commit f987a640 authored by Juntong Deng's avatar Juntong Deng Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add tests for bpf_task_from_vpid() kfunc 



This patch adds test cases for bpf_task_from_vpid() kfunc.

task_kfunc_from_vpid_no_null_check is used to test the case where
the return value is not checked for NULL pointer.

test_task_from_vpid_current is used to test obtaining the
struct task_struct of the process in the pid namespace based on vpid.

test_task_from_vpid_invalid is used to test the case of invalid vpid.

test_task_from_vpid_current and test_task_from_vpid_invalid will run
in the new namespace.

Signed-off-by: default avatarJuntong Deng <juntong.deng@outlook.com>
Link: https://lore.kernel.org/r/AM6PR03MB5848F13435CD650AC4B7BD7099442@AM6PR03MB5848.eurprd03.prod.outlook.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 675c3596

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

+80 −0
Original line number Diff line number Diff line
@@ -68,6 +68,74 @@ static void run_success_test(const char *prog_name) 
	task_kfunc_success__destroy(skel);

}



static int run_vpid_test(void *prog_name)

{

	struct task_kfunc_success *skel;

	struct bpf_program *prog;

	int prog_fd, err = 0;



	if (getpid() != 1)

		return 1;



	skel = open_load_task_kfunc_skel();

	if (!skel)

		return 2;



	if (skel->bss->err) {

		err = 3;

		goto cleanup;

	}



	prog = bpf_object__find_program_by_name(skel->obj, prog_name);

	if (!prog) {

		err = 4;

		goto cleanup;

	}



	prog_fd = bpf_program__fd(prog);

	if (prog_fd < 0) {

		err = 5;

		goto cleanup;

	}



	if (bpf_prog_test_run_opts(prog_fd, NULL)) {

		err = 6;

		goto cleanup;

	}



	if (skel->bss->err)

		err = 7 + skel->bss->err;

cleanup:

	task_kfunc_success__destroy(skel);

	return err;

}



static void run_vpid_success_test(const char *prog_name)

{

	const int stack_size = 1024 * 1024;

	int child_pid, wstatus;

	char *stack;



	stack = (char *)malloc(stack_size);

	if (!ASSERT_OK_PTR(stack, "clone_stack"))

		return;



	child_pid = clone(run_vpid_test, stack + stack_size,

			  CLONE_NEWPID | SIGCHLD, (void *)prog_name);

	if (!ASSERT_GT(child_pid, -1, "child_pid"))

		goto cleanup;



	if (!ASSERT_GT(waitpid(child_pid, &wstatus, 0), -1, "waitpid"))

		goto cleanup;



	if (WEXITSTATUS(wstatus) > 7)

		ASSERT_OK(WEXITSTATUS(wstatus) - 7, "vpid_test_failure");

	else

		ASSERT_OK(WEXITSTATUS(wstatus), "run_vpid_test_err");

cleanup:

	free(stack);

}



static const char * const success_tests[] = {

	"test_task_acquire_release_argument",

	"test_task_acquire_release_current",
@@ -83,6 +151,11 @@ static const char * const success_tests[] = { 
	"test_task_kfunc_flavor_relo_not_found",

};



static const char * const vpid_success_tests[] = {

	"test_task_from_vpid_current",

	"test_task_from_vpid_invalid",

};



void test_task_kfunc(void)

{

	int i;
@@ -94,5 +167,12 @@ void test_task_kfunc(void) 
		run_success_test(success_tests[i]);

	}



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

		if (!test__start_subtest(vpid_success_tests[i]))

			continue;



		run_vpid_success_test(vpid_success_tests[i]);

	}



	RUN_TESTS(task_kfunc_failure);

}

tools/testing/selftests/bpf/progs/task_kfunc_common.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ struct { 
struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;

void bpf_task_release(struct task_struct *p) __ksym;

struct task_struct *bpf_task_from_pid(s32 pid) __ksym;

struct task_struct *bpf_task_from_vpid(s32 vpid) __ksym;

void bpf_rcu_read_lock(void) __ksym;

void bpf_rcu_read_unlock(void) __ksym;

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

+14 −0
Original line number Diff line number Diff line
@@ -247,6 +247,20 @@ int BPF_PROG(task_kfunc_from_pid_no_null_check, struct task_struct *task, u64 cl 
	return 0;

}



SEC("tp_btf/task_newtask")

__failure __msg("Possibly NULL pointer passed to trusted arg0")

int BPF_PROG(task_kfunc_from_vpid_no_null_check, struct task_struct *task, u64 clone_flags)

{

	struct task_struct *acquired;



	acquired = bpf_task_from_vpid(task->pid);



	/* Releasing bpf_task_from_vpid() lookup without a NULL check. */

	bpf_task_release(acquired);



	return 0;

}



SEC("lsm/task_free")

__failure __msg("R1 must be a rcu pointer")

int BPF_PROG(task_kfunc_from_lsm_task_free, struct task_struct *task)

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

+51 −0
Original line number Diff line number Diff line
@@ -366,3 +366,54 @@ int BPF_PROG(task_kfunc_acquire_trusted_walked, struct task_struct *task, u64 cl 


	return 0;

}



SEC("syscall")

int test_task_from_vpid_current(const void *ctx)

{

	struct task_struct *current, *v_task;



	v_task = bpf_task_from_vpid(1);

	if (!v_task) {

		err = 1;

		return 0;

	}



	current = bpf_get_current_task_btf();



	/* The current process should be the init process (pid 1) in the new pid namespace. */

	if (current != v_task)

		err = 2;



	bpf_task_release(v_task);

	return 0;

}



SEC("syscall")

int test_task_from_vpid_invalid(const void *ctx)

{

	struct task_struct *v_task;



	v_task = bpf_task_from_vpid(-1);

	if (v_task) {

		err = 1;

		goto err;

	}



	/* There should be only one process (current process) in the new pid namespace. */

	v_task = bpf_task_from_vpid(2);

	if (v_task) {

		err = 2;

		goto err;

	}



	v_task = bpf_task_from_vpid(9999);

	if (v_task) {

		err = 3;

		goto err;

	}



	return 0;

err:

	bpf_task_release(v_task);

	return 0;

}