Commit f471748b authored by David Vernet's avatar David Vernet Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add selftests for bpf_task_from_pid() 



Add some selftest testcases that validate the expected behavior of the
bpf_task_from_pid() kfunc that was added in the prior patch.

Signed-off-by: default avatarDavid Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221122145300.251210-3-void@manifault.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 3f0e6f2b

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

+4 −0
Original line number Diff line number Diff line
@@ -78,6 +78,9 @@ static const char * const success_tests[] = { 
	"test_task_xchg_release",

	"test_task_get_release",

	"test_task_current_acquire_release",

	"test_task_from_pid_arg",

	"test_task_from_pid_current",

	"test_task_from_pid_invalid",

};



static struct {
@@ -99,6 +102,7 @@ static struct { 
	{"task_kfunc_release_fp", "arg#0 pointer type STRUCT task_struct must point"},

	{"task_kfunc_release_null", "arg#0 is ptr_or_null_ expected ptr_ or socket"},

	{"task_kfunc_release_unacquired", "release kernel function bpf_task_release expects"},

	{"task_kfunc_from_pid_no_null_check", "arg#0 is ptr_or_null_ expected ptr_ or socket"},

};



static void verify_fail(const char *prog_name, const char *expected_err_msg)

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

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

struct task_struct *bpf_task_kptr_get(struct task_struct **pp) __ksym;

void bpf_task_release(struct task_struct *p) __ksym;

struct task_struct *bpf_task_from_pid(s32 pid) __ksym;



static inline struct __tasks_kfunc_map_value *tasks_kfunc_map_value_lookup(struct task_struct *p)

{

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

+13 −0
Original line number Diff line number Diff line
@@ -258,3 +258,16 @@ int BPF_PROG(task_kfunc_release_unacquired, struct task_struct *task, u64 clone_ 


	return 0;

}



SEC("tp_btf/task_newtask")

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

{

	struct task_struct *acquired;



	acquired = bpf_task_from_pid(task->pid);



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

	bpf_task_release(acquired);



	return 0;

}

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

+73 −0
Original line number Diff line number Diff line
@@ -147,3 +147,76 @@ int BPF_PROG(test_task_current_acquire_release, struct task_struct *task, u64 cl 


	return 0;

}



static void lookup_compare_pid(const struct task_struct *p)

{

	struct task_struct *acquired;



	acquired = bpf_task_from_pid(p->pid);

	if (!acquired) {

		err = 1;

		return;

	}



	if (acquired->pid != p->pid)

		err = 2;

	bpf_task_release(acquired);

}



SEC("tp_btf/task_newtask")

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

{

	struct task_struct *acquired;



	if (!is_test_kfunc_task())

		return 0;



	lookup_compare_pid(task);

	return 0;

}



SEC("tp_btf/task_newtask")

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

{

	struct task_struct *current, *acquired;



	if (!is_test_kfunc_task())

		return 0;



	lookup_compare_pid(bpf_get_current_task_btf());

	return 0;

}



static int is_pid_lookup_valid(s32 pid)

{

	struct task_struct *acquired;



	acquired = bpf_task_from_pid(pid);

	if (acquired) {

		bpf_task_release(acquired);

		return 1;

	}



	return 0;

}



SEC("tp_btf/task_newtask")

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

{

	struct task_struct *acquired;



	if (!is_test_kfunc_task())

		return 0;



	if (is_pid_lookup_valid(-1)) {

		err = 1;

		return 0;

	}



	if (is_pid_lookup_valid(0xcafef00d)) {

		err = 2;

		return 0;

	}



	return 0;

}