From f471748b7fe5ab7ec6de4cbadffabfa7bb5b6240 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Tue, 22 Nov 2022 08:53:00 -0600 Subject: [PATCH] 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: David Vernet Link: https://lore.kernel.org/r/20221122145300.251210-3-void@manifault.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/task_kfunc.c | 4 + .../selftests/bpf/progs/task_kfunc_common.h | 1 + .../selftests/bpf/progs/task_kfunc_failure.c | 13 ++++ .../selftests/bpf/progs/task_kfunc_success.c | 73 +++++++++++++++++++ 4 files changed, 91 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c index 4994fe6092cc..ffd8ef4303c8 100644 --- a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c +++ b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c @@ -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) diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_common.h b/tools/testing/selftests/bpf/progs/task_kfunc_common.h index 160d6dde00be..c0ffd171743e 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/task_kfunc_common.h @@ -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) { diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c index 93e934ddfcb6..e310473190d5 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c @@ -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; +} diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c index be4534b5ba2e..60c7ead41cfc 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_success.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c @@ -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; +}