[PATCH bpf-next v9 03/23] selftests/bpf: add test for accessing ctx from syscall program type
From: Benjamin Tissoires <hidden>
Date: 2022-08-24 13:41:43
Also in:
bpf, linux-doc, linux-input, linux-kselftest, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
We need to also export the kfunc set to the syscall program type, and then add a couple of eBPF programs that are testing those calls. The first one checks for valid access, and the second one is OK from a static analysis point of view but fails at run time because we are trying to access outside of the allocated memory. Signed-off-by: Benjamin Tissoires <redacted> --- no changes in v9 no changes in v8 changes in v7: - add 1 more case to ensure we can read the entire sizeof(ctx) - add a test case for when the context is NULL new in v6 --- net/bpf/test_run.c | 1 + .../selftests/bpf/prog_tests/kfunc_call.c | 28 +++++++++++++++ .../selftests/bpf/progs/kfunc_call_test.c | 36 +++++++++++++++++++ 3 files changed, 65 insertions(+)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 25d8ecf105aa..f16baf977a21 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c@@ -1634,6 +1634,7 @@ static int __init bpf_prog_test_run_init(void) ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_prog_test_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_prog_test_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_prog_test_kfunc_set); return ret ?: register_btf_id_dtor_kfuncs(bpf_prog_test_dtor_kfunc, ARRAY_SIZE(bpf_prog_test_dtor_kfunc), THIS_MODULE);
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index eede7c304f86..1edad012fe01 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c@@ -9,10 +9,22 @@ #include "cap_helpers.h" +struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + static void test_main(void) { struct kfunc_call_test_lskel *skel; int prog_fd, err; + struct syscall_test_args args = { + .size = 10, + }; + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, syscall_topts, + .ctx_in = &args, + .ctx_size_in = sizeof(args), + ); LIBBPF_OPTS(bpf_test_run_opts, topts, .data_in = &pkt_v4, .data_size_in = sizeof(pkt_v4),
@@ -38,6 +50,22 @@ static void test_main(void) ASSERT_OK(err, "bpf_prog_test_run(test_ref_btf_id)"); ASSERT_EQ(topts.retval, 0, "test_ref_btf_id-retval"); + prog_fd = skel->progs.kfunc_syscall_test.prog_fd; + err = bpf_prog_test_run_opts(prog_fd, &syscall_topts); + ASSERT_OK(err, "bpf_prog_test_run(syscall_test)"); + + prog_fd = skel->progs.kfunc_syscall_test_fail.prog_fd; + err = bpf_prog_test_run_opts(prog_fd, &syscall_topts); + ASSERT_ERR(err, "bpf_prog_test_run(syscall_test_fail)"); + + syscall_topts.ctx_in = NULL; + syscall_topts.ctx_size_in = 0; + + prog_fd = skel->progs.kfunc_syscall_test_null.prog_fd; + err = bpf_prog_test_run_opts(prog_fd, &syscall_topts); + ASSERT_OK(err, "bpf_prog_test_run(syscall_test_null)"); + ASSERT_EQ(syscall_topts.retval, 0, "syscall_test_null-retval"); + kfunc_call_test_lskel__destroy(skel); }
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
index 5aecbb9fdc68..da7ae0ef9100 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c@@ -92,4 +92,40 @@ int kfunc_call_test_pass(struct __sk_buff *skb) return 0; } +struct syscall_test_args { + __u8 data[16]; + size_t size; +}; + +SEC("syscall") +int kfunc_syscall_test(struct syscall_test_args *args) +{ + const int size = args->size; + + if (size > sizeof(args->data)) + return -7; /* -E2BIG */ + + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(args->data)); + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(*args)); + bpf_kfunc_call_test_mem_len_pass1(&args->data, size); + + return 0; +} + +SEC("syscall") +int kfunc_syscall_test_null(struct syscall_test_args *args) +{ + bpf_kfunc_call_test_mem_len_pass1(args, 0); + + return 0; +} + +SEC("syscall") +int kfunc_syscall_test_fail(struct syscall_test_args *args) +{ + bpf_kfunc_call_test_mem_len_pass1(&args->data, sizeof(*args) + 1); + + return 0; +} + char _license[] SEC("license") = "GPL";
--
2.36.1