On Mon, 5 Sept 2022 at 16:36, Roberto Sassu roberto.sassu@huaweicloud.com wrote:
From: Roberto Sassu roberto.sassu@huawei.com
Add tests to ensure that only supported dynamic pointer types are accepted, that the passed argument is actually a dynamic pointer, and that the passed argument is a pointer to the stack.
The tests are currently in the deny list for s390x (JIT does not support calling kernel function).
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com
tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../bpf/prog_tests/kfunc_dynptr_param.c | 103 ++++++++++++++++++ .../bpf/progs/test_kfunc_dynptr_param.c | 57 ++++++++++ 3 files changed, 161 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c create mode 100644 tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 4e305baa5277..9a6dc3671c65 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -71,3 +71,4 @@ cgroup_hierarchical_stats # JIT does not support calling kernel f htab_update # failed to attach: ERROR: strerror_r(-524)=22 (trampoline) lookup_key # JIT does not support calling kernel function (kfunc) verify_pkcs7_sig # JIT does not support calling kernel function (kfunc) +kfunc_dynptr_param # JIT does not support calling kernel function (kfunc) diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c new file mode 100644 index 000000000000..ea655a5c9d8b --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0
+/*
- Copyright (c) 2022 Facebook
- Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
- Author: Roberto Sassu roberto.sassu@huawei.com
- */
+#include <test_progs.h> +#include "test_kfunc_dynptr_param.skel.h"
+static size_t log_buf_sz = 1048576; /* 1 MB */ +static char obj_log_buf[1048576];
+static struct {
const char *prog_name;const char *expected_err_msg;+} kfunc_dynptr_tests[] = {
{"dynptr_type_not_supp","arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type"},{"not_valid_dynptr","arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized"},{"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack"},+};
+static bool kfunc_not_supported;
+static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt,
va_list args)+{
if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found in kernel or module BTFs\n"))return 0;if (strcmp(va_arg(args, char *), "bpf_verify_pkcs7_signature"))return 0;kfunc_not_supported = true;return 0;+}
+static void verify_fail(const char *prog_name, const char *expected_err_msg) +{
struct test_kfunc_dynptr_param *skel;LIBBPF_OPTS(bpf_object_open_opts, opts);libbpf_print_fn_t old_print_cb;struct bpf_program *prog;int err;opts.kernel_log_buf = obj_log_buf;opts.kernel_log_size = log_buf_sz;opts.kernel_log_level = 1;skel = test_kfunc_dynptr_param__open_opts(&opts);if (!ASSERT_OK_PTR(skel, "test_kfunc_dynptr_param__open_opts"))goto cleanup;prog = bpf_object__find_program_by_name(skel->obj, prog_name);if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))goto cleanup;bpf_program__set_autoload(prog, true);bpf_map__set_max_entries(skel->maps.ringbuf, getpagesize());kfunc_not_supported = false;old_print_cb = libbpf_set_print(libbpf_print_cb);err = test_kfunc_dynptr_param__load(skel);libbpf_set_print(old_print_cb);if (err < 0 && kfunc_not_supported) {fprintf(stderr,"%s:SKIP:bpf_verify_pkcs7_signature() kfunc not supported\n",__func__);test__skip();goto cleanup;}if (!ASSERT_ERR(err, "unexpected load success"))goto cleanup;if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) {fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg);fprintf(stderr, "Verifier output: %s\n", obj_log_buf);}+cleanup:
test_kfunc_dynptr_param__destroy(skel);+}
+void test_kfunc_dynptr_param(void) +{
int i;for (i = 0; i < ARRAY_SIZE(kfunc_dynptr_tests); i++) {if (!test__start_subtest(kfunc_dynptr_tests[i].prog_name))continue;verify_fail(kfunc_dynptr_tests[i].prog_name,kfunc_dynptr_tests[i].expected_err_msg);}+} diff --git a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c new file mode 100644 index 000000000000..2f09f91a1576 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0
+/*
- Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
- Author: Roberto Sassu roberto.sassu@huawei.com
- */
+#include "vmlinux.h" +#include <errno.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h>
+struct bpf_dynptr {
__u64 :64;__u64 :64;+} __attribute__((aligned(8)));
+extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
struct bpf_dynptr *sig_ptr,struct bpf_key *trusted_keyring) __ksym;+struct {
__uint(type, BPF_MAP_TYPE_RINGBUF);+} ringbuf SEC(".maps");
+char _license[] SEC("license") = "GPL";
+SEC("?lsm.s/bpf") +int BPF_PROG(dynptr_type_not_supp, int cmd, union bpf_attr *attr,
unsigned int size)+{
char write_data[64] = "hello there, world!!";struct bpf_dynptr ptr;bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0, &ptr);return bpf_verify_pkcs7_signature(&ptr, &ptr, NULL);+}
+SEC("?lsm.s/bpf") +int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr, unsigned int size) +{
unsigned long val;return bpf_verify_pkcs7_signature((struct bpf_dynptr *)&val,(struct bpf_dynptr *)&val, NULL);+}
+SEC("?lsm.s/bpf") +int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr, unsigned int size) +{
unsigned long val;return bpf_verify_pkcs7_signature((struct bpf_dynptr *)val,(struct bpf_dynptr *)val, NULL);
Please also include a test where you cause the dynptr to be set to NULL, e.g. by passing invalid stuff to ringbuf_reserve_dynptr, and then try to pass it to bpf_verify_pkc7_signature.
+}
2.25.1