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); +}