From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, mykolal@fb.com,
dhowells@redhat.com, jarkko@kernel.org, rostedt@goodmis.org,
mingo@redhat.com, paul@paul-moore.com, jmorris@namei.org,
serge@hallyn.com, shuah@kernel.org
Cc: bpf@vger.kernel.org, keyrings@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
deso@posteo.net, memxor@gmail.com,
Roberto Sassu <roberto.sassu@huawei.com>
Subject: [PATCH v17 12/12] selftests/bpf: Add tests for dynamic pointers parameters in kfuncs
Date: Fri, 9 Sep 2022 14:07:36 +0200 [thread overview]
Message-ID: <20220909120736.1027040-13-roberto.sassu@huaweicloud.com> (raw)
In-Reply-To: <20220909120736.1027040-1-roberto.sassu@huaweicloud.com>
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, that the passed
argument is a pointer to the stack, and that bpf_verify_pkcs7_signature()
correctly handles dynamic pointers with data set to NULL.
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>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
tools/testing/selftests/bpf/DENYLIST.s390x | 1 +
.../bpf/prog_tests/kfunc_dynptr_param.c | 164 ++++++++++++++++++
.../bpf/progs/test_kfunc_dynptr_param.c | 99 +++++++++++
3 files changed, 264 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 759b2bb53b53..5fc7d0de19f3 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -73,3 +73,4 @@ htab_update # failed to attach: ERROR: strerror_r(-
tracing_struct # failed to auto-attach: -524 (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..c210657d4d0a
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c
@@ -0,0 +1,164 @@
+// 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_verifier_err_msg;
+ int expected_runtime_err;
+} kfunc_dynptr_tests[] = {
+ {"dynptr_type_not_supp",
+ "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type", 0},
+ {"not_valid_dynptr",
+ "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized", 0},
+ {"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack", 0},
+ {"dynptr_data_null", NULL, -EBADMSG},
+};
+
+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);
+}
+
+static void verify_success(const char *prog_name, int expected_runtime_err)
+{
+ struct test_kfunc_dynptr_param *skel;
+ libbpf_print_fn_t old_print_cb;
+ struct bpf_program *prog;
+ struct bpf_link *link;
+ __u32 next_id;
+ int err;
+
+ skel = test_kfunc_dynptr_param__open();
+ if (!ASSERT_OK_PTR(skel, "test_kfunc_dynptr_param__open"))
+ return;
+
+ skel->bss->pid = getpid();
+
+ 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_OK(err, "test_kfunc_dynptr_param__load"))
+ 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;
+
+ link = bpf_program__attach(prog);
+ if (!ASSERT_OK_PTR(link, "bpf_program__attach"))
+ goto cleanup;
+
+ err = bpf_prog_get_next_id(0, &next_id);
+
+ bpf_link__destroy(link);
+
+ if (!ASSERT_OK(err, "bpf_prog_get_next_id"))
+ goto cleanup;
+
+ ASSERT_EQ(skel->bss->err, expected_runtime_err, "err");
+
+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;
+
+ if (kfunc_dynptr_tests[i].expected_verifier_err_msg)
+ verify_fail(kfunc_dynptr_tests[i].prog_name,
+ kfunc_dynptr_tests[i].expected_verifier_err_msg);
+ else
+ verify_success(kfunc_dynptr_tests[i].prog_name,
+ kfunc_dynptr_tests[i].expected_runtime_err);
+ }
+}
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..704eabe4fe46
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
@@ -0,0 +1,99 @@
+// 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 struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym;
+extern void bpf_key_put(struct bpf_key *key) __ksym;
+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");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} array_map SEC(".maps");
+
+int err, pid;
+
+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);
+}
+
+SEC("lsm.s/bpf")
+int BPF_PROG(dynptr_data_null, int cmd, union bpf_attr *attr, unsigned int size)
+{
+ struct bpf_key *trusted_keyring;
+ struct bpf_dynptr ptr;
+ __u32 *value;
+ int ret, zero = 0;
+
+ if (bpf_get_current_pid_tgid() >> 32 != pid)
+ return 0;
+
+ value = bpf_map_lookup_elem(&array_map, &zero);
+ if (!value)
+ return 0;
+
+ /* Pass invalid flags. */
+ ret = bpf_dynptr_from_mem(value, sizeof(*value), ((u64)~0ULL), &ptr);
+ if (ret != -EINVAL)
+ return 0;
+
+ trusted_keyring = bpf_lookup_system_key(0);
+ if (!trusted_keyring)
+ return 0;
+
+ err = bpf_verify_pkcs7_signature(&ptr, &ptr, trusted_keyring);
+
+ bpf_key_put(trusted_keyring);
+
+ return 0;
+}
--
2.25.1
next prev parent reply other threads:[~2022-09-09 12:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-09 12:07 [PATCH v17 00/12] bpf: Add kfuncs for PKCS#7 signature verification Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 01/12] bpf: Allow kfuncs to be used in LSM programs Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 02/12] bpf: Move dynptr type check to is_dynptr_type_expected() Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 03/12] btf: Allow dynamic pointer parameters in kfuncs Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 04/12] bpf: Export bpf_dynptr_get_size() Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 05/12] KEYS: Move KEY_LOOKUP_ to include/linux/key.h and define KEY_LOOKUP_ALL Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 06/12] bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs Roberto Sassu
2022-09-09 16:05 ` Song Liu
2022-09-09 12:07 ` [PATCH v17 07/12] bpf: Add bpf_verify_pkcs7_signature() kfunc Roberto Sassu
2022-09-09 16:06 ` Song Liu
2022-09-11 11:40 ` KP Singh
2022-09-11 21:08 ` Kumar Kartikeya Dwivedi
2022-09-09 12:07 ` [PATCH v17 08/12] selftests/bpf: Compile kernel with everything as built-in Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 09/12] selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put() Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 10/12] selftests/bpf: Add additional tests for bpf_lookup_*_key() Roberto Sassu
2022-09-09 12:07 ` [PATCH v17 11/12] selftests/bpf: Add test for bpf_verify_pkcs7_signature() kfunc Roberto Sassu
2022-09-15 16:11 ` KP Singh
2022-09-19 11:17 ` Roberto Sassu
2022-09-19 13:09 ` Roberto Sassu
2022-09-19 14:27 ` [PATCH v18 02/13] btf: Export bpf_dynptr definition Roberto Sassu
2022-09-20 5:30 ` Yonghong Song
2022-09-22 1:10 ` patchwork-bot+netdevbpf
2022-09-20 5:26 ` [PATCH v17 11/12] selftests/bpf: Add test for bpf_verify_pkcs7_signature() kfunc Yonghong Song
2022-09-20 4:21 ` Yonghong Song
2022-09-09 12:07 ` Roberto Sassu [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-09-07 2:34 [PATCH v16 12/12] selftests/bpf: Add tests for dynamic pointers parameters in kfuncs Kumar Kartikeya Dwivedi
2022-09-07 14:59 ` [PATCH v17 " Roberto Sassu
2022-09-07 16:02 ` Kumar Kartikeya Dwivedi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220909120736.1027040-13-roberto.sassu@huaweicloud.com \
--to=roberto.sassu@huaweicloud.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=deso@posteo.net \
--cc=dhowells@redhat.com \
--cc=haoluo@google.com \
--cc=jarkko@kernel.org \
--cc=jmorris@namei.org \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=keyrings@vger.kernel.org \
--cc=kpsingh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=martin.lau@linux.dev \
--cc=memxor@gmail.com \
--cc=mingo@redhat.com \
--cc=mykolal@fb.com \
--cc=paul@paul-moore.com \
--cc=roberto.sassu@huawei.com \
--cc=rostedt@goodmis.org \
--cc=sdf@google.com \
--cc=serge@hallyn.com \
--cc=shuah@kernel.org \
--cc=song@kernel.org \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.