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Date: Fri, 2 Sep 2022 15:29:19 +0200
From: Benjamin Tissoires <benjamin.tissoires@...hat.com>
To: Greg KH <gregkh@...uxfoundation.org>,
Jiri Kosina <jikos@...nel.org>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
Kumar Kartikeya Dwivedi <memxor@...il.com>,
John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...nel.org>, Shuah Khan <shuah@...nel.org>,
Dave Marchevsky <davemarchevsky@...com>,
Joe Stringer <joe@...ium.io>, Jonathan Corbet <corbet@....net>
Cc: Tero Kristo <tero.kristo@...ux.intel.com>,
linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
netdev@...r.kernel.org, bpf@...r.kernel.org,
linux-kselftest@...r.kernel.org, linux-doc@...r.kernel.org,
Benjamin Tissoires <benjamin.tissoires@...hat.com>
Subject: [PATCH bpf-next v10 04/23] selftests/bpf: add test for accessing ctx from syscall program type
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 <benjamin.tissoires@...hat.com>
---
changes in v10:
- use new definitions for tests in an array
- add a new kfunc syscall_test_null_fail test
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 | 128 ++++++++++++++++--
.../selftests/bpf/progs/kfunc_call_fail.c | 39 ++++++
.../selftests/bpf/progs/kfunc_call_test.c | 38 ++++++
4 files changed, 197 insertions(+), 9 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_fail.c
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 21e347f46c93..84798979f3a7 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -2,6 +2,7 @@
/* Copyright (c) 2021 Facebook */
#include <test_progs.h>
#include <network_helpers.h>
+#include "kfunc_call_fail.skel.h"
#include "kfunc_call_test.skel.h"
#include "kfunc_call_test_subprog.skel.h"
#include "kfunc_call_test_subprog.lskel.h"
@@ -9,27 +10,68 @@
#include "cap_helpers.h"
+static size_t log_buf_sz = 1048576; /* 1 MB */
+static char obj_log_buf[1048576];
+
+enum kfunc_test_type {
+ tc_test = 0,
+ syscall_test,
+ syscall_null_ctx_test,
+};
+
struct kfunc_test_params {
const char *prog_name;
int retval;
+ enum kfunc_test_type test_type;
+ const char *expected_err_msg;
};
static struct kfunc_test_params kfunc_tests[] = {
- {"kfunc_call_test1", 12},
- {"kfunc_call_test2", 3},
- {"kfunc_call_test_ref_btf_id", 0},
+ /* failure cases:
+ * if retval is 0 -> the program will fail to load and the error message is an error
+ * if retval is not 0 -> the program can be loaded but running it will gives the
+ * provided return value. The error message is thus the one
+ * from a successful load
+ */
+ {"kfunc_syscall_test_fail", -EINVAL, syscall_null_ctx_test, "processed 4 insns"},
+ {"kfunc_syscall_test_null_fail", -EINVAL, syscall_null_ctx_test, "processed 4 insns"},
+
+ /* success cases */
+ {"kfunc_call_test1", 12, tc_test, NULL},
+ {"kfunc_call_test2", 3, tc_test, NULL},
+ {"kfunc_call_test_ref_btf_id", 0, tc_test, NULL},
+ {"kfunc_syscall_test", 0, syscall_test, NULL},
+ {"kfunc_syscall_test_null", 0, syscall_null_ctx_test, NULL},
+};
+
+struct syscall_test_args {
+ __u8 data[16];
+ size_t size;
};
static void verify_success(struct kfunc_test_params *param)
{
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
struct kfunc_call_test *skel;
struct bpf_program *prog;
int prog_fd, err;
- LIBBPF_OPTS(bpf_test_run_opts, topts,
- .data_in = &pkt_v4,
- .data_size_in = sizeof(pkt_v4),
- .repeat = 1,
- );
+ struct syscall_test_args args = {
+ .size = 10,
+ };
+
+ switch (param->test_type) {
+ case syscall_test:
+ topts.ctx_in = &args;
+ topts.ctx_size_in = sizeof(args);
+ /* fallthrough */
+ case syscall_null_ctx_test:
+ break;
+ case tc_test:
+ topts.data_in = &pkt_v4;
+ topts.data_size_in = sizeof(pkt_v4);
+ topts.repeat = 1;
+ break;
+ }
skel = kfunc_call_test__open_and_load();
if (!ASSERT_OK_PTR(skel, "skel"))
@@ -50,6 +92,71 @@ static void verify_success(struct kfunc_test_params *param)
kfunc_call_test__destroy(skel);
}
+static void verify_fail(struct kfunc_test_params *param)
+{
+ LIBBPF_OPTS(bpf_object_open_opts, opts);
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+ struct bpf_program *prog;
+ struct kfunc_call_fail *skel;
+ int prog_fd, err;
+ struct syscall_test_args args = {
+ .size = 10,
+ };
+
+ opts.kernel_log_buf = obj_log_buf;
+ opts.kernel_log_size = log_buf_sz;
+ opts.kernel_log_level = 1;
+
+ switch (param->test_type) {
+ case syscall_test:
+ topts.ctx_in = &args;
+ topts.ctx_size_in = sizeof(args);
+ /* fallthrough */
+ case syscall_null_ctx_test:
+ break;
+ case tc_test:
+ topts.data_in = &pkt_v4;
+ topts.data_size_in = sizeof(pkt_v4);
+ break;
+ topts.repeat = 1;
+ }
+
+ skel = kfunc_call_fail__open_opts(&opts);
+ if (!ASSERT_OK_PTR(skel, "kfunc_call_fail__open_opts"))
+ goto cleanup;
+
+ prog = bpf_object__find_program_by_name(skel->obj, param->prog_name);
+ if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+ goto cleanup;
+
+ bpf_program__set_autoload(prog, true);
+
+ err = kfunc_call_fail__load(skel);
+ if (!param->retval) {
+ /* the verifier is supposed to complain and refuses to load */
+ if (!ASSERT_ERR(err, "unexpected load success"))
+ goto out_err;
+
+ } else {
+ /* the program is loaded but must dynamically fail */
+ if (!ASSERT_OK(err, "unexpected load error"))
+ goto out_err;
+
+ prog_fd = bpf_program__fd(prog);
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ if (!ASSERT_EQ(err, param->retval, param->prog_name))
+ goto out_err;
+ }
+
+out_err:
+ if (!ASSERT_OK_PTR(strstr(obj_log_buf, param->expected_err_msg), "expected_err_msg")) {
+ fprintf(stderr, "Expected err_msg: %s\n", param->expected_err_msg);
+ fprintf(stderr, "Verifier output: %s\n", obj_log_buf);
+ }
+cleanup:
+ kfunc_call_fail__destroy(skel);
+}
+
static void test_main(void)
{
int i;
@@ -58,7 +165,10 @@ static void test_main(void)
if (!test__start_subtest(kfunc_tests[i].prog_name))
continue;
- verify_success(&kfunc_tests[i]);
+ if (!kfunc_tests[i].expected_err_msg)
+ verify_success(&kfunc_tests[i]);
+ else
+ verify_fail(&kfunc_tests[i]);
}
}
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
new file mode 100644
index 000000000000..4168027f2ab1
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
+
+struct syscall_test_args {
+ __u8 data[16];
+ size_t size;
+};
+
+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;
+}
+
+SEC("?syscall")
+int kfunc_syscall_test_null_fail(struct syscall_test_args *args)
+{
+ /* Must be called with args as a NULL pointer
+ * we do not check for it to have the verifier consider that
+ * the pointer might not be null, and so we can load it.
+ *
+ * So the following can not be added:
+ *
+ * if (args)
+ * return -22;
+ */
+
+ bpf_kfunc_call_test_mem_len_pass1(args, sizeof(*args));
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
index 5aecbb9fdc68..94c05267e5e7 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -92,4 +92,42 @@ 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)
+{
+ /* Must be called with args as a NULL pointer
+ * we do not check for it to have the verifier consider that
+ * the pointer might not be null, and so we can load it.
+ *
+ * So the following can not be added:
+ *
+ * if (args)
+ * return -22;
+ */
+
+ bpf_kfunc_call_test_mem_len_pass1(args, 0);
+
+ return 0;
+}
+
char _license[] SEC("license") = "GPL";
--
2.36.1
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