Merge branch 'bpf-core changes for preparation of HID-bpf'

Benjamin Tissoires says:

====================

Hi,

well, given that the HID changes haven't moved a lot in the past
revisions and that I am cc-ing a bunch of people, I have dropped them
while we focus on the last 2 requirements in bpf-core changes.

I'll submit a HID targeted series when we get these in tree, which
would make things a lore more independent.

For reference, the whole reasons for these 2 main changes are at
https://lore.kernel.org/bpf/20220902132938.2409206-1-benjamin.tissoires@redhat.com/

Compared to v10 (in addition of dropping the HID changes), I have
changed the selftests so we can test both light skeletons and libbbpf
calls.

Cheers,
Benjamin
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

4 files changed, 440 insertions, 23 deletions

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index c10adecb5a73..6cd327f1f216 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -351,11 +351,12 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
 		test_subskeleton.skel.h test_subskeleton_lib.skel.h	\
 		test_usdt.skel.h
 
-LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
+LSKELS := fentry_test.c fexit_test.c fexit_sleep.c \
 	test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c \
 	map_ptr_kern.c core_kern.c core_kern_overflow.c
 # Generate both light skeleton and libbpf skeleton for these
-LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test_subprog.c
+LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \
+	kfunc_call_test_subprog.c
 SKEL_BLACKLIST += $$(LSKELS)
 
 test_static_linked.skel.h-deps := test_static_linked1.bpf.o test_static_linked2.bpf.o
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index eede7c304f86..5af1ee8f0e6e 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -2,6 +2,8 @@
 /* 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.lskel.h"
 #include "kfunc_call_test_subprog.skel.h"
 #include "kfunc_call_test_subprog.lskel.h"
@@ -9,36 +11,220 @@
 
 #include "cap_helpers.h"
 
-static void test_main(void)
+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;
+	unsigned long lskel_prog_desc_offset;
+	int retval;
+	enum kfunc_test_type test_type;
+	const char *expected_err_msg;
+};
+
+#define __BPF_TEST_SUCCESS(name, __retval, type) \
+	{ \
+	  .prog_name = #name, \
+	  .lskel_prog_desc_offset = offsetof(struct kfunc_call_test_lskel, progs.name), \
+	  .retval = __retval, \
+	  .test_type = type, \
+	  .expected_err_msg = NULL, \
+	}
+
+#define __BPF_TEST_FAIL(name, __retval, type, error_msg) \
+	{ \
+	  .prog_name = #name, \
+	  .lskel_prog_desc_offset = 0 /* unused when test is failing */, \
+	  .retval = __retval, \
+	  .test_type = type, \
+	  .expected_err_msg = error_msg, \
+	}
+
+#define TC_TEST(name, retval) __BPF_TEST_SUCCESS(name, retval, tc_test)
+#define SYSCALL_TEST(name, retval) __BPF_TEST_SUCCESS(name, retval, syscall_test)
+#define SYSCALL_NULL_CTX_TEST(name, retval) __BPF_TEST_SUCCESS(name, retval, syscall_null_ctx_test)
+
+#define TC_FAIL(name, retval, error_msg) __BPF_TEST_FAIL(name, retval, tc_test, error_msg)
+#define SYSCALL_NULL_CTX_FAIL(name, retval, error_msg) \
+	__BPF_TEST_FAIL(name, retval, syscall_null_ctx_test, error_msg)
+
+static struct kfunc_test_params kfunc_tests[] = {
+	/* 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
+	 */
+	SYSCALL_NULL_CTX_FAIL(kfunc_syscall_test_fail, -EINVAL, "processed 4 insns"),
+	SYSCALL_NULL_CTX_FAIL(kfunc_syscall_test_null_fail, -EINVAL, "processed 4 insns"),
+	TC_FAIL(kfunc_call_test_get_mem_fail_rdonly, 0, "R0 cannot write into rdonly_mem"),
+	TC_FAIL(kfunc_call_test_get_mem_fail_use_after_free, 0, "invalid mem access 'scalar'"),
+	TC_FAIL(kfunc_call_test_get_mem_fail_oob, 0, "min value is outside of the allowed memory range"),
+	TC_FAIL(kfunc_call_test_get_mem_fail_not_const, 0, "is not a const"),
+	TC_FAIL(kfunc_call_test_mem_acquire_fail, 0, "acquire kernel function does not return PTR_TO_BTF_ID"),
+
+	/* success cases */
+	TC_TEST(kfunc_call_test1, 12),
+	TC_TEST(kfunc_call_test2, 3),
+	TC_TEST(kfunc_call_test_ref_btf_id, 0),
+	TC_TEST(kfunc_call_test_get_mem, 42),
+	SYSCALL_TEST(kfunc_syscall_test, 0),
+	SYSCALL_NULL_CTX_TEST(kfunc_syscall_test_null, 0),
+};
+
+struct syscall_test_args {
+	__u8 data[16];
+	size_t size;
+};
+
+static void verify_success(struct kfunc_test_params *param)
 {
-	struct kfunc_call_test_lskel *skel;
+	struct kfunc_call_test_lskel *lskel = NULL;
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	struct bpf_prog_desc *lskel_prog;
+	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_lskel__open_and_load();
+	/* first test with normal libbpf */
+	skel = kfunc_call_test__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel"))
 		return;
 
-	prog_fd = skel->progs.kfunc_call_test1.prog_fd;
-	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "bpf_prog_test_run(test1)");
-	ASSERT_EQ(topts.retval, 12, "test1-retval");
+	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;
 
-	prog_fd = skel->progs.kfunc_call_test2.prog_fd;
+	prog_fd = bpf_program__fd(prog);
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "bpf_prog_test_run(test2)");
-	ASSERT_EQ(topts.retval, 3, "test2-retval");
+	if (!ASSERT_OK(err, param->prog_name))
+		goto cleanup;
+
+	if (!ASSERT_EQ(topts.retval, param->retval, "retval"))
+		goto cleanup;
+
+	/* second test with light skeletons */
+	lskel = kfunc_call_test_lskel__open_and_load();
+	if (!ASSERT_OK_PTR(lskel, "lskel"))
+		goto cleanup;
 
-	prog_fd = skel->progs.kfunc_call_test_ref_btf_id.prog_fd;
+	lskel_prog = (struct bpf_prog_desc *)((char *)lskel + param->lskel_prog_desc_offset);
+
+	prog_fd = lskel_prog->prog_fd;
 	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "bpf_prog_test_run(test_ref_btf_id)");
-	ASSERT_EQ(topts.retval, 0, "test_ref_btf_id-retval");
+	if (!ASSERT_OK(err, param->prog_name))
+		goto cleanup;
+
+	ASSERT_EQ(topts.retval, param->retval, "retval");
+
+cleanup:
+	kfunc_call_test__destroy(skel);
+	if (lskel)
+		kfunc_call_test_lskel__destroy(lskel);
+}
+
+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;
+
+	for (i = 0; i < ARRAY_SIZE(kfunc_tests); i++) {
+		if (!test__start_subtest(kfunc_tests[i].prog_name))
+			continue;
 
-	kfunc_call_test_lskel__destroy(skel);
+		if (!kfunc_tests[i].expected_err_msg)
+			verify_success(&kfunc_tests[i]);
+		else
+			verify_fail(&kfunc_tests[i]);
+	}
 }
 
 static void test_subprog(void)
@@ -121,8 +307,7 @@ static void test_destructive(void)
 
 void test_kfunc_call(void)
 {
-	if (test__start_subtest("main"))
-		test_main();
+	test_main();
 
 	if (test__start_subtest("subprog"))
 		test_subprog();
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..b98313d391c6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
+extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
+extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
+extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
+extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
+extern int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
+extern void bpf_kfunc_call_int_mem_release(int *p) __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;
+}
+
+SEC("?tc")
+int kfunc_call_test_get_mem_fail_rdonly(struct __sk_buff *skb)
+{
+	struct prog_test_ref_kfunc *pt;
+	unsigned long s = 0;
+	int *p = NULL;
+	int ret = 0;
+
+	pt = bpf_kfunc_call_test_acquire(&s);
+	if (pt) {
+		p = bpf_kfunc_call_test_get_rdonly_mem(pt, 2 * sizeof(int));
+		if (p)
+			p[0] = 42; /* this is a read-only buffer, so -EACCES */
+		else
+			ret = -1;
+
+		bpf_kfunc_call_test_release(pt);
+	}
+	return ret;
+}
+
+SEC("?tc")
+int kfunc_call_test_get_mem_fail_use_after_free(struct __sk_buff *skb)
+{
+	struct prog_test_ref_kfunc *pt;
+	unsigned long s = 0;
+	int *p = NULL;
+	int ret = 0;
+
+	pt = bpf_kfunc_call_test_acquire(&s);
+	if (pt) {
+		p = bpf_kfunc_call_test_get_rdwr_mem(pt, 2 * sizeof(int));
+		if (p) {
+			p[0] = 42;
+			ret = p[1]; /* 108 */
+		} else {
+			ret = -1;
+		}
+
+		bpf_kfunc_call_test_release(pt);
+	}
+	if (p)
+		ret = p[0]; /* p is not valid anymore */
+
+	return ret;
+}
+
+SEC("?tc")
+int kfunc_call_test_get_mem_fail_oob(struct __sk_buff *skb)
+{
+	struct prog_test_ref_kfunc *pt;
+	unsigned long s = 0;
+	int *p = NULL;
+	int ret = 0;
+
+	pt = bpf_kfunc_call_test_acquire(&s);
+	if (pt) {
+		p = bpf_kfunc_call_test_get_rdonly_mem(pt, 2 * sizeof(int));
+		if (p)
+			ret = p[2 * sizeof(int)]; /* oob access, so -EACCES */
+		else
+			ret = -1;
+
+		bpf_kfunc_call_test_release(pt);
+	}
+	return ret;
+}
+
+int not_const_size = 2 * sizeof(int);
+
+SEC("?tc")
+int kfunc_call_test_get_mem_fail_not_const(struct __sk_buff *skb)
+{
+	struct prog_test_ref_kfunc *pt;
+	unsigned long s = 0;
+	int *p = NULL;
+	int ret = 0;
+
+	pt = bpf_kfunc_call_test_acquire(&s);
+	if (pt) {
+		p = bpf_kfunc_call_test_get_rdonly_mem(pt, not_const_size); /* non const size, -EINVAL */
+		if (p)
+			ret = p[0];
+		else
+			ret = -1;
+
+		bpf_kfunc_call_test_release(pt);
+	}
+	return ret;
+}
+
+SEC("?tc")
+int kfunc_call_test_mem_acquire_fail(struct __sk_buff *skb)
+{
+	struct prog_test_ref_kfunc *pt;
+	unsigned long s = 0;
+	int *p = NULL;
+	int ret = 0;
+
+	pt = bpf_kfunc_call_test_acquire(&s);
+	if (pt) {
+		/* we are failing on this one, because we are not acquiring a PTR_TO_BTF_ID (a struct ptr) */
+		p = bpf_kfunc_call_test_acq_rdonly_mem(pt, 2 * sizeof(int));
+		if (p)
+			ret = p[0];
+		else
+			ret = -1;
+
+		bpf_kfunc_call_int_mem_release(p);
+
+		bpf_kfunc_call_test_release(pt);
+	}
+	return ret;
+}
+
+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..f636e50be259 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -14,6 +14,8 @@ extern void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym;
 extern void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
 extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
 extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
+extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
+extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
 
 SEC("tc")
 int kfunc_call_test2(struct __sk_buff *skb)
@@ -92,4 +94,73 @@ 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 long 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;
+}
+
+SEC("tc")
+int kfunc_call_test_get_mem(struct __sk_buff *skb)
+{
+	struct prog_test_ref_kfunc *pt;
+	unsigned long s = 0;
+	int *p = NULL;
+	int ret = 0;
+
+	pt = bpf_kfunc_call_test_acquire(&s);
+	if (pt) {
+		p = bpf_kfunc_call_test_get_rdwr_mem(pt, 2 * sizeof(int));
+		if (p) {
+			p[0] = 42;
+			ret = p[1]; /* 108 */
+		} else {
+			ret = -1;
+		}
+
+		if (ret >= 0) {
+			p = bpf_kfunc_call_test_get_rdonly_mem(pt, 2 * sizeof(int));
+			if (p)
+				ret = p[0]; /* 42 */
+			else
+				ret = -1;
+		}
+
+		bpf_kfunc_call_test_release(pt);
+	}
+	return ret;
+}
+
 char _license[] SEC("license") = "GPL";