1 files changed, 148 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/test_strncmp.c b/tools/testing/selftests/bpf/prog_tests/test_strncmp.c
new file mode 100644
index 000000000000..7ddd6615b7e7
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_strncmp.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2021. Huawei Technologies Co., Ltd */
+#include <test_progs.h>
+#include "strncmp_test.skel.h"
+
+static int trigger_strncmp(const struct strncmp_test *skel)
+{
+	int cmp;
+
+	usleep(1);
+
+	cmp = skel->bss->cmp_ret;
+	if (cmp > 0)
+		return 1;
+	if (cmp < 0)
+		return -1;
+	return 0;
+}
+
+/*
+ * Compare str and target after making str[i] != target[i].
+ * When exp is -1, make str[i] < target[i] and delta = -1.
+ */
+static void strncmp_full_str_cmp(struct strncmp_test *skel, const char *name,
+				 int exp)
+{
+	size_t nr = sizeof(skel->bss->str);
+	char *str = skel->bss->str;
+	int delta = exp;
+	int got;
+	size_t i;
+
+	memcpy(str, skel->rodata->target, nr);
+	for (i = 0; i < nr - 1; i++) {
+		str[i] += delta;
+
+		got = trigger_strncmp(skel);
+		ASSERT_EQ(got, exp, name);
+
+		str[i] -= delta;
+	}
+}
+
+static void test_strncmp_ret(void)
+{
+	struct strncmp_test *skel;
+	int err, got;
+
+	skel = strncmp_test__open();
+	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.do_strncmp, true);
+
+	err = strncmp_test__load(skel);
+	if (!ASSERT_EQ(err, 0, "strncmp_test load"))
+		goto out;
+
+	err = strncmp_test__attach(skel);
+	if (!ASSERT_EQ(err, 0, "strncmp_test attach"))
+		goto out;
+
+	skel->bss->target_pid = getpid();
+
+	/* Empty str */
+	skel->bss->str[0] = '\0';
+	got = trigger_strncmp(skel);
+	ASSERT_EQ(got, -1, "strncmp: empty str");
+
+	/* Same string */
+	memcpy(skel->bss->str, skel->rodata->target, sizeof(skel->bss->str));
+	got = trigger_strncmp(skel);
+	ASSERT_EQ(got, 0, "strncmp: same str");
+
+	/* Not-null-termainted string  */
+	memcpy(skel->bss->str, skel->rodata->target, sizeof(skel->bss->str));
+	skel->bss->str[sizeof(skel->bss->str) - 1] = 'A';
+	got = trigger_strncmp(skel);
+	ASSERT_EQ(got, 1, "strncmp: not-null-term str");
+
+	strncmp_full_str_cmp(skel, "strncmp: less than", -1);
+	strncmp_full_str_cmp(skel, "strncmp: greater than", 1);
+out:
+	strncmp_test__destroy(skel);
+}
+
+static void test_strncmp_bad_not_const_str_size(void)
+{
+	struct strncmp_test *skel;
+	int err;
+
+	skel = strncmp_test__open();
+	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.strncmp_bad_not_const_str_size, true);
+
+	err = strncmp_test__load(skel);
+	ASSERT_ERR(err, "strncmp_test load bad_not_const_str_size");
+
+	strncmp_test__destroy(skel);
+}
+
+static void test_strncmp_bad_writable_target(void)
+{
+	struct strncmp_test *skel;
+	int err;
+
+	skel = strncmp_test__open();
+	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.strncmp_bad_writable_target, true);
+
+	err = strncmp_test__load(skel);
+	ASSERT_ERR(err, "strncmp_test load bad_writable_target");
+
+	strncmp_test__destroy(skel);
+}
+
+static void test_strncmp_bad_not_null_term_target(void)
+{
+	struct strncmp_test *skel;
+	int err;
+
+	skel = strncmp_test__open();
+	if (!ASSERT_OK_PTR(skel, "strncmp_test open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.strncmp_bad_not_null_term_target, true);
+
+	err = strncmp_test__load(skel);
+	ASSERT_ERR(err, "strncmp_test load bad_not_null_term_target");
+
+	strncmp_test__destroy(skel);
+}
+
+void test_test_strncmp(void)
+{
+	if (test__start_subtest("strncmp_ret"))
+		test_strncmp_ret();
+	if (test__start_subtest("strncmp_bad_not_const_str_size"))
+		test_strncmp_bad_not_const_str_size();
+	if (test__start_subtest("strncmp_bad_writable_target"))
+		test_strncmp_bad_writable_target();
+	if (test__start_subtest("strncmp_bad_not_null_term_target"))
+		test_strncmp_bad_not_null_term_target();
+}