1 files changed, 385 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
new file mode 100644
index 000000000000..c397336fe1ed
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -0,0 +1,385 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+
+#ifdef __x86_64__
+
+#include <unistd.h>
+#include <asm/ptrace.h>
+#include <linux/compiler.h>
+#include <linux/stringify.h>
+#include <sys/wait.h>
+#include <sys/syscall.h>
+#include <sys/prctl.h>
+#include <asm/prctl.h>
+#include "uprobe_syscall.skel.h"
+#include "uprobe_syscall_executed.skel.h"
+
+__naked unsigned long uretprobe_regs_trigger(void)
+{
+	asm volatile (
+		"movq $0xdeadbeef, %rax\n"
+		"ret\n"
+	);
+}
+
+__naked void uretprobe_regs(struct pt_regs *before, struct pt_regs *after)
+{
+	asm volatile (
+		"movq %r15,   0(%rdi)\n"
+		"movq %r14,   8(%rdi)\n"
+		"movq %r13,  16(%rdi)\n"
+		"movq %r12,  24(%rdi)\n"
+		"movq %rbp,  32(%rdi)\n"
+		"movq %rbx,  40(%rdi)\n"
+		"movq %r11,  48(%rdi)\n"
+		"movq %r10,  56(%rdi)\n"
+		"movq  %r9,  64(%rdi)\n"
+		"movq  %r8,  72(%rdi)\n"
+		"movq %rax,  80(%rdi)\n"
+		"movq %rcx,  88(%rdi)\n"
+		"movq %rdx,  96(%rdi)\n"
+		"movq %rsi, 104(%rdi)\n"
+		"movq %rdi, 112(%rdi)\n"
+		"movq   $0, 120(%rdi)\n" /* orig_rax */
+		"movq   $0, 128(%rdi)\n" /* rip      */
+		"movq   $0, 136(%rdi)\n" /* cs       */
+		"pushf\n"
+		"pop %rax\n"
+		"movq %rax, 144(%rdi)\n" /* eflags   */
+		"movq %rsp, 152(%rdi)\n" /* rsp      */
+		"movq   $0, 160(%rdi)\n" /* ss       */
+
+		/* save 2nd argument */
+		"pushq %rsi\n"
+		"call uretprobe_regs_trigger\n"
+
+		/* save  return value and load 2nd argument pointer to rax */
+		"pushq %rax\n"
+		"movq 8(%rsp), %rax\n"
+
+		"movq %r15,   0(%rax)\n"
+		"movq %r14,   8(%rax)\n"
+		"movq %r13,  16(%rax)\n"
+		"movq %r12,  24(%rax)\n"
+		"movq %rbp,  32(%rax)\n"
+		"movq %rbx,  40(%rax)\n"
+		"movq %r11,  48(%rax)\n"
+		"movq %r10,  56(%rax)\n"
+		"movq  %r9,  64(%rax)\n"
+		"movq  %r8,  72(%rax)\n"
+		"movq %rcx,  88(%rax)\n"
+		"movq %rdx,  96(%rax)\n"
+		"movq %rsi, 104(%rax)\n"
+		"movq %rdi, 112(%rax)\n"
+		"movq   $0, 120(%rax)\n" /* orig_rax */
+		"movq   $0, 128(%rax)\n" /* rip      */
+		"movq   $0, 136(%rax)\n" /* cs       */
+
+		/* restore return value and 2nd argument */
+		"pop %rax\n"
+		"pop %rsi\n"
+
+		"movq %rax,  80(%rsi)\n"
+
+		"pushf\n"
+		"pop %rax\n"
+
+		"movq %rax, 144(%rsi)\n" /* eflags   */
+		"movq %rsp, 152(%rsi)\n" /* rsp      */
+		"movq   $0, 160(%rsi)\n" /* ss       */
+		"ret\n"
+);
+}
+
+static void test_uretprobe_regs_equal(void)
+{
+	struct uprobe_syscall *skel = NULL;
+	struct pt_regs before = {}, after = {};
+	unsigned long *pb = (unsigned long *) &before;
+	unsigned long *pa = (unsigned long *) &after;
+	unsigned long *pp;
+	unsigned int i, cnt;
+	int err;
+
+	skel = uprobe_syscall__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall__open_and_load"))
+		goto cleanup;
+
+	err = uprobe_syscall__attach(skel);
+	if (!ASSERT_OK(err, "uprobe_syscall__attach"))
+		goto cleanup;
+
+	uretprobe_regs(&before, &after);
+
+	pp = (unsigned long *) &skel->bss->regs;
+	cnt = sizeof(before)/sizeof(*pb);
+
+	for (i = 0; i < cnt; i++) {
+		unsigned int offset = i * sizeof(unsigned long);
+
+		/*
+		 * Check register before and after uretprobe_regs_trigger call
+		 * that triggers the uretprobe.
+		 */
+		switch (offset) {
+		case offsetof(struct pt_regs, rax):
+			ASSERT_EQ(pa[i], 0xdeadbeef, "return value");
+			break;
+		default:
+			if (!ASSERT_EQ(pb[i], pa[i], "register before-after value check"))
+				fprintf(stdout, "failed register offset %u\n", offset);
+		}
+
+		/*
+		 * Check register seen from bpf program and register after
+		 * uretprobe_regs_trigger call
+		 */
+		switch (offset) {
+		/*
+		 * These values will be different (not set in uretprobe_regs),
+		 * we don't care.
+		 */
+		case offsetof(struct pt_regs, orig_rax):
+		case offsetof(struct pt_regs, rip):
+		case offsetof(struct pt_regs, cs):
+		case offsetof(struct pt_regs, rsp):
+		case offsetof(struct pt_regs, ss):
+			break;
+		default:
+			if (!ASSERT_EQ(pp[i], pa[i], "register prog-after value check"))
+				fprintf(stdout, "failed register offset %u\n", offset);
+		}
+	}
+
+cleanup:
+	uprobe_syscall__destroy(skel);
+}
+
+#define BPF_TESTMOD_UPROBE_TEST_FILE "/sys/kernel/bpf_testmod_uprobe"
+
+static int write_bpf_testmod_uprobe(unsigned long offset)
+{
+	size_t n, ret;
+	char buf[30];
+	int fd;
+
+	n = sprintf(buf, "%lu", offset);
+
+	fd = open(BPF_TESTMOD_UPROBE_TEST_FILE, O_WRONLY);
+	if (fd < 0)
+		return -errno;
+
+	ret = write(fd, buf, n);
+	close(fd);
+	return ret != n ? (int) ret : 0;
+}
+
+static void test_uretprobe_regs_change(void)
+{
+	struct pt_regs before = {}, after = {};
+	unsigned long *pb = (unsigned long *) &before;
+	unsigned long *pa = (unsigned long *) &after;
+	unsigned long cnt = sizeof(before)/sizeof(*pb);
+	unsigned int i, err, offset;
+
+	offset = get_uprobe_offset(uretprobe_regs_trigger);
+
+	err = write_bpf_testmod_uprobe(offset);
+	if (!ASSERT_OK(err, "register_uprobe"))
+		return;
+
+	uretprobe_regs(&before, &after);
+
+	err = write_bpf_testmod_uprobe(0);
+	if (!ASSERT_OK(err, "unregister_uprobe"))
+		return;
+
+	for (i = 0; i < cnt; i++) {
+		unsigned int offset = i * sizeof(unsigned long);
+
+		switch (offset) {
+		case offsetof(struct pt_regs, rax):
+			ASSERT_EQ(pa[i], 0x12345678deadbeef, "rax");
+			break;
+		case offsetof(struct pt_regs, rcx):
+			ASSERT_EQ(pa[i], 0x87654321feebdaed, "rcx");
+			break;
+		case offsetof(struct pt_regs, r11):
+			ASSERT_EQ(pa[i], (__u64) -1, "r11");
+			break;
+		default:
+			if (!ASSERT_EQ(pa[i], pb[i], "register before-after value check"))
+				fprintf(stdout, "failed register offset %u\n", offset);
+		}
+	}
+}
+
+#ifndef __NR_uretprobe
+#define __NR_uretprobe 335
+#endif
+
+__naked unsigned long uretprobe_syscall_call_1(void)
+{
+	/*
+	 * Pretend we are uretprobe trampoline to trigger the return
+	 * probe invocation in order to verify we get SIGILL.
+	 */
+	asm volatile (
+		"pushq %rax\n"
+		"pushq %rcx\n"
+		"pushq %r11\n"
+		"movq $" __stringify(__NR_uretprobe) ", %rax\n"
+		"syscall\n"
+		"popq %r11\n"
+		"popq %rcx\n"
+		"retq\n"
+	);
+}
+
+__naked unsigned long uretprobe_syscall_call(void)
+{
+	asm volatile (
+		"call uretprobe_syscall_call_1\n"
+		"retq\n"
+	);
+}
+
+static void test_uretprobe_syscall_call(void)
+{
+	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
+		.retprobe = true,
+	);
+	struct uprobe_syscall_executed *skel;
+	int pid, status, err, go[2], c;
+
+	if (!ASSERT_OK(pipe(go), "pipe"))
+		return;
+
+	skel = uprobe_syscall_executed__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+		goto cleanup;
+
+	pid = fork();
+	if (!ASSERT_GE(pid, 0, "fork"))
+		goto cleanup;
+
+	/* child */
+	if (pid == 0) {
+		close(go[1]);
+
+		/* wait for parent's kick */
+		err = read(go[0], &c, 1);
+		if (err != 1)
+			exit(-1);
+
+		uretprobe_syscall_call();
+		_exit(0);
+	}
+
+	skel->links.test = bpf_program__attach_uprobe_multi(skel->progs.test, pid,
+							    "/proc/self/exe",
+							    "uretprobe_syscall_call", &opts);
+	if (!ASSERT_OK_PTR(skel->links.test, "bpf_program__attach_uprobe_multi"))
+		goto cleanup;
+
+	/* kick the child */
+	write(go[1], &c, 1);
+	err = waitpid(pid, &status, 0);
+	ASSERT_EQ(err, pid, "waitpid");
+
+	/* verify the child got killed with SIGILL */
+	ASSERT_EQ(WIFSIGNALED(status), 1, "WIFSIGNALED");
+	ASSERT_EQ(WTERMSIG(status), SIGILL, "WTERMSIG");
+
+	/* verify the uretprobe program wasn't called */
+	ASSERT_EQ(skel->bss->executed, 0, "executed");
+
+cleanup:
+	uprobe_syscall_executed__destroy(skel);
+	close(go[1]);
+	close(go[0]);
+}
+
+/*
+ * Borrowed from tools/testing/selftests/x86/test_shadow_stack.c.
+ *
+ * For use in inline enablement of shadow stack.
+ *
+ * The program can't return from the point where shadow stack gets enabled
+ * because there will be no address on the shadow stack. So it can't use
+ * syscall() for enablement, since it is a function.
+ *
+ * Based on code from nolibc.h. Keep a copy here because this can't pull
+ * in all of nolibc.h.
+ */
+#define ARCH_PRCTL(arg1, arg2)					\
+({								\
+	long _ret;						\
+	register long _num  asm("eax") = __NR_arch_prctl;	\
+	register long _arg1 asm("rdi") = (long)(arg1);		\
+	register long _arg2 asm("rsi") = (long)(arg2);		\
+								\
+	asm volatile (						\
+		"syscall\n"					\
+		: "=a"(_ret)					\
+		: "r"(_arg1), "r"(_arg2),			\
+		  "0"(_num)					\
+		: "rcx", "r11", "memory", "cc"			\
+	);							\
+	_ret;							\
+})
+
+#ifndef ARCH_SHSTK_ENABLE
+#define ARCH_SHSTK_ENABLE	0x5001
+#define ARCH_SHSTK_DISABLE	0x5002
+#define ARCH_SHSTK_SHSTK	(1ULL <<  0)
+#endif
+
+static void test_uretprobe_shadow_stack(void)
+{
+	if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
+		test__skip();
+		return;
+	}
+
+	/* Run all of the uretprobe tests. */
+	test_uretprobe_regs_equal();
+	test_uretprobe_regs_change();
+	test_uretprobe_syscall_call();
+
+	ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
+}
+#else
+static void test_uretprobe_regs_equal(void)
+{
+	test__skip();
+}
+
+static void test_uretprobe_regs_change(void)
+{
+	test__skip();
+}
+
+static void test_uretprobe_syscall_call(void)
+{
+	test__skip();
+}
+
+static void test_uretprobe_shadow_stack(void)
+{
+	test__skip();
+}
+#endif
+
+void test_uprobe_syscall(void)
+{
+	if (test__start_subtest("uretprobe_regs_equal"))
+		test_uretprobe_regs_equal();
+	if (test__start_subtest("uretprobe_regs_change"))
+		test_uretprobe_regs_change();
+	if (test__start_subtest("uretprobe_syscall_call"))
+		test_uretprobe_syscall_call();
+	if (test__start_subtest("uretprobe_shadow_stack"))
+		test_uretprobe_shadow_stack();
+}