// 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();
}
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