--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "../../kselftest.h"
+#include <sys/signal.h>
+#include <asm/ucontext.h>
+#include <linux/prctl.h>
+#include <errno.h>
+#include <linux/ptrace.h>
+#include <sys/wait.h>
+#include <linux/elf.h>
+#include <sys/uio.h>
+#include <asm-generic/unistd.h>
+
+#include "cfi_rv_test.h"
+
+/* do not optimize cfi related test functions */
+#pragma GCC push_options
+#pragma GCC optimize("O0")
+
+void sigsegv_handler(int signum, siginfo_t *si, void *uc)
+{
+ struct ucontext *ctx = (struct ucontext *)uc;
+
+ if (si->si_code == SEGV_CPERR) {
+ ksft_print_msg("Control flow violation happened somewhere\n");
+ ksft_print_msg("PC where violation happened %lx\n", ctx->uc_mcontext.gregs[0]);
+ exit(-1);
+ }
+
+ /* all other cases are expected to be of shadow stack write case */
+ exit(CHILD_EXIT_CODE_SSWRITE);
+}
+
+bool register_signal_handler(void)
+{
+ struct sigaction sa = {};
+
+ sa.sa_sigaction = sigsegv_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL)) {
+ ksft_print_msg("Registering signal handler for landing pad violation failed\n");
+ return false;
+ }
+
+ return true;
+}
+
+long ptrace(int request, pid_t pid, void *addr, void *data);
+
+bool cfi_ptrace_test(void)
+{
+ pid_t pid;
+ int status, ret = 0;
+ unsigned long ptrace_test_num = 0, total_ptrace_tests = 2;
+
+ struct user_cfi_state cfi_reg;
+ struct iovec iov;
+
+ pid = fork();
+
+ if (pid == -1) {
+ ksft_exit_fail_msg("%s: fork failed\n", __func__);
+ exit(1);
+ }
+
+ if (pid == 0) {
+ /* allow to be traced */
+ ptrace(PTRACE_TRACEME, 0, NULL, NULL);
+ raise(SIGSTOP);
+ asm volatile ("la a5, 1f\n"
+ "jalr a5\n"
+ "nop\n"
+ "nop\n"
+ "1: nop\n"
+ : : : "a5");
+ exit(11);
+ /* child shouldn't go beyond here */
+ }
+
+ /* parent's code goes here */
+ iov.iov_base = &cfi_reg;
+ iov.iov_len = sizeof(cfi_reg);
+
+ while (ptrace_test_num < total_ptrace_tests) {
+ memset(&cfi_reg, 0, sizeof(cfi_reg));
+ waitpid(pid, &status, 0);
+ if (WIFSTOPPED(status)) {
+ errno = 0;
+ ret = ptrace(PTRACE_GETREGSET, pid, (void *)NT_RISCV_USER_CFI, &iov);
+ if (ret == -1 && errno)
+ ksft_exit_fail_msg("%s: PTRACE_GETREGSET failed\n", __func__);
+ } else {
+ ksft_exit_fail_msg("%s: child didn't stop, failed\n", __func__);
+ }
+
+ switch (ptrace_test_num) {
+#define CFI_ENABLE_MASK (PTRACE_CFI_LP_EN_STATE | \
+ PTRACE_CFI_SS_EN_STATE | \
+ PTRACE_CFI_SS_PTR_STATE)
+ case 0:
+ if ((cfi_reg.cfi_status.cfi_state & CFI_ENABLE_MASK) != CFI_ENABLE_MASK)
+ ksft_exit_fail_msg("%s: ptrace_getregset failed, %llu\n", __func__,
+ cfi_reg.cfi_status.cfi_state);
+ if (!cfi_reg.shstk_ptr)
+ ksft_exit_fail_msg("%s: NULL shadow stack pointer, test failed\n",
+ __func__);
+ break;
+ case 1:
+ if (!(cfi_reg.cfi_status.cfi_state & PTRACE_CFI_ELP_STATE))
+ ksft_exit_fail_msg("%s: elp must have been set\n", __func__);
+ /* clear elp state. not interested in anything else */
+ cfi_reg.cfi_status.cfi_state = 0;
+
+ ret = ptrace(PTRACE_SETREGSET, pid, (void *)NT_RISCV_USER_CFI, &iov);
+ if (ret == -1 && errno)
+ ksft_exit_fail_msg("%s: PTRACE_GETREGSET failed\n", __func__);
+ break;
+ default:
+ ksft_exit_fail_msg("%s: unreachable switch case\n", __func__);
+ break;
+ }
+ ptrace(PTRACE_CONT, pid, NULL, NULL);
+ ptrace_test_num++;
+ }
+
+ waitpid(pid, &status, 0);
+ if (WEXITSTATUS(status) != 11)
+ ksft_print_msg("%s, bad return code from child\n", __func__);
+
+ ksft_print_msg("%s, ptrace test succeeded\n", __func__);
+ return true;
+}
+
+int main(int argc, char *argv[])
+{
+ int ret = 0;
+ unsigned long lpad_status = 0, ss_status = 0;
+
+ ksft_print_header();
+
+ ksft_print_msg("Starting risc-v tests\n");
+
+ /*
+ * Landing pad test. Not a lot of kernel changes to support landing
+ * pads for user mode except lighting up a bit in senvcfg via a prctl.
+ * Enable landing pad support throughout the execution of the test binary.
+ */
+ ret = my_syscall5(__NR_prctl, PR_GET_INDIR_BR_LP_STATUS, &lpad_status, 0, 0, 0);
+ if (ret)
+ ksft_exit_fail_msg("Get landing pad status failed with %d\n", ret);
+
+ if (!(lpad_status & PR_INDIR_BR_LP_ENABLE))
+ ksft_exit_fail_msg("Landing pad is not enabled, should be enabled via glibc\n");
+
+ ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS, &ss_status, 0, 0, 0);
+ if (ret)
+ ksft_exit_fail_msg("Get shadow stack failed with %d\n", ret);
+
+ if (!(ss_status & PR_SHADOW_STACK_ENABLE))
+ ksft_exit_fail_msg("Shadow stack is not enabled, should be enabled via glibc\n");
+
+ if (!register_signal_handler())
+ ksft_exit_fail_msg("Registering signal handler for SIGSEGV failed\n");
+
+ ksft_print_msg("Landing pad and shadow stack are enabled for binary\n");
+ cfi_ptrace_test();
+
+ execute_shadow_stack_tests();
+
+ return 0;
+}
+
+#pragma GCC pop_options
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "../../kselftest.h"
+#include <sys/wait.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <asm-generic/unistd.h>
+#include <sys/mman.h>
+#include "shadowstack.h"
+#include "cfi_rv_test.h"
+
+static struct shadow_stack_tests shstk_tests[] = {
+ { "shstk fork test\n", shadow_stack_fork_test },
+ { "map shadow stack syscall\n", shadow_stack_map_test },
+ { "shadow stack gup tests\n", shadow_stack_gup_tests },
+ { "shadow stack signal tests\n", shadow_stack_signal_test},
+ { "memory protections of shadow stack memory\n", shadow_stack_protection_test }
+};
+
+#define RISCV_SHADOW_STACK_TESTS ARRAY_SIZE(shstk_tests)
+
+/* do not optimize shadow stack related test functions */
+#pragma GCC push_options
+#pragma GCC optimize("O0")
+
+void zar(void)
+{
+ unsigned long ssp = 0;
+
+ ssp = csr_read(CSR_SSP);
+ ksft_print_msg("Spewing out shadow stack ptr: %lx\n"
+ " This is to ensure shadow stack is indeed enabled and working\n",
+ ssp);
+}
+
+void bar(void)
+{
+ zar();
+}
+
+void foo(void)
+{
+ bar();
+}
+
+void zar_child(void)
+{
+ unsigned long ssp = 0;
+
+ ssp = csr_read(CSR_SSP);
+ ksft_print_msg("Spewing out shadow stack ptr: %lx\n"
+ " This is to ensure shadow stack is indeed enabled and working\n",
+ ssp);
+}
+
+void bar_child(void)
+{
+ zar_child();
+}
+
+void foo_child(void)
+{
+ bar_child();
+}
+
+typedef void (call_func_ptr)(void);
+/*
+ * call couple of functions to test push/pop.
+ */
+int shadow_stack_call_tests(call_func_ptr fn_ptr, bool parent)
+{
+ ksft_print_msg("dummy calls for sspush and sspopchk in context of %s\n",
+ parent ? "parent" : "child");
+
+ (fn_ptr)();
+
+ return 0;
+}
+
+/* forks a thread, and ensure shadow stacks fork out */
+bool shadow_stack_fork_test(unsigned long test_num, void *ctx)
+{
+ int pid = 0, child_status = 0, parent_pid = 0, ret = 0;
+ unsigned long ss_status = 0;
+
+ ksft_print_msg("Exercising shadow stack fork test\n");
+
+ ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS, &ss_status, 0, 0, 0);
+ if (ret) {
+ ksft_exit_skip("Shadow stack get status prctl failed with errorcode %d\n", ret);
+ return false;
+ }
+
+ if (!(ss_status & PR_SHADOW_STACK_ENABLE))
+ ksft_exit_skip("Shadow stack is not enabled, should be enabled via glibc\n");
+
+ parent_pid = getpid();
+ pid = fork();
+
+ if (pid) {
+ ksft_print_msg("Parent pid %d and child pid %d\n", parent_pid, pid);
+ shadow_stack_call_tests(&foo, true);
+ } else {
+ shadow_stack_call_tests(&foo_child, false);
+ }
+
+ if (pid) {
+ ksft_print_msg("Waiting on child to finish\n");
+ wait(&child_status);
+ } else {
+ /* exit child gracefully */
+ exit(0);
+ }
+
+ if (pid && WIFSIGNALED(child_status)) {
+ ksft_print_msg("Child faulted, fork test failed\n");
+ return false;
+ }
+
+ return true;
+}
+
+/* exercise 'map_shadow_stack', pivot to it and call some functions to ensure it works */
+#define SHADOW_STACK_ALLOC_SIZE 4096
+bool shadow_stack_map_test(unsigned long test_num, void *ctx)
+{
+ unsigned long shdw_addr;
+ int ret = 0;
+
+ ksft_print_msg("Exercising shadow stack map test\n");
+
+ shdw_addr = my_syscall3(__NR_map_shadow_stack, NULL, SHADOW_STACK_ALLOC_SIZE, 0);
+
+ if (((long)shdw_addr) <= 0) {
+ ksft_print_msg("map_shadow_stack failed with error code %d\n",
+ (int)shdw_addr);
+ return false;
+ }
+
+ ret = munmap((void *)shdw_addr, SHADOW_STACK_ALLOC_SIZE);
+
+ if (ret) {
+ ksft_print_msg("munmap failed with error code %d\n", ret);
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * shadow stack protection tests. map a shadow stack and
+ * validate all memory protections work on it
+ */
+bool shadow_stack_protection_test(unsigned long test_num, void *ctx)
+{
+ unsigned long shdw_addr;
+ unsigned long *write_addr = NULL;
+ int ret = 0, pid = 0, child_status = 0;
+
+ ksft_print_msg("Exercising shadow stack protection test (WPT)\n");
+
+ shdw_addr = my_syscall3(__NR_map_shadow_stack, NULL, SHADOW_STACK_ALLOC_SIZE, 0);
+
+ if (((long)shdw_addr) <= 0) {
+ ksft_print_msg("map_shadow_stack failed with error code %d\n",
+ (int)shdw_addr);
+ return false;
+ }
+
+ write_addr = (unsigned long *)shdw_addr;
+ pid = fork();
+
+ /* no child was created, return false */
+ if (pid == -1)
+ return false;
+
+ /*
+ * try to perform a store from child on shadow stack memory
+ * it should result in SIGSEGV
+ */
+ if (!pid) {
+ /* below write must lead to SIGSEGV */
+ *write_addr = 0xdeadbeef;
+ } else {
+ wait(&child_status);
+ }
+
+ /* test fail, if 0xdeadbeef present on shadow stack address */
+ if (*write_addr == 0xdeadbeef) {
+ ksft_print_msg("Shadow stack WPT failed\n");
+ return false;
+ }
+
+ /* if child reached here, then fail */
+ if (!pid) {
+ ksft_print_msg("Shadow stack WPT failed: child reached unreachable state\n");
+ return false;
+ }
+
+ /* if child exited via signal handler but not for write on ss */
+ if (WIFEXITED(child_status) &&
+ WEXITSTATUS(child_status) != CHILD_EXIT_CODE_SSWRITE) {
+ ksft_print_msg("Shadow stack WPT failed: child wasn't signaled for write\n");
+ return false;
+ }
+
+ ret = munmap(write_addr, SHADOW_STACK_ALLOC_SIZE);
+ if (ret) {
+ ksft_print_msg("Shadow stack WPT failed: munmap failed, error code %d\n",
+ ret);
+ return false;
+ }
+
+ return true;
+}
+
+#define SS_MAGIC_WRITE_VAL 0xbeefdead
+
+int gup_tests(int mem_fd, unsigned long *shdw_addr)
+{
+ unsigned long val = 0;
+
+ lseek(mem_fd, (unsigned long)shdw_addr, SEEK_SET);
+ if (read(mem_fd, &val, sizeof(val)) < 0) {
+ ksft_print_msg("Reading shadow stack mem via gup failed\n");
+ return 1;
+ }
+
+ val = SS_MAGIC_WRITE_VAL;
+ lseek(mem_fd, (unsigned long)shdw_addr, SEEK_SET);
+ if (write(mem_fd, &val, sizeof(val)) < 0) {
+ ksft_print_msg("Writing shadow stack mem via gup failed\n");
+ return 1;
+ }
+
+ if (*shdw_addr != SS_MAGIC_WRITE_VAL) {
+ ksft_print_msg("GUP write to shadow stack memory failed\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+bool shadow_stack_gup_tests(unsigned long test_num, void *ctx)
+{
+ unsigned long shdw_addr = 0;
+ unsigned long *write_addr = NULL;
+ int fd = 0;
+ bool ret = false;
+
+ ksft_print_msg("Exercising shadow stack gup tests\n");
+ shdw_addr = my_syscall3(__NR_map_shadow_stack, NULL, SHADOW_STACK_ALLOC_SIZE, 0);
+
+ if (((long)shdw_addr) <= 0) {
+ ksft_print_msg("map_shadow_stack failed with error code %d\n", (int)shdw_addr);
+ return false;
+ }
+
+ write_addr = (unsigned long *)shdw_addr;
+
+ fd = open("/proc/self/mem", O_RDWR);
+ if (fd == -1)
+ return false;
+
+ if (gup_tests(fd, write_addr)) {
+ ksft_print_msg("gup tests failed\n");
+ goto out;
+ }
+
+ ret = true;
+out:
+ if (shdw_addr && munmap(write_addr, SHADOW_STACK_ALLOC_SIZE)) {
+ ksft_print_msg("munmap failed with error code %d\n", ret);
+ ret = false;
+ }
+
+ return ret;
+}
+
+volatile bool break_loop;
+
+void sigusr1_handler(int signo)
+{
+ break_loop = true;
+}
+
+bool sigusr1_signal_test(void)
+{
+ struct sigaction sa = {};
+
+ sa.sa_handler = sigusr1_handler;
+ sa.sa_flags = 0;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(SIGUSR1, &sa, NULL)) {
+ ksft_print_msg("Registering signal handler for SIGUSR1 failed\n");
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * shadow stack signal test. shadow stack must be enabled.
+ * register a signal, fork another thread which is waiting
+ * on signal. Send a signal from parent to child, verify
+ * that signal was received by child. If not test fails
+ */
+bool shadow_stack_signal_test(unsigned long test_num, void *ctx)
+{
+ int pid = 0, child_status = 0, ret = 0;
+ unsigned long ss_status = 0;
+
+ ksft_print_msg("Exercising shadow stack signal test\n");
+
+ ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS, &ss_status, 0, 0, 0);
+ if (ret) {
+ ksft_print_msg("Shadow stack get status prctl failed with errorcode %d\n", ret);
+ return false;
+ }
+
+ if (!(ss_status & PR_SHADOW_STACK_ENABLE))
+ ksft_print_msg("Shadow stack is not enabled, should be enabled via glibc\n");
+
+ /* this should be caught by signal handler and do an exit */
+ if (!sigusr1_signal_test()) {
+ ksft_print_msg("Registering sigusr1 handler failed\n");
+ exit(-1);
+ }
+
+ pid = fork();
+
+ if (pid == -1) {
+ ksft_print_msg("Signal test: fork failed\n");
+ goto out;
+ }
+
+ if (pid == 0) {
+ while (!break_loop)
+ sleep(1);
+
+ exit(11);
+ /* child shouldn't go beyond here */
+ }
+
+ /* send SIGUSR1 to child */
+ kill(pid, SIGUSR1);
+ wait(&child_status);
+
+out:
+
+ return (WIFEXITED(child_status) &&
+ WEXITSTATUS(child_status) == 11);
+}
+
+int execute_shadow_stack_tests(void)
+{
+ int ret = 0;
+ unsigned long test_count = 0;
+ unsigned long shstk_status = 0;
+ bool test_pass = false;
+
+ ksft_print_msg("Executing RISC-V shadow stack self tests\n");
+ ksft_set_plan(RISCV_SHADOW_STACK_TESTS);
+
+ ret = my_syscall5(__NR_prctl, PR_GET_SHADOW_STACK_STATUS, &shstk_status, 0, 0, 0);
+
+ if (ret != 0)
+ ksft_exit_fail_msg("Get shadow stack status failed with %d\n", ret);
+
+ /*
+ * If we are here that means get shadow stack status succeeded and
+ * thus shadow stack support is baked in the kernel.
+ */
+ while (test_count < RISCV_SHADOW_STACK_TESTS) {
+ test_pass = (*shstk_tests[test_count].t_func)(test_count, NULL);
+ ksft_test_result(test_pass, shstk_tests[test_count].name);
+ test_count++;
+ }
+
+ ksft_finished();
+
+ return 0;
+}
+
+#pragma GCC pop_options
projects / thirdparty / linux.git / commitdiff
