Add a simple selftest for exercising some shadow stack behavior:
- map_shadow_stack syscall and pivot
- Faulting in shadow stack memory
- Handling shadow stack violations
- GUP of shadow stack memory
- mprotect() of shadow stack memory
- Userfaultfd on shadow stack memory
- 32 bit segmentation
- Guard gap test
- Ptrace test
Co-developed-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Acked-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Tested-by: Pengfei Xu <pengfei.xu@xxxxxxxxx>
Tested-by: John Allen <john.allen@xxxxxxx>
Tested-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
v9:
- Fix race in userfaultfd test
- Add guard gap test
- Add ptrace test
---
tools/testing/selftests/x86/Makefile | 2 +-
.../testing/selftests/x86/test_shadow_stack.c | 884 ++++++++++++++++++
2 files changed, 885 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/x86/test_shadow_stack.c
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 598135d3162b..7e8c937627dd 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -18,7 +18,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \
- corrupt_xstate_header amx lam
+ corrupt_xstate_header amx lam test_shadow_stack
# Some selftests require 32bit support enabled also on 64bit systems
TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c
new file mode 100644
index 000000000000..5ab788dc1ce6
--- /dev/null
+++ b/tools/testing/selftests/x86/test_shadow_stack.c
@@ -0,0 +1,884 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This program test's basic kernel shadow stack support. It enables shadow
+ * stack manual via the arch_prctl(), instead of relying on glibc. It's
+ * Makefile doesn't compile with shadow stack support, so it doesn't rely on
+ * any particular glibc. As a result it can't do any operations that require
+ * special glibc shadow stack support (longjmp(), swapcontext(), etc). Just
+ * stick to the basics and hope the compiler doesn't do anything strange.
+ */
+
+#define _GNU_SOURCE
+
+#include <sys/syscall.h>
+#include <asm/mman.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <x86intrin.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+#include <stdint.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/ioctl.h>
+#include <linux/userfaultfd.h>
+#include <setjmp.h>
+#include <sys/ptrace.h>
+#include <sys/signal.h>
+#include <linux/elf.h>
+
+/*
+ * Define the ABI defines if needed, so people can run the tests
+ * without building the headers.
+ */
+#ifndef __NR_map_shadow_stack
+#define __NR_map_shadow_stack 451
+
+#define SHADOW_STACK_SET_TOKEN (1ULL << 0)
+
+#define ARCH_SHSTK_ENABLE 0x5001
+#define ARCH_SHSTK_DISABLE 0x5002
+#define ARCH_SHSTK_LOCK 0x5003
+#define ARCH_SHSTK_UNLOCK 0x5004
+#define ARCH_SHSTK_STATUS 0x5005
+
+#define ARCH_SHSTK_SHSTK (1ULL << 0)
+#define ARCH_SHSTK_WRSS (1ULL << 1)
+
+#define NT_X86_SHSTK 0x204
+#endif
+
+#define SS_SIZE 0x200000
+#define PAGE_SIZE 0x1000
+
+#if (__GNUC__ < 8) || (__GNUC__ == 8 && __GNUC_MINOR__ < 5)
+int main(int argc, char *argv[])
+{
+ printf("[SKIP]\tCompiler does not support CET.\n");
+ return 0;
+}
+#else
+void write_shstk(unsigned long *addr, unsigned long val)
+{
+ asm volatile("wrssq %[val], (%[addr])\n"
+ : "=m" (addr)
+ : [addr] "r" (addr), [val] "r" (val));
+}
+
+static inline unsigned long __attribute__((always_inline)) get_ssp(void)
+{
+ unsigned long ret = 0;
+
+ asm volatile("xor %0, %0; rdsspq %0" : "=r" (ret));
+ return ret;
+}
+
+/*
+ * 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; \
+})
+
+void *create_shstk(void *addr)
+{
+ return (void *)syscall(__NR_map_shadow_stack, addr, SS_SIZE, SHADOW_STACK_SET_TOKEN);
+}
+
+void *create_normal_mem(void *addr)
+{
+ return mmap(addr, SS_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+}
+
+void free_shstk(void *shstk)
+{
+ munmap(shstk, SS_SIZE);
+}
+
+int reset_shstk(void *shstk)
+{
+ return madvise(shstk, SS_SIZE, MADV_DONTNEED);
+}
+
+void try_shstk(unsigned long new_ssp)
+{
+ unsigned long ssp;
+
+ printf("[INFO]\tnew_ssp = %lx, *new_ssp = %lx\n",
+ new_ssp, *((unsigned long *)new_ssp));
+
+ ssp = get_ssp();
+ printf("[INFO]\tchanging ssp from %lx to %lx\n", ssp, new_ssp);
+
+ asm volatile("rstorssp (%0)\n":: "r" (new_ssp));
+ asm volatile("saveprevssp");
+ printf("[INFO]\tssp is now %lx\n", get_ssp());
+
+ /* Switch back to original shadow stack */
+ ssp -= 8;
+ asm volatile("rstorssp (%0)\n":: "r" (ssp));
+ asm volatile("saveprevssp");
+}
+
+int test_shstk_pivot(void)
+{
+ void *shstk = create_shstk(0);
+
+ if (shstk == MAP_FAILED) {
+ printf("[FAIL]\tError creating shadow stack: %d\n", errno);
+ return 1;
+ }
+ try_shstk((unsigned long)shstk + SS_SIZE - 8);
+ free_shstk(shstk);
+
+ printf("[OK]\tShadow stack pivot\n");
+ return 0;
+}
+
+int test_shstk_faults(void)
+{
+ unsigned long *shstk = create_shstk(0);
+
+ /* Read shadow stack, test if it's zero to not get read optimized out */
+ if (*shstk != 0)
+ goto err;
+
+ /* Wrss memory that was already read. */
+ write_shstk(shstk, 1);
+ if (*shstk != 1)
+ goto err;
+
+ /* Page out memory, so we can wrss it again. */
+ if (reset_shstk((void *)shstk))
+ goto err;
+
+ write_shstk(shstk, 1);
+ if (*shstk != 1)
+ goto err;
+
+ printf("[OK]\tShadow stack faults\n");
+ return 0;
+
+err:
+ return 1;
+}
+
+unsigned long saved_ssp;
+unsigned long saved_ssp_val;
+volatile bool segv_triggered;
+
+void __attribute__((noinline)) violate_ss(void)
+{
+ saved_ssp = get_ssp();
+ saved_ssp_val = *(unsigned long *)saved_ssp;
+
+ /* Corrupt shadow stack */
+ printf("[INFO]\tCorrupting shadow stack\n");
+ write_shstk((void *)saved_ssp, 0);
+}
+
+void segv_handler(int signum, siginfo_t *si, void *uc)
+{
+ printf("[INFO]\tGenerated shadow stack violation successfully\n");
+
+ segv_triggered = true;
+
+ /* Fix shadow stack */
+ write_shstk((void *)saved_ssp, saved_ssp_val);
+}
+
+int test_shstk_violation(void)
+{
+ struct sigaction sa = {};
+
+ sa.sa_sigaction = segv_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ segv_triggered = false;
+
+ /* Make sure segv_triggered is set before violate_ss() */
+ asm volatile("" : : : "memory");
+
+ violate_ss();
+
+ signal(SIGSEGV, SIG_DFL);
+
+ printf("[OK]\tShadow stack violation test\n");
+
+ return !segv_triggered;
+}
+
+/* Gup test state */
+#define MAGIC_VAL 0x12345678
+bool is_shstk_access;
+void *shstk_ptr;
+int fd;
+
+void reset_test_shstk(void *addr)
+{
+ if (shstk_ptr)
+ free_shstk(shstk_ptr);
+ shstk_ptr = create_shstk(addr);
+}
+
+void test_access_fix_handler(int signum, siginfo_t *si, void *uc)
+{
+ printf("[INFO]\tViolation from %s\n", is_shstk_access ? "shstk access" : "normal write");
+
+ segv_triggered = true;
+
+ /* Fix shadow stack */
+ if (is_shstk_access) {
+ reset_test_shstk(shstk_ptr);
+ return;
+ }
+
+ free_shstk(shstk_ptr);
+ create_normal_mem(shstk_ptr);
+}
+
+bool test_shstk_access(void *ptr)
+{
+ is_shstk_access = true;
+ segv_triggered = false;
+ write_shstk(ptr, MAGIC_VAL);
+
+ asm volatile("" : : : "memory");
+
+ return segv_triggered;
+}
+
+bool test_write_access(void *ptr)
+{
+ is_shstk_access = false;
+ segv_triggered = false;
+ *(unsigned long *)ptr = MAGIC_VAL;
+
+ asm volatile("" : : : "memory");
+
+ return segv_triggered;
+}
+
+bool gup_write(void *ptr)
+{
+ unsigned long val;
+
+ lseek(fd, (unsigned long)ptr, SEEK_SET);
+ if (write(fd, &val, sizeof(val)) < 0)
+ return 1;
+
+ return 0;
+}
+
+bool gup_read(void *ptr)
+{
+ unsigned long val;
+
+ lseek(fd, (unsigned long)ptr, SEEK_SET);
+ if (read(fd, &val, sizeof(val)) < 0)
+ return 1;
+
+ return 0;
+}
+
+int test_gup(void)
+{
+ struct sigaction sa = {};
+ int status;
+ pid_t pid;
+
+ sa.sa_sigaction = test_access_fix_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ segv_triggered = false;
+
+ fd = open("/proc/self/mem", O_RDWR);
+ if (fd == -1)
+ return 1;
+
+ reset_test_shstk(0);
+ if (gup_read(shstk_ptr))
+ return 1;
+ if (test_shstk_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup read -> shstk access success\n");
+
+ reset_test_shstk(0);
+ if (gup_write(shstk_ptr))
+ return 1;
+ if (test_shstk_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup write -> shstk access success\n");
+
+ reset_test_shstk(0);
+ if (gup_read(shstk_ptr))
+ return 1;
+ if (!test_write_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup read -> write access success\n");
+
+ reset_test_shstk(0);
+ if (gup_write(shstk_ptr))
+ return 1;
+ if (!test_write_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup write -> write access success\n");
+
+ close(fd);
+
+ /* COW/gup test */
+ reset_test_shstk(0);
+ pid = fork();
+ if (!pid) {
+ fd = open("/proc/self/mem", O_RDWR);
+ if (fd == -1)
+ exit(1);
+
+ if (gup_write(shstk_ptr)) {
+ close(fd);
+ exit(1);
+ }
+ close(fd);
+ exit(0);
+ }
+ waitpid(pid, &status, 0);
+ if (WEXITSTATUS(status)) {
+ printf("[FAIL]\tWrite in child failed\n");
+ return 1;
+ }
+ if (*(unsigned long *)shstk_ptr == MAGIC_VAL) {
+ printf("[FAIL]\tWrite in child wrote through to shared memory\n");
+ return 1;
+ }
+
+ printf("[INFO]\tCow gup write -> write access success\n");
+
+ free_shstk(shstk_ptr);
+
+ signal(SIGSEGV, SIG_DFL);
+
+ printf("[OK]\tShadow gup test\n");
+
+ return 0;
+}
+
+int test_mprotect(void)
+{
+ struct sigaction sa = {};
+
+ sa.sa_sigaction = test_access_fix_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ segv_triggered = false;
+
+ /* mprotect a shadow stack as read only */
+ reset_test_shstk(0);
+ if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
+ printf("[FAIL]\tmprotect(PROT_READ) failed\n");
+ return 1;
+ }
+
+ /* try to wrss it and fail */
+ if (!test_shstk_access(shstk_ptr)) {
+ printf("[FAIL]\tShadow stack access to read-only memory succeeded\n");
+ return 1;
+ }
+
+ /*
+ * The shadow stack was reset above to resolve the fault, make the new one
+ * read-only.
+ */
+ if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
+ printf("[FAIL]\tmprotect(PROT_READ) failed\n");
+ return 1;
+ }
+
+ /* then back to writable */
+ if (mprotect(shstk_ptr, SS_SIZE, PROT_WRITE | PROT_READ) < 0) {
+ printf("[FAIL]\tmprotect(PROT_WRITE) failed\n");
+ return 1;
+ }
+
+ /* then wrss to it and succeed */
+ if (test_shstk_access(shstk_ptr)) {
+ printf("[FAIL]\tShadow stack access to mprotect() writable memory failed\n");
+ return 1;
+ }
+
+ free_shstk(shstk_ptr);
+
+ signal(SIGSEGV, SIG_DFL);
+
+ printf("[OK]\tmprotect() test\n");
+
+ return 0;
+}
+
+char zero[4096];
+
+static void *uffd_thread(void *arg)
+{
+ struct uffdio_copy req;
+ int uffd = *(int *)arg;
+ struct uffd_msg msg;
+ int ret;
+
+ while (1) {
+ ret = read(uffd, &msg, sizeof(msg));
+ if (ret > 0)
+ break;
+ else if (errno == EAGAIN)
+ continue;
+ return (void *)1;
+ }
+
+ req.dst = msg.arg.pagefault.address;
+ req.src = (__u64)zero;
+ req.len = 4096;
+ req.mode = 0;
+
+ if (ioctl(uffd, UFFDIO_COPY, &req))
+ return (void *)1;
+
+ return (void *)0;
+}
+
+int test_userfaultfd(void)
+{
+ struct uffdio_register uffdio_register;
+ struct uffdio_api uffdio_api;
+ struct sigaction sa = {};
+ pthread_t thread;
+ void *res;
+ int uffd;
+
+ sa.sa_sigaction = test_access_fix_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+ if (uffd < 0) {
+ printf("[SKIP]\tUserfaultfd unavailable.\n");
+ return 0;
+ }
+
+ reset_test_shstk(0);
+
+ uffdio_api.api = UFFD_API;
+ uffdio_api.features = 0;
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api))
+ goto err;
+
+ uffdio_register.range.start = (__u64)shstk_ptr;
+ uffdio_register.range.len = 4096;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ goto err;
+
+ if (pthread_create(&thread, NULL, &uffd_thread, &uffd))
+ goto err;
+
+ reset_shstk(shstk_ptr);
+ test_shstk_access(shstk_ptr);
+
+ if (pthread_join(thread, &res))
+ goto err;
+
+ if (test_shstk_access(shstk_ptr))
+ goto err;
+
+ free_shstk(shstk_ptr);
+
+ signal(SIGSEGV, SIG_DFL);
+
+ if (!res)
+ printf("[OK]\tUserfaultfd test\n");
+ return !!res;
+err:
+ free_shstk(shstk_ptr);
+ close(uffd);
+ signal(SIGSEGV, SIG_DFL);
+ return 1;
+}
+
+/* Simple linked list for keeping track of mappings in test_guard_gap() */
+struct node {
+ struct node *next;
+ void *mapping;
+};
+
+/*
+ * This tests whether mmap will place other mappings in a shadow stack's guard
+ * gap. The steps are:
+ * 1. Finds an empty place by mapping and unmapping something.
+ * 2. Map a shadow stack in the middle of the known empty area.
+ * 3. Map a bunch of PAGE_SIZE mappings. These will use the search down
+ * direction, filling any gaps until it encounters the shadow stack's
+ * guard gap.
+ * 4. When a mapping lands below the shadow stack from step 2, then all
+ * of the above gaps are filled. The search down algorithm will have
+ * looked at the shadow stack gaps.
+ * 5. See if it landed in the gap.
+ */
+int test_guard_gap(void)
+{
+ void *free_area, *shstk, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
+ struct node *head = NULL, *cur;
+
+ free_area = mmap(0, SS_SIZE * 3, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ munmap(free_area, SS_SIZE * 3);
+
+ shstk = create_shstk(free_area + SS_SIZE);
+ if (shstk == MAP_FAILED)
+ return 1;
+
+ while (test_map > shstk) {
+ test_map = mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (test_map == MAP_FAILED)
+ return 1;
+ cur = malloc(sizeof(*cur));
+ cur->mapping = test_map;
+
+ cur->next = head;
+ head = cur;
+ }
+
+ while (head) {
+ cur = head;
+ head = cur->next;
+ munmap(cur->mapping, PAGE_SIZE);
+ free(cur);
+ }
+
+ free_shstk(shstk);
+
+ if (shstk - test_map - PAGE_SIZE != PAGE_SIZE)
+ return 1;
+
+ printf("[OK]\tGuard gap test\n");
+
+ return 0;
+}
+
+/*
+ * Too complicated to pull it out of the 32 bit header, but also get the
+ * 64 bit one needed above. Just define a copy here.
+ */
+#define __NR_compat_sigaction 67
+
+/*
+ * Call 32 bit signal handler to get 32 bit signals ABI. Make sure
+ * to push the registers that will get clobbered.
+ */
+int sigaction32(int signum, const struct sigaction *restrict act,
+ struct sigaction *restrict oldact)
+{
+ register long syscall_reg asm("eax") = __NR_compat_sigaction;
+ register long signum_reg asm("ebx") = signum;
+ register long act_reg asm("ecx") = (long)act;
+ register long oldact_reg asm("edx") = (long)oldact;
+ int ret = 0;
+
+ asm volatile ("int $0x80;"
+ : "=a"(ret), "=m"(oldact)
+ : "r"(syscall_reg), "r"(signum_reg), "r"(act_reg),
+ "r"(oldact_reg)
+ : "r8", "r9", "r10", "r11"
+ );
+
+ return ret;
+}
+
+sigjmp_buf jmp_buffer;
+
+void segv_gp_handler(int signum, siginfo_t *si, void *uc)
+{
+ segv_triggered = true;
+
+ /*
+ * To work with old glibc, this can't rely on siglongjmp working with
+ * shadow stack enabled, so disable shadow stack before siglongjmp().
+ */
+ ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
+ siglongjmp(jmp_buffer, -1);
+}
+
+/*
+ * Transition to 32 bit mode and check that a #GP triggers a segfault.
+ */
+int test_32bit(void)
+{
+ struct sigaction sa = {};
+ struct sigaction *sa32;
+
+ /* Create sigaction in 32 bit address range */
+ sa32 = mmap(0, 4096, PROT_READ | PROT_WRITE,
+ MAP_32BIT | MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+ sa32->sa_flags = SA_SIGINFO;
+
+ sa.sa_sigaction = segv_gp_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+
+ segv_triggered = false;
+
+ /* Make sure segv_triggered is set before triggering the #GP */
+ asm volatile("" : : : "memory");
+
+ /*
+ * Set handler to somewhere in 32 bit address space
+ */
+ sa32->sa_handler = (void *)sa32;
+ if (sigaction32(SIGUSR1, sa32, NULL))
+ return 1;
+
+ if (!sigsetjmp(jmp_buffer, 1))
+ raise(SIGUSR1);
+
+ if (segv_triggered)
+ printf("[OK]\t32 bit test\n");
+
+ return !segv_triggered;
+}
+
+void segv_handler_ptrace(int signum, siginfo_t *si, void *uc)
+{
+ /* The SSP adjustment caused a segfault. */
+ exit(0);
+}
+
+int test_ptrace(void)
+{
+ unsigned long saved_ssp, ssp = 0;
+ struct sigaction sa= {};
+ struct iovec iov;
+ int status;
+ int pid;
+
+ iov.iov_base = &ssp;
+ iov.iov_len = sizeof(ssp);
+
+ pid = fork();
+ if (!pid) {
+ ssp = get_ssp();
+
+ sa.sa_sigaction = segv_handler_ptrace;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ ptrace(PTRACE_TRACEME, NULL, NULL, NULL);
+ /*
+ * The parent will tweak the SSP and return from this function
+ * will #CP.
+ */
+ raise(SIGTRAP);
+
+ exit(1);
+ }
+
+ while (waitpid(pid, &status, 0) != -1 && WSTOPSIG(status) != SIGTRAP);
+
+ if (ptrace(PTRACE_GETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tFailed to PTRACE_GETREGS\n");
+ goto out_kill;
+ }
+
+ if (!ssp) {
+ printf("[INFO]\tPtrace child SSP was 0\n");
+ goto out_kill;
+ }
+
+ saved_ssp = ssp;
+
+ iov.iov_len = 0;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tToo small size accepted via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ iov.iov_len = sizeof(ssp) + 1;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tToo large size accepted via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ ssp += 1;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tUnaligned SSP written via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ ssp = 0xFFFFFFFFFFFF0000;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tKernel range SSP written via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ /*
+ * Tweak the SSP so the child with #CP when it resumes and returns
+ * from raise()
+ */
+ ssp = saved_ssp + 8;
+ iov.iov_len = sizeof(ssp);
+ if (ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tFailed to PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ if (ptrace(PTRACE_DETACH, pid, NULL, NULL)) {
+ printf("[INFO]\tFailed to PTRACE_DETACH\n");
+ goto out_kill;
+ }
+
+ waitpid(pid, &status, 0);
+ if (WEXITSTATUS(status))
+ return 1;
+
+ printf("[OK]\tPtrace test\n");
+ return 0;
+
+out_kill:
+ kill(pid, SIGKILL);
+ return 1;
+}
+
+int main(int argc, char *argv[])
+{
+ int ret = 0;
+
+ if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
+ printf("[SKIP]\tCould not enable Shadow stack\n");
+ return 1;
+ }
+
+ if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK)) {
+ ret = 1;
+ printf("[FAIL]\tDisabling shadow stack failed\n");
+ }
+
+ if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
+ printf("[SKIP]\tCould not re-enable Shadow stack\n");
+ return 1;
+ }
+
+ if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_WRSS)) {
+ printf("[SKIP]\tCould not enable WRSS\n");
+ ret = 1;
+ goto out;
+ }
+
+ /* Should have succeeded if here, but this is a test, so double check. */
+ if (!get_ssp()) {
+ printf("[FAIL]\tShadow stack disabled\n");
+ return 1;
+ }
+
+ if (test_shstk_pivot()) {
+ ret = 1;
+ printf("[FAIL]\tShadow stack pivot\n");
+ goto out;
+ }
+
+ if (test_shstk_faults()) {
+ ret = 1;
+ printf("[FAIL]\tShadow stack fault test\n");
+ goto out;
+ }
+
+ if (test_shstk_violation()) {
+ ret = 1;
+ printf("[FAIL]\tShadow stack violation test\n");
+ goto out;
+ }
+
+ if (test_gup()) {
+ ret = 1;
+ printf("[FAIL]\tShadow shadow stack gup\n");
+ goto out;
+ }
+
+ if (test_mprotect()) {
+ ret = 1;
+ printf("[FAIL]\tShadow shadow mprotect test\n");
+ goto out;
+ }
+
+ if (test_userfaultfd()) {
+ ret = 1;
+ printf("[FAIL]\tUserfaultfd test\n");
+ goto out;
+ }
+
+ if (test_guard_gap()) {
+ ret = 1;
+ printf("[FAIL]\tGuard gap test\n");
+ goto out;
+ }
+
+ if (test_ptrace()) {
+ ret = 1;
+ printf("[FAIL]\tptrace test\n");
+ }
+
+ if (test_32bit()) {
+ ret = 1;
+ printf("[FAIL]\t32 bit test\n");
+ goto out;
+ }
+
+ return ret;
+
+out:
+ /*
+ * Disable shadow stack before the function returns, or there will be a
+ * shadow stack violation.
+ */
+ if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK)) {
+ ret = 1;
+ printf("[FAIL]\tDisabling shadow stack failed\n");
+ }
+
+ return ret;
+}
+#endif
--
2.34.1
