Resguardo inicial

This commit is contained in:
lastdragon
2026-09-06 12:53:21 -06:00
parent 662efe3c2a
commit ad2088d178
94853 changed files with 43200404 additions and 0 deletions
@@ -0,0 +1,2 @@
cfitests
shadowstack
@@ -0,0 +1,25 @@
# SPDX-License-Identifier: GPL-2.0
CFLAGS += $(KHDR_INCLUDES)
CFLAGS += -I$(top_srcdir)/tools/include
CFLAGS += -march=rv64gc_zicfilp_zicfiss -fcf-protection=full
# Check for zicfi* extensions needs cross compiler
# which is not set until lib.mk is included
ifeq ($(LLVM)$(CC),cc)
CC := $(CROSS_COMPILE)gcc
endif
ifeq ($(shell $(CC) $(CFLAGS) -nostdlib -xc /dev/null -o /dev/null > /dev/null 2>&1; echo $$?),0)
TEST_GEN_PROGS := cfitests
$(OUTPUT)/cfitests: cfitests.c shadowstack.c
$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $^
else
$(shell echo "Toolchain doesn't support CFI, skipping CFI kselftest." >&2)
endif
include ../../lib.mk
@@ -0,0 +1,82 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef SELFTEST_RISCV_CFI_H
#define SELFTEST_RISCV_CFI_H
#include <stddef.h>
#include <sys/types.h>
#include "shadowstack.h"
#define CHILD_EXIT_CODE_SSWRITE 10
#define CHILD_EXIT_CODE_SIG_TEST 11
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3") = (long)(arg4); \
register long _arg5 __asm__ ("a4") = (long)(arg5); \
\
__asm__ volatile( \
"ecall\n" \
: "+r" \
(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
\
__asm__ volatile( \
"ecall\n" \
: "+r" (_arg1) \
: "r"(_arg2), "r"(_arg3), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#ifndef __NR_prctl
#define __NR_prctl 167
#endif
#ifndef __NR_map_shadow_stack
#define __NR_map_shadow_stack 453
#endif
#define CSR_SSP 0x011
#ifdef __ASSEMBLY__
#define __ASM_STR(x) x
#else
#define __ASM_STR(x) #x
#endif
#define csr_read(csr) \
({ \
register unsigned long __v; \
__asm__ __volatile__ ("csrr %0, " __ASM_STR(csr) \
: "=r" (__v) : \
: "memory"); \
__v; \
})
#define csr_write(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrw " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#endif
@@ -0,0 +1,180 @@
// 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_BRANCH_LANDING_PAD_EN_STATE | \
PTRACE_CFI_SHADOW_STACK_EN_STATE | \
PTRACE_CFI_SHADOW_STACK_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_BRANCH_EXPECTED_LANDING_PAD_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");
/* Test unknown PR_CFI bits */
ret = my_syscall5(__NR_prctl, PR_SET_CFI, PR_CFI_BRANCH_LANDING_PADS,
PR_CFI_ENABLE | 0xffff0, 0, 0);
if (!ret)
ksft_exit_fail_msg("PR_SET_CFI accepted reserved branch landing pad bits\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_CFI, PR_CFI_BRANCH_LANDING_PADS, &lpad_status, 0, 0);
if (ret)
ksft_exit_fail_msg("Get landing pad status failed with %d\n", ret);
if (!(lpad_status & PR_CFI_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
@@ -0,0 +1,385 @@
// 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
@@ -0,0 +1,27 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef SELFTEST_SHADOWSTACK_TEST_H
#define SELFTEST_SHADOWSTACK_TEST_H
#include <stddef.h>
#include <linux/prctl.h>
/*
* A CFI test returns true for success or false for fail.
* Takes a test number to index into array, and a void pointer.
*/
typedef bool (*shstk_test_func)(unsigned long test_num, void *);
struct shadow_stack_tests {
char *name;
shstk_test_func t_func;
};
bool shadow_stack_fork_test(unsigned long test_num, void *ctx);
bool shadow_stack_map_test(unsigned long test_num, void *ctx);
bool shadow_stack_protection_test(unsigned long test_num, void *ctx);
bool shadow_stack_gup_tests(unsigned long test_num, void *ctx);
bool shadow_stack_signal_test(unsigned long test_num, void *ctx);
int execute_shadow_stack_tests(void);
#endif