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/*
* Copyright (c) 2014 Fujitsu Ltd.
* Author: Xing Gu <gux.fnst@cn.fujitsu.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* Description:
* Verify that,
* 1) mprotect() succeeds to set a region of memory with no access,
* when 'prot' is set to PROT_NONE. An attempt to access the contents
* of the region gives rise to the signal SIGSEGV.
* 2) mprotect() succeeds to set a region of memory to be executed, when
* 'prot' is set to PROT_EXEC.
*/
#include "config.h"
#include <signal.h>
#include <setjmp.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/mman.h>
#include <stdlib.h>
#include "test.h"
#include "safe_macros.h"
static void sighandler(int sig);
static void setup(void);
static void cleanup(void);
static void testfunc_protnone(void);
static void testfunc_protexec(void);
static void (*testfunc[])(void) = { testfunc_protnone, testfunc_protexec };
char *TCID = "mprotect04";
int TST_TOTAL = ARRAY_SIZE(testfunc);
static volatile int sig_caught;
static sigjmp_buf env;
static unsigned int page_sz;
typedef void (*func_ptr_t)(void);
int main(int ac, char **av)
{
int lc;
int i;
tst_parse_opts(ac, av, NULL, NULL);
setup();
for (lc = 0; TEST_LOOPING(lc); lc++) {
tst_count = 0;
for (i = 0; i < TST_TOTAL; i++)
(*testfunc[i])();
}
cleanup();
tst_exit();
}
static void sighandler(int sig)
{
sig_caught = sig;
siglongjmp(env, 1);
}
static void setup(void)
{
tst_tmpdir();
tst_sig(NOFORK, sighandler, cleanup);
page_sz = getpagesize();
TEST_PAUSE;
}
static void testfunc_protnone(void)
{
char *addr;
sig_caught = 0;
addr = SAFE_MMAP(cleanup, 0, page_sz, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
/* Change the protection to PROT_NONE. */
TEST(mprotect(addr, page_sz, PROT_NONE));
if (TEST_RETURN == -1) {
tst_resm(TFAIL | TTERRNO, "mprotect failed");
} else {
if (sigsetjmp(env, 1) == 0)
addr[0] = 1;
switch (sig_caught) {
case SIGSEGV:
tst_resm(TPASS, "test PROT_NONE for mprotect success");
break;
case 0:
tst_resm(TFAIL, "test PROT_NONE for mprotect failed");
break;
default:
tst_brkm(TBROK, cleanup,
"received an unexpected signal: %d",
sig_caught);
}
}
SAFE_MUNMAP(cleanup, addr, page_sz);
}
static void exec_func(void)
{
return;
}
static int page_present(void *p)
{
int fd;
fd = SAFE_OPEN(cleanup, "page_present", O_WRONLY|O_CREAT, 0644);
TEST(write(fd, p, 1));
SAFE_CLOSE(cleanup, fd);
if (TEST_RETURN >= 0)
return 1;
if (TEST_ERRNO != EFAULT)
tst_brkm(TBROK | TTERRNO, cleanup, "page_present write");
return 0;
}
static void clear_cache(void *start, int len)
{
#if HAVE_BUILTIN_CLEAR_CACHE == 1
__builtin___clear_cache(start, start + len);
#else
tst_brkm(TCONF, cleanup,
"compiler doesn't have __builtin___clear_cache()");
#endif
}
/*
* To check for the ABI version, because ppc64le can technically use
* function descriptors.
*/
#if defined(__powerpc64__) && (!defined(_CALL_ELF) || _CALL_ELF < 2)
#define USE_FUNCTION_DESCRIPTORS
#endif
#ifdef USE_FUNCTION_DESCRIPTORS
typedef struct {
uintptr_t entry;
uintptr_t toc;
uintptr_t env;
} func_descr_t;
#endif
/*
* Copy page where &exec_func resides. Also try to copy subsequent page
* in case exec_func is close to page boundary.
*/
static void *get_func(void *mem, uintptr_t *func_page_offset)
{
uintptr_t page_sz = getpagesize();
uintptr_t page_mask = ~(page_sz - 1);
void *func_copy_start, *page_to_copy;
void *mem_start = mem;
#ifdef USE_FUNCTION_DESCRIPTORS
func_descr_t *opd = (func_descr_t *)&exec_func;
*func_page_offset = (uintptr_t)opd->entry & (page_sz - 1);
func_copy_start = mem + *func_page_offset;
page_to_copy = (void *)((uintptr_t)opd->entry & page_mask);
#else
*func_page_offset = (uintptr_t)&exec_func & (page_sz - 1);
func_copy_start = mem + *func_page_offset;
page_to_copy = (void *)((uintptr_t)&exec_func & page_mask);
#endif
tst_resm(TINFO, "exec_func: %p, page_to_copy: %p",
&exec_func, page_to_copy);
/* Copy 1st page. If it's not accessible, we might be running on a
* platform that supports execute-only page access permissions, in which
* case we have to explicitly change access protections to allow the
* memory to be read. */
if (!page_present(page_to_copy)) {
TEST(mprotect(page_to_copy, page_sz, PROT_READ | PROT_EXEC));
if (TEST_RETURN == -1) {
tst_resm(TFAIL | TTERRNO,
"mprotect(PROT_READ|PROT_EXEC) failed");
return NULL;
}
/* If the memory is still not accessible, then something must be
* wrong. */
if (!page_present(page_to_copy))
tst_brkm(TBROK, cleanup, "page_to_copy not present\n");
}
memcpy(mem, page_to_copy, page_sz);
clear_cache(mem_start, page_sz);
/* return pointer to area where copy of exec_func resides */
return func_copy_start;
}
static void testfunc_protexec(void)
{
func_ptr_t func;
uintptr_t func_page_offset;
void *p;
sig_caught = 0;
p = SAFE_MMAP(cleanup, 0, page_sz, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
#ifdef USE_FUNCTION_DESCRIPTORS
func_descr_t opd;
opd.entry = (uintptr_t)get_func(p, &func_page_offset);
func = (func_ptr_t)&opd;
#else
func = get_func(p, &func_page_offset);
#endif
if (!func)
goto out;
if (func_page_offset + 64 > page_sz) {
SAFE_MUNMAP(cleanup, p, page_sz);
tst_brkm(TCONF, cleanup, "func too close to page boundary, "
"maybe your compiler ignores -falign-functions?");
}
/* Change the protection to PROT_EXEC. */
TEST(mprotect(p, page_sz, PROT_EXEC));
if (TEST_RETURN == -1) {
tst_resm(TFAIL | TTERRNO, "mprotect failed");
} else {
if (sigsetjmp(env, 1) == 0)
(*func)();
switch (sig_caught) {
case SIGSEGV:
tst_resm(TFAIL, "test PROT_EXEC for mprotect failed");
break;
case 0:
tst_resm(TPASS, "test PROT_EXEC for mprotect success");
break;
default:
tst_brkm(TBROK, cleanup,
"received an unexpected signal: %d",
sig_caught);
}
}
out:
SAFE_MUNMAP(cleanup, p, page_sz);
}
static void cleanup(void)
{
tst_rmdir();
}