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// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <sys/mman.h>
#include <stdint.h>
#include <asm-generic/unistd.h>
#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <stdbool.h>
#include "../kselftest.h"
#include <syscall.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/vfs.h>
#include <sys/stat.h>
#include "mseal_helpers.h"
/*
* define sys_xyx to call syscall directly.
*/
static int sys_mseal(void *start, size_t len)
{
int sret;
errno = 0;
sret = syscall(__NR_mseal, start, len, 0);
return sret;
}
static inline int sys_mprotect(void *ptr, size_t size, unsigned long prot)
{
int sret;
errno = 0;
sret = syscall(__NR_mprotect, ptr, size, prot);
return sret;
}
static bool seal_support(void)
{
int ret;
void *ptr;
unsigned long page_size = getpagesize();
ptr = mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
if (ptr == (void *) -1)
return false;
ret = sys_mseal(ptr, page_size);
if (ret < 0)
return false;
return true;
}
const char somestr[4096] = {"READONLY"};
static void test_seal_elf(void)
{
int ret;
FILE *maps;
char line[512];
uintptr_t addr_start, addr_end;
char prot[5];
char filename[256];
unsigned long page_size = getpagesize();
unsigned long long ptr = (unsigned long long) somestr;
char *somestr2 = (char *)somestr;
/*
* Modify the protection of readonly somestr
*/
if (((unsigned long long)ptr % page_size) != 0)
ptr = (unsigned long long)ptr & ~(page_size - 1);
ksft_print_msg("somestr = %s\n", somestr);
ksft_print_msg("change protection to rw\n");
ret = sys_mprotect((void *)ptr, page_size, PROT_READ|PROT_WRITE);
FAIL_TEST_IF_FALSE(!ret);
*somestr2 = 'A';
ksft_print_msg("somestr is modified to: %s\n", somestr);
ret = sys_mprotect((void *)ptr, page_size, PROT_READ);
FAIL_TEST_IF_FALSE(!ret);
maps = fopen("/proc/self/maps", "r");
FAIL_TEST_IF_FALSE(maps);
/*
* apply sealing to elf binary
*/
while (fgets(line, sizeof(line), maps)) {
if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*u %255[^\n]",
&addr_start, &addr_end, prot, filename) == 4) {
if (strlen(filename)) {
/*
* seal the mapping if read only.
*/
if (strstr(prot, "r-")) {
ret = sys_mseal((void *)addr_start, addr_end - addr_start);
FAIL_TEST_IF_FALSE(!ret);
ksft_print_msg("sealed: %lx-%lx %s %s\n",
addr_start, addr_end, prot, filename);
if ((uintptr_t) somestr >= addr_start &&
(uintptr_t) somestr <= addr_end)
ksft_print_msg("mapping for somestr found\n");
}
}
}
}
fclose(maps);
ret = sys_mprotect((void *)ptr, page_size, PROT_READ | PROT_WRITE);
FAIL_TEST_IF_FALSE(ret < 0);
ksft_print_msg("somestr is sealed, mprotect is rejected\n");
REPORT_TEST_PASS();
}
int main(int argc, char **argv)
{
bool test_seal = seal_support();
ksft_print_header();
ksft_print_msg("pid=%d\n", getpid());
if (!test_seal)
ksft_exit_skip("sealing not supported, check CONFIG_64BIT\n");
ksft_set_plan(1);
test_seal_elf();
ksft_finished();
}
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