1// SPDX-License-Identifier: GPL-2.0
  2#define _GNU_SOURCE
  3#include <sys/mman.h>
  4#include <stdint.h>
  5#include <asm-generic/unistd.h>
  6#include <string.h>
  7#include <sys/time.h>
  8#include <sys/resource.h>
  9#include <stdbool.h>
 10#include "../kselftest.h"
 11#include <syscall.h>
 12#include <errno.h>
 13#include <stdio.h>
 14#include <stdlib.h>
 15#include <fcntl.h>
 16#include <sys/ioctl.h>
 17#include <sys/vfs.h>
 18#include <sys/stat.h>
 19#include "mseal_helpers.h"
 20
 21/*
 22 * define sys_xyx to call syscall directly.
 23 */
 24static int sys_mseal(void *start, size_t len)
 25{
 26	int sret;
 27
 28	errno = 0;
 29	sret = syscall(__NR_mseal, start, len, 0);
 30	return sret;
 31}
 32
 33static inline int sys_mprotect(void *ptr, size_t size, unsigned long prot)
 34{
 35	int sret;
 36
 37	errno = 0;
 38	sret = syscall(__NR_mprotect, ptr, size, prot);
 39	return sret;
 40}
 41
 42static bool seal_support(void)
 43{
 44	int ret;
 45	void *ptr;
 46	unsigned long page_size = getpagesize();
 47
 48	ptr = mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 49	if (ptr == (void *) -1)
 50		return false;
 51
 52	ret = sys_mseal(ptr, page_size);
 53	if (ret < 0)
 54		return false;
 55
 56	return true;
 57}
 58
 59const char somestr[4096] = {"READONLY"};
 60
 61static void test_seal_elf(void)
 62{
 63	int ret;
 64	FILE *maps;
 65	char line[512];
 66	uintptr_t  addr_start, addr_end;
 67	char prot[5];
 68	char filename[256];
 69	unsigned long page_size = getpagesize();
 70	unsigned long long ptr = (unsigned long long) somestr;
 71	char *somestr2 = (char *)somestr;
 72
 73	/*
 74	 * Modify the protection of readonly somestr
 75	 */
 76	if (((unsigned long long)ptr % page_size) != 0)
 77		ptr = (unsigned long long)ptr & ~(page_size - 1);
 78
 79	ksft_print_msg("somestr = %s\n", somestr);
 80	ksft_print_msg("change protection to rw\n");
 81	ret = sys_mprotect((void *)ptr, page_size, PROT_READ|PROT_WRITE);
 82	FAIL_TEST_IF_FALSE(!ret);
 83	*somestr2 = 'A';
 84	ksft_print_msg("somestr is modified to: %s\n", somestr);
 85	ret = sys_mprotect((void *)ptr, page_size, PROT_READ);
 86	FAIL_TEST_IF_FALSE(!ret);
 87
 88	maps = fopen("/proc/self/maps", "r");
 89	FAIL_TEST_IF_FALSE(maps);
 90
 91	/*
 92	 * apply sealing to elf binary
 93	 */
 94	while (fgets(line, sizeof(line), maps)) {
 95		if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*u %255[^\n]",
 96			&addr_start, &addr_end, prot, filename) == 4) {
 97			if (strlen(filename)) {
 98				/*
 99				 * seal the mapping if read only.
100				 */
101				if (strstr(prot, "r-")) {
102					ret = sys_mseal((void *)addr_start, addr_end - addr_start);
103					FAIL_TEST_IF_FALSE(!ret);
104					ksft_print_msg("sealed: %lx-%lx %s %s\n",
105						addr_start, addr_end, prot, filename);
106					if ((uintptr_t) somestr >= addr_start &&
107						(uintptr_t) somestr <= addr_end)
108						ksft_print_msg("mapping for somestr found\n");
109				}
110			}
111		}
112	}
113	fclose(maps);
114
115	ret = sys_mprotect((void *)ptr, page_size, PROT_READ | PROT_WRITE);
116	FAIL_TEST_IF_FALSE(ret < 0);
117	ksft_print_msg("somestr is sealed, mprotect is rejected\n");
118
119	REPORT_TEST_PASS();
120}
121
122int main(int argc, char **argv)
123{
124	bool test_seal = seal_support();
125
126	ksft_print_header();
127	ksft_print_msg("pid=%d\n", getpid());
128
129	if (!test_seal)
130		ksft_exit_skip("sealing not supported, check CONFIG_64BIT\n");
131
132	ksft_set_plan(1);
133
134	test_seal_elf();
135
136	ksft_finished();
137}