diff options
Diffstat (limited to 'tools/testing/selftests/mm/seal_elf.c')
| -rw-r--r-- | tools/testing/selftests/mm/seal_elf.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/seal_elf.c b/tools/testing/selftests/mm/seal_elf.c new file mode 100644 index 000000000000..f2babec79bb6 --- /dev/null +++ b/tools/testing/selftests/mm/seal_elf.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <sys/mman.h> +#include <stdint.h> +#include <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> + +/* + * need those definition for manually build using gcc. + * gcc -I ../../../../usr/include -DDEBUG -O3 -DDEBUG -O3 seal_elf.c -o seal_elf + */ +#define FAIL_TEST_IF_FALSE(c) do {\ + if (!(c)) {\ + ksft_test_result_fail("%s, line:%d\n", __func__, __LINE__);\ + goto test_end;\ + } \ + } \ + while (0) + +#define SKIP_TEST_IF_FALSE(c) do {\ + if (!(c)) {\ + ksft_test_result_skip("%s, line:%d\n", __func__, __LINE__);\ + goto test_end;\ + } \ + } \ + while (0) + + +#define TEST_END_CHECK() {\ + ksft_test_result_pass("%s\n", __func__);\ + return;\ +test_end:\ + return;\ +} + +#ifndef u64 +#define u64 unsigned long long +#endif + +/* + * 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 void *sys_mmap(void *addr, unsigned long len, unsigned long prot, + unsigned long flags, unsigned long fd, unsigned long offset) +{ + void *sret; + + errno = 0; + sret = (void *) syscall(__NR_mmap, addr, len, prot, + flags, fd, offset); + 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 = sys_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"); + + TEST_END_CHECK(); +} + +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(); +} |