Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 1 | /* Copyright 2015 The Chromium OS Authors. All rights reserved. |
| 2 | * Use of this source code is governed by a BSD-style license that can be |
| 3 | * found in the LICENSE file. |
| 4 | * |
| 5 | * This utility wraps around "cgpt" execution to work with NAND. If the target |
| 6 | * device is an MTD device, this utility will read the GPT structures from |
| 7 | * FMAP, invokes "cgpt" on that, and writes the result back to NOR flash. */ |
| 8 | |
Alex Deymo | 3fec0e4 | 2015-02-21 01:10:30 -0800 | [diff] [blame] | 9 | #include <err.h> |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 10 | #include <errno.h> |
| 11 | #include <fcntl.h> |
| 12 | #include <inttypes.h> |
| 13 | #include <limits.h> |
| 14 | #include <linux/major.h> |
| 15 | #include <stdbool.h> |
| 16 | #include <stdlib.h> |
| 17 | #include <stdint.h> |
| 18 | #include <stdio.h> |
| 19 | #include <string.h> |
| 20 | #include <sys/stat.h> |
| 21 | #include <sys/types.h> |
| 22 | #include <unistd.h> |
| 23 | |
| 24 | #include "cgpt.h" |
| 25 | #include "cgpt_nor.h" |
Nam T. Nguyen | c67b061 | 2015-01-21 11:18:32 -0800 | [diff] [blame] | 26 | #include "cryptolib.h" |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 27 | |
| 28 | // Check if cmdline |argv| has "-D". "-D" signifies that GPT structs are stored |
| 29 | // off device, and hence we should not wrap around cgpt. |
| 30 | static bool has_dash_D(int argc, const char *const argv[]) { |
| 31 | int i; |
| 32 | // We go from 2, because the second arg is a cgpt command such as "create". |
| 33 | for (i = 2; i < argc; ++i) { |
| 34 | if (strcmp("-D", argv[i]) == 0) { |
| 35 | return true; |
| 36 | } |
| 37 | } |
| 38 | return false; |
| 39 | } |
| 40 | |
| 41 | // Check if |device_path| is an MTD device based on its major number being 90. |
| 42 | static bool is_mtd(const char *device_path) { |
| 43 | struct stat stat; |
| 44 | if (lstat(device_path, &stat) != 0) { |
| 45 | return false; |
| 46 | } |
| 47 | |
| 48 | if (major(stat.st_rdev) != MTD_CHAR_MAJOR) { |
| 49 | return false; |
| 50 | } |
| 51 | |
| 52 | return true; |
| 53 | } |
| 54 | |
| 55 | // Return the element in |argv| that is an MTD device. |
| 56 | static const char *find_mtd_device(int argc, const char *const argv[]) { |
| 57 | int i; |
| 58 | for (i = 2; i < argc; ++i) { |
| 59 | if (is_mtd(argv[i])) { |
| 60 | return argv[i]; |
| 61 | } |
| 62 | } |
| 63 | return NULL; |
| 64 | } |
| 65 | |
| 66 | static int wrap_cgpt(int argc, |
| 67 | const char *const argv[], |
| 68 | const char *mtd_device) { |
Nam T. Nguyen | c67b061 | 2015-01-21 11:18:32 -0800 | [diff] [blame] | 69 | uint8_t *original_hash = NULL; |
| 70 | uint8_t *modified_hash = NULL; |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 71 | int ret = 0; |
| 72 | |
| 73 | // Create a temp dir to work in. |
| 74 | ret++; |
| 75 | char temp_dir[] = "/tmp/cgpt_wrapper.XXXXXX"; |
| 76 | if (ReadNorFlash(temp_dir) != 0) { |
| 77 | return ret; |
| 78 | } |
| 79 | char rw_gpt_path[PATH_MAX]; |
| 80 | if (snprintf(rw_gpt_path, sizeof(rw_gpt_path), "%s/rw_gpt", temp_dir) < 0) { |
| 81 | goto cleanup; |
| 82 | } |
Nam T. Nguyen | c67b061 | 2015-01-21 11:18:32 -0800 | [diff] [blame] | 83 | original_hash = DigestFile(rw_gpt_path, SHA1_DIGEST_ALGORITHM); |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 84 | |
| 85 | // Obtain the MTD size. |
| 86 | ret++; |
| 87 | uint64_t drive_size = 0; |
| 88 | if (GetMtdSize(mtd_device, &drive_size) != 0) { |
| 89 | Error("Cannot get the size of %s.\n", mtd_device); |
| 90 | goto cleanup; |
| 91 | } |
| 92 | |
| 93 | // Launch cgpt on "rw_gpt" with -D size. |
| 94 | ret++; |
| 95 | const char** my_argv = calloc(argc + 2 + 1, sizeof(char *)); |
| 96 | if (my_argv == NULL) { |
| 97 | errno = ENOMEM; |
| 98 | goto cleanup; |
| 99 | } |
| 100 | memcpy(my_argv, argv, sizeof(char *) * argc); |
| 101 | char *real_cgpt; |
| 102 | if (asprintf(&real_cgpt, "%s.bin", argv[0]) == -1) { |
| 103 | free(my_argv); |
| 104 | goto cleanup; |
| 105 | } |
| 106 | my_argv[0] = real_cgpt; |
| 107 | |
| 108 | int i; |
| 109 | for (i = 2; i < argc; ++i) { |
| 110 | if (strcmp(my_argv[i], mtd_device) == 0) { |
| 111 | my_argv[i] = rw_gpt_path; |
| 112 | } |
| 113 | } |
| 114 | my_argv[argc] = "-D"; |
| 115 | char size[32]; |
| 116 | snprintf(size, sizeof(size), "%" PRIu64, drive_size); |
| 117 | my_argv[argc + 1] = size; |
| 118 | i = ForkExecV(NULL, my_argv); |
| 119 | free(real_cgpt); |
| 120 | free(my_argv); |
| 121 | if (i != 0) { |
| 122 | Error("Cannot exec cgpt to modify rw_gpt.\n"); |
| 123 | goto cleanup; |
| 124 | } |
| 125 | |
| 126 | // Write back "rw_gpt" to NOR flash in two chunks. |
| 127 | ret++; |
Nam T. Nguyen | c67b061 | 2015-01-21 11:18:32 -0800 | [diff] [blame] | 128 | modified_hash = DigestFile(rw_gpt_path, SHA1_DIGEST_ALGORITHM); |
Nam T. Nguyen | 9a8dfd0 | 2015-01-26 12:55:05 -0800 | [diff] [blame] | 129 | if (original_hash != NULL && modified_hash != NULL) { |
| 130 | if (memcmp(original_hash, modified_hash, SHA1_DIGEST_SIZE) != 0) { |
| 131 | ret = WriteNorFlash(temp_dir); |
| 132 | } else { |
Nam T. Nguyen | c67b061 | 2015-01-21 11:18:32 -0800 | [diff] [blame] | 133 | ret = 0; |
| 134 | } |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 135 | } |
| 136 | |
| 137 | cleanup: |
Nam T. Nguyen | c67b061 | 2015-01-21 11:18:32 -0800 | [diff] [blame] | 138 | free(original_hash); |
| 139 | free(modified_hash); |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 140 | RemoveDir(temp_dir); |
| 141 | return ret; |
| 142 | } |
| 143 | |
| 144 | int main(int argc, const char *argv[]) { |
Nam T. Nguyen | 9fa6afc | 2015-01-21 14:02:13 -0800 | [diff] [blame] | 145 | char resolved_cgpt[PATH_MAX]; |
| 146 | pid_t pid = getpid(); |
| 147 | char exe_link[40]; |
| 148 | |
| 149 | if (argc < 1) { |
| 150 | return -1; |
| 151 | } |
| 152 | |
| 153 | snprintf(exe_link, sizeof(exe_link), "/proc/%d/exe", pid); |
| 154 | memset(resolved_cgpt, 0, sizeof(resolved_cgpt)); |
| 155 | if (readlink(exe_link, resolved_cgpt, sizeof(resolved_cgpt) - 1) == -1) { |
| 156 | perror("readlink"); |
| 157 | return -1; |
| 158 | } |
| 159 | |
| 160 | argv[0] = resolved_cgpt; |
| 161 | |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 162 | if (argc > 2 && !has_dash_D(argc, argv)) { |
| 163 | const char *mtd_device = find_mtd_device(argc, argv); |
| 164 | if (mtd_device) { |
| 165 | return wrap_cgpt(argc, argv, mtd_device); |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | // Forward to cgpt as-is. Real cgpt has been renamed cgpt.bin. |
| 170 | char *real_cgpt; |
| 171 | if (asprintf(&real_cgpt, "%s.bin", argv[0]) == -1) { |
| 172 | return -1; |
| 173 | } |
| 174 | argv[0] = real_cgpt; |
Alex Deymo | 3fec0e4 | 2015-02-21 01:10:30 -0800 | [diff] [blame] | 175 | if (execv(argv[0], (char * const *)argv) == -1) { |
| 176 | err(-2, "execv(%s) failed", real_cgpt); |
| 177 | } |
| 178 | return -2; |
Nam T. Nguyen | d1236e4 | 2015-01-08 11:43:27 -0800 | [diff] [blame] | 179 | } |