autoboot.c 8.9 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * (C) Copyright 2000
  4. * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  5. */
  6. #include <common.h>
  7. #include <autoboot.h>
  8. #include <bootretry.h>
  9. #include <cli.h>
  10. #include <command.h>
  11. #include <console.h>
  12. #include <env.h>
  13. #include <fdtdec.h>
  14. #include <hash.h>
  15. #include <log.h>
  16. #include <malloc.h>
  17. #include <memalign.h>
  18. #include <menu.h>
  19. #include <post.h>
  20. #include <time.h>
  21. #include <linux/delay.h>
  22. #include <u-boot/sha256.h>
  23. #include <bootcount.h>
  24. DECLARE_GLOBAL_DATA_PTR;
  25. #define MAX_DELAY_STOP_STR 32
  26. #ifndef DEBUG_BOOTKEYS
  27. #define DEBUG_BOOTKEYS 0
  28. #endif
  29. #define debug_bootkeys(fmt, args...) \
  30. debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
  31. /* Stored value of bootdelay, used by autoboot_command() */
  32. static int stored_bootdelay;
  33. static int menukey;
  34. #ifdef CONFIG_AUTOBOOT_ENCRYPTION
  35. #define AUTOBOOT_STOP_STR_SHA256 CONFIG_AUTOBOOT_STOP_STR_SHA256
  36. #else
  37. #define AUTOBOOT_STOP_STR_SHA256 ""
  38. #endif
  39. #ifdef CONFIG_USE_AUTOBOOT_MENUKEY
  40. #define AUTOBOOT_MENUKEY CONFIG_USE_AUTOBOOT_MENUKEY
  41. #else
  42. #define AUTOBOOT_MENUKEY 0
  43. #endif
  44. /*
  45. * Use a "constant-length" time compare function for this
  46. * hash compare:
  47. *
  48. * https://crackstation.net/hashing-security.htm
  49. */
  50. static int slow_equals(u8 *a, u8 *b, int len)
  51. {
  52. int diff = 0;
  53. int i;
  54. for (i = 0; i < len; i++)
  55. diff |= a[i] ^ b[i];
  56. return diff == 0;
  57. }
  58. /**
  59. * passwd_abort_sha256() - check for a hashed key sequence to abort booting
  60. *
  61. * This checks for the user entering a SHA256 hash within a given time.
  62. *
  63. * @etime: Timeout value ticks (stop when get_ticks() reachs this)
  64. * @return 0 if autoboot should continue, 1 if it should stop
  65. */
  66. static int passwd_abort_sha256(uint64_t etime)
  67. {
  68. const char *sha_env_str = env_get("bootstopkeysha256");
  69. u8 sha_env[SHA256_SUM_LEN];
  70. u8 *sha;
  71. char *presskey;
  72. const char *algo_name = "sha256";
  73. u_int presskey_len = 0;
  74. int abort = 0;
  75. int size = sizeof(sha);
  76. int ret;
  77. if (sha_env_str == NULL)
  78. sha_env_str = AUTOBOOT_STOP_STR_SHA256;
  79. /*
  80. * Generate the binary value from the environment hash value
  81. * so that we can compare this value with the computed hash
  82. * from the user input
  83. */
  84. ret = hash_parse_string(algo_name, sha_env_str, sha_env);
  85. if (ret) {
  86. printf("Hash %s not supported!\n", algo_name);
  87. return 0;
  88. }
  89. presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR);
  90. sha = malloc_cache_aligned(SHA256_SUM_LEN);
  91. size = SHA256_SUM_LEN;
  92. /*
  93. * We don't know how long the stop-string is, so we need to
  94. * generate the sha256 hash upon each input character and
  95. * compare the value with the one saved in the environment
  96. */
  97. do {
  98. if (tstc()) {
  99. /* Check for input string overflow */
  100. if (presskey_len >= MAX_DELAY_STOP_STR) {
  101. free(presskey);
  102. free(sha);
  103. return 0;
  104. }
  105. presskey[presskey_len++] = getc();
  106. /* Calculate sha256 upon each new char */
  107. hash_block(algo_name, (const void *)presskey,
  108. presskey_len, sha, &size);
  109. /* And check if sha matches saved value in env */
  110. if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
  111. abort = 1;
  112. }
  113. } while (!abort && get_ticks() <= etime);
  114. free(presskey);
  115. free(sha);
  116. return abort;
  117. }
  118. /**
  119. * passwd_abort_key() - check for a key sequence to aborted booting
  120. *
  121. * This checks for the user entering a string within a given time.
  122. *
  123. * @etime: Timeout value ticks (stop when get_ticks() reachs this)
  124. * @return 0 if autoboot should continue, 1 if it should stop
  125. */
  126. static int passwd_abort_key(uint64_t etime)
  127. {
  128. int abort = 0;
  129. struct {
  130. char *str;
  131. u_int len;
  132. int retry;
  133. }
  134. delaykey[] = {
  135. { .str = env_get("bootdelaykey"), .retry = 1 },
  136. { .str = env_get("bootstopkey"), .retry = 0 },
  137. };
  138. char presskey[MAX_DELAY_STOP_STR];
  139. u_int presskey_len = 0;
  140. u_int presskey_max = 0;
  141. u_int i;
  142. # ifdef CONFIG_AUTOBOOT_DELAY_STR
  143. if (delaykey[0].str == NULL)
  144. delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
  145. # endif
  146. # ifdef CONFIG_AUTOBOOT_STOP_STR
  147. if (delaykey[1].str == NULL)
  148. delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
  149. # endif
  150. for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
  151. delaykey[i].len = delaykey[i].str == NULL ?
  152. 0 : strlen(delaykey[i].str);
  153. delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
  154. MAX_DELAY_STOP_STR : delaykey[i].len;
  155. presskey_max = presskey_max > delaykey[i].len ?
  156. presskey_max : delaykey[i].len;
  157. debug_bootkeys("%s key:<%s>\n",
  158. delaykey[i].retry ? "delay" : "stop",
  159. delaykey[i].str ? delaykey[i].str : "NULL");
  160. }
  161. /* In order to keep up with incoming data, check timeout only
  162. * when catch up.
  163. */
  164. do {
  165. if (tstc()) {
  166. if (presskey_len < presskey_max) {
  167. presskey[presskey_len++] = getc();
  168. } else {
  169. for (i = 0; i < presskey_max - 1; i++)
  170. presskey[i] = presskey[i + 1];
  171. presskey[i] = getc();
  172. }
  173. }
  174. for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
  175. if (delaykey[i].len > 0 &&
  176. presskey_len >= delaykey[i].len &&
  177. memcmp(presskey + presskey_len -
  178. delaykey[i].len, delaykey[i].str,
  179. delaykey[i].len) == 0) {
  180. debug_bootkeys("got %skey\n",
  181. delaykey[i].retry ? "delay" :
  182. "stop");
  183. /* don't retry auto boot */
  184. if (!delaykey[i].retry)
  185. bootretry_dont_retry();
  186. abort = 1;
  187. }
  188. }
  189. } while (!abort && get_ticks() <= etime);
  190. return abort;
  191. }
  192. /***************************************************************************
  193. * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
  194. * returns: 0 - no key string, allow autoboot 1 - got key string, abort
  195. */
  196. static int abortboot_key_sequence(int bootdelay)
  197. {
  198. int abort;
  199. uint64_t etime = endtick(bootdelay);
  200. # ifdef CONFIG_AUTOBOOT_PROMPT
  201. /*
  202. * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
  203. * To print the bootdelay value upon bootup.
  204. */
  205. printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
  206. # endif
  207. if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION))
  208. abort = passwd_abort_sha256(etime);
  209. else
  210. abort = passwd_abort_key(etime);
  211. if (!abort)
  212. debug_bootkeys("key timeout\n");
  213. return abort;
  214. }
  215. static int abortboot_single_key(int bootdelay)
  216. {
  217. int abort = 0;
  218. unsigned long ts;
  219. printf("Hit any key to stop autoboot: %2d ", bootdelay);
  220. /*
  221. * Check if key already pressed
  222. */
  223. if (tstc()) { /* we got a key press */
  224. (void) getc(); /* consume input */
  225. puts("\b\b\b 0");
  226. abort = 1; /* don't auto boot */
  227. }
  228. while ((bootdelay > 0) && (!abort)) {
  229. --bootdelay;
  230. /* delay 1000 ms */
  231. ts = get_timer(0);
  232. do {
  233. if (tstc()) { /* we got a key press */
  234. int key;
  235. abort = 1; /* don't auto boot */
  236. bootdelay = 0; /* no more delay */
  237. key = getc(); /* consume input */
  238. if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY))
  239. menukey = key;
  240. break;
  241. }
  242. udelay(10000);
  243. } while (!abort && get_timer(ts) < 1000);
  244. printf("\b\b\b%2d ", bootdelay);
  245. }
  246. putc('\n');
  247. return abort;
  248. }
  249. static int abortboot(int bootdelay)
  250. {
  251. int abort = 0;
  252. if (bootdelay >= 0) {
  253. if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
  254. abort = abortboot_key_sequence(bootdelay);
  255. else
  256. abort = abortboot_single_key(bootdelay);
  257. }
  258. if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
  259. gd->flags &= ~GD_FLG_SILENT;
  260. return abort;
  261. }
  262. static void process_fdt_options(const void *blob)
  263. {
  264. #ifdef CONFIG_SYS_TEXT_BASE
  265. ulong addr;
  266. /* Add an env variable to point to a kernel payload, if available */
  267. addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
  268. if (addr)
  269. env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
  270. /* Add an env variable to point to a root disk, if available */
  271. addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
  272. if (addr)
  273. env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
  274. #endif /* CONFIG_SYS_TEXT_BASE */
  275. }
  276. const char *bootdelay_process(void)
  277. {
  278. char *s;
  279. int bootdelay;
  280. bootcount_inc();
  281. s = env_get("bootdelay");
  282. bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
  283. if (IS_ENABLED(CONFIG_OF_CONTROL))
  284. bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
  285. bootdelay);
  286. debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
  287. if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
  288. bootdelay = menu_show(bootdelay);
  289. bootretry_init_cmd_timeout();
  290. #ifdef CONFIG_POST
  291. if (gd->flags & GD_FLG_POSTFAIL) {
  292. s = env_get("failbootcmd");
  293. } else
  294. #endif /* CONFIG_POST */
  295. if (bootcount_error())
  296. s = env_get("altbootcmd");
  297. else
  298. s = env_get("bootcmd");
  299. if (IS_ENABLED(CONFIG_OF_CONTROL))
  300. process_fdt_options(gd->fdt_blob);
  301. stored_bootdelay = bootdelay;
  302. return s;
  303. }
  304. void autoboot_command(const char *s)
  305. {
  306. debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
  307. if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
  308. bool lock;
  309. int prev;
  310. lock = IS_ENABLED(CONFIG_AUTOBOOT_KEYED) &&
  311. !IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
  312. if (lock)
  313. prev = disable_ctrlc(1); /* disable Ctrl-C checking */
  314. run_command_list(s, -1, 0);
  315. if (lock)
  316. disable_ctrlc(prev); /* restore Ctrl-C checking */
  317. }
  318. if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY) &&
  319. menukey == AUTOBOOT_MENUKEY) {
  320. s = env_get("menucmd");
  321. if (s)
  322. run_command_list(s, -1, 0);
  323. }
  324. }