autoboot.c 8.8 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 <console.h>
  11. #include <env.h>
  12. #include <fdtdec.h>
  13. #include <hash.h>
  14. #include <memalign.h>
  15. #include <menu.h>
  16. #include <post.h>
  17. #include <u-boot/sha256.h>
  18. #include <bootcount.h>
  19. DECLARE_GLOBAL_DATA_PTR;
  20. #define MAX_DELAY_STOP_STR 32
  21. #ifndef DEBUG_BOOTKEYS
  22. #define DEBUG_BOOTKEYS 0
  23. #endif
  24. #define debug_bootkeys(fmt, args...) \
  25. debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
  26. /* Stored value of bootdelay, used by autoboot_command() */
  27. static int stored_bootdelay;
  28. static int menukey;
  29. #ifdef CONFIG_AUTOBOOT_ENCRYPTION
  30. #define AUTOBOOT_STOP_STR_SHA256 CONFIG_AUTOBOOT_STOP_STR_SHA256
  31. #else
  32. #define AUTOBOOT_STOP_STR_SHA256 ""
  33. #endif
  34. #ifdef CONFIG_USE_AUTOBOOT_MENUKEY
  35. #define AUTOBOOT_MENUKEY CONFIG_USE_AUTOBOOT_MENUKEY
  36. #else
  37. #define AUTOBOOT_MENUKEY 0
  38. #endif
  39. /*
  40. * Use a "constant-length" time compare function for this
  41. * hash compare:
  42. *
  43. * https://crackstation.net/hashing-security.htm
  44. */
  45. static int slow_equals(u8 *a, u8 *b, int len)
  46. {
  47. int diff = 0;
  48. int i;
  49. for (i = 0; i < len; i++)
  50. diff |= a[i] ^ b[i];
  51. return diff == 0;
  52. }
  53. /**
  54. * passwd_abort_sha256() - check for a hashed key sequence to abort booting
  55. *
  56. * This checks for the user entering a SHA256 hash within a given time.
  57. *
  58. * @etime: Timeout value ticks (stop when get_ticks() reachs this)
  59. * @return 0 if autoboot should continue, 1 if it should stop
  60. */
  61. static int passwd_abort_sha256(uint64_t etime)
  62. {
  63. const char *sha_env_str = env_get("bootstopkeysha256");
  64. u8 sha_env[SHA256_SUM_LEN];
  65. u8 *sha;
  66. char *presskey;
  67. const char *algo_name = "sha256";
  68. u_int presskey_len = 0;
  69. int abort = 0;
  70. int size = sizeof(sha);
  71. int ret;
  72. if (sha_env_str == NULL)
  73. sha_env_str = AUTOBOOT_STOP_STR_SHA256;
  74. /*
  75. * Generate the binary value from the environment hash value
  76. * so that we can compare this value with the computed hash
  77. * from the user input
  78. */
  79. ret = hash_parse_string(algo_name, sha_env_str, sha_env);
  80. if (ret) {
  81. printf("Hash %s not supported!\n", algo_name);
  82. return 0;
  83. }
  84. presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR);
  85. sha = malloc_cache_aligned(SHA256_SUM_LEN);
  86. size = SHA256_SUM_LEN;
  87. /*
  88. * We don't know how long the stop-string is, so we need to
  89. * generate the sha256 hash upon each input character and
  90. * compare the value with the one saved in the environment
  91. */
  92. do {
  93. if (tstc()) {
  94. /* Check for input string overflow */
  95. if (presskey_len >= MAX_DELAY_STOP_STR) {
  96. free(presskey);
  97. free(sha);
  98. return 0;
  99. }
  100. presskey[presskey_len++] = getc();
  101. /* Calculate sha256 upon each new char */
  102. hash_block(algo_name, (const void *)presskey,
  103. presskey_len, sha, &size);
  104. /* And check if sha matches saved value in env */
  105. if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
  106. abort = 1;
  107. }
  108. } while (!abort && get_ticks() <= etime);
  109. free(presskey);
  110. free(sha);
  111. return abort;
  112. }
  113. /**
  114. * passwd_abort_key() - check for a key sequence to aborted booting
  115. *
  116. * This checks for the user entering a string within a given time.
  117. *
  118. * @etime: Timeout value ticks (stop when get_ticks() reachs this)
  119. * @return 0 if autoboot should continue, 1 if it should stop
  120. */
  121. static int passwd_abort_key(uint64_t etime)
  122. {
  123. int abort = 0;
  124. struct {
  125. char *str;
  126. u_int len;
  127. int retry;
  128. }
  129. delaykey[] = {
  130. { .str = env_get("bootdelaykey"), .retry = 1 },
  131. { .str = env_get("bootstopkey"), .retry = 0 },
  132. };
  133. char presskey[MAX_DELAY_STOP_STR];
  134. u_int presskey_len = 0;
  135. u_int presskey_max = 0;
  136. u_int i;
  137. # ifdef CONFIG_AUTOBOOT_DELAY_STR
  138. if (delaykey[0].str == NULL)
  139. delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
  140. # endif
  141. # ifdef CONFIG_AUTOBOOT_STOP_STR
  142. if (delaykey[1].str == NULL)
  143. delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
  144. # endif
  145. for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
  146. delaykey[i].len = delaykey[i].str == NULL ?
  147. 0 : strlen(delaykey[i].str);
  148. delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
  149. MAX_DELAY_STOP_STR : delaykey[i].len;
  150. presskey_max = presskey_max > delaykey[i].len ?
  151. presskey_max : delaykey[i].len;
  152. debug_bootkeys("%s key:<%s>\n",
  153. delaykey[i].retry ? "delay" : "stop",
  154. delaykey[i].str ? delaykey[i].str : "NULL");
  155. }
  156. /* In order to keep up with incoming data, check timeout only
  157. * when catch up.
  158. */
  159. do {
  160. if (tstc()) {
  161. if (presskey_len < presskey_max) {
  162. presskey[presskey_len++] = getc();
  163. } else {
  164. for (i = 0; i < presskey_max - 1; i++)
  165. presskey[i] = presskey[i + 1];
  166. presskey[i] = getc();
  167. }
  168. }
  169. for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
  170. if (delaykey[i].len > 0 &&
  171. presskey_len >= delaykey[i].len &&
  172. memcmp(presskey + presskey_len -
  173. delaykey[i].len, delaykey[i].str,
  174. delaykey[i].len) == 0) {
  175. debug_bootkeys("got %skey\n",
  176. delaykey[i].retry ? "delay" :
  177. "stop");
  178. /* don't retry auto boot */
  179. if (!delaykey[i].retry)
  180. bootretry_dont_retry();
  181. abort = 1;
  182. }
  183. }
  184. } while (!abort && get_ticks() <= etime);
  185. return abort;
  186. }
  187. /***************************************************************************
  188. * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
  189. * returns: 0 - no key string, allow autoboot 1 - got key string, abort
  190. */
  191. static int abortboot_key_sequence(int bootdelay)
  192. {
  193. int abort;
  194. uint64_t etime = endtick(bootdelay);
  195. # ifdef CONFIG_AUTOBOOT_PROMPT
  196. /*
  197. * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
  198. * To print the bootdelay value upon bootup.
  199. */
  200. printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
  201. # endif
  202. if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION))
  203. abort = passwd_abort_sha256(etime);
  204. else
  205. abort = passwd_abort_key(etime);
  206. if (!abort)
  207. debug_bootkeys("key timeout\n");
  208. return abort;
  209. }
  210. static int abortboot_single_key(int bootdelay)
  211. {
  212. int abort = 0;
  213. unsigned long ts;
  214. printf("Hit any key to stop autoboot: %2d ", bootdelay);
  215. /*
  216. * Check if key already pressed
  217. */
  218. if (tstc()) { /* we got a key press */
  219. (void) getc(); /* consume input */
  220. puts("\b\b\b 0");
  221. abort = 1; /* don't auto boot */
  222. }
  223. while ((bootdelay > 0) && (!abort)) {
  224. --bootdelay;
  225. /* delay 1000 ms */
  226. ts = get_timer(0);
  227. do {
  228. if (tstc()) { /* we got a key press */
  229. int key;
  230. abort = 1; /* don't auto boot */
  231. bootdelay = 0; /* no more delay */
  232. key = getc(); /* consume input */
  233. if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY))
  234. menukey = key;
  235. break;
  236. }
  237. udelay(10000);
  238. } while (!abort && get_timer(ts) < 1000);
  239. printf("\b\b\b%2d ", bootdelay);
  240. }
  241. putc('\n');
  242. return abort;
  243. }
  244. static int abortboot(int bootdelay)
  245. {
  246. int abort = 0;
  247. if (bootdelay >= 0) {
  248. if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
  249. abort = abortboot_key_sequence(bootdelay);
  250. else
  251. abort = abortboot_single_key(bootdelay);
  252. }
  253. if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
  254. gd->flags &= ~GD_FLG_SILENT;
  255. return abort;
  256. }
  257. static void process_fdt_options(const void *blob)
  258. {
  259. #ifdef CONFIG_SYS_TEXT_BASE
  260. ulong addr;
  261. /* Add an env variable to point to a kernel payload, if available */
  262. addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
  263. if (addr)
  264. env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
  265. /* Add an env variable to point to a root disk, if available */
  266. addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
  267. if (addr)
  268. env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
  269. #endif /* CONFIG_SYS_TEXT_BASE */
  270. }
  271. const char *bootdelay_process(void)
  272. {
  273. char *s;
  274. int bootdelay;
  275. bootcount_inc();
  276. s = env_get("bootdelay");
  277. bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
  278. if (IS_ENABLED(CONFIG_OF_CONTROL))
  279. bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
  280. bootdelay);
  281. debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
  282. if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
  283. bootdelay = menu_show(bootdelay);
  284. bootretry_init_cmd_timeout();
  285. #ifdef CONFIG_POST
  286. if (gd->flags & GD_FLG_POSTFAIL) {
  287. s = env_get("failbootcmd");
  288. } else
  289. #endif /* CONFIG_POST */
  290. if (bootcount_error())
  291. s = env_get("altbootcmd");
  292. else
  293. s = env_get("bootcmd");
  294. if (IS_ENABLED(CONFIG_OF_CONTROL))
  295. process_fdt_options(gd->fdt_blob);
  296. stored_bootdelay = bootdelay;
  297. return s;
  298. }
  299. void autoboot_command(const char *s)
  300. {
  301. debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
  302. if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
  303. bool lock;
  304. int prev;
  305. lock = IS_ENABLED(CONFIG_AUTOBOOT_KEYED) &&
  306. !IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
  307. if (lock)
  308. prev = disable_ctrlc(1); /* disable Ctrl-C checking */
  309. run_command_list(s, -1, 0);
  310. if (lock)
  311. disable_ctrlc(prev); /* restore Ctrl-C checking */
  312. }
  313. if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY) &&
  314. menukey == AUTOBOOT_MENUKEY) {
  315. s = env_get("menucmd");
  316. if (s)
  317. run_command_list(s, -1, 0);
  318. }
  319. }