1 // SPDX-License-Identifier: GPL-2.0+
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
22 #include <asm/global_data.h>
23 #include <linux/delay.h>
24 #include <u-boot/sha256.h>
25 #include <bootcount.h>
27 #include <dm/ofnode.h>
29 DECLARE_GLOBAL_DATA_PTR;
31 #define DELAY_STOP_STR_MAX_LENGTH 64
33 #ifndef DEBUG_BOOTKEYS
34 #define DEBUG_BOOTKEYS 0
36 #define debug_bootkeys(fmt, args...) \
37 debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
39 /* Stored value of bootdelay, used by autoboot_command() */
40 static int stored_bootdelay;
43 #if defined(CONFIG_AUTOBOOT_STOP_STR_CRYPT)
44 #define AUTOBOOT_STOP_STR_CRYPT CONFIG_AUTOBOOT_STOP_STR_CRYPT
46 #define AUTOBOOT_STOP_STR_CRYPT ""
48 #if defined(CONFIG_AUTOBOOT_STOP_STR_SHA256)
49 #define AUTOBOOT_STOP_STR_SHA256 CONFIG_AUTOBOOT_STOP_STR_SHA256
51 #define AUTOBOOT_STOP_STR_SHA256 ""
54 #ifdef CONFIG_AUTOBOOT_USE_MENUKEY
55 #define AUTOBOOT_MENUKEY CONFIG_AUTOBOOT_MENUKEY
57 #define AUTOBOOT_MENUKEY 0
61 * passwd_abort_crypt() - check for a crypt-style hashed key sequence to abort booting
63 * This checks for the user entering a password within a given time.
65 * The entered password is hashed via one of the crypt-style hash methods
66 * and compared to the pre-defined value from either
67 * the environment variable "bootstopkeycrypt"
69 * the config value CONFIG_AUTOBOOT_STOP_STR_CRYPT
71 * In case the config value CONFIG_AUTOBOOT_NEVER_TIMEOUT has been enabled
72 * this function never times out if the user presses the <Enter> key
73 * before starting to enter the password.
75 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
76 * Return: 0 if autoboot should continue, 1 if it should stop
78 static int passwd_abort_crypt(uint64_t etime)
80 const char *crypt_env_str = env_get("bootstopkeycrypt");
81 char presskey[DELAY_STOP_STR_MAX_LENGTH];
82 u_int presskey_len = 0;
84 int never_timeout = 0;
87 if (IS_ENABLED(CONFIG_AUTOBOOT_STOP_STR_ENABLE) && !crypt_env_str)
88 crypt_env_str = AUTOBOOT_STOP_STR_CRYPT;
93 /* We expect the stop-string to be newline-terminated */
96 /* Check for input string overflow */
97 if (presskey_len >= sizeof(presskey))
100 presskey[presskey_len] = getchar();
102 if ((presskey[presskey_len] == '\r') ||
103 (presskey[presskey_len] == '\n')) {
104 if (IS_ENABLED(CONFIG_AUTOBOOT_NEVER_TIMEOUT) &&
109 presskey[presskey_len] = '\0';
110 err = crypt_compare(crypt_env_str, presskey,
114 "crypt_compare() failed with: %s\n",
116 /* you had one chance */
123 } while (never_timeout || get_ticks() <= etime);
129 * Use a "constant-length" time compare function for this
132 * https://crackstation.net/hashing-security.htm
134 static int slow_equals(u8 *a, u8 *b, int len)
139 for (i = 0; i < len; i++)
146 * passwd_abort_sha256() - check for a hashed key sequence to abort booting
148 * This checks for the user entering a SHA256 hash within a given time.
150 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
151 * Return: 0 if autoboot should continue, 1 if it should stop
153 static int passwd_abort_sha256(uint64_t etime)
155 const char *sha_env_str = env_get("bootstopkeysha256");
156 u8 sha_env[SHA256_SUM_LEN];
160 const char *algo_name = "sha256";
161 u_int presskey_len = 0;
163 int size = sizeof(sha);
166 if (sha_env_str == NULL)
167 sha_env_str = AUTOBOOT_STOP_STR_SHA256;
169 presskey = malloc_cache_aligned(DELAY_STOP_STR_MAX_LENGTH);
170 c = strstr(sha_env_str, ":");
171 if (c && (c - sha_env_str < DELAY_STOP_STR_MAX_LENGTH)) {
172 /* preload presskey with salt */
173 memcpy(presskey, sha_env_str, c - sha_env_str);
174 presskey_len = c - sha_env_str;
178 * Generate the binary value from the environment hash value
179 * so that we can compare this value with the computed hash
180 * from the user input
182 ret = hash_parse_string(algo_name, sha_env_str, sha_env);
184 printf("Hash %s not supported!\n", algo_name);
188 sha = malloc_cache_aligned(SHA256_SUM_LEN);
189 size = SHA256_SUM_LEN;
191 * We don't know how long the stop-string is, so we need to
192 * generate the sha256 hash upon each input character and
193 * compare the value with the one saved in the environment
197 /* Check for input string overflow */
198 if (presskey_len >= DELAY_STOP_STR_MAX_LENGTH) {
204 presskey[presskey_len++] = getchar();
206 /* Calculate sha256 upon each new char */
207 hash_block(algo_name, (const void *)presskey,
208 presskey_len, sha, &size);
210 /* And check if sha matches saved value in env */
211 if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
215 } while (!abort && get_ticks() <= etime);
223 * passwd_abort_key() - check for a key sequence to aborted booting
225 * This checks for the user entering a string within a given time.
227 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
228 * Return: 0 if autoboot should continue, 1 if it should stop
230 static int passwd_abort_key(uint64_t etime)
239 { .str = env_get("bootdelaykey"), .retry = 1 },
240 { .str = env_get("bootstopkey"), .retry = 0 },
243 char presskey[DELAY_STOP_STR_MAX_LENGTH];
244 int presskey_len = 0;
245 int presskey_max = 0;
248 # ifdef CONFIG_AUTOBOOT_DELAY_STR
249 if (delaykey[0].str == NULL)
250 delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
252 # ifdef CONFIG_AUTOBOOT_STOP_STR
253 if (delaykey[1].str == NULL)
254 delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
257 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
258 delaykey[i].len = delaykey[i].str == NULL ?
259 0 : strlen(delaykey[i].str);
260 delaykey[i].len = delaykey[i].len > DELAY_STOP_STR_MAX_LENGTH ?
261 DELAY_STOP_STR_MAX_LENGTH : delaykey[i].len;
263 presskey_max = presskey_max > delaykey[i].len ?
264 presskey_max : delaykey[i].len;
266 debug_bootkeys("%s key:<%s>\n",
267 delaykey[i].retry ? "delay" : "stop",
268 delaykey[i].str ? delaykey[i].str : "NULL");
271 /* In order to keep up with incoming data, check timeout only
276 if (presskey_len < presskey_max) {
277 presskey[presskey_len++] = getchar();
279 for (i = 0; i < presskey_max - 1; i++)
280 presskey[i] = presskey[i + 1];
282 presskey[i] = getchar();
286 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
287 if (delaykey[i].len > 0 &&
288 presskey_len >= delaykey[i].len &&
289 memcmp(presskey + presskey_len -
290 delaykey[i].len, delaykey[i].str,
291 delaykey[i].len) == 0) {
292 debug_bootkeys("got %skey\n",
293 delaykey[i].retry ? "delay" :
296 /* don't retry auto boot */
297 if (!delaykey[i].retry)
298 bootretry_dont_retry();
303 } while (!abort && get_ticks() <= etime);
309 * flush_stdin() - drops all pending characters from stdin
311 static void flush_stdin(void)
318 * fallback_to_sha256() - check whether we should fall back to sha256
321 * This checks for the environment variable `bootstopusesha256` in case
322 * sha256-fallback has been enabled via the config setting
323 * `AUTOBOOT_SHA256_FALLBACK`.
325 * Return: `false` if we must not fall-back, `true` if plain sha256 should be tried
327 static bool fallback_to_sha256(void)
329 if (IS_ENABLED(CONFIG_AUTOBOOT_SHA256_FALLBACK))
330 return env_get_yesno("bootstopusesha256") == 1;
331 else if (IS_ENABLED(CONFIG_CRYPT_PW))
337 /***************************************************************************
338 * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
339 * returns: 0 - no key string, allow autoboot 1 - got key string, abort
341 static int abortboot_key_sequence(int bootdelay)
344 uint64_t etime = endtick(bootdelay);
346 if (IS_ENABLED(CONFIG_AUTOBOOT_FLUSH_STDIN))
348 # ifdef CONFIG_AUTOBOOT_PROMPT
350 * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
351 * To print the bootdelay value upon bootup.
353 printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
356 if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION)) {
357 if (IS_ENABLED(CONFIG_CRYPT_PW) && !fallback_to_sha256())
358 abort = passwd_abort_crypt(etime);
360 abort = passwd_abort_sha256(etime);
362 abort = passwd_abort_key(etime);
365 debug_bootkeys("key timeout\n");
370 static int abortboot_single_key(int bootdelay)
375 printf("Hit any key to stop autoboot: %2d ", bootdelay);
378 * Check if key already pressed
380 if (tstc()) { /* we got a key press */
381 getchar(); /* consume input */
383 abort = 1; /* don't auto boot */
386 while ((bootdelay > 0) && (!abort)) {
391 if (tstc()) { /* we got a key press */
394 abort = 1; /* don't auto boot */
395 bootdelay = 0; /* no more delay */
396 key = getchar();/* consume input */
397 if (IS_ENABLED(CONFIG_AUTOBOOT_USE_MENUKEY))
402 } while (!abort && get_timer(ts) < 1000);
404 printf("\b\b\b%2d ", bootdelay);
412 static int abortboot(int bootdelay)
416 if (bootdelay >= 0) {
417 if (autoboot_keyed())
418 abort = abortboot_key_sequence(bootdelay);
420 abort = abortboot_single_key(bootdelay);
423 if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
424 gd->flags &= ~GD_FLG_SILENT;
429 static void process_fdt_options(void)
431 #ifdef CONFIG_TEXT_BASE
434 /* Add an env variable to point to a kernel payload, if available */
435 addr = ofnode_conf_read_int("kernel-offset", 0);
437 env_set_addr("kernaddr", (void *)(CONFIG_TEXT_BASE + addr));
439 /* Add an env variable to point to a root disk, if available */
440 addr = ofnode_conf_read_int("rootdisk-offset", 0);
442 env_set_addr("rootaddr", (void *)(CONFIG_TEXT_BASE + addr));
443 #endif /* CONFIG_TEXT_BASE */
446 const char *bootdelay_process(void)
453 s = env_get("bootdelay");
454 bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
457 * Does it really make sense that the devicetree overrides the user
458 * setting? It is possibly helpful for security since the device tree
459 * may be signed whereas the environment is often loaded from storage.
461 if (IS_ENABLED(CONFIG_OF_CONTROL))
462 bootdelay = ofnode_conf_read_int("bootdelay", bootdelay);
464 debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
466 if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
467 bootdelay = menu_show(bootdelay);
468 bootretry_init_cmd_timeout();
471 if (gd->flags & GD_FLG_POSTFAIL) {
472 s = env_get("failbootcmd");
474 #endif /* CONFIG_POST */
475 if (bootcount_error())
476 s = env_get("altbootcmd");
478 s = env_get("bootcmd");
480 if (IS_ENABLED(CONFIG_OF_CONTROL))
481 process_fdt_options();
482 stored_bootdelay = bootdelay;
487 void autoboot_command(const char *s)
489 debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
491 if (s && (stored_bootdelay == -2 ||
492 (stored_bootdelay != -1 && !abortboot(stored_bootdelay)))) {
496 lock = autoboot_keyed() &&
497 !IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
499 prev = disable_ctrlc(1); /* disable Ctrl-C checking */
501 run_command_list(s, -1, 0);
504 disable_ctrlc(prev); /* restore Ctrl-C checking */
507 if (IS_ENABLED(CONFIG_AUTOBOOT_USE_MENUKEY) &&
508 menukey == AUTOBOOT_MENUKEY) {
509 s = env_get("menucmd");
511 run_command_list(s, -1, 0);