1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2000
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 */
6
7 #include <common.h>
8 #include <autoboot.h>
9 #include <bootretry.h>
10 #include <cli.h>
11 #include <command.h>
12 #include <console.h>
13 #include <env.h>
14 #include <fdtdec.h>
15 #include <hash.h>
16 #include <log.h>
17 #include <malloc.h>
18 #include <memalign.h>
19 #include <menu.h>
20 #include <post.h>
21 #include <time.h>
22 #include <asm/global_data.h>
23 #include <linux/delay.h>
24 #include <u-boot/sha256.h>
25 #include <bootcount.h>
26 #include <crypt.h>
27 #include <dm/ofnode.h>
28
29 DECLARE_GLOBAL_DATA_PTR;
30
31 #define DELAY_STOP_STR_MAX_LENGTH 64
32
33 #ifndef DEBUG_BOOTKEYS
34 #define DEBUG_BOOTKEYS 0
35 #endif
36 #define debug_bootkeys(fmt, args...) \
37 debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
38
39 /* Stored value of bootdelay, used by autoboot_command() */
40 static int stored_bootdelay;
41 static int menukey;
42
43 #if !defined(CONFIG_AUTOBOOT_STOP_STR_CRYPT)
44 #define CONFIG_AUTOBOOT_STOP_STR_CRYPT ""
45 #endif
46 #if !defined(CONFIG_AUTOBOOT_STOP_STR_SHA256)
47 #define CONFIG_AUTOBOOT_STOP_STR_SHA256 ""
48 #endif
49
50 #ifdef CONFIG_AUTOBOOT_USE_MENUKEY
51 #define AUTOBOOT_MENUKEY CONFIG_AUTOBOOT_MENUKEY
52 #else
53 #define AUTOBOOT_MENUKEY 0
54 #endif
55
56 /**
57 * passwd_abort_crypt() - check for a crypt-style hashed key sequence to abort booting
58 *
59 * This checks for the user entering a password within a given time.
60 *
61 * The entered password is hashed via one of the crypt-style hash methods
62 * and compared to the pre-defined value from either
63 * the environment variable "bootstopkeycrypt"
64 * or
65 * the config value CONFIG_AUTOBOOT_STOP_STR_CRYPT
66 *
67 * In case the config value CONFIG_AUTOBOOT_NEVER_TIMEOUT has been enabled
68 * this function never times out if the user presses the <Enter> key
69 * before starting to enter the password.
70 *
71 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
72 * @return 0 if autoboot should continue, 1 if it should stop
73 */
passwd_abort_crypt(uint64_t etime)74 static int passwd_abort_crypt(uint64_t etime)
75 {
76 const char *crypt_env_str = env_get("bootstopkeycrypt");
77 char presskey[DELAY_STOP_STR_MAX_LENGTH];
78 u_int presskey_len = 0;
79 int abort = 0;
80 int never_timeout = 0;
81 int err;
82
83 if (IS_ENABLED(CONFIG_AUTOBOOT_STOP_STR_ENABLE) && !crypt_env_str)
84 crypt_env_str = CONFIG_AUTOBOOT_STOP_STR_CRYPT;
85
86 if (!crypt_env_str)
87 return 0;
88
89 /* We expect the stop-string to be newline-terminated */
90 do {
91 if (tstc()) {
92 /* Check for input string overflow */
93 if (presskey_len >= sizeof(presskey))
94 return 0;
95
96 presskey[presskey_len] = getchar();
97
98 if ((presskey[presskey_len] == '\r') ||
99 (presskey[presskey_len] == '\n')) {
100 if (IS_ENABLED(CONFIG_AUTOBOOT_NEVER_TIMEOUT) &&
101 !presskey_len) {
102 never_timeout = 1;
103 continue;
104 }
105 presskey[presskey_len] = '\0';
106 err = crypt_compare(crypt_env_str, presskey,
107 &abort);
108 if (err)
109 debug_bootkeys(
110 "crypt_compare() failed with: %s\n",
111 errno_str(err));
112 /* you had one chance */
113 break;
114 } else {
115 presskey_len++;
116 }
117 }
118 } while (never_timeout || get_ticks() <= etime);
119
120 return abort;
121 }
122
123 /*
124 * Use a "constant-length" time compare function for this
125 * hash compare:
126 *
127 * https://crackstation.net/hashing-security.htm
128 */
slow_equals(u8 * a,u8 * b,int len)129 static int slow_equals(u8 *a, u8 *b, int len)
130 {
131 int diff = 0;
132 int i;
133
134 for (i = 0; i < len; i++)
135 diff |= a[i] ^ b[i];
136
137 return diff == 0;
138 }
139
140 /**
141 * passwd_abort_sha256() - check for a hashed key sequence to abort booting
142 *
143 * This checks for the user entering a SHA256 hash within a given time.
144 *
145 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
146 * @return 0 if autoboot should continue, 1 if it should stop
147 */
passwd_abort_sha256(uint64_t etime)148 static int passwd_abort_sha256(uint64_t etime)
149 {
150 const char *sha_env_str = env_get("bootstopkeysha256");
151 u8 sha_env[SHA256_SUM_LEN];
152 u8 *sha;
153 char *presskey;
154 char *c;
155 const char *algo_name = "sha256";
156 u_int presskey_len = 0;
157 int abort = 0;
158 int size = sizeof(sha);
159 int ret;
160
161 if (sha_env_str == NULL)
162 sha_env_str = CONFIG_AUTOBOOT_STOP_STR_SHA256;
163
164 presskey = malloc_cache_aligned(DELAY_STOP_STR_MAX_LENGTH);
165 c = strstr(sha_env_str, ":");
166 if (c && (c - sha_env_str < DELAY_STOP_STR_MAX_LENGTH)) {
167 /* preload presskey with salt */
168 memcpy(presskey, sha_env_str, c - sha_env_str);
169 presskey_len = c - sha_env_str;
170 sha_env_str = c + 1;
171 }
172 /*
173 * Generate the binary value from the environment hash value
174 * so that we can compare this value with the computed hash
175 * from the user input
176 */
177 ret = hash_parse_string(algo_name, sha_env_str, sha_env);
178 if (ret) {
179 printf("Hash %s not supported!\n", algo_name);
180 return 0;
181 }
182
183 sha = malloc_cache_aligned(SHA256_SUM_LEN);
184 size = SHA256_SUM_LEN;
185 /*
186 * We don't know how long the stop-string is, so we need to
187 * generate the sha256 hash upon each input character and
188 * compare the value with the one saved in the environment
189 */
190 do {
191 if (tstc()) {
192 /* Check for input string overflow */
193 if (presskey_len >= DELAY_STOP_STR_MAX_LENGTH) {
194 free(presskey);
195 free(sha);
196 return 0;
197 }
198
199 presskey[presskey_len++] = getchar();
200
201 /* Calculate sha256 upon each new char */
202 hash_block(algo_name, (const void *)presskey,
203 presskey_len, sha, &size);
204
205 /* And check if sha matches saved value in env */
206 if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
207 abort = 1;
208 }
209 } while (!abort && get_ticks() <= etime);
210
211 free(presskey);
212 free(sha);
213 return abort;
214 }
215
216 /**
217 * passwd_abort_key() - check for a key sequence to aborted booting
218 *
219 * This checks for the user entering a string within a given time.
220 *
221 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
222 * @return 0 if autoboot should continue, 1 if it should stop
223 */
passwd_abort_key(uint64_t etime)224 static int passwd_abort_key(uint64_t etime)
225 {
226 int abort = 0;
227 struct {
228 char *str;
229 u_int len;
230 int retry;
231 }
232 delaykey[] = {
233 { .str = env_get("bootdelaykey"), .retry = 1 },
234 { .str = env_get("bootstopkey"), .retry = 0 },
235 };
236
237 char presskey[DELAY_STOP_STR_MAX_LENGTH];
238 int presskey_len = 0;
239 int presskey_max = 0;
240 int i;
241
242 # ifdef CONFIG_AUTOBOOT_DELAY_STR
243 if (delaykey[0].str == NULL)
244 delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
245 # endif
246 # ifdef CONFIG_AUTOBOOT_STOP_STR
247 if (delaykey[1].str == NULL)
248 delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
249 # endif
250
251 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
252 delaykey[i].len = delaykey[i].str == NULL ?
253 0 : strlen(delaykey[i].str);
254 delaykey[i].len = delaykey[i].len > DELAY_STOP_STR_MAX_LENGTH ?
255 DELAY_STOP_STR_MAX_LENGTH : delaykey[i].len;
256
257 presskey_max = presskey_max > delaykey[i].len ?
258 presskey_max : delaykey[i].len;
259
260 debug_bootkeys("%s key:<%s>\n",
261 delaykey[i].retry ? "delay" : "stop",
262 delaykey[i].str ? delaykey[i].str : "NULL");
263 }
264
265 /* In order to keep up with incoming data, check timeout only
266 * when catch up.
267 */
268 do {
269 if (tstc()) {
270 if (presskey_len < presskey_max) {
271 presskey[presskey_len++] = getchar();
272 } else {
273 for (i = 0; i < presskey_max - 1; i++)
274 presskey[i] = presskey[i + 1];
275
276 presskey[i] = getchar();
277 }
278 }
279
280 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
281 if (delaykey[i].len > 0 &&
282 presskey_len >= delaykey[i].len &&
283 memcmp(presskey + presskey_len -
284 delaykey[i].len, delaykey[i].str,
285 delaykey[i].len) == 0) {
286 debug_bootkeys("got %skey\n",
287 delaykey[i].retry ? "delay" :
288 "stop");
289
290 /* don't retry auto boot */
291 if (!delaykey[i].retry)
292 bootretry_dont_retry();
293 abort = 1;
294 }
295 }
296 } while (!abort && get_ticks() <= etime);
297
298 return abort;
299 }
300
301 /**
302 * flush_stdin() - drops all pending characters from stdin
303 */
flush_stdin(void)304 static void flush_stdin(void)
305 {
306 while (tstc())
307 (void)getchar();
308 }
309
310 /**
311 * fallback_to_sha256() - check whether we should fall back to sha256
312 * password checking
313 *
314 * This checks for the environment variable `bootstopusesha256` in case
315 * sha256-fallback has been enabled via the config setting
316 * `AUTOBOOT_SHA256_FALLBACK`.
317 *
318 * @return `false` if we must not fall-back, `true` if plain sha256 should be tried
319 */
fallback_to_sha256(void)320 static bool fallback_to_sha256(void)
321 {
322 if (IS_ENABLED(CONFIG_AUTOBOOT_SHA256_FALLBACK))
323 return env_get_yesno("bootstopusesha256") == 1;
324 else if (IS_ENABLED(CONFIG_CRYPT_PW))
325 return false;
326 else
327 return true;
328 }
329
330 /***************************************************************************
331 * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
332 * returns: 0 - no key string, allow autoboot 1 - got key string, abort
333 */
abortboot_key_sequence(int bootdelay)334 static int abortboot_key_sequence(int bootdelay)
335 {
336 int abort;
337 uint64_t etime = endtick(bootdelay);
338
339 if (IS_ENABLED(CONFIG_AUTOBOOT_FLUSH_STDIN))
340 flush_stdin();
341 # ifdef CONFIG_AUTOBOOT_PROMPT
342 /*
343 * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
344 * To print the bootdelay value upon bootup.
345 */
346 printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
347 # endif
348
349 if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION)) {
350 if (IS_ENABLED(CONFIG_CRYPT_PW) && !fallback_to_sha256())
351 abort = passwd_abort_crypt(etime);
352 else
353 abort = passwd_abort_sha256(etime);
354 } else {
355 abort = passwd_abort_key(etime);
356 }
357 if (!abort)
358 debug_bootkeys("key timeout\n");
359
360 return abort;
361 }
362
abortboot_single_key(int bootdelay)363 static int abortboot_single_key(int bootdelay)
364 {
365 int abort = 0;
366 unsigned long ts;
367
368 printf("Hit any key to stop autoboot: %2d ", bootdelay);
369
370 /*
371 * Check if key already pressed
372 */
373 if (tstc()) { /* we got a key press */
374 getchar(); /* consume input */
375 puts("\b\b\b 0");
376 abort = 1; /* don't auto boot */
377 }
378
379 while ((bootdelay > 0) && (!abort)) {
380 --bootdelay;
381 /* delay 1000 ms */
382 ts = get_timer(0);
383 do {
384 if (tstc()) { /* we got a key press */
385 int key;
386
387 abort = 1; /* don't auto boot */
388 bootdelay = 0; /* no more delay */
389 key = getchar();/* consume input */
390 if (IS_ENABLED(CONFIG_AUTOBOOT_USE_MENUKEY))
391 menukey = key;
392 break;
393 }
394 udelay(10000);
395 } while (!abort && get_timer(ts) < 1000);
396
397 printf("\b\b\b%2d ", bootdelay);
398 }
399
400 putc('\n');
401
402 return abort;
403 }
404
abortboot(int bootdelay)405 static int abortboot(int bootdelay)
406 {
407 int abort = 0;
408
409 if (bootdelay >= 0) {
410 if (autoboot_keyed())
411 abort = abortboot_key_sequence(bootdelay);
412 else
413 abort = abortboot_single_key(bootdelay);
414 }
415
416 if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
417 gd->flags &= ~GD_FLG_SILENT;
418
419 return abort;
420 }
421
process_fdt_options(const void * blob)422 static void process_fdt_options(const void *blob)
423 {
424 #ifdef CONFIG_SYS_TEXT_BASE
425 ulong addr;
426
427 /* Add an env variable to point to a kernel payload, if available */
428 addr = ofnode_conf_read_int("kernel-offset", 0);
429 if (addr)
430 env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
431
432 /* Add an env variable to point to a root disk, if available */
433 addr = ofnode_conf_read_int("rootdisk-offset", 0);
434 if (addr)
435 env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
436 #endif /* CONFIG_SYS_TEXT_BASE */
437 }
438
bootdelay_process(void)439 const char *bootdelay_process(void)
440 {
441 char *s;
442 int bootdelay;
443
444 bootcount_inc();
445
446 s = env_get("bootdelay");
447 bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
448
449 if (IS_ENABLED(CONFIG_OF_CONTROL))
450 bootdelay = ofnode_conf_read_int("bootdelay", bootdelay);
451
452 debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
453
454 if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
455 bootdelay = menu_show(bootdelay);
456 bootretry_init_cmd_timeout();
457
458 #ifdef CONFIG_POST
459 if (gd->flags & GD_FLG_POSTFAIL) {
460 s = env_get("failbootcmd");
461 } else
462 #endif /* CONFIG_POST */
463 if (bootcount_error())
464 s = env_get("altbootcmd");
465 else
466 s = env_get("bootcmd");
467
468 if (IS_ENABLED(CONFIG_OF_CONTROL))
469 process_fdt_options(gd->fdt_blob);
470 stored_bootdelay = bootdelay;
471
472 return s;
473 }
474
autoboot_command(const char * s)475 void autoboot_command(const char *s)
476 {
477 debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
478
479 if (s && (stored_bootdelay == -2 ||
480 (stored_bootdelay != -1 && !abortboot(stored_bootdelay)))) {
481 bool lock;
482 int prev;
483
484 lock = autoboot_keyed() &&
485 !IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
486 if (lock)
487 prev = disable_ctrlc(1); /* disable Ctrl-C checking */
488
489 run_command_list(s, -1, 0);
490
491 if (lock)
492 disable_ctrlc(prev); /* restore Ctrl-C checking */
493 }
494
495 if (IS_ENABLED(CONFIG_AUTOBOOT_USE_MENUKEY) &&
496 menukey == AUTOBOOT_MENUKEY) {
497 s = env_get("menucmd");
498 if (s)
499 run_command_list(s, -1, 0);
500 }
501 }
502