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
27 DECLARE_GLOBAL_DATA_PTR;
28
29 #define MAX_DELAY_STOP_STR 64
30
31 #ifndef DEBUG_BOOTKEYS
32 #define DEBUG_BOOTKEYS 0
33 #endif
34 #define debug_bootkeys(fmt, args...) \
35 debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
36
37 /* Stored value of bootdelay, used by autoboot_command() */
38 static int stored_bootdelay;
39 static int menukey;
40
41 #ifdef CONFIG_AUTOBOOT_ENCRYPTION
42 #define AUTOBOOT_STOP_STR_SHA256 CONFIG_AUTOBOOT_STOP_STR_SHA256
43 #else
44 #define AUTOBOOT_STOP_STR_SHA256 ""
45 #endif
46
47 #ifdef CONFIG_USE_AUTOBOOT_MENUKEY
48 #define AUTOBOOT_MENUKEY CONFIG_USE_AUTOBOOT_MENUKEY
49 #else
50 #define AUTOBOOT_MENUKEY 0
51 #endif
52
53 /*
54 * Use a "constant-length" time compare function for this
55 * hash compare:
56 *
57 * https://crackstation.net/hashing-security.htm
58 */
slow_equals(u8 * a,u8 * b,int len)59 static int slow_equals(u8 *a, u8 *b, int len)
60 {
61 int diff = 0;
62 int i;
63
64 for (i = 0; i < len; i++)
65 diff |= a[i] ^ b[i];
66
67 return diff == 0;
68 }
69
70 /**
71 * passwd_abort_sha256() - check for a hashed key sequence to abort booting
72 *
73 * This checks for the user entering a SHA256 hash within a given time.
74 *
75 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
76 * @return 0 if autoboot should continue, 1 if it should stop
77 */
passwd_abort_sha256(uint64_t etime)78 static int passwd_abort_sha256(uint64_t etime)
79 {
80 const char *sha_env_str = env_get("bootstopkeysha256");
81 u8 sha_env[SHA256_SUM_LEN];
82 u8 *sha;
83 char *presskey;
84 char *c;
85 const char *algo_name = "sha256";
86 u_int presskey_len = 0;
87 int abort = 0;
88 int size = sizeof(sha);
89 int ret;
90
91 if (sha_env_str == NULL)
92 sha_env_str = AUTOBOOT_STOP_STR_SHA256;
93
94 presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR);
95 c = strstr(sha_env_str, ":");
96 if (c && (c - sha_env_str < MAX_DELAY_STOP_STR)) {
97 /* preload presskey with salt */
98 memcpy(presskey, sha_env_str, c - sha_env_str);
99 presskey_len = c - sha_env_str;
100 sha_env_str = c + 1;
101 }
102 /*
103 * Generate the binary value from the environment hash value
104 * so that we can compare this value with the computed hash
105 * from the user input
106 */
107 ret = hash_parse_string(algo_name, sha_env_str, sha_env);
108 if (ret) {
109 printf("Hash %s not supported!\n", algo_name);
110 return 0;
111 }
112
113 sha = malloc_cache_aligned(SHA256_SUM_LEN);
114 size = SHA256_SUM_LEN;
115 /*
116 * We don't know how long the stop-string is, so we need to
117 * generate the sha256 hash upon each input character and
118 * compare the value with the one saved in the environment
119 */
120 do {
121 if (tstc()) {
122 /* Check for input string overflow */
123 if (presskey_len >= MAX_DELAY_STOP_STR) {
124 free(presskey);
125 free(sha);
126 return 0;
127 }
128
129 presskey[presskey_len++] = getchar();
130
131 /* Calculate sha256 upon each new char */
132 hash_block(algo_name, (const void *)presskey,
133 presskey_len, sha, &size);
134
135 /* And check if sha matches saved value in env */
136 if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
137 abort = 1;
138 }
139 } while (!abort && get_ticks() <= etime);
140
141 free(presskey);
142 free(sha);
143 return abort;
144 }
145
146 /**
147 * passwd_abort_key() - check for a key sequence to aborted booting
148 *
149 * This checks for the user entering a string within a given time.
150 *
151 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
152 * @return 0 if autoboot should continue, 1 if it should stop
153 */
passwd_abort_key(uint64_t etime)154 static int passwd_abort_key(uint64_t etime)
155 {
156 int abort = 0;
157 struct {
158 char *str;
159 u_int len;
160 int retry;
161 }
162 delaykey[] = {
163 { .str = env_get("bootdelaykey"), .retry = 1 },
164 { .str = env_get("bootstopkey"), .retry = 0 },
165 };
166
167 char presskey[MAX_DELAY_STOP_STR];
168 int presskey_len = 0;
169 int presskey_max = 0;
170 int i;
171
172 # ifdef CONFIG_AUTOBOOT_DELAY_STR
173 if (delaykey[0].str == NULL)
174 delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
175 # endif
176 # ifdef CONFIG_AUTOBOOT_STOP_STR
177 if (delaykey[1].str == NULL)
178 delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
179 # endif
180
181 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
182 delaykey[i].len = delaykey[i].str == NULL ?
183 0 : strlen(delaykey[i].str);
184 delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
185 MAX_DELAY_STOP_STR : delaykey[i].len;
186
187 presskey_max = presskey_max > delaykey[i].len ?
188 presskey_max : delaykey[i].len;
189
190 debug_bootkeys("%s key:<%s>\n",
191 delaykey[i].retry ? "delay" : "stop",
192 delaykey[i].str ? delaykey[i].str : "NULL");
193 }
194
195 /* In order to keep up with incoming data, check timeout only
196 * when catch up.
197 */
198 do {
199 if (tstc()) {
200 if (presskey_len < presskey_max) {
201 presskey[presskey_len++] = getchar();
202 } else {
203 for (i = 0; i < presskey_max - 1; i++)
204 presskey[i] = presskey[i + 1];
205
206 presskey[i] = getchar();
207 }
208 }
209
210 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
211 if (delaykey[i].len > 0 &&
212 presskey_len >= delaykey[i].len &&
213 memcmp(presskey + presskey_len -
214 delaykey[i].len, delaykey[i].str,
215 delaykey[i].len) == 0) {
216 debug_bootkeys("got %skey\n",
217 delaykey[i].retry ? "delay" :
218 "stop");
219
220 /* don't retry auto boot */
221 if (!delaykey[i].retry)
222 bootretry_dont_retry();
223 abort = 1;
224 }
225 }
226 } while (!abort && get_ticks() <= etime);
227
228 return abort;
229 }
230
231 /***************************************************************************
232 * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
233 * returns: 0 - no key string, allow autoboot 1 - got key string, abort
234 */
abortboot_key_sequence(int bootdelay)235 static int abortboot_key_sequence(int bootdelay)
236 {
237 int abort;
238 uint64_t etime = endtick(bootdelay);
239
240 # ifdef CONFIG_AUTOBOOT_PROMPT
241 /*
242 * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
243 * To print the bootdelay value upon bootup.
244 */
245 printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
246 # endif
247
248 if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION))
249 abort = passwd_abort_sha256(etime);
250 else
251 abort = passwd_abort_key(etime);
252 if (!abort)
253 debug_bootkeys("key timeout\n");
254
255 return abort;
256 }
257
abortboot_single_key(int bootdelay)258 static int abortboot_single_key(int bootdelay)
259 {
260 int abort = 0;
261 unsigned long ts;
262
263 printf("Hit any key to stop autoboot: %2d ", bootdelay);
264
265 /*
266 * Check if key already pressed
267 */
268 if (tstc()) { /* we got a key press */
269 getchar(); /* consume input */
270 puts("\b\b\b 0");
271 abort = 1; /* don't auto boot */
272 }
273
274 while ((bootdelay > 0) && (!abort)) {
275 --bootdelay;
276 /* delay 1000 ms */
277 ts = get_timer(0);
278 do {
279 if (tstc()) { /* we got a key press */
280 int key;
281
282 abort = 1; /* don't auto boot */
283 bootdelay = 0; /* no more delay */
284 key = getchar();/* consume input */
285 if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY))
286 menukey = key;
287 break;
288 }
289 udelay(10000);
290 } while (!abort && get_timer(ts) < 1000);
291
292 printf("\b\b\b%2d ", bootdelay);
293 }
294
295 putc('\n');
296
297 return abort;
298 }
299
abortboot(int bootdelay)300 static int abortboot(int bootdelay)
301 {
302 int abort = 0;
303
304 if (bootdelay >= 0) {
305 if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
306 abort = abortboot_key_sequence(bootdelay);
307 else
308 abort = abortboot_single_key(bootdelay);
309 }
310
311 if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
312 gd->flags &= ~GD_FLG_SILENT;
313
314 return abort;
315 }
316
process_fdt_options(const void * blob)317 static void process_fdt_options(const void *blob)
318 {
319 #ifdef CONFIG_SYS_TEXT_BASE
320 ulong addr;
321
322 /* Add an env variable to point to a kernel payload, if available */
323 addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
324 if (addr)
325 env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
326
327 /* Add an env variable to point to a root disk, if available */
328 addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
329 if (addr)
330 env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
331 #endif /* CONFIG_SYS_TEXT_BASE */
332 }
333
bootdelay_process(void)334 const char *bootdelay_process(void)
335 {
336 char *s;
337 int bootdelay;
338
339 bootcount_inc();
340
341 s = env_get("bootdelay");
342 bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
343
344 if (IS_ENABLED(CONFIG_OF_CONTROL))
345 bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
346 bootdelay);
347
348 debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
349
350 if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
351 bootdelay = menu_show(bootdelay);
352 bootretry_init_cmd_timeout();
353
354 #ifdef CONFIG_POST
355 if (gd->flags & GD_FLG_POSTFAIL) {
356 s = env_get("failbootcmd");
357 } else
358 #endif /* CONFIG_POST */
359 if (bootcount_error())
360 s = env_get("altbootcmd");
361 else
362 s = env_get("bootcmd");
363
364 if (IS_ENABLED(CONFIG_OF_CONTROL))
365 process_fdt_options(gd->fdt_blob);
366 stored_bootdelay = bootdelay;
367
368 return s;
369 }
370
autoboot_command(const char * s)371 void autoboot_command(const char *s)
372 {
373 debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
374
375 if (s && (stored_bootdelay == -2 ||
376 (stored_bootdelay != -1 && !abortboot(stored_bootdelay)))) {
377 bool lock;
378 int prev;
379
380 lock = IS_ENABLED(CONFIG_AUTOBOOT_KEYED) &&
381 !IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
382 if (lock)
383 prev = disable_ctrlc(1); /* disable Ctrl-C checking */
384
385 run_command_list(s, -1, 0);
386
387 if (lock)
388 disable_ctrlc(prev); /* restore Ctrl-C checking */
389 }
390
391 if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY) &&
392 menukey == AUTOBOOT_MENUKEY) {
393 s = env_get("menucmd");
394 if (s)
395 run_command_list(s, -1, 0);
396 }
397 }
398