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 <memalign.h>
17 #include <menu.h>
18 #include <post.h>
19 #include <time.h>
20 #include <u-boot/sha256.h>
21 #include <bootcount.h>
22
23 DECLARE_GLOBAL_DATA_PTR;
24
25 #define MAX_DELAY_STOP_STR 32
26
27 #ifndef DEBUG_BOOTKEYS
28 #define DEBUG_BOOTKEYS 0
29 #endif
30 #define debug_bootkeys(fmt, args...) \
31 debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
32
33 /* Stored value of bootdelay, used by autoboot_command() */
34 static int stored_bootdelay;
35 static int menukey;
36
37 #ifdef CONFIG_AUTOBOOT_ENCRYPTION
38 #define AUTOBOOT_STOP_STR_SHA256 CONFIG_AUTOBOOT_STOP_STR_SHA256
39 #else
40 #define AUTOBOOT_STOP_STR_SHA256 ""
41 #endif
42
43 #ifdef CONFIG_USE_AUTOBOOT_MENUKEY
44 #define AUTOBOOT_MENUKEY CONFIG_USE_AUTOBOOT_MENUKEY
45 #else
46 #define AUTOBOOT_MENUKEY 0
47 #endif
48
49 /*
50 * Use a "constant-length" time compare function for this
51 * hash compare:
52 *
53 * https://crackstation.net/hashing-security.htm
54 */
slow_equals(u8 * a,u8 * b,int len)55 static int slow_equals(u8 *a, u8 *b, int len)
56 {
57 int diff = 0;
58 int i;
59
60 for (i = 0; i < len; i++)
61 diff |= a[i] ^ b[i];
62
63 return diff == 0;
64 }
65
66 /**
67 * passwd_abort_sha256() - check for a hashed key sequence to abort booting
68 *
69 * This checks for the user entering a SHA256 hash within a given time.
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_sha256(uint64_t etime)74 static int passwd_abort_sha256(uint64_t etime)
75 {
76 const char *sha_env_str = env_get("bootstopkeysha256");
77 u8 sha_env[SHA256_SUM_LEN];
78 u8 *sha;
79 char *presskey;
80 const char *algo_name = "sha256";
81 u_int presskey_len = 0;
82 int abort = 0;
83 int size = sizeof(sha);
84 int ret;
85
86 if (sha_env_str == NULL)
87 sha_env_str = AUTOBOOT_STOP_STR_SHA256;
88
89 /*
90 * Generate the binary value from the environment hash value
91 * so that we can compare this value with the computed hash
92 * from the user input
93 */
94 ret = hash_parse_string(algo_name, sha_env_str, sha_env);
95 if (ret) {
96 printf("Hash %s not supported!\n", algo_name);
97 return 0;
98 }
99
100 presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR);
101 sha = malloc_cache_aligned(SHA256_SUM_LEN);
102 size = SHA256_SUM_LEN;
103 /*
104 * We don't know how long the stop-string is, so we need to
105 * generate the sha256 hash upon each input character and
106 * compare the value with the one saved in the environment
107 */
108 do {
109 if (tstc()) {
110 /* Check for input string overflow */
111 if (presskey_len >= MAX_DELAY_STOP_STR) {
112 free(presskey);
113 free(sha);
114 return 0;
115 }
116
117 presskey[presskey_len++] = getc();
118
119 /* Calculate sha256 upon each new char */
120 hash_block(algo_name, (const void *)presskey,
121 presskey_len, sha, &size);
122
123 /* And check if sha matches saved value in env */
124 if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
125 abort = 1;
126 }
127 } while (!abort && get_ticks() <= etime);
128
129 free(presskey);
130 free(sha);
131 return abort;
132 }
133
134 /**
135 * passwd_abort_key() - check for a key sequence to aborted booting
136 *
137 * This checks for the user entering a string within a given time.
138 *
139 * @etime: Timeout value ticks (stop when get_ticks() reachs this)
140 * @return 0 if autoboot should continue, 1 if it should stop
141 */
passwd_abort_key(uint64_t etime)142 static int passwd_abort_key(uint64_t etime)
143 {
144 int abort = 0;
145 struct {
146 char *str;
147 u_int len;
148 int retry;
149 }
150 delaykey[] = {
151 { .str = env_get("bootdelaykey"), .retry = 1 },
152 { .str = env_get("bootstopkey"), .retry = 0 },
153 };
154
155 char presskey[MAX_DELAY_STOP_STR];
156 u_int presskey_len = 0;
157 u_int presskey_max = 0;
158 u_int i;
159
160 # ifdef CONFIG_AUTOBOOT_DELAY_STR
161 if (delaykey[0].str == NULL)
162 delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
163 # endif
164 # ifdef CONFIG_AUTOBOOT_STOP_STR
165 if (delaykey[1].str == NULL)
166 delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
167 # endif
168
169 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
170 delaykey[i].len = delaykey[i].str == NULL ?
171 0 : strlen(delaykey[i].str);
172 delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
173 MAX_DELAY_STOP_STR : delaykey[i].len;
174
175 presskey_max = presskey_max > delaykey[i].len ?
176 presskey_max : delaykey[i].len;
177
178 debug_bootkeys("%s key:<%s>\n",
179 delaykey[i].retry ? "delay" : "stop",
180 delaykey[i].str ? delaykey[i].str : "NULL");
181 }
182
183 /* In order to keep up with incoming data, check timeout only
184 * when catch up.
185 */
186 do {
187 if (tstc()) {
188 if (presskey_len < presskey_max) {
189 presskey[presskey_len++] = getc();
190 } else {
191 for (i = 0; i < presskey_max - 1; i++)
192 presskey[i] = presskey[i + 1];
193
194 presskey[i] = getc();
195 }
196 }
197
198 for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
199 if (delaykey[i].len > 0 &&
200 presskey_len >= delaykey[i].len &&
201 memcmp(presskey + presskey_len -
202 delaykey[i].len, delaykey[i].str,
203 delaykey[i].len) == 0) {
204 debug_bootkeys("got %skey\n",
205 delaykey[i].retry ? "delay" :
206 "stop");
207
208 /* don't retry auto boot */
209 if (!delaykey[i].retry)
210 bootretry_dont_retry();
211 abort = 1;
212 }
213 }
214 } while (!abort && get_ticks() <= etime);
215
216 return abort;
217 }
218
219 /***************************************************************************
220 * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
221 * returns: 0 - no key string, allow autoboot 1 - got key string, abort
222 */
abortboot_key_sequence(int bootdelay)223 static int abortboot_key_sequence(int bootdelay)
224 {
225 int abort;
226 uint64_t etime = endtick(bootdelay);
227
228 # ifdef CONFIG_AUTOBOOT_PROMPT
229 /*
230 * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
231 * To print the bootdelay value upon bootup.
232 */
233 printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
234 # endif
235
236 if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION))
237 abort = passwd_abort_sha256(etime);
238 else
239 abort = passwd_abort_key(etime);
240 if (!abort)
241 debug_bootkeys("key timeout\n");
242
243 return abort;
244 }
245
abortboot_single_key(int bootdelay)246 static int abortboot_single_key(int bootdelay)
247 {
248 int abort = 0;
249 unsigned long ts;
250
251 printf("Hit any key to stop autoboot: %2d ", bootdelay);
252
253 /*
254 * Check if key already pressed
255 */
256 if (tstc()) { /* we got a key press */
257 (void) getc(); /* consume input */
258 puts("\b\b\b 0");
259 abort = 1; /* don't auto boot */
260 }
261
262 while ((bootdelay > 0) && (!abort)) {
263 --bootdelay;
264 /* delay 1000 ms */
265 ts = get_timer(0);
266 do {
267 if (tstc()) { /* we got a key press */
268 int key;
269
270 abort = 1; /* don't auto boot */
271 bootdelay = 0; /* no more delay */
272 key = getc(); /* consume input */
273 if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY))
274 menukey = key;
275 break;
276 }
277 udelay(10000);
278 } while (!abort && get_timer(ts) < 1000);
279
280 printf("\b\b\b%2d ", bootdelay);
281 }
282
283 putc('\n');
284
285 return abort;
286 }
287
abortboot(int bootdelay)288 static int abortboot(int bootdelay)
289 {
290 int abort = 0;
291
292 if (bootdelay >= 0) {
293 if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
294 abort = abortboot_key_sequence(bootdelay);
295 else
296 abort = abortboot_single_key(bootdelay);
297 }
298
299 if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
300 gd->flags &= ~GD_FLG_SILENT;
301
302 return abort;
303 }
304
process_fdt_options(const void * blob)305 static void process_fdt_options(const void *blob)
306 {
307 #ifdef CONFIG_SYS_TEXT_BASE
308 ulong addr;
309
310 /* Add an env variable to point to a kernel payload, if available */
311 addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
312 if (addr)
313 env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
314
315 /* Add an env variable to point to a root disk, if available */
316 addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
317 if (addr)
318 env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
319 #endif /* CONFIG_SYS_TEXT_BASE */
320 }
321
bootdelay_process(void)322 const char *bootdelay_process(void)
323 {
324 char *s;
325 int bootdelay;
326
327 bootcount_inc();
328
329 s = env_get("bootdelay");
330 bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
331
332 if (IS_ENABLED(CONFIG_OF_CONTROL))
333 bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
334 bootdelay);
335
336 debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
337
338 if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
339 bootdelay = menu_show(bootdelay);
340 bootretry_init_cmd_timeout();
341
342 #ifdef CONFIG_POST
343 if (gd->flags & GD_FLG_POSTFAIL) {
344 s = env_get("failbootcmd");
345 } else
346 #endif /* CONFIG_POST */
347 if (bootcount_error())
348 s = env_get("altbootcmd");
349 else
350 s = env_get("bootcmd");
351
352 if (IS_ENABLED(CONFIG_OF_CONTROL))
353 process_fdt_options(gd->fdt_blob);
354 stored_bootdelay = bootdelay;
355
356 return s;
357 }
358
autoboot_command(const char * s)359 void autoboot_command(const char *s)
360 {
361 debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
362
363 if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
364 bool lock;
365 int prev;
366
367 lock = IS_ENABLED(CONFIG_AUTOBOOT_KEYED) &&
368 !IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
369 if (lock)
370 prev = disable_ctrlc(1); /* disable Ctrl-C checking */
371
372 run_command_list(s, -1, 0);
373
374 if (lock)
375 disable_ctrlc(prev); /* restore Ctrl-C checking */
376 }
377
378 if (IS_ENABLED(CONFIG_USE_AUTOBOOT_MENUKEY) &&
379 menukey == AUTOBOOT_MENUKEY) {
380 s = env_get("menucmd");
381 if (s)
382 run_command_list(s, -1, 0);
383 }
384 }
385