xref: /openbmc/u-boot/common/autoboot.c (revision f37770c7)
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 <console.h>
12 #include <fdtdec.h>
13 #include <menu.h>
14 #include <post.h>
15 #include <u-boot/sha256.h>
16 #include <bootcount.h>
17 
18 DECLARE_GLOBAL_DATA_PTR;
19 
20 #define MAX_DELAY_STOP_STR 32
21 
22 #ifndef DEBUG_BOOTKEYS
23 #define DEBUG_BOOTKEYS 0
24 #endif
25 #define debug_bootkeys(fmt, args...)		\
26 	debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
27 
28 /* Stored value of bootdelay, used by autoboot_command() */
29 static int stored_bootdelay;
30 
31 #if defined(CONFIG_AUTOBOOT_KEYED)
32 #if defined(CONFIG_AUTOBOOT_STOP_STR_SHA256)
33 
34 /*
35  * Use a "constant-length" time compare function for this
36  * hash compare:
37  *
38  * https://crackstation.net/hashing-security.htm
39  */
40 static int slow_equals(u8 *a, u8 *b, int len)
41 {
42 	int diff = 0;
43 	int i;
44 
45 	for (i = 0; i < len; i++)
46 		diff |= a[i] ^ b[i];
47 
48 	return diff == 0;
49 }
50 
51 static int passwd_abort(uint64_t etime)
52 {
53 	const char *sha_env_str = env_get("bootstopkeysha256");
54 	u8 sha_env[SHA256_SUM_LEN];
55 	u8 sha[SHA256_SUM_LEN];
56 	char presskey[MAX_DELAY_STOP_STR];
57 	const char *algo_name = "sha256";
58 	u_int presskey_len = 0;
59 	int abort = 0;
60 	int size = sizeof(sha);
61 	int ret;
62 
63 	if (sha_env_str == NULL)
64 		sha_env_str = CONFIG_AUTOBOOT_STOP_STR_SHA256;
65 
66 	/*
67 	 * Generate the binary value from the environment hash value
68 	 * so that we can compare this value with the computed hash
69 	 * from the user input
70 	 */
71 	ret = hash_parse_string(algo_name, sha_env_str, sha_env);
72 	if (ret) {
73 		printf("Hash %s not supported!\n", algo_name);
74 		return 0;
75 	}
76 
77 	/*
78 	 * We don't know how long the stop-string is, so we need to
79 	 * generate the sha256 hash upon each input character and
80 	 * compare the value with the one saved in the environment
81 	 */
82 	do {
83 		if (tstc()) {
84 			/* Check for input string overflow */
85 			if (presskey_len >= MAX_DELAY_STOP_STR)
86 				return 0;
87 
88 			presskey[presskey_len++] = getc();
89 
90 			/* Calculate sha256 upon each new char */
91 			hash_block(algo_name, (const void *)presskey,
92 				   presskey_len, sha, &size);
93 
94 			/* And check if sha matches saved value in env */
95 			if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
96 				abort = 1;
97 		}
98 	} while (!abort && get_ticks() <= etime);
99 
100 	return abort;
101 }
102 #else
103 static int passwd_abort(uint64_t etime)
104 {
105 	int abort = 0;
106 	struct {
107 		char *str;
108 		u_int len;
109 		int retry;
110 	}
111 	delaykey[] = {
112 		{ .str = env_get("bootdelaykey"),  .retry = 1 },
113 		{ .str = env_get("bootstopkey"),   .retry = 0 },
114 	};
115 
116 	char presskey[MAX_DELAY_STOP_STR];
117 	u_int presskey_len = 0;
118 	u_int presskey_max = 0;
119 	u_int i;
120 
121 #  ifdef CONFIG_AUTOBOOT_DELAY_STR
122 	if (delaykey[0].str == NULL)
123 		delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
124 #  endif
125 #  ifdef CONFIG_AUTOBOOT_STOP_STR
126 	if (delaykey[1].str == NULL)
127 		delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
128 #  endif
129 
130 	for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
131 		delaykey[i].len = delaykey[i].str == NULL ?
132 				    0 : strlen(delaykey[i].str);
133 		delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
134 				    MAX_DELAY_STOP_STR : delaykey[i].len;
135 
136 		presskey_max = presskey_max > delaykey[i].len ?
137 				    presskey_max : delaykey[i].len;
138 
139 		debug_bootkeys("%s key:<%s>\n",
140 			       delaykey[i].retry ? "delay" : "stop",
141 			       delaykey[i].str ? delaykey[i].str : "NULL");
142 	}
143 
144 	/* In order to keep up with incoming data, check timeout only
145 	 * when catch up.
146 	 */
147 	do {
148 		if (tstc()) {
149 			if (presskey_len < presskey_max) {
150 				presskey[presskey_len++] = getc();
151 			} else {
152 				for (i = 0; i < presskey_max - 1; i++)
153 					presskey[i] = presskey[i + 1];
154 
155 				presskey[i] = getc();
156 			}
157 		}
158 
159 		for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
160 			if (delaykey[i].len > 0 &&
161 			    presskey_len >= delaykey[i].len &&
162 				memcmp(presskey + presskey_len -
163 					delaykey[i].len, delaykey[i].str,
164 					delaykey[i].len) == 0) {
165 					debug_bootkeys("got %skey\n",
166 						delaykey[i].retry ? "delay" :
167 						"stop");
168 
169 				/* don't retry auto boot */
170 				if (!delaykey[i].retry)
171 					bootretry_dont_retry();
172 				abort = 1;
173 			}
174 		}
175 	} while (!abort && get_ticks() <= etime);
176 
177 	return abort;
178 }
179 #endif
180 
181 /***************************************************************************
182  * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
183  * returns: 0 -  no key string, allow autoboot 1 - got key string, abort
184  */
185 static int __abortboot(int bootdelay)
186 {
187 	int abort;
188 	uint64_t etime = endtick(bootdelay);
189 
190 #  ifdef CONFIG_AUTOBOOT_PROMPT
191 	/*
192 	 * CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
193 	 * To print the bootdelay value upon bootup.
194 	 */
195 	printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
196 #  endif
197 
198 	abort = passwd_abort(etime);
199 	if (!abort)
200 		debug_bootkeys("key timeout\n");
201 
202 	return abort;
203 }
204 
205 # else	/* !defined(CONFIG_AUTOBOOT_KEYED) */
206 
207 #ifdef CONFIG_MENUKEY
208 static int menukey;
209 #endif
210 
211 static int __abortboot(int bootdelay)
212 {
213 	int abort = 0;
214 	unsigned long ts;
215 
216 #ifdef CONFIG_MENUPROMPT
217 	printf(CONFIG_MENUPROMPT);
218 #else
219 	printf("Hit any key to stop autoboot: %2d ", bootdelay);
220 #endif
221 
222 	/*
223 	 * Check if key already pressed
224 	 */
225 	if (tstc()) {	/* we got a key press	*/
226 		(void) getc();  /* consume input	*/
227 		puts("\b\b\b 0");
228 		abort = 1;	/* don't auto boot	*/
229 	}
230 
231 	while ((bootdelay > 0) && (!abort)) {
232 		--bootdelay;
233 		/* delay 1000 ms */
234 		ts = get_timer(0);
235 		do {
236 			if (tstc()) {	/* we got a key press	*/
237 				abort  = 1;	/* don't auto boot	*/
238 				bootdelay = 0;	/* no more delay	*/
239 # ifdef CONFIG_MENUKEY
240 				menukey = getc();
241 # else
242 				(void) getc();  /* consume input	*/
243 # endif
244 				break;
245 			}
246 			udelay(10000);
247 		} while (!abort && get_timer(ts) < 1000);
248 
249 		printf("\b\b\b%2d ", bootdelay);
250 	}
251 
252 	putc('\n');
253 
254 	return abort;
255 }
256 # endif	/* CONFIG_AUTOBOOT_KEYED */
257 
258 static int abortboot(int bootdelay)
259 {
260 	int abort = 0;
261 
262 	if (bootdelay >= 0)
263 		abort = __abortboot(bootdelay);
264 
265 #ifdef CONFIG_SILENT_CONSOLE
266 	if (abort)
267 		gd->flags &= ~GD_FLG_SILENT;
268 #endif
269 
270 	return abort;
271 }
272 
273 static void process_fdt_options(const void *blob)
274 {
275 #if defined(CONFIG_OF_CONTROL) && defined(CONFIG_SYS_TEXT_BASE)
276 	ulong addr;
277 
278 	/* Add an env variable to point to a kernel payload, if available */
279 	addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
280 	if (addr)
281 		env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
282 
283 	/* Add an env variable to point to a root disk, if available */
284 	addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
285 	if (addr)
286 		env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
287 #endif /* CONFIG_OF_CONTROL && CONFIG_SYS_TEXT_BASE */
288 }
289 
290 const char *bootdelay_process(void)
291 {
292 	char *s;
293 	int bootdelay;
294 
295 	bootcount_inc();
296 
297 	s = env_get("bootdelay");
298 	bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
299 
300 #ifdef CONFIG_OF_CONTROL
301 	bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
302 			bootdelay);
303 #endif
304 
305 	debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
306 
307 #if defined(CONFIG_MENU_SHOW)
308 	bootdelay = menu_show(bootdelay);
309 #endif
310 	bootretry_init_cmd_timeout();
311 
312 #ifdef CONFIG_POST
313 	if (gd->flags & GD_FLG_POSTFAIL) {
314 		s = env_get("failbootcmd");
315 	} else
316 #endif /* CONFIG_POST */
317 	if (bootcount_error())
318 		s = env_get("altbootcmd");
319 	else
320 		s = env_get("bootcmd");
321 
322 	process_fdt_options(gd->fdt_blob);
323 	stored_bootdelay = bootdelay;
324 
325 	return s;
326 }
327 
328 void autoboot_command(const char *s)
329 {
330 	debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
331 
332 	if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
333 #if defined(CONFIG_AUTOBOOT_KEYED) && !defined(CONFIG_AUTOBOOT_KEYED_CTRLC)
334 		int prev = disable_ctrlc(1);	/* disable Control C checking */
335 #endif
336 
337 		run_command_list(s, -1, 0);
338 
339 #if defined(CONFIG_AUTOBOOT_KEYED) && !defined(CONFIG_AUTOBOOT_KEYED_CTRLC)
340 		disable_ctrlc(prev);	/* restore Control C checking */
341 #endif
342 	}
343 
344 #ifdef CONFIG_MENUKEY
345 	if (menukey == CONFIG_MENUKEY) {
346 		s = env_get("menucmd");
347 		if (s)
348 			run_command_list(s, -1, 0);
349 	}
350 #endif /* CONFIG_MENUKEY */
351 }
352