xref: /openbmc/u-boot/common/hash.c (revision 18652864)
1 /*
2  * Copyright (c) 2012 The Chromium OS Authors.
3  *
4  * (C) Copyright 2011
5  * Joe Hershberger, National Instruments, joe.hershberger@ni.com
6  *
7  * (C) Copyright 2000
8  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of
13  * the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
23  * MA 02111-1307 USA
24  */
25 
26 #include <common.h>
27 #include <command.h>
28 #include <hash.h>
29 #include <sha1.h>
30 #include <sha256.h>
31 #include <asm/io.h>
32 
33 /*
34  * These are the hash algorithms we support. Chips which support accelerated
35  * crypto could perhaps add named version of these algorithms here. Note that
36  * algorithm names must be in lower case.
37  */
38 static struct hash_algo hash_algo[] = {
39 	/*
40 	 * This is CONFIG_CMD_SHA1SUM instead of CONFIG_SHA1 since otherwise
41 	 * it bloats the code for boards which use SHA1 but not the 'hash'
42 	 * or 'sha1sum' commands.
43 	 */
44 #ifdef CONFIG_CMD_SHA1SUM
45 	{
46 		"sha1",
47 		SHA1_SUM_LEN,
48 		sha1_csum_wd,
49 		CHUNKSZ_SHA1,
50 	},
51 #define MULTI_HASH
52 #endif
53 #ifdef CONFIG_SHA256
54 	{
55 		"sha256",
56 		SHA256_SUM_LEN,
57 		sha256_csum_wd,
58 		CHUNKSZ_SHA256,
59 	},
60 #define MULTI_HASH
61 #endif
62 	{
63 		"crc32",
64 		4,
65 		crc32_wd_buf,
66 		CHUNKSZ_CRC32,
67 	},
68 };
69 
70 #if defined(CONFIG_HASH_VERIFY) || defined(CONFIG_CMD_HASH)
71 #define MULTI_HASH
72 #endif
73 
74 /* Try to minimize code size for boards that don't want much hashing */
75 #ifdef MULTI_HASH
76 #define multi_hash()	1
77 #else
78 #define multi_hash()	0
79 #endif
80 
81 /**
82  * store_result: Store the resulting sum to an address or variable
83  *
84  * @algo:		Hash algorithm being used
85  * @sum:		Hash digest (algo->digest_size bytes)
86  * @dest:		Destination, interpreted as a hex address if it starts
87  *			with * (or allow_env_vars is 0) or otherwise as an
88  *			environment variable.
89  * @allow_env_vars:	non-zero to permit storing the result to an
90  *			variable environment
91  */
92 static void store_result(struct hash_algo *algo, const u8 *sum,
93 			 const char *dest, int allow_env_vars)
94 {
95 	unsigned int i;
96 	int env_var = 0;
97 
98 	/*
99 	 * If environment variables are allowed, then we assume that 'dest'
100 	 * is an environment variable, unless it starts with *, in which
101 	 * case we assume it is an address. If not allowed, it is always an
102 	 * address. This is to support the crc32 command.
103 	 */
104 	if (allow_env_vars) {
105 		if (*dest == '*')
106 			dest++;
107 		else
108 			env_var = 1;
109 	}
110 
111 	if (env_var) {
112 		char str_output[HASH_MAX_DIGEST_SIZE * 2 + 1];
113 		char *str_ptr = str_output;
114 
115 		for (i = 0; i < algo->digest_size; i++) {
116 			sprintf(str_ptr, "%02x", sum[i]);
117 			str_ptr += 2;
118 		}
119 		str_ptr = '\0';
120 		setenv(dest, str_output);
121 	} else {
122 		ulong addr;
123 		void *buf;
124 
125 		addr = simple_strtoul(dest, NULL, 16);
126 		buf = map_sysmem(addr, algo->digest_size);
127 		memcpy(buf, sum, algo->digest_size);
128 		unmap_sysmem(buf);
129 	}
130 }
131 
132 /**
133  * parse_verify_sum: Parse a hash verification parameter
134  *
135  * @algo:		Hash algorithm being used
136  * @verify_str:		Argument to parse. If it starts with * then it is
137  *			interpreted as a hex address containing the hash.
138  *			If the length is exactly the right number of hex digits
139  *			for the digest size, then we assume it is a hex digest.
140  *			Otherwise we assume it is an environment variable, and
141  *			look up its value (it must contain a hex digest).
142  * @vsum:		Returns binary digest value (algo->digest_size bytes)
143  * @allow_env_vars:	non-zero to permit storing the result to an environment
144  *			variable. If 0 then verify_str is assumed to be an
145  *			address, and the * prefix is not expected.
146  * @return 0 if ok, non-zero on error
147  */
148 static int parse_verify_sum(struct hash_algo *algo, char *verify_str, u8 *vsum,
149 			    int allow_env_vars)
150 {
151 	int env_var = 0;
152 
153 	/* See comment above in store_result() */
154 	if (allow_env_vars) {
155 		if (*verify_str == '*')
156 			verify_str++;
157 		else
158 			env_var = 1;
159 	}
160 
161 	if (env_var) {
162 		ulong addr;
163 		void *buf;
164 
165 		addr = simple_strtoul(verify_str, NULL, 16);
166 		buf = map_sysmem(addr, algo->digest_size);
167 		memcpy(vsum, buf, algo->digest_size);
168 	} else {
169 		unsigned int i;
170 		char *vsum_str;
171 		int digits = algo->digest_size * 2;
172 
173 		/*
174 		 * As with the original code from sha1sum.c, we assume that a
175 		 * string which matches the digest size exactly is a hex
176 		 * string and not an environment variable.
177 		 */
178 		if (strlen(verify_str) == digits)
179 			vsum_str = verify_str;
180 		else {
181 			vsum_str = getenv(verify_str);
182 			if (vsum_str == NULL || strlen(vsum_str) != digits) {
183 				printf("Expected %d hex digits in env var\n",
184 				       digits);
185 				return 1;
186 			}
187 		}
188 
189 		for (i = 0; i < algo->digest_size; i++) {
190 			char *nullp = vsum_str + (i + 1) * 2;
191 			char end = *nullp;
192 
193 			*nullp = '\0';
194 			vsum[i] = simple_strtoul(vsum_str + (i * 2), NULL, 16);
195 			*nullp = end;
196 		}
197 	}
198 	return 0;
199 }
200 
201 static struct hash_algo *find_hash_algo(const char *name)
202 {
203 	int i;
204 
205 	for (i = 0; i < ARRAY_SIZE(hash_algo); i++) {
206 		if (!strcmp(name, hash_algo[i].name))
207 			return &hash_algo[i];
208 	}
209 
210 	return NULL;
211 }
212 
213 static void show_hash(struct hash_algo *algo, ulong addr, ulong len,
214 		      u8 *output)
215 {
216 	int i;
217 
218 	printf("%s for %08lx ... %08lx ==> ", algo->name, addr, addr + len - 1);
219 	for (i = 0; i < algo->digest_size; i++)
220 		printf("%02x", output[i]);
221 }
222 
223 int hash_command(const char *algo_name, int flags, cmd_tbl_t *cmdtp, int flag,
224 		 int argc, char * const argv[])
225 {
226 	ulong addr, len;
227 
228 	if (argc < 2)
229 		return CMD_RET_USAGE;
230 
231 	addr = simple_strtoul(*argv++, NULL, 16);
232 	len = simple_strtoul(*argv++, NULL, 16);
233 
234 	if (multi_hash()) {
235 		struct hash_algo *algo;
236 		u8 output[HASH_MAX_DIGEST_SIZE];
237 		u8 vsum[HASH_MAX_DIGEST_SIZE];
238 		void *buf;
239 
240 		algo = find_hash_algo(algo_name);
241 		if (!algo) {
242 			printf("Unknown hash algorithm '%s'\n", algo_name);
243 			return CMD_RET_USAGE;
244 		}
245 		argc -= 2;
246 
247 		if (algo->digest_size > HASH_MAX_DIGEST_SIZE) {
248 			puts("HASH_MAX_DIGEST_SIZE exceeded\n");
249 			return 1;
250 		}
251 
252 		buf = map_sysmem(addr, len);
253 		algo->hash_func_ws(buf, len, output, algo->chunk_size);
254 		unmap_sysmem(buf);
255 
256 		/* Try to avoid code bloat when verify is not needed */
257 #ifdef CONFIG_HASH_VERIFY
258 		if (flags & HASH_FLAG_VERIFY) {
259 #else
260 		if (0) {
261 #endif
262 			if (!argc)
263 				return CMD_RET_USAGE;
264 			if (parse_verify_sum(algo, *argv, vsum,
265 					flags & HASH_FLAG_ENV)) {
266 				printf("ERROR: %s does not contain a valid "
267 					"%s sum\n", *argv, algo->name);
268 				return 1;
269 			}
270 			if (memcmp(output, vsum, algo->digest_size) != 0) {
271 				int i;
272 
273 				show_hash(algo, addr, len, output);
274 				printf(" != ");
275 				for (i = 0; i < algo->digest_size; i++)
276 					printf("%02x", vsum[i]);
277 				puts(" ** ERROR **\n");
278 				return 1;
279 			}
280 		} else {
281 			show_hash(algo, addr, len, output);
282 			printf("\n");
283 
284 			if (argc) {
285 				store_result(algo, output, *argv,
286 					flags & HASH_FLAG_ENV);
287 			}
288 		}
289 
290 	/* Horrible code size hack for boards that just want crc32 */
291 	} else {
292 		ulong crc;
293 		ulong *ptr;
294 
295 		crc = crc32_wd(0, (const uchar *)addr, len, CHUNKSZ_CRC32);
296 
297 		printf("CRC32 for %08lx ... %08lx ==> %08lx\n",
298 				addr, addr + len - 1, crc);
299 
300 		if (argc > 3) {
301 			ptr = (ulong *)simple_strtoul(argv[3], NULL, 16);
302 			*ptr = crc;
303 		}
304 	}
305 
306 	return 0;
307 }
308