xref: /openbmc/u-boot/common/hash.c (revision 71a988aa)
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 
32 /*
33  * These are the hash algorithms we support. Chips which support accelerated
34  * crypto could perhaps add named version of these algorithms here.
35  */
36 static struct hash_algo hash_algo[] = {
37 #ifdef CONFIG_SHA1
38 	{
39 		"SHA1",
40 		SHA1_SUM_LEN,
41 		sha1_csum_wd,
42 		CHUNKSZ_SHA1,
43 	},
44 #endif
45 #ifdef CONFIG_SHA256
46 	{
47 		"SHA256",
48 		SHA256_SUM_LEN,
49 		sha256_csum_wd,
50 		CHUNKSZ_SHA256,
51 	},
52 #endif
53 };
54 
55 /**
56  * store_result: Store the resulting sum to an address or variable
57  *
58  * @algo:		Hash algorithm being used
59  * @sum:		Hash digest (algo->digest_size bytes)
60  * @dest:		Destination, interpreted as a hex address if it starts
61  *			with * or otherwise as an environment variable.
62  */
63 static void store_result(struct hash_algo *algo, const u8 *sum,
64 			 const char *dest)
65 {
66 	unsigned int i;
67 
68 	if (*dest == '*') {
69 		u8 *ptr;
70 
71 		ptr = (u8 *)simple_strtoul(dest + 1, NULL, 16);
72 		memcpy(ptr, sum, algo->digest_size);
73 	} else {
74 		char str_output[HASH_MAX_DIGEST_SIZE * 2 + 1];
75 		char *str_ptr = str_output;
76 
77 		for (i = 0; i < algo->digest_size; i++) {
78 			sprintf(str_ptr, "%02x", sum[i]);
79 			str_ptr += 2;
80 		}
81 		str_ptr = '\0';
82 		setenv(dest, str_output);
83 	}
84 }
85 
86 /**
87  * parse_verify_sum: Parse a hash verification parameter
88  *
89  * @algo:		Hash algorithm being used
90  * @verify_str:		Argument to parse. If it starts with * then it is
91  *			interpreted as a hex address containing the hash.
92  *			If the length is exactly the right number of hex digits
93  *			for the digest size, then we assume it is a hex digest.
94  *			Otherwise we assume it is an environment variable, and
95  *			look up its value (it must contain a hex digest).
96  * @vsum:		Returns binary digest value (algo->digest_size bytes)
97  * @return 0 if ok, non-zero on error
98  */
99 static int parse_verify_sum(struct hash_algo *algo, char *verify_str, u8 *vsum)
100 {
101 	if (*verify_str == '*') {
102 		u8 *ptr;
103 
104 		ptr = (u8 *)simple_strtoul(verify_str + 1, NULL, 16);
105 		memcpy(vsum, ptr, algo->digest_size);
106 	} else {
107 		unsigned int i;
108 		char *vsum_str;
109 		int digits = algo->digest_size * 2;
110 
111 		/*
112 		 * As with the original code from sha1sum.c, we assume that a
113 		 * string which matches the digest size exactly is a hex
114 		 * string and not an environment variable.
115 		 */
116 		if (strlen(verify_str) == digits)
117 			vsum_str = verify_str;
118 		else {
119 			vsum_str = getenv(verify_str);
120 			if (vsum_str == NULL || strlen(vsum_str) != digits) {
121 				printf("Expected %d hex digits in env var\n",
122 				       digits);
123 				return 1;
124 			}
125 		}
126 
127 		for (i = 0; i < algo->digest_size; i++) {
128 			char *nullp = vsum_str + (i + 1) * 2;
129 			char end = *nullp;
130 
131 			*nullp = '\0';
132 			vsum[i] = simple_strtoul(vsum_str + (i * 2), NULL, 16);
133 			*nullp = end;
134 		}
135 	}
136 	return 0;
137 }
138 
139 static struct hash_algo *find_hash_algo(const char *name)
140 {
141 	int i;
142 
143 	for (i = 0; i < ARRAY_SIZE(hash_algo); i++) {
144 		if (!strcasecmp(name, hash_algo[i].name))
145 			return &hash_algo[i];
146 	}
147 
148 	return NULL;
149 }
150 
151 static void show_hash(struct hash_algo *algo, ulong addr, ulong len,
152 		      u8 *output)
153 {
154 	int i;
155 
156 	printf("%s for %08lx ... %08lx ==> ", algo->name, addr, addr + len - 1);
157 	for (i = 0; i < algo->digest_size; i++)
158 		printf("%02x", output[i]);
159 }
160 
161 int hash_command(const char *algo_name, int verify, cmd_tbl_t *cmdtp, int flag,
162 		 int argc, char * const argv[])
163 {
164 	struct hash_algo *algo;
165 	ulong addr, len;
166 	u8 output[HASH_MAX_DIGEST_SIZE];
167 	u8 vsum[HASH_MAX_DIGEST_SIZE];
168 
169 	if (argc < 2)
170 		return CMD_RET_USAGE;
171 
172 	algo = find_hash_algo(algo_name);
173 	if (!algo) {
174 		printf("Unknown hash algorithm '%s'\n", algo_name);
175 		return CMD_RET_USAGE;
176 	}
177 	addr = simple_strtoul(*argv++, NULL, 16);
178 	len = simple_strtoul(*argv++, NULL, 16);
179 	argc -= 2;
180 
181 	if (algo->digest_size > HASH_MAX_DIGEST_SIZE) {
182 		puts("HASH_MAX_DIGEST_SIZE exceeded\n");
183 		return 1;
184 	}
185 
186 	algo->hash_func_ws((const unsigned char *)addr, len, output,
187 			   algo->chunk_size);
188 
189 	/* Try to avoid code bloat when verify is not needed */
190 #ifdef CONFIG_HASH_VERIFY
191 	if (verify) {
192 #else
193 	if (0) {
194 #endif
195 		if (!argc)
196 			return CMD_RET_USAGE;
197 		if (parse_verify_sum(algo, *argv, vsum)) {
198 			printf("ERROR: %s does not contain a valid %s sum\n",
199 				*argv, algo->name);
200 			return 1;
201 		}
202 		if (memcmp(output, vsum, algo->digest_size) != 0) {
203 			int i;
204 
205 			show_hash(algo, addr, len, output);
206 			printf(" != ");
207 			for (i = 0; i < algo->digest_size; i++)
208 				printf("%02x", vsum[i]);
209 			puts(" ** ERROR **\n");
210 			return 1;
211 		}
212 	} else {
213 		show_hash(algo, addr, len, output);
214 		printf("\n");
215 
216 		if (argc)
217 			store_result(algo, output, *argv);
218 	}
219 
220 	return 0;
221 }
222