xref: /openbsd/usr.bin/ssh/digest-libc.c (revision 76d0caae) 
1 /* $OpenBSD: digest-libc.c,v 1.7 2020/02/26 13:40:09 jsg Exp $ */
2 /*
3  * Copyright (c) 2013 Damien Miller <djm@mindrot.org>
4  * Copyright (c) 2014 Markus Friedl.  All rights reserved.
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 #include <limits.h>
21 #include <stdlib.h>
22 #include <string.h>
23 
24 #include <md5.h>
25 #include <rmd160.h>
26 #include <sha1.h>
27 #include <sha2.h>
28 
29 #include "ssherr.h"
30 #include "sshbuf.h"
31 #include "digest.h"
32 
33 typedef void md_init_fn(void *mdctx);
34 typedef void md_update_fn(void *mdctx, const u_int8_t *m, size_t mlen);
35 typedef void md_final_fn(u_int8_t[], void *mdctx);
36 
37 struct ssh_digest_ctx {
38 	int alg;
39 	void *mdctx;
40 };
41 
42 struct ssh_digest {
43 	int id;
44 	const char *name;
45 	size_t block_len;
46 	size_t digest_len;
47 	size_t ctx_len;
48 	md_init_fn *md_init;
49 	md_update_fn *md_update;
50 	md_final_fn *md_final;
51 };
52 
53 /* NB. Indexed directly by algorithm number */
54 const struct ssh_digest digests[SSH_DIGEST_MAX] = {
55 	{
56 		SSH_DIGEST_MD5,
57 		"MD5",
58 		MD5_BLOCK_LENGTH,
59 		MD5_DIGEST_LENGTH,
60 		sizeof(MD5_CTX),
61 		(md_init_fn *) MD5Init,
62 		(md_update_fn *) MD5Update,
63 		(md_final_fn *) MD5Final
64 	},
65 	{
66 		SSH_DIGEST_SHA1,
67 		"SHA1",
68 		SHA1_BLOCK_LENGTH,
69 		SHA1_DIGEST_LENGTH,
70 		sizeof(SHA1_CTX),
71 		(md_init_fn *) SHA1Init,
72 		(md_update_fn *) SHA1Update,
73 		(md_final_fn *) SHA1Final
74 	},
75 	{
76 		SSH_DIGEST_SHA256,
77 		"SHA256",
78 		SHA256_BLOCK_LENGTH,
79 		SHA256_DIGEST_LENGTH,
80 		sizeof(SHA2_CTX),
81 		(md_init_fn *) SHA256Init,
82 		(md_update_fn *) SHA256Update,
83 		(md_final_fn *) SHA256Final
84 	},
85 	{
86 		SSH_DIGEST_SHA384,
87 		"SHA384",
88 		SHA384_BLOCK_LENGTH,
89 		SHA384_DIGEST_LENGTH,
90 		sizeof(SHA2_CTX),
91 		(md_init_fn *) SHA384Init,
92 		(md_update_fn *) SHA384Update,
93 		(md_final_fn *) SHA384Final
94 	},
95 	{
96 		SSH_DIGEST_SHA512,
97 		"SHA512",
98 		SHA512_BLOCK_LENGTH,
99 		SHA512_DIGEST_LENGTH,
100 		sizeof(SHA2_CTX),
101 		(md_init_fn *) SHA512Init,
102 		(md_update_fn *) SHA512Update,
103 		(md_final_fn *) SHA512Final
104 	}
105 };
106 
107 static const struct ssh_digest *
108 ssh_digest_by_alg(int alg)
109 {
110 	if (alg < 0 || alg >= SSH_DIGEST_MAX)
111 		return NULL;
112 	if (digests[alg].id != alg) /* sanity */
113 		return NULL;
114 	return &(digests[alg]);
115 }
116 
117 int
118 ssh_digest_alg_by_name(const char *name)
119 {
120 	int alg;
121 
122 	for (alg = 0; alg < SSH_DIGEST_MAX; alg++) {
123 		if (strcasecmp(name, digests[alg].name) == 0)
124 			return digests[alg].id;
125 	}
126 	return -1;
127 }
128 
129 const char *
130 ssh_digest_alg_name(int alg)
131 {
132 	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
133 
134 	return digest == NULL ? NULL : digest->name;
135 }
136 
137 size_t
138 ssh_digest_bytes(int alg)
139 {
140 	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
141 
142 	return digest == NULL ? 0 : digest->digest_len;
143 }
144 
145 size_t
146 ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
147 {
148 	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
149 
150 	return digest == NULL ? 0 : digest->block_len;
151 }
152 
153 struct ssh_digest_ctx *
154 ssh_digest_start(int alg)
155 {
156 	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
157 	struct ssh_digest_ctx *ret;
158 
159 	if (digest == NULL || (ret = calloc(1, sizeof(*ret))) == NULL)
160 		return NULL;
161 	if ((ret->mdctx = calloc(1, digest->ctx_len)) == NULL) {
162 		free(ret);
163 		return NULL;
164 	}
165 	ret->alg = alg;
166 	digest->md_init(ret->mdctx);
167 	return ret;
168 }
169 
170 int
171 ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to)
172 {
173 	const struct ssh_digest *digest = ssh_digest_by_alg(from->alg);
174 
175 	if (digest == NULL || from->alg != to->alg)
176 		return SSH_ERR_INVALID_ARGUMENT;
177 	memcpy(to->mdctx, from->mdctx, digest->ctx_len);
178 	return 0;
179 }
180 
181 int
182 ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
183 {
184 	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
185 
186 	if (digest == NULL)
187 		return SSH_ERR_INVALID_ARGUMENT;
188 	digest->md_update(ctx->mdctx, m, mlen);
189 	return 0;
190 }
191 
192 int
193 ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const struct sshbuf *b)
194 {
195 	return ssh_digest_update(ctx, sshbuf_ptr(b), sshbuf_len(b));
196 }
197 
198 int
199 ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
200 {
201 	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
202 
203 	if (digest == NULL)
204 		return SSH_ERR_INVALID_ARGUMENT;
205 	if (dlen > UINT_MAX)
206 		return SSH_ERR_INVALID_ARGUMENT;
207 	if (dlen < digest->digest_len) /* No truncation allowed */
208 		return SSH_ERR_INVALID_ARGUMENT;
209 	digest->md_final(d, ctx->mdctx);
210 	return 0;
211 }
212 
213 void
214 ssh_digest_free(struct ssh_digest_ctx *ctx)
215 {
216 	const struct ssh_digest *digest;
217 
218 	if (ctx != NULL) {
219 		digest = ssh_digest_by_alg(ctx->alg);
220 		if (digest) {
221 			explicit_bzero(ctx->mdctx, digest->ctx_len);
222 			free(ctx->mdctx);
223 			freezero(ctx, sizeof(*ctx));
224 		}
225 	}
226 }
227 
228 int
229 ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
230 {
231 	struct ssh_digest_ctx *ctx = ssh_digest_start(alg);
232 
233 	if (ctx == NULL)
234 		return SSH_ERR_INVALID_ARGUMENT;
235 	if (ssh_digest_update(ctx, m, mlen) != 0 ||
236 	    ssh_digest_final(ctx, d, dlen) != 0)
237 		return SSH_ERR_INVALID_ARGUMENT;
238 	ssh_digest_free(ctx);
239 	return 0;
240 }
241 
242 int
243 ssh_digest_buffer(int alg, const struct sshbuf *b, u_char *d, size_t dlen)
244 {
245 	return ssh_digest_memory(alg, sshbuf_ptr(b), sshbuf_len(b), d, dlen);
246 }
247