digest-libc.c revision 294193 
1/* $OpenBSD: digest-libc.c,v 1.2 2014/02/02 03:44:31 djm 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 "includes.h"
20
21#include <sys/types.h>
22#include <limits.h>
23#include <stdlib.h>
24#include <string.h>
25
26#include <md5.h>
27#include <rmd160.h>
28#include <sha1.h>
29#include <sha2.h>
30
31#include "buffer.h"
32#include "digest.h"
33
34typedef void md_init_fn(void *mdctx);
35typedef void md_update_fn(void *mdctx, const u_int8_t *m, size_t mlen);
36typedef void md_final_fn(u_int8_t[], void *mdctx);
37
38struct ssh_digest_ctx {
39	int alg;
40	void *mdctx;
41};
42
43struct ssh_digest {
44	int id;
45	const char *name;
46	size_t block_len;
47	size_t digest_len;
48	size_t ctx_len;
49	md_init_fn *md_init;
50	md_update_fn *md_update;
51	md_final_fn *md_final;
52};
53
54/* NB. Indexed directly by algorithm number */
55const struct ssh_digest digests[SSH_DIGEST_MAX] = {
56	{
57		SSH_DIGEST_MD5,
58		"MD5",
59		MD5_BLOCK_LENGTH,
60		MD5_DIGEST_LENGTH,
61		sizeof(MD5_CTX),
62		(md_init_fn *) MD5Init,
63		(md_update_fn *) MD5Update,
64		(md_final_fn *) MD5Final
65	},
66	{
67		SSH_DIGEST_RIPEMD160,
68		"RIPEMD160",
69		RMD160_BLOCK_LENGTH,
70		RMD160_DIGEST_LENGTH,
71		sizeof(RMD160_CTX),
72		(md_init_fn *) RMD160Init,
73		(md_update_fn *) RMD160Update,
74		(md_final_fn *) RMD160Final
75	},
76	{
77		SSH_DIGEST_SHA1,
78		"SHA1",
79		SHA1_BLOCK_LENGTH,
80		SHA1_DIGEST_LENGTH,
81		sizeof(SHA1_CTX),
82		(md_init_fn *) SHA1Init,
83		(md_update_fn *) SHA1Update,
84		(md_final_fn *) SHA1Final
85	},
86	{
87		SSH_DIGEST_SHA256,
88		"SHA256",
89		SHA256_BLOCK_LENGTH,
90		SHA256_DIGEST_LENGTH,
91		sizeof(SHA2_CTX),
92		(md_init_fn *) SHA256Init,
93		(md_update_fn *) SHA256Update,
94		(md_final_fn *) SHA256Final
95	},
96	{
97		SSH_DIGEST_SHA384,
98		"SHA384",
99		SHA384_BLOCK_LENGTH,
100		SHA384_DIGEST_LENGTH,
101		sizeof(SHA2_CTX),
102		(md_init_fn *) SHA384Init,
103		(md_update_fn *) SHA384Update,
104		(md_final_fn *) SHA384Final
105	},
106	{
107		SSH_DIGEST_SHA512,
108		"SHA512",
109		SHA512_BLOCK_LENGTH,
110		SHA512_DIGEST_LENGTH,
111		sizeof(SHA2_CTX),
112		(md_init_fn *) SHA512Init,
113		(md_update_fn *) SHA512Update,
114		(md_final_fn *) SHA512Final
115	}
116};
117
118static const struct ssh_digest *
119ssh_digest_by_alg(int alg)
120{
121	if (alg < 0 || alg >= SSH_DIGEST_MAX)
122		return NULL;
123	if (digests[alg].id != alg) /* sanity */
124		return NULL;
125	return &(digests[alg]);
126}
127
128size_t
129ssh_digest_bytes(int alg)
130{
131	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
132
133	return digest == NULL ? 0 : digest->digest_len;
134}
135
136size_t
137ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
138{
139	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
140
141	return digest == NULL ? 0 : digest->block_len;
142}
143
144struct ssh_digest_ctx *
145ssh_digest_start(int alg)
146{
147	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
148	struct ssh_digest_ctx *ret;
149
150	if (digest == NULL || (ret = calloc(1, sizeof(*ret))) == NULL)
151		return NULL;
152	if ((ret->mdctx = calloc(1, digest->ctx_len)) == NULL) {
153		free(ret);
154		return NULL;
155	}
156	ret->alg = alg;
157	digest->md_init(ret->mdctx);
158	return ret;
159}
160
161int
162ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to)
163{
164	const struct ssh_digest *digest = ssh_digest_by_alg(from->alg);
165
166	if (digest == NULL || from->alg != to->alg)
167		return -1;
168	memcpy(to->mdctx, from->mdctx, digest->ctx_len);
169	return 0;
170}
171
172int
173ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
174{
175	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
176
177	if (digest == NULL)
178		return -1;
179	digest->md_update(ctx->mdctx, m, mlen);
180	return 0;
181}
182
183int
184ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const Buffer *b)
185{
186	return ssh_digest_update(ctx, buffer_ptr(b), buffer_len(b));
187}
188
189int
190ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
191{
192	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
193
194	if (digest == NULL)
195		return -1;
196	if (dlen > UINT_MAX)
197		return -1;
198	if (dlen < digest->digest_len) /* No truncation allowed */
199		return -1;
200	digest->md_final(d, ctx->mdctx);
201	return 0;
202}
203
204void
205ssh_digest_free(struct ssh_digest_ctx *ctx)
206{
207	const struct ssh_digest *digest;
208
209	if (ctx != NULL) {
210		digest = ssh_digest_by_alg(ctx->alg);
211		if (digest) {
212			explicit_bzero(ctx->mdctx, digest->ctx_len);
213			free(ctx->mdctx);
214			explicit_bzero(ctx, sizeof(*ctx));
215			free(ctx);
216		}
217	}
218}
219
220int
221ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
222{
223	struct ssh_digest_ctx *ctx = ssh_digest_start(alg);
224
225	if (ctx == NULL)
226		return -1;
227	if (ssh_digest_update(ctx, m, mlen) != 0 ||
228	    ssh_digest_final(ctx, d, dlen) != 0)
229		return -1;
230	ssh_digest_free(ctx);
231	return 0;
232}
233
234int
235ssh_digest_buffer(int alg, const Buffer *b, u_char *d, size_t dlen)
236{
237	return ssh_digest_memory(alg, buffer_ptr(b), buffer_len(b), d, dlen);
238}
239