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 "includes.h"
20
21#ifndef WITH_OPENSSL
22
23#include <sys/types.h>
24#include <limits.h>
25#include <stdlib.h>
26#include <string.h>
27
28#if 0
29#include <md5.h>
30#include <rmd160.h>
31#endif
32#ifdef HAVE_SHA1_H
33#include <sha1.h>
34#endif
35#ifdef HAVE_SHA2_H
36#include <sha2.h>
37#endif
38
39#if !defined(SHA256_BLOCK_LENGTH) && defined(SHA256_HMAC_BLOCK_SIZE)
40#define SHA256_BLOCK_LENGTH SHA256_HMAC_BLOCK_SIZE
41#endif
42#if !defined(SHA384_BLOCK_LENGTH) && defined(SHA512_HMAC_BLOCK_SIZE)
43#define SHA384_BLOCK_LENGTH SHA512_HMAC_BLOCK_SIZE
44#endif
45#if !defined(SHA512_BLOCK_LENGTH) && defined(SHA512_HMAC_BLOCK_SIZE)
46#define SHA512_BLOCK_LENGTH SHA512_HMAC_BLOCK_SIZE
47#endif
48
49#include "ssherr.h"
50#include "sshbuf.h"
51#include "digest.h"
52
53typedef void md_init_fn(void *mdctx);
54typedef void md_update_fn(void *mdctx, const u_int8_t *m, size_t mlen);
55typedef void md_final_fn(u_int8_t[], void *mdctx);
56
57struct ssh_digest_ctx {
58	int alg;
59	void *mdctx;
60};
61
62struct ssh_digest {
63	int id;
64	const char *name;
65	size_t block_len;
66	size_t digest_len;
67	size_t ctx_len;
68	md_init_fn *md_init;
69	md_update_fn *md_update;
70	md_final_fn *md_final;
71};
72
73/* NB. Indexed directly by algorithm number */
74const struct ssh_digest digests[SSH_DIGEST_MAX] = {
75	{
76		SSH_DIGEST_MD5,
77		"MD5",
78		MD5_BLOCK_LENGTH,
79		MD5_DIGEST_LENGTH,
80		sizeof(MD5_CTX),
81		(md_init_fn *) MD5Init,
82		(md_update_fn *) MD5Update,
83		(md_final_fn *) MD5Final
84	},
85	{
86		SSH_DIGEST_SHA1,
87		"SHA1",
88		SHA1_BLOCK_LENGTH,
89		SHA1_DIGEST_LENGTH,
90		sizeof(SHA1_CTX),
91		(md_init_fn *) SHA1Init,
92		(md_update_fn *) SHA1Update,
93		(md_final_fn *) SHA1Final
94	},
95	{
96		SSH_DIGEST_SHA256,
97		"SHA256",
98		SHA256_BLOCK_LENGTH,
99		SHA256_DIGEST_LENGTH,
100		sizeof(SHA2_CTX),
101		(md_init_fn *) SHA256Init,
102		(md_update_fn *) SHA256Update,
103		(md_final_fn *) SHA256Final
104	},
105	{
106		SSH_DIGEST_SHA384,
107		"SHA384",
108		SHA384_BLOCK_LENGTH,
109		SHA384_DIGEST_LENGTH,
110		sizeof(SHA2_CTX),
111		(md_init_fn *) SHA384Init,
112		(md_update_fn *) SHA384Update,
113		(md_final_fn *) SHA384Final
114	},
115	{
116		SSH_DIGEST_SHA512,
117		"SHA512",
118		SHA512_BLOCK_LENGTH,
119		SHA512_DIGEST_LENGTH,
120		sizeof(SHA2_CTX),
121		(md_init_fn *) SHA512Init,
122		(md_update_fn *) SHA512Update,
123		(md_final_fn *) SHA512Final
124	}
125};
126
127static const struct ssh_digest *
128ssh_digest_by_alg(int alg)
129{
130	if (alg < 0 || alg >= SSH_DIGEST_MAX)
131		return NULL;
132	if (digests[alg].id != alg) /* sanity */
133		return NULL;
134	return &(digests[alg]);
135}
136
137int
138ssh_digest_alg_by_name(const char *name)
139{
140	int alg;
141
142	for (alg = 0; alg < SSH_DIGEST_MAX; alg++) {
143		if (strcasecmp(name, digests[alg].name) == 0)
144			return digests[alg].id;
145	}
146	return -1;
147}
148
149const char *
150ssh_digest_alg_name(int alg)
151{
152	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
153
154	return digest == NULL ? NULL : digest->name;
155}
156
157size_t
158ssh_digest_bytes(int alg)
159{
160	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
161
162	return digest == NULL ? 0 : digest->digest_len;
163}
164
165size_t
166ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
167{
168	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
169
170	return digest == NULL ? 0 : digest->block_len;
171}
172
173struct ssh_digest_ctx *
174ssh_digest_start(int alg)
175{
176	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
177	struct ssh_digest_ctx *ret;
178
179	if (digest == NULL || (ret = calloc(1, sizeof(*ret))) == NULL)
180		return NULL;
181	if ((ret->mdctx = calloc(1, digest->ctx_len)) == NULL) {
182		free(ret);
183		return NULL;
184	}
185	ret->alg = alg;
186	digest->md_init(ret->mdctx);
187	return ret;
188}
189
190int
191ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to)
192{
193	const struct ssh_digest *digest = ssh_digest_by_alg(from->alg);
194
195	if (digest == NULL || from->alg != to->alg)
196		return SSH_ERR_INVALID_ARGUMENT;
197	memcpy(to->mdctx, from->mdctx, digest->ctx_len);
198	return 0;
199}
200
201int
202ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
203{
204	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
205
206	if (digest == NULL)
207		return SSH_ERR_INVALID_ARGUMENT;
208	digest->md_update(ctx->mdctx, m, mlen);
209	return 0;
210}
211
212int
213ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const struct sshbuf *b)
214{
215	return ssh_digest_update(ctx, sshbuf_ptr(b), sshbuf_len(b));
216}
217
218int
219ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
220{
221	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
222
223	if (digest == NULL)
224		return SSH_ERR_INVALID_ARGUMENT;
225	if (dlen > UINT_MAX)
226		return SSH_ERR_INVALID_ARGUMENT;
227	if (dlen < digest->digest_len) /* No truncation allowed */
228		return SSH_ERR_INVALID_ARGUMENT;
229	digest->md_final(d, ctx->mdctx);
230	return 0;
231}
232
233void
234ssh_digest_free(struct ssh_digest_ctx *ctx)
235{
236	const struct ssh_digest *digest;
237
238	if (ctx != NULL) {
239		digest = ssh_digest_by_alg(ctx->alg);
240		if (digest) {
241			explicit_bzero(ctx->mdctx, digest->ctx_len);
242			free(ctx->mdctx);
243			freezero(ctx, sizeof(*ctx));
244		}
245	}
246}
247
248int
249ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
250{
251	struct ssh_digest_ctx *ctx = ssh_digest_start(alg);
252
253	if (ctx == NULL)
254		return SSH_ERR_INVALID_ARGUMENT;
255	if (ssh_digest_update(ctx, m, mlen) != 0 ||
256	    ssh_digest_final(ctx, d, dlen) != 0)
257		return SSH_ERR_INVALID_ARGUMENT;
258	ssh_digest_free(ctx);
259	return 0;
260}
261
262int
263ssh_digest_buffer(int alg, const struct sshbuf *b, u_char *d, size_t dlen)
264{
265	return ssh_digest_memory(alg, sshbuf_ptr(b), sshbuf_len(b), d, dlen);
266}
267#endif /* !WITH_OPENSSL */
268