1/* $OpenBSD: digest-openssl.c,v 1.9 2020/10/29 02:52:43 djm Exp $ */
2/*
3 * Copyright (c) 2013 Damien Miller <djm@mindrot.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include "includes.h"
19
20#ifdef WITH_OPENSSL
21
22#include <sys/types.h>
23#include <limits.h>
24#include <stdlib.h>
25#include <string.h>
26
27#include <openssl/evp.h>
28
29#include "openbsd-compat/openssl-compat.h"
30
31#include "sshbuf.h"
32#include "digest.h"
33#include "ssherr.h"
34
35#ifndef HAVE_EVP_SHA256
36# define EVP_sha256 NULL
37#endif
38#ifndef HAVE_EVP_SHA384
39# define EVP_sha384 NULL
40#endif
41#ifndef HAVE_EVP_SHA512
42# define EVP_sha512 NULL
43#endif
44
45struct ssh_digest_ctx {
46	int alg;
47	EVP_MD_CTX *mdctx;
48};
49
50struct ssh_digest {
51	int id;
52	const char *name;
53	size_t digest_len;
54	const EVP_MD *(*mdfunc)(void);
55};
56
57/* NB. Indexed directly by algorithm number */
58const struct ssh_digest digests[] = {
59	{ SSH_DIGEST_MD5,	"MD5",		16,	EVP_md5 },
60	{ SSH_DIGEST_SHA1,	"SHA1",		20,	EVP_sha1 },
61	{ SSH_DIGEST_SHA256,	"SHA256",	32,	EVP_sha256 },
62	{ SSH_DIGEST_SHA384,	"SHA384",	48,	EVP_sha384 },
63	{ SSH_DIGEST_SHA512,	"SHA512",	64,	EVP_sha512 },
64	{ -1,			NULL,		0,	NULL },
65};
66
67static const struct ssh_digest *
68ssh_digest_by_alg(int alg)
69{
70	if (alg < 0 || alg >= SSH_DIGEST_MAX)
71		return NULL;
72	if (digests[alg].id != alg) /* sanity */
73		return NULL;
74	if (digests[alg].mdfunc == NULL)
75		return NULL;
76	return &(digests[alg]);
77}
78
79int
80ssh_digest_alg_by_name(const char *name)
81{
82	int alg;
83
84	for (alg = 0; digests[alg].id != -1; alg++) {
85		if (strcasecmp(name, digests[alg].name) == 0)
86			return digests[alg].id;
87	}
88	return -1;
89}
90
91const char *
92ssh_digest_alg_name(int alg)
93{
94	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
95
96	return digest == NULL ? NULL : digest->name;
97}
98
99size_t
100ssh_digest_bytes(int alg)
101{
102	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
103
104	return digest == NULL ? 0 : digest->digest_len;
105}
106
107size_t
108ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
109{
110	return EVP_MD_CTX_block_size(ctx->mdctx);
111}
112
113struct ssh_digest_ctx *
114ssh_digest_start(int alg)
115{
116	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
117	struct ssh_digest_ctx *ret;
118
119	if (digest == NULL || ((ret = calloc(1, sizeof(*ret))) == NULL))
120		return NULL;
121	ret->alg = alg;
122	if ((ret->mdctx = EVP_MD_CTX_new()) == NULL) {
123		free(ret);
124		return NULL;
125	}
126	if (EVP_DigestInit_ex(ret->mdctx, digest->mdfunc(), NULL) != 1) {
127		ssh_digest_free(ret);
128		return NULL;
129	}
130	return ret;
131}
132
133int
134ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to)
135{
136	if (from->alg != to->alg)
137		return SSH_ERR_INVALID_ARGUMENT;
138	/* we have bcopy-style order while openssl has memcpy-style */
139	if (!EVP_MD_CTX_copy_ex(to->mdctx, from->mdctx))
140		return SSH_ERR_LIBCRYPTO_ERROR;
141	return 0;
142}
143
144int
145ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
146{
147	if (EVP_DigestUpdate(ctx->mdctx, m, mlen) != 1)
148		return SSH_ERR_LIBCRYPTO_ERROR;
149	return 0;
150}
151
152int
153ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const struct sshbuf *b)
154{
155	return ssh_digest_update(ctx, sshbuf_ptr(b), sshbuf_len(b));
156}
157
158int
159ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
160{
161	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
162	u_int l = dlen;
163
164	if (digest == NULL || dlen > UINT_MAX)
165		return SSH_ERR_INVALID_ARGUMENT;
166	if (dlen < digest->digest_len) /* No truncation allowed */
167		return SSH_ERR_INVALID_ARGUMENT;
168	if (EVP_DigestFinal_ex(ctx->mdctx, d, &l) != 1)
169		return SSH_ERR_LIBCRYPTO_ERROR;
170	if (l != digest->digest_len) /* sanity */
171		return SSH_ERR_INTERNAL_ERROR;
172	return 0;
173}
174
175void
176ssh_digest_free(struct ssh_digest_ctx *ctx)
177{
178	if (ctx == NULL)
179		return;
180	EVP_MD_CTX_free(ctx->mdctx);
181	freezero(ctx, sizeof(*ctx));
182}
183
184int
185ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
186{
187	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
188	u_int mdlen;
189
190	if (digest == NULL)
191		return SSH_ERR_INVALID_ARGUMENT;
192	if (dlen > UINT_MAX)
193		return SSH_ERR_INVALID_ARGUMENT;
194	if (dlen < digest->digest_len)
195		return SSH_ERR_INVALID_ARGUMENT;
196	mdlen = dlen;
197	if (!EVP_Digest(m, mlen, d, &mdlen, digest->mdfunc(), NULL))
198		return SSH_ERR_LIBCRYPTO_ERROR;
199	return 0;
200}
201
202int
203ssh_digest_buffer(int alg, const struct sshbuf *b, u_char *d, size_t dlen)
204{
205	return ssh_digest_memory(alg, sshbuf_ptr(b), sshbuf_len(b), d, dlen);
206}
207#endif /* WITH_OPENSSL */
208