xref: /openssh-portable/digest-openssl.c (revision 26b2675b)
1 /* $OpenBSD: digest-openssl.c,v 1.7 2017/05/08 22:57:38 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 
45 struct ssh_digest_ctx {
46 	int alg;
47 	EVP_MD_CTX *mdctx;
48 };
49 
50 struct 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 */
58 const 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 
67 static const struct ssh_digest *
ssh_digest_by_alg(int alg)68 ssh_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 
79 int
ssh_digest_alg_by_name(const char * name)80 ssh_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 
91 const char *
ssh_digest_alg_name(int alg)92 ssh_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 
99 size_t
ssh_digest_bytes(int alg)100 ssh_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 
107 size_t
ssh_digest_blocksize(struct ssh_digest_ctx * ctx)108 ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
109 {
110 	return EVP_MD_CTX_block_size(ctx->mdctx);
111 }
112 
113 struct ssh_digest_ctx *
ssh_digest_start(int alg)114 ssh_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 
133 int
ssh_digest_copy_state(struct ssh_digest_ctx * from,struct ssh_digest_ctx * to)134 ssh_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 
144 int
ssh_digest_update(struct ssh_digest_ctx * ctx,const void * m,size_t mlen)145 ssh_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 
152 int
ssh_digest_update_buffer(struct ssh_digest_ctx * ctx,const struct sshbuf * b)153 ssh_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 
158 int
ssh_digest_final(struct ssh_digest_ctx * ctx,u_char * d,size_t dlen)159 ssh_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 
175 void
ssh_digest_free(struct ssh_digest_ctx * ctx)176 ssh_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 
184 int
ssh_digest_memory(int alg,const void * m,size_t mlen,u_char * d,size_t dlen)185 ssh_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 
202 int
ssh_digest_buffer(int alg,const struct sshbuf * b,u_char * d,size_t dlen)203 ssh_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