1/*
2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include "internal/cryptlib.h"
14#include <openssl/hmac.h>
15#include <openssl/opensslconf.h>
16#include "hmac_local.h"
17
18int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
19 const EVP_MD *md, ENGINE *impl)
20{
21 int rv = 0;
22 int i, j, reset = 0;
23 unsigned char pad[HMAC_MAX_MD_CBLOCK_SIZE];
24
25 /* If we are changing MD then we must have a key */
26 if (md != NULL && md != ctx->md && (key == NULL || len < 0))
27 return 0;
28
29 if (md != NULL) {
30 reset = 1;
31 ctx->md = md;
32 } else if (ctx->md) {
33 md = ctx->md;
34 } else {
35 return 0;
36 }
37
38 /*
39 * The HMAC construction is not allowed to be used with the
40 * extendable-output functions (XOF) shake128 and shake256.
41 */
42 if ((EVP_MD_flags(md) & EVP_MD_FLAG_XOF) != 0)
43 return 0;
44
45 if (key != NULL) {
46 reset = 1;
47 j = EVP_MD_block_size(md);
48 if (!ossl_assert(j <= (int)sizeof(ctx->key)))
49 return 0;
50 if (j < len) {
51 if (!EVP_DigestInit_ex(ctx->md_ctx, md, impl)
52 || !EVP_DigestUpdate(ctx->md_ctx, key, len)
53 || !EVP_DigestFinal_ex(ctx->md_ctx, ctx->key,
54 &ctx->key_length))
55 return 0;
56 } else {
57 if (len < 0 || len > (int)sizeof(ctx->key))
58 return 0;
59 memcpy(ctx->key, key, len);
60 ctx->key_length = len;
61 }
62 if (ctx->key_length != HMAC_MAX_MD_CBLOCK_SIZE)
63 memset(&ctx->key[ctx->key_length], 0,
64 HMAC_MAX_MD_CBLOCK_SIZE - ctx->key_length);
65 }
66
67 if (reset) {
68 for (i = 0; i < HMAC_MAX_MD_CBLOCK_SIZE; i++)
69 pad[i] = 0x36 ^ ctx->key[i];
70 if (!EVP_DigestInit_ex(ctx->i_ctx, md, impl)
71 || !EVP_DigestUpdate(ctx->i_ctx, pad, EVP_MD_block_size(md)))
72 goto err;
73
74 for (i = 0; i < HMAC_MAX_MD_CBLOCK_SIZE; i++)
75 pad[i] = 0x5c ^ ctx->key[i];
76 if (!EVP_DigestInit_ex(ctx->o_ctx, md, impl)
77 || !EVP_DigestUpdate(ctx->o_ctx, pad, EVP_MD_block_size(md)))
78 goto err;
79 }
80 if (!EVP_MD_CTX_copy_ex(ctx->md_ctx, ctx->i_ctx))
81 goto err;
82 rv = 1;
83 err:
84 if (reset)
85 OPENSSL_cleanse(pad, sizeof(pad));
86 return rv;
87}
88
89#ifndef OPENSSL_NO_DEPRECATED_1_1_0
90int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
91{
92 if (key && md)
93 HMAC_CTX_reset(ctx);
94 return HMAC_Init_ex(ctx, key, len, md, NULL);
95}
96#endif
97
98int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
99{
100 if (!ctx->md)
101 return 0;
102 return EVP_DigestUpdate(ctx->md_ctx, data, len);
103}
104
105int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
106{
107 unsigned int i;
108 unsigned char buf[EVP_MAX_MD_SIZE];
109
110 if (!ctx->md)
111 goto err;
112
113 if (!EVP_DigestFinal_ex(ctx->md_ctx, buf, &i))
114 goto err;
115 if (!EVP_MD_CTX_copy_ex(ctx->md_ctx, ctx->o_ctx))
116 goto err;
117 if (!EVP_DigestUpdate(ctx->md_ctx, buf, i))
118 goto err;
119 if (!EVP_DigestFinal_ex(ctx->md_ctx, md, len))
120 goto err;
121 return 1;
122 err:
123 return 0;
124}
125
126size_t HMAC_size(const HMAC_CTX *ctx)
127{
128 int size = EVP_MD_size((ctx)->md);
129
130 return (size < 0) ? 0 : size;
131}
132
133HMAC_CTX *HMAC_CTX_new(void)
134{
135 HMAC_CTX *ctx = OPENSSL_zalloc(sizeof(HMAC_CTX));
136
137 if (ctx != NULL) {
138 if (!HMAC_CTX_reset(ctx)) {
139 HMAC_CTX_free(ctx);
140 return NULL;
141 }
142 }
143 return ctx;
144}
145
146static void hmac_ctx_cleanup(HMAC_CTX *ctx)
147{
148 EVP_MD_CTX_reset(ctx->i_ctx);
149 EVP_MD_CTX_reset(ctx->o_ctx);
150 EVP_MD_CTX_reset(ctx->md_ctx);
151 ctx->md = NULL;
152 ctx->key_length = 0;
153 OPENSSL_cleanse(ctx->key, sizeof(ctx->key));
154}
155
156void HMAC_CTX_free(HMAC_CTX *ctx)
157{
158 if (ctx != NULL) {
159 hmac_ctx_cleanup(ctx);
160 EVP_MD_CTX_free(ctx->i_ctx);
161 EVP_MD_CTX_free(ctx->o_ctx);
162 EVP_MD_CTX_free(ctx->md_ctx);
163 OPENSSL_free(ctx);
164 }
165}
166
167static int hmac_ctx_alloc_mds(HMAC_CTX *ctx)
168{
169 if (ctx->i_ctx == NULL)
170 ctx->i_ctx = EVP_MD_CTX_new();
171 if (ctx->i_ctx == NULL)
172 return 0;
173 if (ctx->o_ctx == NULL)
174 ctx->o_ctx = EVP_MD_CTX_new();
175 if (ctx->o_ctx == NULL)
176 return 0;
177 if (ctx->md_ctx == NULL)
178 ctx->md_ctx = EVP_MD_CTX_new();
179 if (ctx->md_ctx == NULL)
180 return 0;
181 return 1;
182}
183
184int HMAC_CTX_reset(HMAC_CTX *ctx)
185{
186 hmac_ctx_cleanup(ctx);
187 if (!hmac_ctx_alloc_mds(ctx)) {
188 hmac_ctx_cleanup(ctx);
189 return 0;
190 }
191 return 1;
192}
193
194int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
195{
196 if (!hmac_ctx_alloc_mds(dctx))
197 goto err;
198 if (!EVP_MD_CTX_copy_ex(dctx->i_ctx, sctx->i_ctx))
199 goto err;
200 if (!EVP_MD_CTX_copy_ex(dctx->o_ctx, sctx->o_ctx))
201 goto err;
202 if (!EVP_MD_CTX_copy_ex(dctx->md_ctx, sctx->md_ctx))
203 goto err;
204 memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK_SIZE);
205 dctx->key_length = sctx->key_length;
206 dctx->md = sctx->md;
207 return 1;
208 err:
209 hmac_ctx_cleanup(dctx);
210 return 0;
211}
212
213unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
214 const unsigned char *d, size_t n, unsigned char *md,
215 unsigned int *md_len)
216{
217 HMAC_CTX *c = NULL;
218 static unsigned char m[EVP_MAX_MD_SIZE];
219 static const unsigned char dummy_key[1] = {'\0'};
220
221 if (md == NULL)
222 md = m;
223 if ((c = HMAC_CTX_new()) == NULL)
224 goto err;
225
226 /* For HMAC_Init_ex, NULL key signals reuse. */
227 if (key == NULL && key_len == 0) {
228 key = dummy_key;
229 }
230
231 if (!HMAC_Init_ex(c, key, key_len, evp_md, NULL))
232 goto err;
233 if (!HMAC_Update(c, d, n))
234 goto err;
235 if (!HMAC_Final(c, md, md_len))
236 goto err;
237 HMAC_CTX_free(c);
238 return md;
239 err:
240 HMAC_CTX_free(c);
241 return NULL;
242}
243
244void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
245{
246 EVP_MD_CTX_set_flags(ctx->i_ctx, flags);
247 EVP_MD_CTX_set_flags(ctx->o_ctx, flags);
248 EVP_MD_CTX_set_flags(ctx->md_ctx, flags);
249}
250
251const EVP_MD *HMAC_CTX_get_md(const HMAC_CTX *ctx)
252{
253 return ctx->md;
254}
255