2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
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
13 #include "internal/cryptlib.h"
14 #include <openssl/hmac.h>
15 #include <openssl/opensslconf.h>
16 #include "hmac_local.h"
18 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
19 const EVP_MD *md, ENGINE *impl)
23 unsigned char pad[HMAC_MAX_MD_CBLOCK_SIZE];
25 /* If we are changing MD then we must have a key */
26 if (md != NULL && md != ctx->md && (key == NULL || len < 0))
39 * The HMAC construction is not allowed to be used with the
40 * extendable-output functions (XOF) shake128 and shake256.
42 if ((EVP_MD_flags(md) & EVP_MD_FLAG_XOF) != 0)
47 j = EVP_MD_block_size(md);
48 if (!ossl_assert(j <= (int)sizeof(ctx->key)))
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,
57 if (len < 0 || len > (int)sizeof(ctx->key))
59 memcpy(ctx->key, key, len);
60 ctx->key_length = len;
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);
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)))
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)))
80 if (!EVP_MD_CTX_copy_ex(ctx->md_ctx, ctx->i_ctx))
85 OPENSSL_cleanse(pad, sizeof(pad));
89 #ifndef OPENSSL_NO_DEPRECATED_1_1_0
90 int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
94 return HMAC_Init_ex(ctx, key, len, md, NULL);
98 int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
102 return EVP_DigestUpdate(ctx->md_ctx, data, len);
105 int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
108 unsigned char buf[EVP_MAX_MD_SIZE];
113 if (!EVP_DigestFinal_ex(ctx->md_ctx, buf, &i))
115 if (!EVP_MD_CTX_copy_ex(ctx->md_ctx, ctx->o_ctx))
117 if (!EVP_DigestUpdate(ctx->md_ctx, buf, i))
119 if (!EVP_DigestFinal_ex(ctx->md_ctx, md, len))
126 size_t HMAC_size(const HMAC_CTX *ctx)
128 int size = EVP_MD_size((ctx)->md);
130 return (size < 0) ? 0 : size;
133 HMAC_CTX *HMAC_CTX_new(void)
135 HMAC_CTX *ctx = OPENSSL_zalloc(sizeof(HMAC_CTX));
138 if (!HMAC_CTX_reset(ctx)) {
146 static void hmac_ctx_cleanup(HMAC_CTX *ctx)
148 EVP_MD_CTX_reset(ctx->i_ctx);
149 EVP_MD_CTX_reset(ctx->o_ctx);
150 EVP_MD_CTX_reset(ctx->md_ctx);
153 OPENSSL_cleanse(ctx->key, sizeof(ctx->key));
156 void HMAC_CTX_free(HMAC_CTX *ctx)
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);
167 static int hmac_ctx_alloc_mds(HMAC_CTX *ctx)
169 if (ctx->i_ctx == NULL)
170 ctx->i_ctx = EVP_MD_CTX_new();
171 if (ctx->i_ctx == NULL)
173 if (ctx->o_ctx == NULL)
174 ctx->o_ctx = EVP_MD_CTX_new();
175 if (ctx->o_ctx == NULL)
177 if (ctx->md_ctx == NULL)
178 ctx->md_ctx = EVP_MD_CTX_new();
179 if (ctx->md_ctx == NULL)
184 int HMAC_CTX_reset(HMAC_CTX *ctx)
186 hmac_ctx_cleanup(ctx);
187 if (!hmac_ctx_alloc_mds(ctx)) {
188 hmac_ctx_cleanup(ctx);
194 int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
196 if (!hmac_ctx_alloc_mds(dctx))
198 if (!EVP_MD_CTX_copy_ex(dctx->i_ctx, sctx->i_ctx))
200 if (!EVP_MD_CTX_copy_ex(dctx->o_ctx, sctx->o_ctx))
202 if (!EVP_MD_CTX_copy_ex(dctx->md_ctx, sctx->md_ctx))
204 memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK_SIZE);
205 dctx->key_length = sctx->key_length;
209 hmac_ctx_cleanup(dctx);
213 unsigned 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)
218 static unsigned char m[EVP_MAX_MD_SIZE];
219 static const unsigned char dummy_key[1] = {'\0'};
223 if ((c = HMAC_CTX_new()) == NULL)
226 /* For HMAC_Init_ex, NULL key signals reuse. */
227 if (key == NULL && key_len == 0) {
231 if (!HMAC_Init_ex(c, key, key_len, evp_md, NULL))
233 if (!HMAC_Update(c, d, n))
235 if (!HMAC_Final(c, md, md_len))
244 void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
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);
251 const EVP_MD *HMAC_CTX_get_md(const HMAC_CTX *ctx)