1 /* 2 * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (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_lcl.h" 17 18 int 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_meth_get_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 #if OPENSSL_API_COMPAT < 0x10100000L 90 int 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 98 int 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 } 104 105 int 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 } 125 126 size_t HMAC_size(const HMAC_CTX *ctx) 127 { 128 int size = EVP_MD_size((ctx)->md); 129 130 return (size < 0) ? 0 : size; 131 } 132 133 HMAC_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 } 145 146 static 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 } 155 156 void 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 } 166 167 static 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 } 183 184 int 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 } 193 194 int 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 } 212 213 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) 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 } 243 244 void 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 } 250 251 const EVP_MD *HMAC_CTX_get_md(const HMAC_CTX *ctx) 252 { 253 return ctx->md; 254 } 255