FreeBSD/Linux Kernel Cross Reference
sys/geom/eli/g_eli_hmac.c

     /*-
      * Copyright (c) 2005-2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/11.2/sys/geom/eli/g_eli_hmac.c 329175 2018-02-12 17:44:35Z kevans $");
    
    #include <sys/param.h>
    #ifdef _KERNEL
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #elif defined(_STANDALONE)
    #include "stand.h"
    #else
    #include <stdint.h>
    #include <string.h>
    #include <strings.h>
    #include <errno.h>
    #include <assert.h>
    #include <openssl/evp.h>
    #define _OpenSSL_
    #endif
    #include <geom/eli/g_eli.h>
    
    void
    g_eli_crypto_hmac_init(struct hmac_ctx *ctx, const uint8_t *hkey,
        size_t hkeylen)
    {
            u_char k_ipad[128], k_opad[128], key[128];
            SHA512_CTX lctx;
            u_int i;
    
            bzero(key, sizeof(key));
            if (hkeylen == 0)
                    ; /* do nothing */
            else if (hkeylen <= 128)
                    bcopy(hkey, key, hkeylen);
            else {
                    /* If key is longer than 128 bytes reset it to key = SHA512(key). */
                    SHA512_Init(&lctx);
                    SHA512_Update(&lctx, hkey, hkeylen);
                    SHA512_Final(key, &lctx);
            }
    
            /* XOR key with ipad and opad values. */
            for (i = 0; i < sizeof(key); i++) {
                    k_ipad[i] = key[i] ^ 0x36;
                    k_opad[i] = key[i] ^ 0x5c;
            }
            explicit_bzero(key, sizeof(key));
            /* Start inner SHA512. */
            SHA512_Init(&ctx->innerctx);
            SHA512_Update(&ctx->innerctx, k_ipad, sizeof(k_ipad));
            explicit_bzero(k_ipad, sizeof(k_ipad));
            /* Start outer SHA512. */
            SHA512_Init(&ctx->outerctx);
            SHA512_Update(&ctx->outerctx, k_opad, sizeof(k_opad));
            explicit_bzero(k_opad, sizeof(k_opad));
    }
    
    void
    g_eli_crypto_hmac_update(struct hmac_ctx *ctx, const uint8_t *data,
        size_t datasize)
    {
    
            SHA512_Update(&ctx->innerctx, data, datasize);
    }
    
    void
    g_eli_crypto_hmac_final(struct hmac_ctx *ctx, uint8_t *md, size_t mdsize)
    {
            u_char digest[SHA512_MDLEN];
    
            /* Complete inner hash */
            SHA512_Final(digest, &ctx->innerctx);
            
           /* Complete outer hash */
           SHA512_Update(&ctx->outerctx, digest, sizeof(digest));
           SHA512_Final(digest, &ctx->outerctx);
           
           explicit_bzero(ctx, sizeof(*ctx));
           /* mdsize == 0 means "Give me the whole hash!" */
           if (mdsize == 0)
                   mdsize = SHA512_MDLEN;
           bcopy(digest, md, mdsize);
           explicit_bzero(digest, sizeof(digest));
   }
   
   void
   g_eli_crypto_hmac(const uint8_t *hkey, size_t hkeysize, const uint8_t *data,
       size_t datasize, uint8_t *md, size_t mdsize)
   {
           struct hmac_ctx ctx;
   
           g_eli_crypto_hmac_init(&ctx, hkey, hkeysize);
           g_eli_crypto_hmac_update(&ctx, data, datasize);
           g_eli_crypto_hmac_final(&ctx, md, mdsize);
   }
   
   /*
    * Here we generate IV. It is unique for every sector.
    */
   void
   g_eli_crypto_ivgen(struct g_eli_softc *sc, off_t offset, u_char *iv,
       size_t size)
   {
           uint8_t off[8];
   
           if ((sc->sc_flags & G_ELI_FLAG_NATIVE_BYTE_ORDER) != 0)
                   bcopy(&offset, off, sizeof(off));
           else
                   le64enc(off, (uint64_t)offset);
   
           switch (sc->sc_ealgo) {
           case CRYPTO_AES_XTS:
                   bcopy(off, iv, sizeof(off));
                   bzero(iv + sizeof(off), size - sizeof(off));
                   break;
           default:
               {
                   u_char hash[SHA256_DIGEST_LENGTH];
                   SHA256_CTX ctx;
   
                   /* Copy precalculated SHA256 context for IV-Key. */
                   bcopy(&sc->sc_ivctx, &ctx, sizeof(ctx));
                   SHA256_Update(&ctx, off, sizeof(off));
                   SHA256_Final(hash, &ctx);
                   bcopy(hash, iv, MIN(sizeof(hash), size));
                   break;
               }
           }
   }

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