text: /*-
   * 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("$FreeBSD$");
  
  #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 char *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 char *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;
  	    }
  	}
  }
  