FreeBSD/Linux Kernel Cross Reference
sys/opencrypto/xform_aes_cbc.c

     /*      $OpenBSD: xform.c,v 1.16 2001/08/28 12:20:43 ben Exp $  */
     /*-
      * The authors of this code are John Ioannidis (ji@tla.org),
      * Angelos D. Keromytis (kermit@csd.uch.gr),
      * Niels Provos (provos@physnet.uni-hamburg.de) and
      * Damien Miller (djm@mindrot.org).
      *
      * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
      * in November 1995.
     *
     * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
     * by Angelos D. Keromytis.
     *
     * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
     * and Niels Provos.
     *
     * Additional features in 1999 by Angelos D. Keromytis.
     *
     * AES XTS implementation in 2008 by Damien Miller
     *
     * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
     * Angelos D. Keromytis and Niels Provos.
     *
     * Copyright (C) 2001, Angelos D. Keromytis.
     *
     * Copyright (C) 2008, Damien Miller
     * Copyright (c) 2014 The FreeBSD Foundation
     * All rights reserved.
     *
     * Portions of this software were developed by John-Mark Gurney
     * under sponsorship of the FreeBSD Foundation and
     * Rubicon Communications, LLC (Netgate).
     *
     * Permission to use, copy, and modify this software with or without fee
     * is hereby granted, provided that this entire notice is included in
     * all copies of any software which is or includes a copy or
     * modification of this software.
     * You may use this code under the GNU public license if you so wish. Please
     * contribute changes back to the authors under this freer than GPL license
     * so that we may further the use of strong encryption without limitations to
     * all.
     *
     * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
     * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
     * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
     * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
     * PURPOSE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/types.h>
    #include <crypto/rijndael/rijndael.h>
    #include <opencrypto/xform_enc.h>
    
    struct aes_cbc_ctx {
            rijndael_ctx key;
            char iv[AES_BLOCK_LEN];
    };
    
    static  int aes_cbc_setkey(void *, const uint8_t *, int);
    static  void aes_cbc_encrypt(void *, const uint8_t *, uint8_t *);
    static  void aes_cbc_decrypt(void *, const uint8_t *, uint8_t *);
    static  void aes_cbc_encrypt_multi(void *, const uint8_t *, uint8_t *, size_t);
    static  void aes_cbc_decrypt_multi(void *, const uint8_t *, uint8_t *, size_t);
    static  void aes_cbc_reinit(void *, const uint8_t *, size_t);
    
    /* Encryption instances */
    const struct enc_xform enc_xform_aes_cbc = {
            .type = CRYPTO_AES_CBC,
            .name = "AES-CBC",
            .ctxsize = sizeof(struct aes_cbc_ctx),
            .blocksize = AES_BLOCK_LEN,
            .ivsize = AES_BLOCK_LEN,
            .minkey = AES_MIN_KEY,
            .maxkey = AES_MAX_KEY,
            .setkey = aes_cbc_setkey,
            .reinit = aes_cbc_reinit,
            .encrypt = aes_cbc_encrypt,
            .decrypt = aes_cbc_decrypt,
            .encrypt_multi = aes_cbc_encrypt_multi,
            .decrypt_multi = aes_cbc_decrypt_multi,
    };
    
    /*
     * Encryption wrapper routines.
     */
    static void
    aes_cbc_encrypt(void *vctx, const uint8_t *in, uint8_t *out)
    {
            struct aes_cbc_ctx *ctx = vctx;
    
            for (u_int i = 0; i < AES_BLOCK_LEN; i++)
                    out[i] = in[i] ^ ctx->iv[i];
            rijndael_encrypt(&ctx->key, out, out);
            memcpy(ctx->iv, out, AES_BLOCK_LEN);
    }
    
   static void
   aes_cbc_decrypt(void *vctx, const uint8_t *in, uint8_t *out)
   {
           struct aes_cbc_ctx *ctx = vctx;
           char block[AES_BLOCK_LEN];
   
           memcpy(block, in, AES_BLOCK_LEN);
           rijndael_decrypt(&ctx->key, in, out);
           for (u_int i = 0; i < AES_BLOCK_LEN; i++)
                   out[i] ^= ctx->iv[i];
           memcpy(ctx->iv, block, AES_BLOCK_LEN);
           explicit_bzero(block, sizeof(block));
   }
   
   static void
   aes_cbc_encrypt_multi(void *vctx, const uint8_t *in, uint8_t *out, size_t len)
   {
           struct aes_cbc_ctx *ctx = vctx;
   
           KASSERT(len % AES_BLOCK_LEN == 0, ("%s: invalid length", __func__));
           while (len > 0) {
                   for (u_int i = 0; i < AES_BLOCK_LEN; i++)
                           out[i] = in[i] ^ ctx->iv[i];
                   rijndael_encrypt(&ctx->key, out, out);
                   memcpy(ctx->iv, out, AES_BLOCK_LEN);
                   out += AES_BLOCK_LEN;
                   in += AES_BLOCK_LEN;
                   len -= AES_BLOCK_LEN;
           }
   }
   
   static void
   aes_cbc_decrypt_multi(void *vctx, const uint8_t *in, uint8_t *out, size_t len)
   {
           struct aes_cbc_ctx *ctx = vctx;
           char block[AES_BLOCK_LEN];
   
           KASSERT(len % AES_BLOCK_LEN == 0, ("%s: invalid length", __func__));
           while (len > 0) {
                   memcpy(block, in, AES_BLOCK_LEN);
                   rijndael_decrypt(&ctx->key, in, out);
                   for (u_int i = 0; i < AES_BLOCK_LEN; i++)
                           out[i] ^= ctx->iv[i];
                   memcpy(ctx->iv, block, AES_BLOCK_LEN);
                   out += AES_BLOCK_LEN;
                   in += AES_BLOCK_LEN;
                   len -= AES_BLOCK_LEN;
           }
           explicit_bzero(block, sizeof(block));
   }
   
   static int
   aes_cbc_setkey(void *vctx, const uint8_t *key, int len)
   {
           struct aes_cbc_ctx *ctx = vctx;
   
           if (len != 16 && len != 24 && len != 32)
                   return (EINVAL);
   
           rijndael_set_key(&ctx->key, key, len * 8);
           return (0);
   }
   
   static void
   aes_cbc_reinit(void *vctx, const uint8_t *iv, size_t iv_len)
   {
           struct aes_cbc_ctx *ctx = vctx;
   
           KASSERT(iv_len == sizeof(ctx->iv), ("%s: bad IV length", __func__));
           memcpy(ctx->iv, iv, sizeof(ctx->iv));
   }

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