1 /* $OpenBSD: xform.c,v 1.16 2001/08/28 12:20:43 ben Exp $ */ 2 /*- 3 * The authors of this code are John Ioannidis (ji@tla.org), 4 * Angelos D. Keromytis (kermit@csd.uch.gr), 5 * Niels Provos (provos@physnet.uni-hamburg.de) and 6 * Damien Miller (djm@mindrot.org). 7 * 8 * This code was written by John Ioannidis for BSD/OS in Athens, Greece, 9 * in November 1995. 10 * 11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 12 * by Angelos D. Keromytis. 13 * 14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 15 * and Niels Provos. 16 * 17 * Additional features in 1999 by Angelos D. Keromytis. 18 * 19 * AES XTS implementation in 2008 by Damien Miller 20 * 21 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 22 * Angelos D. Keromytis and Niels Provos. 23 * 24 * Copyright (C) 2001, Angelos D. Keromytis. 25 * 26 * Copyright (C) 2008, Damien Miller 27 * Copyright (c) 2014 The FreeBSD Foundation 28 * All rights reserved. 29 * 30 * Portions of this software were developed by John-Mark Gurney 31 * under sponsorship of the FreeBSD Foundation and 32 * Rubicon Communications, LLC (Netgate). 33 * 34 * Permission to use, copy, and modify this software with or without fee 35 * is hereby granted, provided that this entire notice is included in 36 * all copies of any software which is or includes a copy or 37 * modification of this software. 38 * You may use this code under the GNU public license if you so wish. Please 39 * contribute changes back to the authors under this freer than GPL license 40 * so that we may further the use of strong encryption without limitations to 41 * all. 42 * 43 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 44 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 45 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 46 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 47 * PURPOSE. 48 */ 49 50 #include <sys/cdefs.h> 51 __FBSDID("$FreeBSD$"); 52 53 #include <sys/types.h> 54 #include <crypto/rijndael/rijndael.h> 55 #include <opencrypto/xform_enc.h> 56 57 struct aes_cbc_ctx { 58 rijndael_ctx key; 59 char iv[AES_BLOCK_LEN]; 60 }; 61 62 static int aes_cbc_setkey(void *, const uint8_t *, int); 63 static void aes_cbc_encrypt(void *, const uint8_t *, uint8_t *); 64 static void aes_cbc_decrypt(void *, const uint8_t *, uint8_t *); 65 static void aes_cbc_encrypt_multi(void *, const uint8_t *, uint8_t *, size_t); 66 static void aes_cbc_decrypt_multi(void *, const uint8_t *, uint8_t *, size_t); 67 static void aes_cbc_reinit(void *, const uint8_t *, size_t); 68 69 /* Encryption instances */ 70 const struct enc_xform enc_xform_aes_cbc = { 71 .type = CRYPTO_AES_CBC, 72 .name = "AES-CBC", 73 .ctxsize = sizeof(struct aes_cbc_ctx), 74 .blocksize = AES_BLOCK_LEN, 75 .ivsize = AES_BLOCK_LEN, 76 .minkey = AES_MIN_KEY, 77 .maxkey = AES_MAX_KEY, 78 .setkey = aes_cbc_setkey, 79 .reinit = aes_cbc_reinit, 80 .encrypt = aes_cbc_encrypt, 81 .decrypt = aes_cbc_decrypt, 82 .encrypt_multi = aes_cbc_encrypt_multi, 83 .decrypt_multi = aes_cbc_decrypt_multi, 84 }; 85 86 /* 87 * Encryption wrapper routines. 88 */ 89 static void 90 aes_cbc_encrypt(void *vctx, const uint8_t *in, uint8_t *out) 91 { 92 struct aes_cbc_ctx *ctx = vctx; 93 94 for (u_int i = 0; i < AES_BLOCK_LEN; i++) 95 out[i] = in[i] ^ ctx->iv[i]; 96 rijndael_encrypt(&ctx->key, out, out); 97 memcpy(ctx->iv, out, AES_BLOCK_LEN); 98 } 99 100 static void 101 aes_cbc_decrypt(void *vctx, const uint8_t *in, uint8_t *out) 102 { 103 struct aes_cbc_ctx *ctx = vctx; 104 char block[AES_BLOCK_LEN]; 105 106 memcpy(block, in, AES_BLOCK_LEN); 107 rijndael_decrypt(&ctx->key, in, out); 108 for (u_int i = 0; i < AES_BLOCK_LEN; i++) 109 out[i] ^= ctx->iv[i]; 110 memcpy(ctx->iv, block, AES_BLOCK_LEN); 111 explicit_bzero(block, sizeof(block)); 112 } 113 114 static void 115 aes_cbc_encrypt_multi(void *vctx, const uint8_t *in, uint8_t *out, size_t len) 116 { 117 struct aes_cbc_ctx *ctx = vctx; 118 119 KASSERT(len % AES_BLOCK_LEN == 0, ("%s: invalid length", __func__)); 120 while (len > 0) { 121 for (u_int i = 0; i < AES_BLOCK_LEN; i++) 122 out[i] = in[i] ^ ctx->iv[i]; 123 rijndael_encrypt(&ctx->key, out, out); 124 memcpy(ctx->iv, out, AES_BLOCK_LEN); 125 out += AES_BLOCK_LEN; 126 in += AES_BLOCK_LEN; 127 len -= AES_BLOCK_LEN; 128 } 129 } 130 131 static void 132 aes_cbc_decrypt_multi(void *vctx, const uint8_t *in, uint8_t *out, size_t len) 133 { 134 struct aes_cbc_ctx *ctx = vctx; 135 char block[AES_BLOCK_LEN]; 136 137 KASSERT(len % AES_BLOCK_LEN == 0, ("%s: invalid length", __func__)); 138 while (len > 0) { 139 memcpy(block, in, AES_BLOCK_LEN); 140 rijndael_decrypt(&ctx->key, in, out); 141 for (u_int i = 0; i < AES_BLOCK_LEN; i++) 142 out[i] ^= ctx->iv[i]; 143 memcpy(ctx->iv, block, AES_BLOCK_LEN); 144 out += AES_BLOCK_LEN; 145 in += AES_BLOCK_LEN; 146 len -= AES_BLOCK_LEN; 147 } 148 explicit_bzero(block, sizeof(block)); 149 } 150 151 static int 152 aes_cbc_setkey(void *vctx, const uint8_t *key, int len) 153 { 154 struct aes_cbc_ctx *ctx = vctx; 155 156 if (len != 16 && len != 24 && len != 32) 157 return (EINVAL); 158 159 rijndael_set_key(&ctx->key, key, len * 8); 160 return (0); 161 } 162 163 static void 164 aes_cbc_reinit(void *vctx, const uint8_t *iv, size_t iv_len) 165 { 166 struct aes_cbc_ctx *ctx = vctx; 167 168 KASSERT(iv_len == sizeof(ctx->iv), ("%s: bad IV length", __func__)); 169 memcpy(ctx->iv, iv, sizeof(ctx->iv)); 170 } 171