1 /** 2 * AES CBC routines supporting VMX instructions on the Power 8 3 * 4 * Copyright (C) 2015 International Business Machines Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 only. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18 * 19 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com> 20 */ 21 22 #include <linux/types.h> 23 #include <linux/err.h> 24 #include <linux/crypto.h> 25 #include <linux/delay.h> 26 #include <linux/hardirq.h> 27 #include <asm/switch_to.h> 28 #include <crypto/aes.h> 29 #include <crypto/scatterwalk.h> 30 31 #include "aesp8-ppc.h" 32 33 struct p8_aes_cbc_ctx { 34 struct crypto_blkcipher *fallback; 35 struct aes_key enc_key; 36 struct aes_key dec_key; 37 }; 38 39 static int p8_aes_cbc_init(struct crypto_tfm *tfm) 40 { 41 const char *alg; 42 struct crypto_blkcipher *fallback; 43 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 44 45 if (!(alg = crypto_tfm_alg_name(tfm))) { 46 printk(KERN_ERR "Failed to get algorithm name.\n"); 47 return -ENOENT; 48 } 49 50 fallback = crypto_alloc_blkcipher(alg, 0 ,CRYPTO_ALG_NEED_FALLBACK); 51 if (IS_ERR(fallback)) { 52 printk(KERN_ERR "Failed to allocate transformation for '%s': %ld\n", 53 alg, PTR_ERR(fallback)); 54 return PTR_ERR(fallback); 55 } 56 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 57 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback)); 58 59 crypto_blkcipher_set_flags(fallback, 60 crypto_blkcipher_get_flags((struct crypto_blkcipher *) tfm)); 61 ctx->fallback = fallback; 62 63 return 0; 64 } 65 66 static void p8_aes_cbc_exit(struct crypto_tfm *tfm) 67 { 68 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 69 70 if (ctx->fallback) { 71 crypto_free_blkcipher(ctx->fallback); 72 ctx->fallback = NULL; 73 } 74 } 75 76 static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key, 77 unsigned int keylen) 78 { 79 int ret; 80 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 81 82 pagefault_disable(); 83 enable_kernel_altivec(); 84 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 85 ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key); 86 pagefault_enable(); 87 88 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 89 return ret; 90 } 91 92 static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 93 struct scatterlist *dst, struct scatterlist *src, 94 unsigned int nbytes) 95 { 96 int ret; 97 struct blkcipher_walk walk; 98 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx( 99 crypto_blkcipher_tfm(desc->tfm)); 100 struct blkcipher_desc fallback_desc = { 101 .tfm = ctx->fallback, 102 .info = desc->info, 103 .flags = desc->flags 104 }; 105 106 if (in_interrupt()) { 107 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes); 108 } else { 109 pagefault_disable(); 110 enable_kernel_altivec(); 111 112 blkcipher_walk_init(&walk, dst, src, nbytes); 113 ret = blkcipher_walk_virt(desc, &walk); 114 while ((nbytes = walk.nbytes)) { 115 aes_p8_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr, 116 nbytes & AES_BLOCK_MASK, &ctx->enc_key, walk.iv, 1); 117 nbytes &= AES_BLOCK_SIZE - 1; 118 ret = blkcipher_walk_done(desc, &walk, nbytes); 119 } 120 121 pagefault_enable(); 122 } 123 124 return ret; 125 } 126 127 static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 128 struct scatterlist *dst, struct scatterlist *src, 129 unsigned int nbytes) 130 { 131 int ret; 132 struct blkcipher_walk walk; 133 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx( 134 crypto_blkcipher_tfm(desc->tfm)); 135 struct blkcipher_desc fallback_desc = { 136 .tfm = ctx->fallback, 137 .info = desc->info, 138 .flags = desc->flags 139 }; 140 141 if (in_interrupt()) { 142 ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src, nbytes); 143 } else { 144 pagefault_disable(); 145 enable_kernel_altivec(); 146 147 blkcipher_walk_init(&walk, dst, src, nbytes); 148 ret = blkcipher_walk_virt(desc, &walk); 149 while ((nbytes = walk.nbytes)) { 150 aes_p8_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr, 151 nbytes & AES_BLOCK_MASK, &ctx->dec_key, walk.iv, 0); 152 nbytes &= AES_BLOCK_SIZE - 1; 153 ret = blkcipher_walk_done(desc, &walk, nbytes); 154 } 155 156 pagefault_enable(); 157 } 158 159 return ret; 160 } 161 162 163 struct crypto_alg p8_aes_cbc_alg = { 164 .cra_name = "cbc(aes)", 165 .cra_driver_name = "p8_aes_cbc", 166 .cra_module = THIS_MODULE, 167 .cra_priority = 1000, 168 .cra_type = &crypto_blkcipher_type, 169 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 170 .cra_alignmask = 0, 171 .cra_blocksize = AES_BLOCK_SIZE, 172 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 173 .cra_init = p8_aes_cbc_init, 174 .cra_exit = p8_aes_cbc_exit, 175 .cra_blkcipher = { 176 .ivsize = 0, 177 .min_keysize = AES_MIN_KEY_SIZE, 178 .max_keysize = AES_MAX_KEY_SIZE, 179 .setkey = p8_aes_cbc_setkey, 180 .encrypt = p8_aes_cbc_encrypt, 181 .decrypt = p8_aes_cbc_decrypt, 182 }, 183 }; 184 185