1 /** 2 * AES CTR 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 #include "aesp8-ppc.h" 31 32 struct p8_aes_ctr_ctx { 33 struct crypto_blkcipher *fallback; 34 struct aes_key enc_key; 35 }; 36 37 static int p8_aes_ctr_init(struct crypto_tfm *tfm) 38 { 39 const char *alg; 40 struct crypto_blkcipher *fallback; 41 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 42 43 if (!(alg = crypto_tfm_alg_name(tfm))) { 44 printk(KERN_ERR "Failed to get algorithm name.\n"); 45 return -ENOENT; 46 } 47 48 fallback = crypto_alloc_blkcipher(alg, 0 ,CRYPTO_ALG_NEED_FALLBACK); 49 if (IS_ERR(fallback)) { 50 printk(KERN_ERR "Failed to allocate transformation for '%s': %ld\n", 51 alg, PTR_ERR(fallback)); 52 return PTR_ERR(fallback); 53 } 54 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 55 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback)); 56 57 crypto_blkcipher_set_flags(fallback, 58 crypto_blkcipher_get_flags((struct crypto_blkcipher *) tfm)); 59 ctx->fallback = fallback; 60 61 return 0; 62 } 63 64 static void p8_aes_ctr_exit(struct crypto_tfm *tfm) 65 { 66 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 67 68 if (ctx->fallback) { 69 crypto_free_blkcipher(ctx->fallback); 70 ctx->fallback = NULL; 71 } 72 } 73 74 static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key, 75 unsigned int keylen) 76 { 77 int ret; 78 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 79 80 pagefault_disable(); 81 enable_kernel_altivec(); 82 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 83 pagefault_enable(); 84 85 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 86 return ret; 87 } 88 89 static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx, 90 struct blkcipher_walk *walk) 91 { 92 u8 *ctrblk = walk->iv; 93 u8 keystream[AES_BLOCK_SIZE]; 94 u8 *src = walk->src.virt.addr; 95 u8 *dst = walk->dst.virt.addr; 96 unsigned int nbytes = walk->nbytes; 97 98 pagefault_disable(); 99 enable_kernel_altivec(); 100 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); 101 pagefault_enable(); 102 103 crypto_xor(keystream, src, nbytes); 104 memcpy(dst, keystream, nbytes); 105 crypto_inc(ctrblk, AES_BLOCK_SIZE); 106 } 107 108 static int p8_aes_ctr_crypt(struct blkcipher_desc *desc, 109 struct scatterlist *dst, struct scatterlist *src, 110 unsigned int nbytes) 111 { 112 int ret; 113 struct blkcipher_walk walk; 114 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx( 115 crypto_blkcipher_tfm(desc->tfm)); 116 struct blkcipher_desc fallback_desc = { 117 .tfm = ctx->fallback, 118 .info = desc->info, 119 .flags = desc->flags 120 }; 121 122 if (in_interrupt()) { 123 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes); 124 } else { 125 blkcipher_walk_init(&walk, dst, src, nbytes); 126 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE); 127 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) { 128 pagefault_disable(); 129 enable_kernel_altivec(); 130 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, walk.dst.virt.addr, 131 (nbytes & AES_BLOCK_MASK)/AES_BLOCK_SIZE, &ctx->enc_key, walk.iv); 132 pagefault_enable(); 133 134 crypto_inc(walk.iv, AES_BLOCK_SIZE); 135 nbytes &= AES_BLOCK_SIZE - 1; 136 ret = blkcipher_walk_done(desc, &walk, nbytes); 137 } 138 if (walk.nbytes) { 139 p8_aes_ctr_final(ctx, &walk); 140 ret = blkcipher_walk_done(desc, &walk, 0); 141 } 142 } 143 144 return ret; 145 } 146 147 struct crypto_alg p8_aes_ctr_alg = { 148 .cra_name = "ctr(aes)", 149 .cra_driver_name = "p8_aes_ctr", 150 .cra_module = THIS_MODULE, 151 .cra_priority = 1000, 152 .cra_type = &crypto_blkcipher_type, 153 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 154 .cra_alignmask = 0, 155 .cra_blocksize = 1, 156 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx), 157 .cra_init = p8_aes_ctr_init, 158 .cra_exit = p8_aes_ctr_exit, 159 .cra_blkcipher = { 160 .ivsize = 0, 161 .min_keysize = AES_MIN_KEY_SIZE, 162 .max_keysize = AES_MAX_KEY_SIZE, 163 .setkey = p8_aes_ctr_setkey, 164 .encrypt = p8_aes_ctr_crypt, 165 .decrypt = p8_aes_ctr_crypt, 166 }, 167 }; 168