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 #include <crypto/skcipher.h> 31 32 #include "aesp8-ppc.h" 33 34 struct p8_aes_cbc_ctx { 35 struct crypto_skcipher *fallback; 36 struct aes_key enc_key; 37 struct aes_key dec_key; 38 }; 39 40 static int p8_aes_cbc_init(struct crypto_tfm *tfm) 41 { 42 const char *alg = crypto_tfm_alg_name(tfm); 43 struct crypto_skcipher *fallback; 44 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 45 46 fallback = crypto_alloc_skcipher(alg, 0, 47 CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK); 48 49 if (IS_ERR(fallback)) { 50 printk(KERN_ERR 51 "Failed to allocate transformation for '%s': %ld\n", 52 alg, PTR_ERR(fallback)); 53 return PTR_ERR(fallback); 54 } 55 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 56 crypto_skcipher_driver_name(fallback)); 57 58 59 crypto_skcipher_set_flags( 60 fallback, 61 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm)); 62 ctx->fallback = fallback; 63 64 return 0; 65 } 66 67 static void p8_aes_cbc_exit(struct crypto_tfm *tfm) 68 { 69 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 70 71 if (ctx->fallback) { 72 crypto_free_skcipher(ctx->fallback); 73 ctx->fallback = NULL; 74 } 75 } 76 77 static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key, 78 unsigned int keylen) 79 { 80 int ret; 81 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 82 83 preempt_disable(); 84 pagefault_disable(); 85 enable_kernel_vsx(); 86 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 87 ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key); 88 disable_kernel_vsx(); 89 pagefault_enable(); 90 preempt_enable(); 91 92 ret += crypto_skcipher_setkey(ctx->fallback, key, keylen); 93 return ret; 94 } 95 96 static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 97 struct scatterlist *dst, 98 struct scatterlist *src, unsigned int nbytes) 99 { 100 int ret; 101 struct blkcipher_walk walk; 102 struct p8_aes_cbc_ctx *ctx = 103 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 104 105 if (in_interrupt()) { 106 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 107 skcipher_request_set_tfm(req, ctx->fallback); 108 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 109 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 110 ret = crypto_skcipher_encrypt(req); 111 skcipher_request_zero(req); 112 } else { 113 preempt_disable(); 114 pagefault_disable(); 115 enable_kernel_vsx(); 116 117 blkcipher_walk_init(&walk, dst, src, nbytes); 118 ret = blkcipher_walk_virt(desc, &walk); 119 while ((nbytes = walk.nbytes)) { 120 aes_p8_cbc_encrypt(walk.src.virt.addr, 121 walk.dst.virt.addr, 122 nbytes & AES_BLOCK_MASK, 123 &ctx->enc_key, walk.iv, 1); 124 nbytes &= AES_BLOCK_SIZE - 1; 125 ret = blkcipher_walk_done(desc, &walk, nbytes); 126 } 127 128 disable_kernel_vsx(); 129 pagefault_enable(); 130 preempt_enable(); 131 } 132 133 return ret; 134 } 135 136 static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 137 struct scatterlist *dst, 138 struct scatterlist *src, unsigned int nbytes) 139 { 140 int ret; 141 struct blkcipher_walk walk; 142 struct p8_aes_cbc_ctx *ctx = 143 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 144 145 if (in_interrupt()) { 146 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 147 skcipher_request_set_tfm(req, ctx->fallback); 148 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 149 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 150 ret = crypto_skcipher_decrypt(req); 151 skcipher_request_zero(req); 152 } else { 153 preempt_disable(); 154 pagefault_disable(); 155 enable_kernel_vsx(); 156 157 blkcipher_walk_init(&walk, dst, src, nbytes); 158 ret = blkcipher_walk_virt(desc, &walk); 159 while ((nbytes = walk.nbytes)) { 160 aes_p8_cbc_encrypt(walk.src.virt.addr, 161 walk.dst.virt.addr, 162 nbytes & AES_BLOCK_MASK, 163 &ctx->dec_key, walk.iv, 0); 164 nbytes &= AES_BLOCK_SIZE - 1; 165 ret = blkcipher_walk_done(desc, &walk, nbytes); 166 } 167 168 disable_kernel_vsx(); 169 pagefault_enable(); 170 preempt_enable(); 171 } 172 173 return ret; 174 } 175 176 177 struct crypto_alg p8_aes_cbc_alg = { 178 .cra_name = "cbc(aes)", 179 .cra_driver_name = "p8_aes_cbc", 180 .cra_module = THIS_MODULE, 181 .cra_priority = 2000, 182 .cra_type = &crypto_blkcipher_type, 183 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 184 .cra_alignmask = 0, 185 .cra_blocksize = AES_BLOCK_SIZE, 186 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 187 .cra_init = p8_aes_cbc_init, 188 .cra_exit = p8_aes_cbc_exit, 189 .cra_blkcipher = { 190 .ivsize = AES_BLOCK_SIZE, 191 .min_keysize = AES_MIN_KEY_SIZE, 192 .max_keysize = AES_MAX_KEY_SIZE, 193 .setkey = p8_aes_cbc_setkey, 194 .encrypt = p8_aes_cbc_encrypt, 195 .decrypt = p8_aes_cbc_decrypt, 196 }, 197 }; 198