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; 43 struct crypto_skcipher *fallback; 44 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 45 46 if (!(alg = crypto_tfm_alg_name(tfm))) { 47 printk(KERN_ERR "Failed to get algorithm name.\n"); 48 return -ENOENT; 49 } 50 51 fallback = crypto_alloc_skcipher(alg, 0, 52 CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK); 53 54 if (IS_ERR(fallback)) { 55 printk(KERN_ERR 56 "Failed to allocate transformation for '%s': %ld\n", 57 alg, PTR_ERR(fallback)); 58 return PTR_ERR(fallback); 59 } 60 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 61 crypto_skcipher_driver_name(fallback)); 62 63 64 crypto_skcipher_set_flags( 65 fallback, 66 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm)); 67 ctx->fallback = fallback; 68 69 return 0; 70 } 71 72 static void p8_aes_cbc_exit(struct crypto_tfm *tfm) 73 { 74 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 75 76 if (ctx->fallback) { 77 crypto_free_skcipher(ctx->fallback); 78 ctx->fallback = NULL; 79 } 80 } 81 82 static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key, 83 unsigned int keylen) 84 { 85 int ret; 86 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 87 88 preempt_disable(); 89 pagefault_disable(); 90 enable_kernel_vsx(); 91 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 92 ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key); 93 disable_kernel_vsx(); 94 pagefault_enable(); 95 preempt_enable(); 96 97 ret += crypto_skcipher_setkey(ctx->fallback, key, keylen); 98 return ret; 99 } 100 101 static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 102 struct scatterlist *dst, 103 struct scatterlist *src, unsigned int nbytes) 104 { 105 int ret; 106 struct blkcipher_walk walk; 107 struct p8_aes_cbc_ctx *ctx = 108 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 109 110 if (in_interrupt()) { 111 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 112 skcipher_request_set_tfm(req, ctx->fallback); 113 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 114 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 115 ret = crypto_skcipher_encrypt(req); 116 skcipher_request_zero(req); 117 } else { 118 preempt_disable(); 119 pagefault_disable(); 120 enable_kernel_vsx(); 121 122 blkcipher_walk_init(&walk, dst, src, nbytes); 123 ret = blkcipher_walk_virt(desc, &walk); 124 while ((nbytes = walk.nbytes)) { 125 aes_p8_cbc_encrypt(walk.src.virt.addr, 126 walk.dst.virt.addr, 127 nbytes & AES_BLOCK_MASK, 128 &ctx->enc_key, walk.iv, 1); 129 nbytes &= AES_BLOCK_SIZE - 1; 130 ret = blkcipher_walk_done(desc, &walk, nbytes); 131 } 132 133 disable_kernel_vsx(); 134 pagefault_enable(); 135 preempt_enable(); 136 } 137 138 return ret; 139 } 140 141 static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 142 struct scatterlist *dst, 143 struct scatterlist *src, unsigned int nbytes) 144 { 145 int ret; 146 struct blkcipher_walk walk; 147 struct p8_aes_cbc_ctx *ctx = 148 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 149 150 if (in_interrupt()) { 151 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 152 skcipher_request_set_tfm(req, ctx->fallback); 153 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 154 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 155 ret = crypto_skcipher_decrypt(req); 156 skcipher_request_zero(req); 157 } else { 158 preempt_disable(); 159 pagefault_disable(); 160 enable_kernel_vsx(); 161 162 blkcipher_walk_init(&walk, dst, src, nbytes); 163 ret = blkcipher_walk_virt(desc, &walk); 164 while ((nbytes = walk.nbytes)) { 165 aes_p8_cbc_encrypt(walk.src.virt.addr, 166 walk.dst.virt.addr, 167 nbytes & AES_BLOCK_MASK, 168 &ctx->dec_key, walk.iv, 0); 169 nbytes &= AES_BLOCK_SIZE - 1; 170 ret = blkcipher_walk_done(desc, &walk, nbytes); 171 } 172 173 disable_kernel_vsx(); 174 pagefault_enable(); 175 preempt_enable(); 176 } 177 178 return ret; 179 } 180 181 182 struct crypto_alg p8_aes_cbc_alg = { 183 .cra_name = "cbc(aes)", 184 .cra_driver_name = "p8_aes_cbc", 185 .cra_module = THIS_MODULE, 186 .cra_priority = 2000, 187 .cra_type = &crypto_blkcipher_type, 188 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 189 .cra_alignmask = 0, 190 .cra_blocksize = AES_BLOCK_SIZE, 191 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 192 .cra_init = p8_aes_cbc_init, 193 .cra_exit = p8_aes_cbc_exit, 194 .cra_blkcipher = { 195 .ivsize = AES_BLOCK_SIZE, 196 .min_keysize = AES_MIN_KEY_SIZE, 197 .max_keysize = AES_MAX_KEY_SIZE, 198 .setkey = p8_aes_cbc_setkey, 199 .encrypt = p8_aes_cbc_encrypt, 200 .decrypt = p8_aes_cbc_decrypt, 201 }, 202 }; 203