1 /* 2 * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support 3 * 4 * Copyright (C) 2013 Advanced Micro Devices, Inc. 5 * 6 * Author: Tom Lendacky <thomas.lendacky@amd.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/module.h> 14 #include <linux/sched.h> 15 #include <linux/delay.h> 16 #include <linux/scatterlist.h> 17 #include <linux/crypto.h> 18 #include <crypto/algapi.h> 19 #include <crypto/aes.h> 20 #include <crypto/scatterwalk.h> 21 22 #include "ccp-crypto.h" 23 24 25 struct ccp_aes_xts_def { 26 const char *name; 27 const char *drv_name; 28 }; 29 30 static struct ccp_aes_xts_def aes_xts_algs[] = { 31 { 32 .name = "xts(aes)", 33 .drv_name = "xts-aes-ccp", 34 }, 35 }; 36 37 struct ccp_unit_size_map { 38 unsigned int size; 39 u32 value; 40 }; 41 42 static struct ccp_unit_size_map unit_size_map[] = { 43 { 44 .size = 4096, 45 .value = CCP_XTS_AES_UNIT_SIZE_4096, 46 }, 47 { 48 .size = 2048, 49 .value = CCP_XTS_AES_UNIT_SIZE_2048, 50 }, 51 { 52 .size = 1024, 53 .value = CCP_XTS_AES_UNIT_SIZE_1024, 54 }, 55 { 56 .size = 512, 57 .value = CCP_XTS_AES_UNIT_SIZE_512, 58 }, 59 { 60 .size = 256, 61 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 62 }, 63 { 64 .size = 128, 65 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 66 }, 67 { 68 .size = 64, 69 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 70 }, 71 { 72 .size = 32, 73 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 74 }, 75 { 76 .size = 16, 77 .value = CCP_XTS_AES_UNIT_SIZE_16, 78 }, 79 { 80 .size = 1, 81 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 82 }, 83 }; 84 85 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret) 86 { 87 struct ablkcipher_request *req = ablkcipher_request_cast(async_req); 88 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 89 90 if (ret) 91 return ret; 92 93 memcpy(req->info, rctx->iv, AES_BLOCK_SIZE); 94 95 return 0; 96 } 97 98 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key, 99 unsigned int key_len) 100 { 101 struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm)); 102 103 /* Only support 128-bit AES key with a 128-bit Tweak key, 104 * otherwise use the fallback 105 */ 106 switch (key_len) { 107 case AES_KEYSIZE_128 * 2: 108 memcpy(ctx->u.aes.key, key, key_len); 109 break; 110 } 111 ctx->u.aes.key_len = key_len / 2; 112 sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len); 113 114 return crypto_ablkcipher_setkey(ctx->u.aes.tfm_ablkcipher, key, 115 key_len); 116 } 117 118 static int ccp_aes_xts_crypt(struct ablkcipher_request *req, 119 unsigned int encrypt) 120 { 121 struct crypto_tfm *tfm = 122 crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req)); 123 struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm); 124 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 125 unsigned int unit; 126 int ret; 127 128 if (!ctx->u.aes.key_len) 129 return -EINVAL; 130 131 if (req->nbytes & (AES_BLOCK_SIZE - 1)) 132 return -EINVAL; 133 134 if (!req->info) 135 return -EINVAL; 136 137 for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) 138 if (!(req->nbytes & (unit_size_map[unit].size - 1))) 139 break; 140 141 if ((unit_size_map[unit].value == CCP_XTS_AES_UNIT_SIZE__LAST) || 142 (ctx->u.aes.key_len != AES_KEYSIZE_128)) { 143 /* Use the fallback to process the request for any 144 * unsupported unit sizes or key sizes 145 */ 146 ablkcipher_request_set_tfm(req, ctx->u.aes.tfm_ablkcipher); 147 ret = (encrypt) ? crypto_ablkcipher_encrypt(req) : 148 crypto_ablkcipher_decrypt(req); 149 ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm)); 150 151 return ret; 152 } 153 154 memcpy(rctx->iv, req->info, AES_BLOCK_SIZE); 155 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE); 156 157 memset(&rctx->cmd, 0, sizeof(rctx->cmd)); 158 INIT_LIST_HEAD(&rctx->cmd.entry); 159 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128; 160 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT 161 : CCP_AES_ACTION_DECRYPT; 162 rctx->cmd.u.xts.unit_size = unit_size_map[unit].value; 163 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg; 164 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len; 165 rctx->cmd.u.xts.iv = &rctx->iv_sg; 166 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE; 167 rctx->cmd.u.xts.src = req->src; 168 rctx->cmd.u.xts.src_len = req->nbytes; 169 rctx->cmd.u.xts.dst = req->dst; 170 171 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd); 172 173 return ret; 174 } 175 176 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req) 177 { 178 return ccp_aes_xts_crypt(req, 1); 179 } 180 181 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req) 182 { 183 return ccp_aes_xts_crypt(req, 0); 184 } 185 186 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm) 187 { 188 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 189 struct crypto_ablkcipher *fallback_tfm; 190 191 ctx->complete = ccp_aes_xts_complete; 192 ctx->u.aes.key_len = 0; 193 194 fallback_tfm = crypto_alloc_ablkcipher(tfm->__crt_alg->cra_name, 0, 195 CRYPTO_ALG_ASYNC | 196 CRYPTO_ALG_NEED_FALLBACK); 197 if (IS_ERR(fallback_tfm)) { 198 pr_warn("could not load fallback driver %s\n", 199 tfm->__crt_alg->cra_name); 200 return PTR_ERR(fallback_tfm); 201 } 202 ctx->u.aes.tfm_ablkcipher = fallback_tfm; 203 204 tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx) + 205 fallback_tfm->base.crt_ablkcipher.reqsize; 206 207 return 0; 208 } 209 210 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm) 211 { 212 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 213 214 if (ctx->u.aes.tfm_ablkcipher) 215 crypto_free_ablkcipher(ctx->u.aes.tfm_ablkcipher); 216 ctx->u.aes.tfm_ablkcipher = NULL; 217 } 218 219 220 static int ccp_register_aes_xts_alg(struct list_head *head, 221 const struct ccp_aes_xts_def *def) 222 { 223 struct ccp_crypto_ablkcipher_alg *ccp_alg; 224 struct crypto_alg *alg; 225 int ret; 226 227 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL); 228 if (!ccp_alg) 229 return -ENOMEM; 230 231 INIT_LIST_HEAD(&ccp_alg->entry); 232 233 alg = &ccp_alg->alg; 234 235 snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name); 236 snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s", 237 def->drv_name); 238 alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC | 239 CRYPTO_ALG_KERN_DRIVER_ONLY | 240 CRYPTO_ALG_NEED_FALLBACK; 241 alg->cra_blocksize = AES_BLOCK_SIZE; 242 alg->cra_ctxsize = sizeof(struct ccp_ctx); 243 alg->cra_priority = CCP_CRA_PRIORITY; 244 alg->cra_type = &crypto_ablkcipher_type; 245 alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey; 246 alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt; 247 alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt; 248 alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2; 249 alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2; 250 alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE; 251 alg->cra_init = ccp_aes_xts_cra_init; 252 alg->cra_exit = ccp_aes_xts_cra_exit; 253 alg->cra_module = THIS_MODULE; 254 255 ret = crypto_register_alg(alg); 256 if (ret) { 257 pr_err("%s ablkcipher algorithm registration error (%d)\n", 258 alg->cra_name, ret); 259 kfree(ccp_alg); 260 return ret; 261 } 262 263 list_add(&ccp_alg->entry, head); 264 265 return 0; 266 } 267 268 int ccp_register_aes_xts_algs(struct list_head *head) 269 { 270 int i, ret; 271 272 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) { 273 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]); 274 if (ret) 275 return ret; 276 } 277 278 return 0; 279 } 280