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 struct ccp_aes_xts_def { 25 const char *name; 26 const char *drv_name; 27 }; 28 29 static struct ccp_aes_xts_def aes_xts_algs[] = { 30 { 31 .name = "xts(aes)", 32 .drv_name = "xts-aes-ccp", 33 }, 34 }; 35 36 struct ccp_unit_size_map { 37 unsigned int size; 38 u32 value; 39 }; 40 41 static struct ccp_unit_size_map unit_size_map[] = { 42 { 43 .size = 4096, 44 .value = CCP_XTS_AES_UNIT_SIZE_4096, 45 }, 46 { 47 .size = 2048, 48 .value = CCP_XTS_AES_UNIT_SIZE_2048, 49 }, 50 { 51 .size = 1024, 52 .value = CCP_XTS_AES_UNIT_SIZE_1024, 53 }, 54 { 55 .size = 512, 56 .value = CCP_XTS_AES_UNIT_SIZE_512, 57 }, 58 { 59 .size = 256, 60 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 61 }, 62 { 63 .size = 128, 64 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 65 }, 66 { 67 .size = 64, 68 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 69 }, 70 { 71 .size = 32, 72 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 73 }, 74 { 75 .size = 16, 76 .value = CCP_XTS_AES_UNIT_SIZE_16, 77 }, 78 { 79 .size = 1, 80 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 81 }, 82 }; 83 84 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret) 85 { 86 struct ablkcipher_request *req = ablkcipher_request_cast(async_req); 87 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 88 89 if (ret) 90 return ret; 91 92 memcpy(req->info, rctx->iv, AES_BLOCK_SIZE); 93 94 return 0; 95 } 96 97 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key, 98 unsigned int key_len) 99 { 100 struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm)); 101 102 /* Only support 128-bit AES key with a 128-bit Tweak key, 103 * otherwise use the fallback 104 */ 105 switch (key_len) { 106 case AES_KEYSIZE_128 * 2: 107 memcpy(ctx->u.aes.key, key, key_len); 108 break; 109 } 110 ctx->u.aes.key_len = key_len / 2; 111 sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len); 112 113 return crypto_ablkcipher_setkey(ctx->u.aes.tfm_ablkcipher, key, 114 key_len); 115 } 116 117 static int ccp_aes_xts_crypt(struct ablkcipher_request *req, 118 unsigned int encrypt) 119 { 120 struct crypto_tfm *tfm = 121 crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req)); 122 struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm); 123 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 124 unsigned int unit; 125 u32 unit_size; 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 unit_size = CCP_XTS_AES_UNIT_SIZE__LAST; 138 if (req->nbytes <= unit_size_map[0].size) { 139 for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) { 140 if (!(req->nbytes & (unit_size_map[unit].size - 1))) { 141 unit_size = unit_size_map[unit].value; 142 break; 143 } 144 } 145 } 146 147 if ((unit_size == CCP_XTS_AES_UNIT_SIZE__LAST) || 148 (ctx->u.aes.key_len != AES_KEYSIZE_128)) { 149 /* Use the fallback to process the request for any 150 * unsupported unit sizes or key sizes 151 */ 152 ablkcipher_request_set_tfm(req, ctx->u.aes.tfm_ablkcipher); 153 ret = (encrypt) ? crypto_ablkcipher_encrypt(req) : 154 crypto_ablkcipher_decrypt(req); 155 ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm)); 156 157 return ret; 158 } 159 160 memcpy(rctx->iv, req->info, AES_BLOCK_SIZE); 161 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE); 162 163 memset(&rctx->cmd, 0, sizeof(rctx->cmd)); 164 INIT_LIST_HEAD(&rctx->cmd.entry); 165 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128; 166 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT 167 : CCP_AES_ACTION_DECRYPT; 168 rctx->cmd.u.xts.unit_size = unit_size; 169 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg; 170 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len; 171 rctx->cmd.u.xts.iv = &rctx->iv_sg; 172 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE; 173 rctx->cmd.u.xts.src = req->src; 174 rctx->cmd.u.xts.src_len = req->nbytes; 175 rctx->cmd.u.xts.dst = req->dst; 176 177 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd); 178 179 return ret; 180 } 181 182 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req) 183 { 184 return ccp_aes_xts_crypt(req, 1); 185 } 186 187 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req) 188 { 189 return ccp_aes_xts_crypt(req, 0); 190 } 191 192 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm) 193 { 194 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 195 struct crypto_ablkcipher *fallback_tfm; 196 197 ctx->complete = ccp_aes_xts_complete; 198 ctx->u.aes.key_len = 0; 199 200 fallback_tfm = crypto_alloc_ablkcipher(crypto_tfm_alg_name(tfm), 0, 201 CRYPTO_ALG_ASYNC | 202 CRYPTO_ALG_NEED_FALLBACK); 203 if (IS_ERR(fallback_tfm)) { 204 pr_warn("could not load fallback driver %s\n", 205 crypto_tfm_alg_name(tfm)); 206 return PTR_ERR(fallback_tfm); 207 } 208 ctx->u.aes.tfm_ablkcipher = fallback_tfm; 209 210 tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx) + 211 fallback_tfm->base.crt_ablkcipher.reqsize; 212 213 return 0; 214 } 215 216 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm) 217 { 218 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 219 220 if (ctx->u.aes.tfm_ablkcipher) 221 crypto_free_ablkcipher(ctx->u.aes.tfm_ablkcipher); 222 ctx->u.aes.tfm_ablkcipher = NULL; 223 } 224 225 static int ccp_register_aes_xts_alg(struct list_head *head, 226 const struct ccp_aes_xts_def *def) 227 { 228 struct ccp_crypto_ablkcipher_alg *ccp_alg; 229 struct crypto_alg *alg; 230 int ret; 231 232 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL); 233 if (!ccp_alg) 234 return -ENOMEM; 235 236 INIT_LIST_HEAD(&ccp_alg->entry); 237 238 alg = &ccp_alg->alg; 239 240 snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name); 241 snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s", 242 def->drv_name); 243 alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC | 244 CRYPTO_ALG_KERN_DRIVER_ONLY | 245 CRYPTO_ALG_NEED_FALLBACK; 246 alg->cra_blocksize = AES_BLOCK_SIZE; 247 alg->cra_ctxsize = sizeof(struct ccp_ctx); 248 alg->cra_priority = CCP_CRA_PRIORITY; 249 alg->cra_type = &crypto_ablkcipher_type; 250 alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey; 251 alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt; 252 alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt; 253 alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2; 254 alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2; 255 alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE; 256 alg->cra_init = ccp_aes_xts_cra_init; 257 alg->cra_exit = ccp_aes_xts_cra_exit; 258 alg->cra_module = THIS_MODULE; 259 260 ret = crypto_register_alg(alg); 261 if (ret) { 262 pr_err("%s ablkcipher algorithm registration error (%d)\n", 263 alg->cra_name, ret); 264 kfree(ccp_alg); 265 return ret; 266 } 267 268 list_add(&ccp_alg->entry, head); 269 270 return 0; 271 } 272 273 int ccp_register_aes_xts_algs(struct list_head *head) 274 { 275 int i, ret; 276 277 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) { 278 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]); 279 if (ret) 280 return ret; 281 } 282 283 return 0; 284 } 285