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 int ret; 126 127 if (!ctx->u.aes.key_len) 128 return -EINVAL; 129 130 if (req->nbytes & (AES_BLOCK_SIZE - 1)) 131 return -EINVAL; 132 133 if (!req->info) 134 return -EINVAL; 135 136 for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) 137 if (!(req->nbytes & (unit_size_map[unit].size - 1))) 138 break; 139 140 if ((unit_size_map[unit].value == CCP_XTS_AES_UNIT_SIZE__LAST) || 141 (ctx->u.aes.key_len != AES_KEYSIZE_128)) { 142 /* Use the fallback to process the request for any 143 * unsupported unit sizes or key sizes 144 */ 145 ablkcipher_request_set_tfm(req, ctx->u.aes.tfm_ablkcipher); 146 ret = (encrypt) ? crypto_ablkcipher_encrypt(req) : 147 crypto_ablkcipher_decrypt(req); 148 ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm)); 149 150 return ret; 151 } 152 153 memcpy(rctx->iv, req->info, AES_BLOCK_SIZE); 154 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE); 155 156 memset(&rctx->cmd, 0, sizeof(rctx->cmd)); 157 INIT_LIST_HEAD(&rctx->cmd.entry); 158 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128; 159 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT 160 : CCP_AES_ACTION_DECRYPT; 161 rctx->cmd.u.xts.unit_size = unit_size_map[unit].value; 162 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg; 163 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len; 164 rctx->cmd.u.xts.iv = &rctx->iv_sg; 165 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE; 166 rctx->cmd.u.xts.src = req->src; 167 rctx->cmd.u.xts.src_len = req->nbytes; 168 rctx->cmd.u.xts.dst = req->dst; 169 170 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd); 171 172 return ret; 173 } 174 175 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req) 176 { 177 return ccp_aes_xts_crypt(req, 1); 178 } 179 180 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req) 181 { 182 return ccp_aes_xts_crypt(req, 0); 183 } 184 185 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm) 186 { 187 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 188 struct crypto_ablkcipher *fallback_tfm; 189 190 ctx->complete = ccp_aes_xts_complete; 191 ctx->u.aes.key_len = 0; 192 193 fallback_tfm = crypto_alloc_ablkcipher(crypto_tfm_alg_name(tfm), 0, 194 CRYPTO_ALG_ASYNC | 195 CRYPTO_ALG_NEED_FALLBACK); 196 if (IS_ERR(fallback_tfm)) { 197 pr_warn("could not load fallback driver %s\n", 198 crypto_tfm_alg_name(tfm)); 199 return PTR_ERR(fallback_tfm); 200 } 201 ctx->u.aes.tfm_ablkcipher = fallback_tfm; 202 203 tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx) + 204 fallback_tfm->base.crt_ablkcipher.reqsize; 205 206 return 0; 207 } 208 209 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm) 210 { 211 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 212 213 if (ctx->u.aes.tfm_ablkcipher) 214 crypto_free_ablkcipher(ctx->u.aes.tfm_ablkcipher); 215 ctx->u.aes.tfm_ablkcipher = NULL; 216 } 217 218 static int ccp_register_aes_xts_alg(struct list_head *head, 219 const struct ccp_aes_xts_def *def) 220 { 221 struct ccp_crypto_ablkcipher_alg *ccp_alg; 222 struct crypto_alg *alg; 223 int ret; 224 225 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL); 226 if (!ccp_alg) 227 return -ENOMEM; 228 229 INIT_LIST_HEAD(&ccp_alg->entry); 230 231 alg = &ccp_alg->alg; 232 233 snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name); 234 snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s", 235 def->drv_name); 236 alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC | 237 CRYPTO_ALG_KERN_DRIVER_ONLY | 238 CRYPTO_ALG_NEED_FALLBACK; 239 alg->cra_blocksize = AES_BLOCK_SIZE; 240 alg->cra_ctxsize = sizeof(struct ccp_ctx); 241 alg->cra_priority = CCP_CRA_PRIORITY; 242 alg->cra_type = &crypto_ablkcipher_type; 243 alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey; 244 alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt; 245 alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt; 246 alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2; 247 alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2; 248 alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE; 249 alg->cra_init = ccp_aes_xts_cra_init; 250 alg->cra_exit = ccp_aes_xts_cra_exit; 251 alg->cra_module = THIS_MODULE; 252 253 ret = crypto_register_alg(alg); 254 if (ret) { 255 pr_err("%s ablkcipher algorithm registration error (%d)\n", 256 alg->cra_name, ret); 257 kfree(ccp_alg); 258 return ret; 259 } 260 261 list_add(&ccp_alg->entry, head); 262 263 return 0; 264 } 265 266 int ccp_register_aes_xts_algs(struct list_head *head) 267 { 268 int i, ret; 269 270 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) { 271 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]); 272 if (ret) 273 return ret; 274 } 275 276 return 0; 277 } 278