1 /* 2 * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support 3 * 4 * Copyright (C) 2013,2017 Advanced Micro Devices, Inc. 5 * 6 * Author: Gary R Hook <gary.hook@amd.com> 7 * Author: Tom Lendacky <thomas.lendacky@amd.com> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/module.h> 15 #include <linux/sched.h> 16 #include <linux/delay.h> 17 #include <linux/scatterlist.h> 18 #include <crypto/aes.h> 19 #include <crypto/xts.h> 20 #include <crypto/internal/skcipher.h> 21 #include <crypto/scatterwalk.h> 22 23 #include "ccp-crypto.h" 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 xts_unit_sizes[] = { 43 { 44 .size = 16, 45 .value = CCP_XTS_AES_UNIT_SIZE_16, 46 }, 47 { 48 .size = 512, 49 .value = CCP_XTS_AES_UNIT_SIZE_512, 50 }, 51 { 52 .size = 1024, 53 .value = CCP_XTS_AES_UNIT_SIZE_1024, 54 }, 55 { 56 .size = 2048, 57 .value = CCP_XTS_AES_UNIT_SIZE_2048, 58 }, 59 { 60 .size = 4096, 61 .value = CCP_XTS_AES_UNIT_SIZE_4096, 62 }, 63 }; 64 65 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret) 66 { 67 struct ablkcipher_request *req = ablkcipher_request_cast(async_req); 68 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 69 70 if (ret) 71 return ret; 72 73 memcpy(req->info, rctx->iv, AES_BLOCK_SIZE); 74 75 return 0; 76 } 77 78 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key, 79 unsigned int key_len) 80 { 81 struct crypto_tfm *xfm = crypto_ablkcipher_tfm(tfm); 82 struct ccp_ctx *ctx = crypto_tfm_ctx(xfm); 83 unsigned int ccpversion = ccp_version(); 84 int ret; 85 86 ret = xts_check_key(xfm, key, key_len); 87 if (ret) 88 return ret; 89 90 /* Version 3 devices support 128-bit keys; version 5 devices can 91 * accommodate 128- and 256-bit keys. 92 */ 93 switch (key_len) { 94 case AES_KEYSIZE_128 * 2: 95 memcpy(ctx->u.aes.key, key, key_len); 96 break; 97 case AES_KEYSIZE_256 * 2: 98 if (ccpversion > CCP_VERSION(3, 0)) 99 memcpy(ctx->u.aes.key, key, key_len); 100 break; 101 } 102 ctx->u.aes.key_len = key_len / 2; 103 sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len); 104 105 return crypto_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len); 106 } 107 108 static int ccp_aes_xts_crypt(struct ablkcipher_request *req, 109 unsigned int encrypt) 110 { 111 struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm); 112 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 113 unsigned int ccpversion = ccp_version(); 114 unsigned int fallback = 0; 115 unsigned int unit; 116 u32 unit_size; 117 int ret; 118 119 if (!ctx->u.aes.key_len) 120 return -EINVAL; 121 122 if (req->nbytes & (AES_BLOCK_SIZE - 1)) 123 return -EINVAL; 124 125 if (!req->info) 126 return -EINVAL; 127 128 /* Check conditions under which the CCP can fulfill a request. The 129 * device can handle input plaintext of a length that is a multiple 130 * of the unit_size, bug the crypto implementation only supports 131 * the unit_size being equal to the input length. This limits the 132 * number of scenarios we can handle. 133 */ 134 unit_size = CCP_XTS_AES_UNIT_SIZE__LAST; 135 for (unit = 0; unit < ARRAY_SIZE(xts_unit_sizes); unit++) { 136 if (req->nbytes == xts_unit_sizes[unit].size) { 137 unit_size = unit; 138 break; 139 } 140 } 141 /* The CCP has restrictions on block sizes. Also, a version 3 device 142 * only supports AES-128 operations; version 5 CCPs support both 143 * AES-128 and -256 operations. 144 */ 145 if (unit_size == CCP_XTS_AES_UNIT_SIZE__LAST) 146 fallback = 1; 147 if ((ccpversion < CCP_VERSION(5, 0)) && 148 (ctx->u.aes.key_len != AES_KEYSIZE_128)) 149 fallback = 1; 150 if ((ctx->u.aes.key_len != AES_KEYSIZE_128) && 151 (ctx->u.aes.key_len != AES_KEYSIZE_256)) 152 fallback = 1; 153 if (fallback) { 154 SKCIPHER_REQUEST_ON_STACK(subreq, ctx->u.aes.tfm_skcipher); 155 156 /* Use the fallback to process the request for any 157 * unsupported unit sizes or key sizes 158 */ 159 skcipher_request_set_tfm(subreq, ctx->u.aes.tfm_skcipher); 160 skcipher_request_set_callback(subreq, req->base.flags, 161 NULL, NULL); 162 skcipher_request_set_crypt(subreq, req->src, req->dst, 163 req->nbytes, req->info); 164 ret = encrypt ? crypto_skcipher_encrypt(subreq) : 165 crypto_skcipher_decrypt(subreq); 166 skcipher_request_zero(subreq); 167 return ret; 168 } 169 170 memcpy(rctx->iv, req->info, AES_BLOCK_SIZE); 171 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE); 172 173 memset(&rctx->cmd, 0, sizeof(rctx->cmd)); 174 INIT_LIST_HEAD(&rctx->cmd.entry); 175 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128; 176 rctx->cmd.u.xts.type = CCP_AES_TYPE_128; 177 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT 178 : CCP_AES_ACTION_DECRYPT; 179 rctx->cmd.u.xts.unit_size = unit_size; 180 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg; 181 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len; 182 rctx->cmd.u.xts.iv = &rctx->iv_sg; 183 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE; 184 rctx->cmd.u.xts.src = req->src; 185 rctx->cmd.u.xts.src_len = req->nbytes; 186 rctx->cmd.u.xts.dst = req->dst; 187 188 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd); 189 190 return ret; 191 } 192 193 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req) 194 { 195 return ccp_aes_xts_crypt(req, 1); 196 } 197 198 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req) 199 { 200 return ccp_aes_xts_crypt(req, 0); 201 } 202 203 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm) 204 { 205 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 206 struct crypto_skcipher *fallback_tfm; 207 208 ctx->complete = ccp_aes_xts_complete; 209 ctx->u.aes.key_len = 0; 210 211 fallback_tfm = crypto_alloc_skcipher("xts(aes)", 0, 212 CRYPTO_ALG_ASYNC | 213 CRYPTO_ALG_NEED_FALLBACK); 214 if (IS_ERR(fallback_tfm)) { 215 pr_warn("could not load fallback driver xts(aes)\n"); 216 return PTR_ERR(fallback_tfm); 217 } 218 ctx->u.aes.tfm_skcipher = fallback_tfm; 219 220 tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx); 221 222 return 0; 223 } 224 225 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm) 226 { 227 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 228 229 crypto_free_skcipher(ctx->u.aes.tfm_skcipher); 230 } 231 232 static int ccp_register_aes_xts_alg(struct list_head *head, 233 const struct ccp_aes_xts_def *def) 234 { 235 struct ccp_crypto_ablkcipher_alg *ccp_alg; 236 struct crypto_alg *alg; 237 int ret; 238 239 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL); 240 if (!ccp_alg) 241 return -ENOMEM; 242 243 INIT_LIST_HEAD(&ccp_alg->entry); 244 245 alg = &ccp_alg->alg; 246 247 snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name); 248 snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s", 249 def->drv_name); 250 alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC | 251 CRYPTO_ALG_KERN_DRIVER_ONLY | 252 CRYPTO_ALG_NEED_FALLBACK; 253 alg->cra_blocksize = AES_BLOCK_SIZE; 254 alg->cra_ctxsize = sizeof(struct ccp_ctx); 255 alg->cra_priority = CCP_CRA_PRIORITY; 256 alg->cra_type = &crypto_ablkcipher_type; 257 alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey; 258 alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt; 259 alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt; 260 alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2; 261 alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2; 262 alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE; 263 alg->cra_init = ccp_aes_xts_cra_init; 264 alg->cra_exit = ccp_aes_xts_cra_exit; 265 alg->cra_module = THIS_MODULE; 266 267 ret = crypto_register_alg(alg); 268 if (ret) { 269 pr_err("%s ablkcipher algorithm registration error (%d)\n", 270 alg->cra_name, ret); 271 kfree(ccp_alg); 272 return ret; 273 } 274 275 list_add(&ccp_alg->entry, head); 276 277 return 0; 278 } 279 280 int ccp_register_aes_xts_algs(struct list_head *head) 281 { 282 int i, ret; 283 284 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) { 285 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]); 286 if (ret) 287 return ret; 288 } 289 290 return 0; 291 } 292