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 <crypto/aes.h> 18 #include <crypto/internal/skcipher.h> 19 #include <crypto/scatterwalk.h> 20 21 #include "ccp-crypto.h" 22 23 struct ccp_aes_xts_def { 24 const char *name; 25 const char *drv_name; 26 }; 27 28 static struct ccp_aes_xts_def aes_xts_algs[] = { 29 { 30 .name = "xts(aes)", 31 .drv_name = "xts-aes-ccp", 32 }, 33 }; 34 35 struct ccp_unit_size_map { 36 unsigned int size; 37 u32 value; 38 }; 39 40 static struct ccp_unit_size_map unit_size_map[] = { 41 { 42 .size = 4096, 43 .value = CCP_XTS_AES_UNIT_SIZE_4096, 44 }, 45 { 46 .size = 2048, 47 .value = CCP_XTS_AES_UNIT_SIZE_2048, 48 }, 49 { 50 .size = 1024, 51 .value = CCP_XTS_AES_UNIT_SIZE_1024, 52 }, 53 { 54 .size = 512, 55 .value = CCP_XTS_AES_UNIT_SIZE_512, 56 }, 57 { 58 .size = 256, 59 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 60 }, 61 { 62 .size = 128, 63 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 64 }, 65 { 66 .size = 64, 67 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 68 }, 69 { 70 .size = 32, 71 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 72 }, 73 { 74 .size = 16, 75 .value = CCP_XTS_AES_UNIT_SIZE_16, 76 }, 77 { 78 .size = 1, 79 .value = CCP_XTS_AES_UNIT_SIZE__LAST, 80 }, 81 }; 82 83 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret) 84 { 85 struct ablkcipher_request *req = ablkcipher_request_cast(async_req); 86 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 87 88 if (ret) 89 return ret; 90 91 memcpy(req->info, rctx->iv, AES_BLOCK_SIZE); 92 93 return 0; 94 } 95 96 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key, 97 unsigned int key_len) 98 { 99 struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm)); 100 101 /* Only support 128-bit AES key with a 128-bit Tweak key, 102 * otherwise use the fallback 103 */ 104 switch (key_len) { 105 case AES_KEYSIZE_128 * 2: 106 memcpy(ctx->u.aes.key, key, key_len); 107 break; 108 } 109 ctx->u.aes.key_len = key_len / 2; 110 sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len); 111 112 return crypto_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len); 113 } 114 115 static int ccp_aes_xts_crypt(struct ablkcipher_request *req, 116 unsigned int encrypt) 117 { 118 struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm); 119 struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req); 120 unsigned int unit; 121 u32 unit_size; 122 int ret; 123 124 if (!ctx->u.aes.key_len) 125 return -EINVAL; 126 127 if (req->nbytes & (AES_BLOCK_SIZE - 1)) 128 return -EINVAL; 129 130 if (!req->info) 131 return -EINVAL; 132 133 unit_size = CCP_XTS_AES_UNIT_SIZE__LAST; 134 if (req->nbytes <= unit_size_map[0].size) { 135 for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) { 136 if (!(req->nbytes & (unit_size_map[unit].size - 1))) { 137 unit_size = unit_size_map[unit].value; 138 break; 139 } 140 } 141 } 142 143 if ((unit_size == CCP_XTS_AES_UNIT_SIZE__LAST) || 144 (ctx->u.aes.key_len != AES_KEYSIZE_128)) { 145 SKCIPHER_REQUEST_ON_STACK(subreq, ctx->u.aes.tfm_skcipher); 146 147 /* Use the fallback to process the request for any 148 * unsupported unit sizes or key sizes 149 */ 150 skcipher_request_set_tfm(subreq, ctx->u.aes.tfm_skcipher); 151 skcipher_request_set_callback(subreq, req->base.flags, 152 NULL, NULL); 153 skcipher_request_set_crypt(subreq, req->src, req->dst, 154 req->nbytes, req->info); 155 ret = encrypt ? crypto_skcipher_encrypt(subreq) : 156 crypto_skcipher_decrypt(subreq); 157 skcipher_request_zero(subreq); 158 return ret; 159 } 160 161 memcpy(rctx->iv, req->info, AES_BLOCK_SIZE); 162 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE); 163 164 memset(&rctx->cmd, 0, sizeof(rctx->cmd)); 165 INIT_LIST_HEAD(&rctx->cmd.entry); 166 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128; 167 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT 168 : CCP_AES_ACTION_DECRYPT; 169 rctx->cmd.u.xts.unit_size = unit_size; 170 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg; 171 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len; 172 rctx->cmd.u.xts.iv = &rctx->iv_sg; 173 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE; 174 rctx->cmd.u.xts.src = req->src; 175 rctx->cmd.u.xts.src_len = req->nbytes; 176 rctx->cmd.u.xts.dst = req->dst; 177 178 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd); 179 180 return ret; 181 } 182 183 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req) 184 { 185 return ccp_aes_xts_crypt(req, 1); 186 } 187 188 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req) 189 { 190 return ccp_aes_xts_crypt(req, 0); 191 } 192 193 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm) 194 { 195 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 196 struct crypto_skcipher *fallback_tfm; 197 198 ctx->complete = ccp_aes_xts_complete; 199 ctx->u.aes.key_len = 0; 200 201 fallback_tfm = crypto_alloc_skcipher("xts(aes)", 0, 202 CRYPTO_ALG_ASYNC | 203 CRYPTO_ALG_NEED_FALLBACK); 204 if (IS_ERR(fallback_tfm)) { 205 pr_warn("could not load fallback driver xts(aes)\n"); 206 return PTR_ERR(fallback_tfm); 207 } 208 ctx->u.aes.tfm_skcipher = fallback_tfm; 209 210 tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx); 211 212 return 0; 213 } 214 215 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm) 216 { 217 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm); 218 219 crypto_free_skcipher(ctx->u.aes.tfm_skcipher); 220 } 221 222 static int ccp_register_aes_xts_alg(struct list_head *head, 223 const struct ccp_aes_xts_def *def) 224 { 225 struct ccp_crypto_ablkcipher_alg *ccp_alg; 226 struct crypto_alg *alg; 227 int ret; 228 229 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL); 230 if (!ccp_alg) 231 return -ENOMEM; 232 233 INIT_LIST_HEAD(&ccp_alg->entry); 234 235 alg = &ccp_alg->alg; 236 237 snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name); 238 snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s", 239 def->drv_name); 240 alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC | 241 CRYPTO_ALG_KERN_DRIVER_ONLY | 242 CRYPTO_ALG_NEED_FALLBACK; 243 alg->cra_blocksize = AES_BLOCK_SIZE; 244 alg->cra_ctxsize = sizeof(struct ccp_ctx); 245 alg->cra_priority = CCP_CRA_PRIORITY; 246 alg->cra_type = &crypto_ablkcipher_type; 247 alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey; 248 alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt; 249 alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt; 250 alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2; 251 alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2; 252 alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE; 253 alg->cra_init = ccp_aes_xts_cra_init; 254 alg->cra_exit = ccp_aes_xts_cra_exit; 255 alg->cra_module = THIS_MODULE; 256 257 ret = crypto_register_alg(alg); 258 if (ret) { 259 pr_err("%s ablkcipher algorithm registration error (%d)\n", 260 alg->cra_name, ret); 261 kfree(ccp_alg); 262 return ret; 263 } 264 265 list_add(&ccp_alg->entry, head); 266 267 return 0; 268 } 269 270 int ccp_register_aes_xts_algs(struct list_head *head) 271 { 272 int i, ret; 273 274 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) { 275 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]); 276 if (ret) 277 return ret; 278 } 279 280 return 0; 281 } 282