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
25struct ccp_aes_xts_def {
26 const char *name;
27 const char *drv_name;
28};
29
30static struct ccp_aes_xts_def aes_xts_algs[] = {
31 {
32 .name = "xts(aes)",
33 .drv_name = "xts-aes-ccp",
34 },
35};
36
37struct ccp_unit_size_map {
38 unsigned int size;
39 u32 value;
40};
41
42static 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
65static 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
78static 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_sync_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
106}
107
108static 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 SYNC_SKCIPHER_REQUEST_ON_STACK(subreq,
155 ctx->u.aes.tfm_skcipher);
156
157 /* Use the fallback to process the request for any
158 * unsupported unit sizes or key sizes
159 */
160 skcipher_request_set_sync_tfm(subreq, ctx->u.aes.tfm_skcipher);
161 skcipher_request_set_callback(subreq, req->base.flags,
162 NULL, NULL);
163 skcipher_request_set_crypt(subreq, req->src, req->dst,
164 req->nbytes, req->info);
165 ret = encrypt ? crypto_skcipher_encrypt(subreq) :
166 crypto_skcipher_decrypt(subreq);
167 skcipher_request_zero(subreq);
168 return ret;
169 }
170
171 memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
172 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
173
174 memset(&rctx->cmd, 0, sizeof(rctx->cmd));
175 INIT_LIST_HEAD(&rctx->cmd.entry);
176 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
177 rctx->cmd.u.xts.type = CCP_AES_TYPE_128;
178 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
179 : CCP_AES_ACTION_DECRYPT;
180 rctx->cmd.u.xts.unit_size = unit_size;
181 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
182 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
183 rctx->cmd.u.xts.iv = &rctx->iv_sg;
184 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
185 rctx->cmd.u.xts.src = req->src;
186 rctx->cmd.u.xts.src_len = req->nbytes;
187 rctx->cmd.u.xts.dst = req->dst;
188
189 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
190
191 return ret;
192}
193
194static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
195{
196 return ccp_aes_xts_crypt(req, 1);
197}
198
199static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
200{
201 return ccp_aes_xts_crypt(req, 0);
202}
203
204static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
205{
206 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
207 struct crypto_sync_skcipher *fallback_tfm;
208
209 ctx->complete = ccp_aes_xts_complete;
210 ctx->u.aes.key_len = 0;
211
212 fallback_tfm = crypto_alloc_sync_skcipher("xts(aes)", 0,
213 CRYPTO_ALG_ASYNC |
214 CRYPTO_ALG_NEED_FALLBACK);
215 if (IS_ERR(fallback_tfm)) {
216 pr_warn("could not load fallback driver xts(aes)\n");
217 return PTR_ERR(fallback_tfm);
218 }
219 ctx->u.aes.tfm_skcipher = fallback_tfm;
220
221 tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
222
223 return 0;
224}
225
226static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
227{
228 struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
229
230 crypto_free_sync_skcipher(ctx->u.aes.tfm_skcipher);
231}
232
233static int ccp_register_aes_xts_alg(struct list_head *head,
234 const struct ccp_aes_xts_def *def)
235{
236 struct ccp_crypto_ablkcipher_alg *ccp_alg;
237 struct crypto_alg *alg;
238 int ret;
239
240 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
241 if (!ccp_alg)
242 return -ENOMEM;
243
244 INIT_LIST_HEAD(&ccp_alg->entry);
245
246 alg = &ccp_alg->alg;
247
248 snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
249 snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
250 def->drv_name);
251 alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
252 CRYPTO_ALG_KERN_DRIVER_ONLY |
253 CRYPTO_ALG_NEED_FALLBACK;
254 alg->cra_blocksize = AES_BLOCK_SIZE;
255 alg->cra_ctxsize = sizeof(struct ccp_ctx);
256 alg->cra_priority = CCP_CRA_PRIORITY;
257 alg->cra_type = &crypto_ablkcipher_type;
258 alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
259 alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
260 alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
261 alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
262 alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
263 alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
264 alg->cra_init = ccp_aes_xts_cra_init;
265 alg->cra_exit = ccp_aes_xts_cra_exit;
266 alg->cra_module = THIS_MODULE;
267
268 ret = crypto_register_alg(alg);
269 if (ret) {
270 pr_err("%s ablkcipher algorithm registration error (%d)\n",
271 alg->cra_name, ret);
272 kfree(ccp_alg);
273 return ret;
274 }
275
276 list_add(&ccp_alg->entry, head);
277
278 return 0;
279}
280
281int ccp_register_aes_xts_algs(struct list_head *head)
282{
283 int i, ret;
284
285 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
286 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
287 if (ret)
288 return ret;
289 }
290
291 return 0;
292}
293