1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support
4 *
5 * Copyright (C) 2013,2017 Advanced Micro Devices, Inc.
6 *
7 * Author: Gary R Hook <gary.hook@amd.com>
8 * Author: Tom Lendacky <thomas.lendacky@amd.com>
9 */
10
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/delay.h>
14 #include <linux/scatterlist.h>
15 #include <crypto/aes.h>
16 #include <crypto/xts.h>
17 #include <crypto/internal/skcipher.h>
18 #include <crypto/scatterwalk.h>
19
20 #include "ccp-crypto.h"
21
22 struct ccp_aes_xts_def {
23 const char *name;
24 const char *drv_name;
25 };
26
27 static const struct ccp_aes_xts_def aes_xts_algs[] = {
28 {
29 .name = "xts(aes)",
30 .drv_name = "xts-aes-ccp",
31 },
32 };
33
34 struct ccp_unit_size_map {
35 unsigned int size;
36 u32 value;
37 };
38
39 static struct ccp_unit_size_map xts_unit_sizes[] = {
40 {
41 .size = 16,
42 .value = CCP_XTS_AES_UNIT_SIZE_16,
43 },
44 {
45 .size = 512,
46 .value = CCP_XTS_AES_UNIT_SIZE_512,
47 },
48 {
49 .size = 1024,
50 .value = CCP_XTS_AES_UNIT_SIZE_1024,
51 },
52 {
53 .size = 2048,
54 .value = CCP_XTS_AES_UNIT_SIZE_2048,
55 },
56 {
57 .size = 4096,
58 .value = CCP_XTS_AES_UNIT_SIZE_4096,
59 },
60 };
61
ccp_aes_xts_complete(struct crypto_async_request * async_req,int ret)62 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
63 {
64 struct skcipher_request *req = skcipher_request_cast(async_req);
65 struct ccp_aes_req_ctx *rctx = skcipher_request_ctx(req);
66
67 if (ret)
68 return ret;
69
70 memcpy(req->iv, rctx->iv, AES_BLOCK_SIZE);
71
72 return 0;
73 }
74
ccp_aes_xts_setkey(struct crypto_skcipher * tfm,const u8 * key,unsigned int key_len)75 static int ccp_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
76 unsigned int key_len)
77 {
78 struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
79 unsigned int ccpversion = ccp_version();
80 int ret;
81
82 ret = xts_verify_key(tfm, key, key_len);
83 if (ret)
84 return ret;
85
86 /* Version 3 devices support 128-bit keys; version 5 devices can
87 * accommodate 128- and 256-bit keys.
88 */
89 switch (key_len) {
90 case AES_KEYSIZE_128 * 2:
91 memcpy(ctx->u.aes.key, key, key_len);
92 break;
93 case AES_KEYSIZE_256 * 2:
94 if (ccpversion > CCP_VERSION(3, 0))
95 memcpy(ctx->u.aes.key, key, key_len);
96 break;
97 }
98 ctx->u.aes.key_len = key_len / 2;
99 sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
100
101 return crypto_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
102 }
103
ccp_aes_xts_crypt(struct skcipher_request * req,unsigned int encrypt)104 static int ccp_aes_xts_crypt(struct skcipher_request *req,
105 unsigned int encrypt)
106 {
107 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
108 struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
109 struct ccp_aes_req_ctx *rctx = skcipher_request_ctx(req);
110 unsigned int ccpversion = ccp_version();
111 unsigned int fallback = 0;
112 unsigned int unit;
113 u32 unit_size;
114 int ret;
115
116 if (!ctx->u.aes.key_len)
117 return -EINVAL;
118
119 if (!req->iv)
120 return -EINVAL;
121
122 /* Check conditions under which the CCP can fulfill a request. The
123 * device can handle input plaintext of a length that is a multiple
124 * of the unit_size, bug the crypto implementation only supports
125 * the unit_size being equal to the input length. This limits the
126 * number of scenarios we can handle.
127 */
128 unit_size = CCP_XTS_AES_UNIT_SIZE__LAST;
129 for (unit = 0; unit < ARRAY_SIZE(xts_unit_sizes); unit++) {
130 if (req->cryptlen == xts_unit_sizes[unit].size) {
131 unit_size = unit;
132 break;
133 }
134 }
135 /* The CCP has restrictions on block sizes. Also, a version 3 device
136 * only supports AES-128 operations; version 5 CCPs support both
137 * AES-128 and -256 operations.
138 */
139 if (unit_size == CCP_XTS_AES_UNIT_SIZE__LAST)
140 fallback = 1;
141 if ((ccpversion < CCP_VERSION(5, 0)) &&
142 (ctx->u.aes.key_len != AES_KEYSIZE_128))
143 fallback = 1;
144 if ((ctx->u.aes.key_len != AES_KEYSIZE_128) &&
145 (ctx->u.aes.key_len != AES_KEYSIZE_256))
146 fallback = 1;
147 if (fallback) {
148 /* Use the fallback to process the request for any
149 * unsupported unit sizes or key sizes
150 */
151 skcipher_request_set_tfm(&rctx->fallback_req,
152 ctx->u.aes.tfm_skcipher);
153 skcipher_request_set_callback(&rctx->fallback_req,
154 req->base.flags,
155 req->base.complete,
156 req->base.data);
157 skcipher_request_set_crypt(&rctx->fallback_req, req->src,
158 req->dst, req->cryptlen, req->iv);
159 ret = encrypt ? crypto_skcipher_encrypt(&rctx->fallback_req) :
160 crypto_skcipher_decrypt(&rctx->fallback_req);
161 return ret;
162 }
163
164 memcpy(rctx->iv, req->iv, AES_BLOCK_SIZE);
165 sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
166
167 memset(&rctx->cmd, 0, sizeof(rctx->cmd));
168 INIT_LIST_HEAD(&rctx->cmd.entry);
169 rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
170 rctx->cmd.u.xts.type = CCP_AES_TYPE_128;
171 rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
172 : CCP_AES_ACTION_DECRYPT;
173 rctx->cmd.u.xts.unit_size = unit_size;
174 rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
175 rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
176 rctx->cmd.u.xts.iv = &rctx->iv_sg;
177 rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
178 rctx->cmd.u.xts.src = req->src;
179 rctx->cmd.u.xts.src_len = req->cryptlen;
180 rctx->cmd.u.xts.dst = req->dst;
181
182 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
183
184 return ret;
185 }
186
ccp_aes_xts_encrypt(struct skcipher_request * req)187 static int ccp_aes_xts_encrypt(struct skcipher_request *req)
188 {
189 return ccp_aes_xts_crypt(req, 1);
190 }
191
ccp_aes_xts_decrypt(struct skcipher_request * req)192 static int ccp_aes_xts_decrypt(struct skcipher_request *req)
193 {
194 return ccp_aes_xts_crypt(req, 0);
195 }
196
ccp_aes_xts_init_tfm(struct crypto_skcipher * tfm)197 static int ccp_aes_xts_init_tfm(struct crypto_skcipher *tfm)
198 {
199 struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
200 struct crypto_skcipher *fallback_tfm;
201
202 ctx->complete = ccp_aes_xts_complete;
203 ctx->u.aes.key_len = 0;
204
205 fallback_tfm = crypto_alloc_skcipher("xts(aes)", 0,
206 CRYPTO_ALG_NEED_FALLBACK);
207 if (IS_ERR(fallback_tfm)) {
208 pr_warn("could not load fallback driver xts(aes)\n");
209 return PTR_ERR(fallback_tfm);
210 }
211 ctx->u.aes.tfm_skcipher = fallback_tfm;
212
213 crypto_skcipher_set_reqsize(tfm, sizeof(struct ccp_aes_req_ctx) +
214 crypto_skcipher_reqsize(fallback_tfm));
215
216 return 0;
217 }
218
ccp_aes_xts_exit_tfm(struct crypto_skcipher * tfm)219 static void ccp_aes_xts_exit_tfm(struct crypto_skcipher *tfm)
220 {
221 struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
222
223 crypto_free_skcipher(ctx->u.aes.tfm_skcipher);
224 }
225
ccp_register_aes_xts_alg(struct list_head * head,const struct ccp_aes_xts_def * def)226 static int ccp_register_aes_xts_alg(struct list_head *head,
227 const struct ccp_aes_xts_def *def)
228 {
229 struct ccp_crypto_skcipher_alg *ccp_alg;
230 struct skcipher_alg *alg;
231 int ret;
232
233 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
234 if (!ccp_alg)
235 return -ENOMEM;
236
237 INIT_LIST_HEAD(&ccp_alg->entry);
238
239 alg = &ccp_alg->alg;
240
241 snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
242 snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
243 def->drv_name);
244 alg->base.cra_flags = CRYPTO_ALG_ASYNC |
245 CRYPTO_ALG_ALLOCATES_MEMORY |
246 CRYPTO_ALG_KERN_DRIVER_ONLY |
247 CRYPTO_ALG_NEED_FALLBACK;
248 alg->base.cra_blocksize = AES_BLOCK_SIZE;
249 alg->base.cra_ctxsize = sizeof(struct ccp_ctx);
250 alg->base.cra_priority = CCP_CRA_PRIORITY;
251 alg->base.cra_module = THIS_MODULE;
252
253 alg->setkey = ccp_aes_xts_setkey;
254 alg->encrypt = ccp_aes_xts_encrypt;
255 alg->decrypt = ccp_aes_xts_decrypt;
256 alg->min_keysize = AES_MIN_KEY_SIZE * 2;
257 alg->max_keysize = AES_MAX_KEY_SIZE * 2;
258 alg->ivsize = AES_BLOCK_SIZE;
259 alg->init = ccp_aes_xts_init_tfm;
260 alg->exit = ccp_aes_xts_exit_tfm;
261
262 ret = crypto_register_skcipher(alg);
263 if (ret) {
264 pr_err("%s skcipher algorithm registration error (%d)\n",
265 alg->base.cra_name, ret);
266 kfree(ccp_alg);
267 return ret;
268 }
269
270 list_add(&ccp_alg->entry, head);
271
272 return 0;
273 }
274
ccp_register_aes_xts_algs(struct list_head * head)275 int ccp_register_aes_xts_algs(struct list_head *head)
276 {
277 int i, ret;
278
279 for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
280 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
281 if (ret)
282 return ret;
283 }
284
285 return 0;
286 }
287
