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 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 
62 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
63 {
64 	struct ablkcipher_request *req = ablkcipher_request_cast(async_req);
65 	struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
66 
67 	if (ret)
68 		return ret;
69 
70 	memcpy(req->info, rctx->iv, AES_BLOCK_SIZE);
71 
72 	return 0;
73 }
74 
75 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
76 			      unsigned int key_len)
77 {
78 	struct crypto_tfm *xfm = crypto_ablkcipher_tfm(tfm);
79 	struct ccp_ctx *ctx = crypto_tfm_ctx(xfm);
80 	unsigned int ccpversion = ccp_version();
81 	int ret;
82 
83 	ret = xts_check_key(xfm, key, key_len);
84 	if (ret)
85 		return ret;
86 
87 	/* Version 3 devices support 128-bit keys; version 5 devices can
88 	 * accommodate 128- and 256-bit keys.
89 	 */
90 	switch (key_len) {
91 	case AES_KEYSIZE_128 * 2:
92 		memcpy(ctx->u.aes.key, key, key_len);
93 		break;
94 	case AES_KEYSIZE_256 * 2:
95 		if (ccpversion > CCP_VERSION(3, 0))
96 			memcpy(ctx->u.aes.key, key, key_len);
97 		break;
98 	}
99 	ctx->u.aes.key_len = key_len / 2;
100 	sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
101 
102 	return crypto_sync_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
103 }
104 
105 static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
106 			     unsigned int encrypt)
107 {
108 	struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
109 	struct ccp_aes_req_ctx *rctx = ablkcipher_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->nbytes & (AES_BLOCK_SIZE - 1))
120 		return -EINVAL;
121 
122 	if (!req->info)
123 		return -EINVAL;
124 
125 	/* Check conditions under which the CCP can fulfill a request. The
126 	 * device can handle input plaintext of a length that is a multiple
127 	 * of the unit_size, bug the crypto implementation only supports
128 	 * the unit_size being equal to the input length. This limits the
129 	 * number of scenarios we can handle.
130 	 */
131 	unit_size = CCP_XTS_AES_UNIT_SIZE__LAST;
132 	for (unit = 0; unit < ARRAY_SIZE(xts_unit_sizes); unit++) {
133 		if (req->nbytes == xts_unit_sizes[unit].size) {
134 			unit_size = unit;
135 			break;
136 		}
137 	}
138 	/* The CCP has restrictions on block sizes. Also, a version 3 device
139 	 * only supports AES-128 operations; version 5 CCPs support both
140 	 * AES-128 and -256 operations.
141 	 */
142 	if (unit_size == CCP_XTS_AES_UNIT_SIZE__LAST)
143 		fallback = 1;
144 	if ((ccpversion < CCP_VERSION(5, 0)) &&
145 	    (ctx->u.aes.key_len != AES_KEYSIZE_128))
146 		fallback = 1;
147 	if ((ctx->u.aes.key_len != AES_KEYSIZE_128) &&
148 	    (ctx->u.aes.key_len != AES_KEYSIZE_256))
149 		fallback = 1;
150 	if (fallback) {
151 		SYNC_SKCIPHER_REQUEST_ON_STACK(subreq,
152 					       ctx->u.aes.tfm_skcipher);
153 
154 		/* Use the fallback to process the request for any
155 		 * unsupported unit sizes or key sizes
156 		 */
157 		skcipher_request_set_sync_tfm(subreq, ctx->u.aes.tfm_skcipher);
158 		skcipher_request_set_callback(subreq, req->base.flags,
159 					      NULL, NULL);
160 		skcipher_request_set_crypt(subreq, req->src, req->dst,
161 					   req->nbytes, req->info);
162 		ret = encrypt ? crypto_skcipher_encrypt(subreq) :
163 				crypto_skcipher_decrypt(subreq);
164 		skcipher_request_zero(subreq);
165 		return ret;
166 	}
167 
168 	memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
169 	sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
170 
171 	memset(&rctx->cmd, 0, sizeof(rctx->cmd));
172 	INIT_LIST_HEAD(&rctx->cmd.entry);
173 	rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
174 	rctx->cmd.u.xts.type = CCP_AES_TYPE_128;
175 	rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
176 					   : CCP_AES_ACTION_DECRYPT;
177 	rctx->cmd.u.xts.unit_size = unit_size;
178 	rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
179 	rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
180 	rctx->cmd.u.xts.iv = &rctx->iv_sg;
181 	rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
182 	rctx->cmd.u.xts.src = req->src;
183 	rctx->cmd.u.xts.src_len = req->nbytes;
184 	rctx->cmd.u.xts.dst = req->dst;
185 
186 	ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
187 
188 	return ret;
189 }
190 
191 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
192 {
193 	return ccp_aes_xts_crypt(req, 1);
194 }
195 
196 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
197 {
198 	return ccp_aes_xts_crypt(req, 0);
199 }
200 
201 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
202 {
203 	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
204 	struct crypto_sync_skcipher *fallback_tfm;
205 
206 	ctx->complete = ccp_aes_xts_complete;
207 	ctx->u.aes.key_len = 0;
208 
209 	fallback_tfm = crypto_alloc_sync_skcipher("xts(aes)", 0,
210 					     CRYPTO_ALG_ASYNC |
211 					     CRYPTO_ALG_NEED_FALLBACK);
212 	if (IS_ERR(fallback_tfm)) {
213 		pr_warn("could not load fallback driver xts(aes)\n");
214 		return PTR_ERR(fallback_tfm);
215 	}
216 	ctx->u.aes.tfm_skcipher = fallback_tfm;
217 
218 	tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
219 
220 	return 0;
221 }
222 
223 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
224 {
225 	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
226 
227 	crypto_free_sync_skcipher(ctx->u.aes.tfm_skcipher);
228 }
229 
230 static int ccp_register_aes_xts_alg(struct list_head *head,
231 				    const struct ccp_aes_xts_def *def)
232 {
233 	struct ccp_crypto_ablkcipher_alg *ccp_alg;
234 	struct crypto_alg *alg;
235 	int ret;
236 
237 	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
238 	if (!ccp_alg)
239 		return -ENOMEM;
240 
241 	INIT_LIST_HEAD(&ccp_alg->entry);
242 
243 	alg = &ccp_alg->alg;
244 
245 	snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
246 	snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
247 		 def->drv_name);
248 	alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
249 			 CRYPTO_ALG_KERN_DRIVER_ONLY |
250 			 CRYPTO_ALG_NEED_FALLBACK;
251 	alg->cra_blocksize = AES_BLOCK_SIZE;
252 	alg->cra_ctxsize = sizeof(struct ccp_ctx);
253 	alg->cra_priority = CCP_CRA_PRIORITY;
254 	alg->cra_type = &crypto_ablkcipher_type;
255 	alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
256 	alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
257 	alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
258 	alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
259 	alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
260 	alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
261 	alg->cra_init = ccp_aes_xts_cra_init;
262 	alg->cra_exit = ccp_aes_xts_cra_exit;
263 	alg->cra_module = THIS_MODULE;
264 
265 	ret = crypto_register_alg(alg);
266 	if (ret) {
267 		pr_err("%s ablkcipher algorithm registration error (%d)\n",
268 		       alg->cra_name, ret);
269 		kfree(ccp_alg);
270 		return ret;
271 	}
272 
273 	list_add(&ccp_alg->entry, head);
274 
275 	return 0;
276 }
277 
278 int ccp_register_aes_xts_algs(struct list_head *head)
279 {
280 	int i, ret;
281 
282 	for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
283 		ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
284 		if (ret)
285 			return ret;
286 	}
287 
288 	return 0;
289 }
290