1 /*
2  * AMD Cryptographic Coprocessor (CCP) AES CMAC 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 <linux/crypto.h>
18 #include <crypto/algapi.h>
19 #include <crypto/aes.h>
20 #include <crypto/hash.h>
21 #include <crypto/internal/hash.h>
22 #include <crypto/scatterwalk.h>
23 
24 #include "ccp-crypto.h"
25 
26 static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
27 				 int ret)
28 {
29 	struct ahash_request *req = ahash_request_cast(async_req);
30 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
31 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
32 	unsigned int digest_size = crypto_ahash_digestsize(tfm);
33 
34 	if (ret)
35 		goto e_free;
36 
37 	if (rctx->hash_rem) {
38 		/* Save remaining data to buffer */
39 		unsigned int offset = rctx->nbytes - rctx->hash_rem;
40 
41 		scatterwalk_map_and_copy(rctx->buf, rctx->src,
42 					 offset, rctx->hash_rem, 0);
43 		rctx->buf_count = rctx->hash_rem;
44 	} else {
45 		rctx->buf_count = 0;
46 	}
47 
48 	/* Update result area if supplied */
49 	if (req->result)
50 		memcpy(req->result, rctx->iv, digest_size);
51 
52 e_free:
53 	sg_free_table(&rctx->data_sg);
54 
55 	return ret;
56 }
57 
58 static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
59 			      unsigned int final)
60 {
61 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
62 	struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
63 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
64 	struct scatterlist *sg, *cmac_key_sg = NULL;
65 	unsigned int block_size =
66 		crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
67 	unsigned int need_pad, sg_count;
68 	gfp_t gfp;
69 	u64 len;
70 	int ret;
71 
72 	if (!ctx->u.aes.key_len)
73 		return -EINVAL;
74 
75 	if (nbytes)
76 		rctx->null_msg = 0;
77 
78 	len = (u64)rctx->buf_count + (u64)nbytes;
79 
80 	if (!final && (len <= block_size)) {
81 		scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
82 					 0, nbytes, 0);
83 		rctx->buf_count += nbytes;
84 
85 		return 0;
86 	}
87 
88 	rctx->src = req->src;
89 	rctx->nbytes = nbytes;
90 
91 	rctx->final = final;
92 	rctx->hash_rem = final ? 0 : len & (block_size - 1);
93 	rctx->hash_cnt = len - rctx->hash_rem;
94 	if (!final && !rctx->hash_rem) {
95 		/* CCP can't do zero length final, so keep some data around */
96 		rctx->hash_cnt -= block_size;
97 		rctx->hash_rem = block_size;
98 	}
99 
100 	if (final && (rctx->null_msg || (len & (block_size - 1))))
101 		need_pad = 1;
102 	else
103 		need_pad = 0;
104 
105 	sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));
106 
107 	/* Build the data scatterlist table - allocate enough entries for all
108 	 * possible data pieces (buffer, input data, padding)
109 	 */
110 	sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
111 	gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
112 		GFP_KERNEL : GFP_ATOMIC;
113 	ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
114 	if (ret)
115 		return ret;
116 
117 	sg = NULL;
118 	if (rctx->buf_count) {
119 		sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
120 		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
121 		if (!sg) {
122 			ret = -EINVAL;
123 			goto e_free;
124 		}
125 	}
126 
127 	if (nbytes) {
128 		sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
129 		if (!sg) {
130 			ret = -EINVAL;
131 			goto e_free;
132 		}
133 	}
134 
135 	if (need_pad) {
136 		int pad_length = block_size - (len & (block_size - 1));
137 
138 		rctx->hash_cnt += pad_length;
139 
140 		memset(rctx->pad, 0, sizeof(rctx->pad));
141 		rctx->pad[0] = 0x80;
142 		sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
143 		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
144 		if (!sg) {
145 			ret = -EINVAL;
146 			goto e_free;
147 		}
148 	}
149 	if (sg) {
150 		sg_mark_end(sg);
151 		sg = rctx->data_sg.sgl;
152 	}
153 
154 	/* Initialize the K1/K2 scatterlist */
155 	if (final)
156 		cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
157 					 : &ctx->u.aes.k1_sg;
158 
159 	memset(&rctx->cmd, 0, sizeof(rctx->cmd));
160 	INIT_LIST_HEAD(&rctx->cmd.entry);
161 	rctx->cmd.engine = CCP_ENGINE_AES;
162 	rctx->cmd.u.aes.type = ctx->u.aes.type;
163 	rctx->cmd.u.aes.mode = ctx->u.aes.mode;
164 	rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
165 	rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
166 	rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
167 	rctx->cmd.u.aes.iv = &rctx->iv_sg;
168 	rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
169 	rctx->cmd.u.aes.src = sg;
170 	rctx->cmd.u.aes.src_len = rctx->hash_cnt;
171 	rctx->cmd.u.aes.dst = NULL;
172 	rctx->cmd.u.aes.cmac_key = cmac_key_sg;
173 	rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
174 	rctx->cmd.u.aes.cmac_final = final;
175 
176 	ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
177 
178 	return ret;
179 
180 e_free:
181 	sg_free_table(&rctx->data_sg);
182 
183 	return ret;
184 }
185 
186 static int ccp_aes_cmac_init(struct ahash_request *req)
187 {
188 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
189 
190 	memset(rctx, 0, sizeof(*rctx));
191 
192 	rctx->null_msg = 1;
193 
194 	return 0;
195 }
196 
197 static int ccp_aes_cmac_update(struct ahash_request *req)
198 {
199 	return ccp_do_cmac_update(req, req->nbytes, 0);
200 }
201 
202 static int ccp_aes_cmac_final(struct ahash_request *req)
203 {
204 	return ccp_do_cmac_update(req, 0, 1);
205 }
206 
207 static int ccp_aes_cmac_finup(struct ahash_request *req)
208 {
209 	return ccp_do_cmac_update(req, req->nbytes, 1);
210 }
211 
212 static int ccp_aes_cmac_digest(struct ahash_request *req)
213 {
214 	int ret;
215 
216 	ret = ccp_aes_cmac_init(req);
217 	if (ret)
218 		return ret;
219 
220 	return ccp_aes_cmac_finup(req);
221 }
222 
223 static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
224 			       unsigned int key_len)
225 {
226 	struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
227 	struct ccp_crypto_ahash_alg *alg =
228 		ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
229 	u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
230 	u64 rb_hi = 0x00, rb_lo = 0x87;
231 	__be64 *gk;
232 	int ret;
233 
234 	switch (key_len) {
235 	case AES_KEYSIZE_128:
236 		ctx->u.aes.type = CCP_AES_TYPE_128;
237 		break;
238 	case AES_KEYSIZE_192:
239 		ctx->u.aes.type = CCP_AES_TYPE_192;
240 		break;
241 	case AES_KEYSIZE_256:
242 		ctx->u.aes.type = CCP_AES_TYPE_256;
243 		break;
244 	default:
245 		crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
246 		return -EINVAL;
247 	}
248 	ctx->u.aes.mode = alg->mode;
249 
250 	/* Set to zero until complete */
251 	ctx->u.aes.key_len = 0;
252 
253 	/* Set the key for the AES cipher used to generate the keys */
254 	ret = crypto_cipher_setkey(ctx->u.aes.tfm_cipher, key, key_len);
255 	if (ret)
256 		return ret;
257 
258 	/* Encrypt a block of zeroes - use key area in context */
259 	memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
260 	crypto_cipher_encrypt_one(ctx->u.aes.tfm_cipher, ctx->u.aes.key,
261 				  ctx->u.aes.key);
262 
263 	/* Generate K1 and K2 */
264 	k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
265 	k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));
266 
267 	k1_hi = (k0_hi << 1) | (k0_lo >> 63);
268 	k1_lo = k0_lo << 1;
269 	if (ctx->u.aes.key[0] & 0x80) {
270 		k1_hi ^= rb_hi;
271 		k1_lo ^= rb_lo;
272 	}
273 	gk = (__be64 *)ctx->u.aes.k1;
274 	*gk = cpu_to_be64(k1_hi);
275 	gk++;
276 	*gk = cpu_to_be64(k1_lo);
277 
278 	k2_hi = (k1_hi << 1) | (k1_lo >> 63);
279 	k2_lo = k1_lo << 1;
280 	if (ctx->u.aes.k1[0] & 0x80) {
281 		k2_hi ^= rb_hi;
282 		k2_lo ^= rb_lo;
283 	}
284 	gk = (__be64 *)ctx->u.aes.k2;
285 	*gk = cpu_to_be64(k2_hi);
286 	gk++;
287 	*gk = cpu_to_be64(k2_lo);
288 
289 	ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
290 	sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
291 	sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));
292 
293 	/* Save the supplied key */
294 	memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
295 	memcpy(ctx->u.aes.key, key, key_len);
296 	ctx->u.aes.key_len = key_len;
297 	sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
298 
299 	return ret;
300 }
301 
302 static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
303 {
304 	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
305 	struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
306 	struct crypto_cipher *cipher_tfm;
307 
308 	ctx->complete = ccp_aes_cmac_complete;
309 	ctx->u.aes.key_len = 0;
310 
311 	crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_aes_cmac_req_ctx));
312 
313 	cipher_tfm = crypto_alloc_cipher("aes", 0,
314 					 CRYPTO_ALG_ASYNC |
315 					 CRYPTO_ALG_NEED_FALLBACK);
316 	if (IS_ERR(cipher_tfm)) {
317 		pr_warn("could not load aes cipher driver\n");
318 		return PTR_ERR(cipher_tfm);
319 	}
320 	ctx->u.aes.tfm_cipher = cipher_tfm;
321 
322 	return 0;
323 }
324 
325 static void ccp_aes_cmac_cra_exit(struct crypto_tfm *tfm)
326 {
327 	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
328 
329 	if (ctx->u.aes.tfm_cipher)
330 		crypto_free_cipher(ctx->u.aes.tfm_cipher);
331 	ctx->u.aes.tfm_cipher = NULL;
332 }
333 
334 int ccp_register_aes_cmac_algs(struct list_head *head)
335 {
336 	struct ccp_crypto_ahash_alg *ccp_alg;
337 	struct ahash_alg *alg;
338 	struct hash_alg_common *halg;
339 	struct crypto_alg *base;
340 	int ret;
341 
342 	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
343 	if (!ccp_alg)
344 		return -ENOMEM;
345 
346 	INIT_LIST_HEAD(&ccp_alg->entry);
347 	ccp_alg->mode = CCP_AES_MODE_CMAC;
348 
349 	alg = &ccp_alg->alg;
350 	alg->init = ccp_aes_cmac_init;
351 	alg->update = ccp_aes_cmac_update;
352 	alg->final = ccp_aes_cmac_final;
353 	alg->finup = ccp_aes_cmac_finup;
354 	alg->digest = ccp_aes_cmac_digest;
355 	alg->setkey = ccp_aes_cmac_setkey;
356 
357 	halg = &alg->halg;
358 	halg->digestsize = AES_BLOCK_SIZE;
359 
360 	base = &halg->base;
361 	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
362 	snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
363 	base->cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC |
364 			  CRYPTO_ALG_KERN_DRIVER_ONLY |
365 			  CRYPTO_ALG_NEED_FALLBACK;
366 	base->cra_blocksize = AES_BLOCK_SIZE;
367 	base->cra_ctxsize = sizeof(struct ccp_ctx);
368 	base->cra_priority = CCP_CRA_PRIORITY;
369 	base->cra_type = &crypto_ahash_type;
370 	base->cra_init = ccp_aes_cmac_cra_init;
371 	base->cra_exit = ccp_aes_cmac_cra_exit;
372 	base->cra_module = THIS_MODULE;
373 
374 	ret = crypto_register_ahash(alg);
375 	if (ret) {
376 		pr_err("%s ahash algorithm registration error (%d)\n",
377 		       base->cra_name, ret);
378 		kfree(ccp_alg);
379 		return ret;
380 	}
381 
382 	list_add(&ccp_alg->entry, head);
383 
384 	return 0;
385 }
386