1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AMD Cryptographic Coprocessor (CCP) AES CMAC crypto API support
4  *
5  * Copyright (C) 2013,2018 Advanced Micro Devices, Inc.
6  *
7  * Author: Tom Lendacky <thomas.lendacky@amd.com>
8  */
9 
10 #include <linux/module.h>
11 #include <linux/sched.h>
12 #include <linux/delay.h>
13 #include <linux/scatterlist.h>
14 #include <linux/crypto.h>
15 #include <crypto/algapi.h>
16 #include <crypto/aes.h>
17 #include <crypto/hash.h>
18 #include <crypto/internal/hash.h>
19 #include <crypto/scatterwalk.h>
20 
21 #include "ccp-crypto.h"
22 
23 static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
24 				 int ret)
25 {
26 	struct ahash_request *req = ahash_request_cast(async_req);
27 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
28 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
29 	unsigned int digest_size = crypto_ahash_digestsize(tfm);
30 
31 	if (ret)
32 		goto e_free;
33 
34 	if (rctx->hash_rem) {
35 		/* Save remaining data to buffer */
36 		unsigned int offset = rctx->nbytes - rctx->hash_rem;
37 
38 		scatterwalk_map_and_copy(rctx->buf, rctx->src,
39 					 offset, rctx->hash_rem, 0);
40 		rctx->buf_count = rctx->hash_rem;
41 	} else {
42 		rctx->buf_count = 0;
43 	}
44 
45 	/* Update result area if supplied */
46 	if (req->result && rctx->final)
47 		memcpy(req->result, rctx->iv, digest_size);
48 
49 e_free:
50 	sg_free_table(&rctx->data_sg);
51 
52 	return ret;
53 }
54 
55 static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
56 			      unsigned int final)
57 {
58 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
59 	struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
60 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
61 	struct scatterlist *sg, *cmac_key_sg = NULL;
62 	unsigned int block_size =
63 		crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
64 	unsigned int need_pad, sg_count;
65 	gfp_t gfp;
66 	u64 len;
67 	int ret;
68 
69 	if (!ctx->u.aes.key_len)
70 		return -EINVAL;
71 
72 	if (nbytes)
73 		rctx->null_msg = 0;
74 
75 	len = (u64)rctx->buf_count + (u64)nbytes;
76 
77 	if (!final && (len <= block_size)) {
78 		scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
79 					 0, nbytes, 0);
80 		rctx->buf_count += nbytes;
81 
82 		return 0;
83 	}
84 
85 	rctx->src = req->src;
86 	rctx->nbytes = nbytes;
87 
88 	rctx->final = final;
89 	rctx->hash_rem = final ? 0 : len & (block_size - 1);
90 	rctx->hash_cnt = len - rctx->hash_rem;
91 	if (!final && !rctx->hash_rem) {
92 		/* CCP can't do zero length final, so keep some data around */
93 		rctx->hash_cnt -= block_size;
94 		rctx->hash_rem = block_size;
95 	}
96 
97 	if (final && (rctx->null_msg || (len & (block_size - 1))))
98 		need_pad = 1;
99 	else
100 		need_pad = 0;
101 
102 	sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));
103 
104 	/* Build the data scatterlist table - allocate enough entries for all
105 	 * possible data pieces (buffer, input data, padding)
106 	 */
107 	sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
108 	gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
109 		GFP_KERNEL : GFP_ATOMIC;
110 	ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
111 	if (ret)
112 		return ret;
113 
114 	sg = NULL;
115 	if (rctx->buf_count) {
116 		sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
117 		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
118 		if (!sg) {
119 			ret = -EINVAL;
120 			goto e_free;
121 		}
122 	}
123 
124 	if (nbytes) {
125 		sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
126 		if (!sg) {
127 			ret = -EINVAL;
128 			goto e_free;
129 		}
130 	}
131 
132 	if (need_pad) {
133 		int pad_length = block_size - (len & (block_size - 1));
134 
135 		rctx->hash_cnt += pad_length;
136 
137 		memset(rctx->pad, 0, sizeof(rctx->pad));
138 		rctx->pad[0] = 0x80;
139 		sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
140 		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
141 		if (!sg) {
142 			ret = -EINVAL;
143 			goto e_free;
144 		}
145 	}
146 	if (sg) {
147 		sg_mark_end(sg);
148 		sg = rctx->data_sg.sgl;
149 	}
150 
151 	/* Initialize the K1/K2 scatterlist */
152 	if (final)
153 		cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
154 					 : &ctx->u.aes.k1_sg;
155 
156 	memset(&rctx->cmd, 0, sizeof(rctx->cmd));
157 	INIT_LIST_HEAD(&rctx->cmd.entry);
158 	rctx->cmd.engine = CCP_ENGINE_AES;
159 	rctx->cmd.u.aes.type = ctx->u.aes.type;
160 	rctx->cmd.u.aes.mode = ctx->u.aes.mode;
161 	rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
162 	rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
163 	rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
164 	rctx->cmd.u.aes.iv = &rctx->iv_sg;
165 	rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
166 	rctx->cmd.u.aes.src = sg;
167 	rctx->cmd.u.aes.src_len = rctx->hash_cnt;
168 	rctx->cmd.u.aes.dst = NULL;
169 	rctx->cmd.u.aes.cmac_key = cmac_key_sg;
170 	rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
171 	rctx->cmd.u.aes.cmac_final = final;
172 
173 	ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
174 
175 	return ret;
176 
177 e_free:
178 	sg_free_table(&rctx->data_sg);
179 
180 	return ret;
181 }
182 
183 static int ccp_aes_cmac_init(struct ahash_request *req)
184 {
185 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
186 
187 	memset(rctx, 0, sizeof(*rctx));
188 
189 	rctx->null_msg = 1;
190 
191 	return 0;
192 }
193 
194 static int ccp_aes_cmac_update(struct ahash_request *req)
195 {
196 	return ccp_do_cmac_update(req, req->nbytes, 0);
197 }
198 
199 static int ccp_aes_cmac_final(struct ahash_request *req)
200 {
201 	return ccp_do_cmac_update(req, 0, 1);
202 }
203 
204 static int ccp_aes_cmac_finup(struct ahash_request *req)
205 {
206 	return ccp_do_cmac_update(req, req->nbytes, 1);
207 }
208 
209 static int ccp_aes_cmac_digest(struct ahash_request *req)
210 {
211 	int ret;
212 
213 	ret = ccp_aes_cmac_init(req);
214 	if (ret)
215 		return ret;
216 
217 	return ccp_aes_cmac_finup(req);
218 }
219 
220 static int ccp_aes_cmac_export(struct ahash_request *req, void *out)
221 {
222 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
223 	struct ccp_aes_cmac_exp_ctx state;
224 
225 	/* Don't let anything leak to 'out' */
226 	memset(&state, 0, sizeof(state));
227 
228 	state.null_msg = rctx->null_msg;
229 	memcpy(state.iv, rctx->iv, sizeof(state.iv));
230 	state.buf_count = rctx->buf_count;
231 	memcpy(state.buf, rctx->buf, sizeof(state.buf));
232 
233 	/* 'out' may not be aligned so memcpy from local variable */
234 	memcpy(out, &state, sizeof(state));
235 
236 	return 0;
237 }
238 
239 static int ccp_aes_cmac_import(struct ahash_request *req, const void *in)
240 {
241 	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
242 	struct ccp_aes_cmac_exp_ctx state;
243 
244 	/* 'in' may not be aligned so memcpy to local variable */
245 	memcpy(&state, in, sizeof(state));
246 
247 	memset(rctx, 0, sizeof(*rctx));
248 	rctx->null_msg = state.null_msg;
249 	memcpy(rctx->iv, state.iv, sizeof(rctx->iv));
250 	rctx->buf_count = state.buf_count;
251 	memcpy(rctx->buf, state.buf, sizeof(rctx->buf));
252 
253 	return 0;
254 }
255 
256 static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
257 			       unsigned int key_len)
258 {
259 	struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
260 	struct ccp_crypto_ahash_alg *alg =
261 		ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
262 	u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
263 	u64 rb_hi = 0x00, rb_lo = 0x87;
264 	struct crypto_aes_ctx aes;
265 	__be64 *gk;
266 	int ret;
267 
268 	switch (key_len) {
269 	case AES_KEYSIZE_128:
270 		ctx->u.aes.type = CCP_AES_TYPE_128;
271 		break;
272 	case AES_KEYSIZE_192:
273 		ctx->u.aes.type = CCP_AES_TYPE_192;
274 		break;
275 	case AES_KEYSIZE_256:
276 		ctx->u.aes.type = CCP_AES_TYPE_256;
277 		break;
278 	default:
279 		return -EINVAL;
280 	}
281 	ctx->u.aes.mode = alg->mode;
282 
283 	/* Set to zero until complete */
284 	ctx->u.aes.key_len = 0;
285 
286 	/* Set the key for the AES cipher used to generate the keys */
287 	ret = aes_expandkey(&aes, key, key_len);
288 	if (ret)
289 		return ret;
290 
291 	/* Encrypt a block of zeroes - use key area in context */
292 	memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
293 	aes_encrypt(&aes, ctx->u.aes.key, ctx->u.aes.key);
294 	memzero_explicit(&aes, sizeof(aes));
295 
296 	/* Generate K1 and K2 */
297 	k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
298 	k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));
299 
300 	k1_hi = (k0_hi << 1) | (k0_lo >> 63);
301 	k1_lo = k0_lo << 1;
302 	if (ctx->u.aes.key[0] & 0x80) {
303 		k1_hi ^= rb_hi;
304 		k1_lo ^= rb_lo;
305 	}
306 	gk = (__be64 *)ctx->u.aes.k1;
307 	*gk = cpu_to_be64(k1_hi);
308 	gk++;
309 	*gk = cpu_to_be64(k1_lo);
310 
311 	k2_hi = (k1_hi << 1) | (k1_lo >> 63);
312 	k2_lo = k1_lo << 1;
313 	if (ctx->u.aes.k1[0] & 0x80) {
314 		k2_hi ^= rb_hi;
315 		k2_lo ^= rb_lo;
316 	}
317 	gk = (__be64 *)ctx->u.aes.k2;
318 	*gk = cpu_to_be64(k2_hi);
319 	gk++;
320 	*gk = cpu_to_be64(k2_lo);
321 
322 	ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
323 	sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
324 	sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));
325 
326 	/* Save the supplied key */
327 	memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
328 	memcpy(ctx->u.aes.key, key, key_len);
329 	ctx->u.aes.key_len = key_len;
330 	sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
331 
332 	return ret;
333 }
334 
335 static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
336 {
337 	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
338 	struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
339 
340 	ctx->complete = ccp_aes_cmac_complete;
341 	ctx->u.aes.key_len = 0;
342 
343 	crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_aes_cmac_req_ctx));
344 
345 	return 0;
346 }
347 
348 int ccp_register_aes_cmac_algs(struct list_head *head)
349 {
350 	struct ccp_crypto_ahash_alg *ccp_alg;
351 	struct ahash_alg *alg;
352 	struct hash_alg_common *halg;
353 	struct crypto_alg *base;
354 	int ret;
355 
356 	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
357 	if (!ccp_alg)
358 		return -ENOMEM;
359 
360 	INIT_LIST_HEAD(&ccp_alg->entry);
361 	ccp_alg->mode = CCP_AES_MODE_CMAC;
362 
363 	alg = &ccp_alg->alg;
364 	alg->init = ccp_aes_cmac_init;
365 	alg->update = ccp_aes_cmac_update;
366 	alg->final = ccp_aes_cmac_final;
367 	alg->finup = ccp_aes_cmac_finup;
368 	alg->digest = ccp_aes_cmac_digest;
369 	alg->export = ccp_aes_cmac_export;
370 	alg->import = ccp_aes_cmac_import;
371 	alg->setkey = ccp_aes_cmac_setkey;
372 
373 	halg = &alg->halg;
374 	halg->digestsize = AES_BLOCK_SIZE;
375 	halg->statesize = sizeof(struct ccp_aes_cmac_exp_ctx);
376 
377 	base = &halg->base;
378 	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
379 	snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
380 	base->cra_flags = CRYPTO_ALG_ASYNC |
381 			  CRYPTO_ALG_ALLOCATES_MEMORY |
382 			  CRYPTO_ALG_KERN_DRIVER_ONLY |
383 			  CRYPTO_ALG_NEED_FALLBACK;
384 	base->cra_blocksize = AES_BLOCK_SIZE;
385 	base->cra_ctxsize = sizeof(struct ccp_ctx);
386 	base->cra_priority = CCP_CRA_PRIORITY;
387 	base->cra_init = ccp_aes_cmac_cra_init;
388 	base->cra_module = THIS_MODULE;
389 
390 	ret = crypto_register_ahash(alg);
391 	if (ret) {
392 		pr_err("%s ahash algorithm registration error (%d)\n",
393 		       base->cra_name, ret);
394 		kfree(ccp_alg);
395 		return ret;
396 	}
397 
398 	list_add(&ccp_alg->entry, head);
399 
400 	return 0;
401 }
402