1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AMD Cryptographic Coprocessor (CCP) RSA crypto API support
4 *
5 * Copyright (C) 2017 Advanced Micro Devices, Inc.
6 *
7 * Author: Gary R Hook <gary.hook@amd.com>
8 */
9
10#include <linux/module.h>
11#include <linux/sched.h>
12#include <linux/scatterlist.h>
13#include <linux/crypto.h>
14#include <crypto/algapi.h>
15#include <crypto/internal/rsa.h>
16#include <crypto/internal/akcipher.h>
17#include <crypto/akcipher.h>
18#include <crypto/scatterwalk.h>
19
20#include "ccp-crypto.h"
21
22static inline struct akcipher_request *akcipher_request_cast(
23	struct crypto_async_request *req)
24{
25	return container_of(req, struct akcipher_request, base);
26}
27
28static inline int ccp_copy_and_save_keypart(u8 **kpbuf, unsigned int *kplen,
29					    const u8 *buf, size_t sz)
30{
31	int nskip;
32
33	for (nskip = 0; nskip < sz; nskip++)
34		if (buf[nskip])
35			break;
36	*kplen = sz - nskip;
37	*kpbuf = kmemdup(buf + nskip, *kplen, GFP_KERNEL);
38	if (!*kpbuf)
39		return -ENOMEM;
40
41	return 0;
42}
43
44static int ccp_rsa_complete(struct crypto_async_request *async_req, int ret)
45{
46	struct akcipher_request *req = akcipher_request_cast(async_req);
47	struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx_dma(req);
48
49	if (ret)
50		return ret;
51
52	req->dst_len = rctx->cmd.u.rsa.key_size >> 3;
53
54	return 0;
55}
56
57static unsigned int ccp_rsa_maxsize(struct crypto_akcipher *tfm)
58{
59	struct ccp_ctx *ctx = akcipher_tfm_ctx_dma(tfm);
60
61	return ctx->u.rsa.n_len;
62}
63
64static int ccp_rsa_crypt(struct akcipher_request *req, bool encrypt)
65{
66	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
67	struct ccp_ctx *ctx = akcipher_tfm_ctx_dma(tfm);
68	struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx_dma(req);
69	int ret = 0;
70
71	memset(&rctx->cmd, 0, sizeof(rctx->cmd));
72	INIT_LIST_HEAD(&rctx->cmd.entry);
73	rctx->cmd.engine = CCP_ENGINE_RSA;
74
75	rctx->cmd.u.rsa.key_size = ctx->u.rsa.key_len; /* in bits */
76	if (encrypt) {
77		rctx->cmd.u.rsa.exp = &ctx->u.rsa.e_sg;
78		rctx->cmd.u.rsa.exp_len = ctx->u.rsa.e_len;
79	} else {
80		rctx->cmd.u.rsa.exp = &ctx->u.rsa.d_sg;
81		rctx->cmd.u.rsa.exp_len = ctx->u.rsa.d_len;
82	}
83	rctx->cmd.u.rsa.mod = &ctx->u.rsa.n_sg;
84	rctx->cmd.u.rsa.mod_len = ctx->u.rsa.n_len;
85	rctx->cmd.u.rsa.src = req->src;
86	rctx->cmd.u.rsa.src_len = req->src_len;
87	rctx->cmd.u.rsa.dst = req->dst;
88
89	ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
90
91	return ret;
92}
93
94static int ccp_rsa_encrypt(struct akcipher_request *req)
95{
96	return ccp_rsa_crypt(req, true);
97}
98
99static int ccp_rsa_decrypt(struct akcipher_request *req)
100{
101	return ccp_rsa_crypt(req, false);
102}
103
104static int ccp_check_key_length(unsigned int len)
105{
106	/* In bits */
107	if (len < 8 || len > 4096)
108		return -EINVAL;
109	return 0;
110}
111
112static void ccp_rsa_free_key_bufs(struct ccp_ctx *ctx)
113{
114	/* Clean up old key data */
115	kfree_sensitive(ctx->u.rsa.e_buf);
116	ctx->u.rsa.e_buf = NULL;
117	ctx->u.rsa.e_len = 0;
118	kfree_sensitive(ctx->u.rsa.n_buf);
119	ctx->u.rsa.n_buf = NULL;
120	ctx->u.rsa.n_len = 0;
121	kfree_sensitive(ctx->u.rsa.d_buf);
122	ctx->u.rsa.d_buf = NULL;
123	ctx->u.rsa.d_len = 0;
124}
125
126static int ccp_rsa_setkey(struct crypto_akcipher *tfm, const void *key,
127			  unsigned int keylen, bool private)
128{
129	struct ccp_ctx *ctx = akcipher_tfm_ctx_dma(tfm);
130	struct rsa_key raw_key;
131	int ret;
132
133	ccp_rsa_free_key_bufs(ctx);
134	memset(&raw_key, 0, sizeof(raw_key));
135
136	/* Code borrowed from crypto/rsa.c */
137	if (private)
138		ret = rsa_parse_priv_key(&raw_key, key, keylen);
139	else
140		ret = rsa_parse_pub_key(&raw_key, key, keylen);
141	if (ret)
142		goto n_key;
143
144	ret = ccp_copy_and_save_keypart(&ctx->u.rsa.n_buf, &ctx->u.rsa.n_len,
145					raw_key.n, raw_key.n_sz);
146	if (ret)
147		goto key_err;
148	sg_init_one(&ctx->u.rsa.n_sg, ctx->u.rsa.n_buf, ctx->u.rsa.n_len);
149
150	ctx->u.rsa.key_len = ctx->u.rsa.n_len << 3; /* convert to bits */
151	if (ccp_check_key_length(ctx->u.rsa.key_len)) {
152		ret = -EINVAL;
153		goto key_err;
154	}
155
156	ret = ccp_copy_and_save_keypart(&ctx->u.rsa.e_buf, &ctx->u.rsa.e_len,
157					raw_key.e, raw_key.e_sz);
158	if (ret)
159		goto key_err;
160	sg_init_one(&ctx->u.rsa.e_sg, ctx->u.rsa.e_buf, ctx->u.rsa.e_len);
161
162	if (private) {
163		ret = ccp_copy_and_save_keypart(&ctx->u.rsa.d_buf,
164						&ctx->u.rsa.d_len,
165						raw_key.d, raw_key.d_sz);
166		if (ret)
167			goto key_err;
168		sg_init_one(&ctx->u.rsa.d_sg,
169			    ctx->u.rsa.d_buf, ctx->u.rsa.d_len);
170	}
171
172	return 0;
173
174key_err:
175	ccp_rsa_free_key_bufs(ctx);
176
177n_key:
178	return ret;
179}
180
181static int ccp_rsa_setprivkey(struct crypto_akcipher *tfm, const void *key,
182			      unsigned int keylen)
183{
184	return ccp_rsa_setkey(tfm, key, keylen, true);
185}
186
187static int ccp_rsa_setpubkey(struct crypto_akcipher *tfm, const void *key,
188			     unsigned int keylen)
189{
190	return ccp_rsa_setkey(tfm, key, keylen, false);
191}
192
193static int ccp_rsa_init_tfm(struct crypto_akcipher *tfm)
194{
195	struct ccp_ctx *ctx = akcipher_tfm_ctx_dma(tfm);
196
197	akcipher_set_reqsize_dma(tfm, sizeof(struct ccp_rsa_req_ctx));
198	ctx->complete = ccp_rsa_complete;
199
200	return 0;
201}
202
203static void ccp_rsa_exit_tfm(struct crypto_akcipher *tfm)
204{
205	struct ccp_ctx *ctx = akcipher_tfm_ctx_dma(tfm);
206
207	ccp_rsa_free_key_bufs(ctx);
208}
209
210static struct akcipher_alg ccp_rsa_defaults = {
211	.encrypt = ccp_rsa_encrypt,
212	.decrypt = ccp_rsa_decrypt,
213	.set_pub_key = ccp_rsa_setpubkey,
214	.set_priv_key = ccp_rsa_setprivkey,
215	.max_size = ccp_rsa_maxsize,
216	.init = ccp_rsa_init_tfm,
217	.exit = ccp_rsa_exit_tfm,
218	.base = {
219		.cra_name = "rsa",
220		.cra_driver_name = "rsa-ccp",
221		.cra_priority = CCP_CRA_PRIORITY,
222		.cra_module = THIS_MODULE,
223		.cra_ctxsize = 2 * sizeof(struct ccp_ctx) + CRYPTO_DMA_PADDING,
224	},
225};
226
227struct ccp_rsa_def {
228	unsigned int version;
229	const char *name;
230	const char *driver_name;
231	unsigned int reqsize;
232	struct akcipher_alg *alg_defaults;
233};
234
235static struct ccp_rsa_def rsa_algs[] = {
236	{
237		.version	= CCP_VERSION(3, 0),
238		.name		= "rsa",
239		.driver_name	= "rsa-ccp",
240		.reqsize	= sizeof(struct ccp_rsa_req_ctx),
241		.alg_defaults	= &ccp_rsa_defaults,
242	}
243};
244
245static int ccp_register_rsa_alg(struct list_head *head,
246			        const struct ccp_rsa_def *def)
247{
248	struct ccp_crypto_akcipher_alg *ccp_alg;
249	struct akcipher_alg *alg;
250	int ret;
251
252	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
253	if (!ccp_alg)
254		return -ENOMEM;
255
256	INIT_LIST_HEAD(&ccp_alg->entry);
257
258	alg = &ccp_alg->alg;
259	*alg = *def->alg_defaults;
260	snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
261	snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
262		 def->driver_name);
263	ret = crypto_register_akcipher(alg);
264	if (ret) {
265		pr_err("%s akcipher algorithm registration error (%d)\n",
266		       alg->base.cra_name, ret);
267		kfree(ccp_alg);
268		return ret;
269	}
270
271	list_add(&ccp_alg->entry, head);
272
273	return 0;
274}
275
276int ccp_register_rsa_algs(struct list_head *head)
277{
278	int i, ret;
279	unsigned int ccpversion = ccp_version();
280
281	/* Register the RSA algorithm in standard mode
282	 * This works for CCP v3 and later
283	 */
284	for (i = 0; i < ARRAY_SIZE(rsa_algs); i++) {
285		if (rsa_algs[i].version > ccpversion)
286			continue;
287		ret = ccp_register_rsa_alg(head, &rsa_algs[i]);
288		if (ret)
289			return ret;
290	}
291
292	return 0;
293}
294