1/*
2 * AMD Cryptographic Coprocessor (CCP) RSA crypto API support
3 *
4 * Copyright (C) 2017 Advanced Micro Devices, Inc.
5 *
6 * Author: Gary R Hook <gary.hook@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/scatterlist.h>
16#include <linux/crypto.h>
17#include <crypto/algapi.h>
18#include <crypto/internal/rsa.h>
19#include <crypto/internal/akcipher.h>
20#include <crypto/akcipher.h>
21#include <crypto/scatterwalk.h>
22
23#include "ccp-crypto.h"
24
25static inline struct akcipher_request *akcipher_request_cast(
26 struct crypto_async_request *req)
27{
28 return container_of(req, struct akcipher_request, base);
29}
30
31static inline int ccp_copy_and_save_keypart(u8 **kpbuf, unsigned int *kplen,
32 const u8 *buf, size_t sz)
33{
34 int nskip;
35
36 for (nskip = 0; nskip < sz; nskip++)
37 if (buf[nskip])
38 break;
39 *kplen = sz - nskip;
40 *kpbuf = kzalloc(*kplen, GFP_KERNEL);
41 if (!*kpbuf)
42 return -ENOMEM;
43 memcpy(*kpbuf, buf + nskip, *kplen);
44
45 return 0;
46}
47
48static int ccp_rsa_complete(struct crypto_async_request *async_req, int ret)
49{
50 struct akcipher_request *req = akcipher_request_cast(async_req);
51 struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx(req);
52
53 if (ret)
54 return ret;
55
56 req->dst_len = rctx->cmd.u.rsa.key_size >> 3;
57
58 return 0;
59}
60
61static unsigned int ccp_rsa_maxsize(struct crypto_akcipher *tfm)
62{
63 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
64
65 return ctx->u.rsa.n_len;
66}
67
68static int ccp_rsa_crypt(struct akcipher_request *req, bool encrypt)
69{
70 struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
71 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
72 struct ccp_rsa_req_ctx *rctx = akcipher_request_ctx(req);
73 int ret = 0;
74
75 memset(&rctx->cmd, 0, sizeof(rctx->cmd));
76 INIT_LIST_HEAD(&rctx->cmd.entry);
77 rctx->cmd.engine = CCP_ENGINE_RSA;
78
79 rctx->cmd.u.rsa.key_size = ctx->u.rsa.key_len; /* in bits */
80 if (encrypt) {
81 rctx->cmd.u.rsa.exp = &ctx->u.rsa.e_sg;
82 rctx->cmd.u.rsa.exp_len = ctx->u.rsa.e_len;
83 } else {
84 rctx->cmd.u.rsa.exp = &ctx->u.rsa.d_sg;
85 rctx->cmd.u.rsa.exp_len = ctx->u.rsa.d_len;
86 }
87 rctx->cmd.u.rsa.mod = &ctx->u.rsa.n_sg;
88 rctx->cmd.u.rsa.mod_len = ctx->u.rsa.n_len;
89 rctx->cmd.u.rsa.src = req->src;
90 rctx->cmd.u.rsa.src_len = req->src_len;
91 rctx->cmd.u.rsa.dst = req->dst;
92
93 ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
94
95 return ret;
96}
97
98static int ccp_rsa_encrypt(struct akcipher_request *req)
99{
100 return ccp_rsa_crypt(req, true);
101}
102
103static int ccp_rsa_decrypt(struct akcipher_request *req)
104{
105 return ccp_rsa_crypt(req, false);
106}
107
108static int ccp_check_key_length(unsigned int len)
109{
110 /* In bits */
111 if (len < 8 || len > 4096)
112 return -EINVAL;
113 return 0;
114}
115
116static void ccp_rsa_free_key_bufs(struct ccp_ctx *ctx)
117{
118 /* Clean up old key data */
119 kzfree(ctx->u.rsa.e_buf);
120 ctx->u.rsa.e_buf = NULL;
121 ctx->u.rsa.e_len = 0;
122 kzfree(ctx->u.rsa.n_buf);
123 ctx->u.rsa.n_buf = NULL;
124 ctx->u.rsa.n_len = 0;
125 kzfree(ctx->u.rsa.d_buf);
126 ctx->u.rsa.d_buf = NULL;
127 ctx->u.rsa.d_len = 0;
128}
129
130static int ccp_rsa_setkey(struct crypto_akcipher *tfm, const void *key,
131 unsigned int keylen, bool private)
132{
133 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
134 struct rsa_key raw_key;
135 int ret;
136
137 ccp_rsa_free_key_bufs(ctx);
138 memset(&raw_key, 0, sizeof(raw_key));
139
140 /* Code borrowed from crypto/rsa.c */
141 if (private)
142 ret = rsa_parse_priv_key(&raw_key, key, keylen);
143 else
144 ret = rsa_parse_pub_key(&raw_key, key, keylen);
145 if (ret)
146 goto n_key;
147
148 ret = ccp_copy_and_save_keypart(&ctx->u.rsa.n_buf, &ctx->u.rsa.n_len,
149 raw_key.n, raw_key.n_sz);
150 if (ret)
151 goto key_err;
152 sg_init_one(&ctx->u.rsa.n_sg, ctx->u.rsa.n_buf, ctx->u.rsa.n_len);
153
154 ctx->u.rsa.key_len = ctx->u.rsa.n_len << 3; /* convert to bits */
155 if (ccp_check_key_length(ctx->u.rsa.key_len)) {
156 ret = -EINVAL;
157 goto key_err;
158 }
159
160 ret = ccp_copy_and_save_keypart(&ctx->u.rsa.e_buf, &ctx->u.rsa.e_len,
161 raw_key.e, raw_key.e_sz);
162 if (ret)
163 goto key_err;
164 sg_init_one(&ctx->u.rsa.e_sg, ctx->u.rsa.e_buf, ctx->u.rsa.e_len);
165
166 if (private) {
167 ret = ccp_copy_and_save_keypart(&ctx->u.rsa.d_buf,
168 &ctx->u.rsa.d_len,
169 raw_key.d, raw_key.d_sz);
170 if (ret)
171 goto key_err;
172 sg_init_one(&ctx->u.rsa.d_sg,
173 ctx->u.rsa.d_buf, ctx->u.rsa.d_len);
174 }
175
176 return 0;
177
178key_err:
179 ccp_rsa_free_key_bufs(ctx);
180
181n_key:
182 return ret;
183}
184
185static int ccp_rsa_setprivkey(struct crypto_akcipher *tfm, const void *key,
186 unsigned int keylen)
187{
188 return ccp_rsa_setkey(tfm, key, keylen, true);
189}
190
191static int ccp_rsa_setpubkey(struct crypto_akcipher *tfm, const void *key,
192 unsigned int keylen)
193{
194 return ccp_rsa_setkey(tfm, key, keylen, false);
195}
196
197static int ccp_rsa_init_tfm(struct crypto_akcipher *tfm)
198{
199 struct ccp_ctx *ctx = akcipher_tfm_ctx(tfm);
200
201 akcipher_set_reqsize(tfm, sizeof(struct ccp_rsa_req_ctx));
202 ctx->complete = ccp_rsa_complete;
203
204 return 0;
205}
206
207static void ccp_rsa_exit_tfm(struct crypto_akcipher *tfm)
208{
209 struct ccp_ctx *ctx = crypto_tfm_ctx(&tfm->base);
210
211 ccp_rsa_free_key_bufs(ctx);
212}
213
214static struct akcipher_alg ccp_rsa_defaults = {
215 .encrypt = ccp_rsa_encrypt,
216 .decrypt = ccp_rsa_decrypt,
217 .sign = ccp_rsa_decrypt,
218 .verify = ccp_rsa_encrypt,
219 .set_pub_key = ccp_rsa_setpubkey,
220 .set_priv_key = ccp_rsa_setprivkey,
221 .max_size = ccp_rsa_maxsize,
222 .init = ccp_rsa_init_tfm,
223 .exit = ccp_rsa_exit_tfm,
224 .base = {
225 .cra_name = "rsa",
226 .cra_driver_name = "rsa-ccp",
227 .cra_priority = CCP_CRA_PRIORITY,
228 .cra_module = THIS_MODULE,
229 .cra_ctxsize = 2 * sizeof(struct ccp_ctx),
230 },
231};
232
233struct ccp_rsa_def {
234 unsigned int version;
235 const char *name;
236 const char *driver_name;
237 unsigned int reqsize;
238 struct akcipher_alg *alg_defaults;
239};
240
241static struct ccp_rsa_def rsa_algs[] = {
242 {
243 .version = CCP_VERSION(3, 0),
244 .name = "rsa",
245 .driver_name = "rsa-ccp",
246 .reqsize = sizeof(struct ccp_rsa_req_ctx),
247 .alg_defaults = &ccp_rsa_defaults,
248 }
249};
250
251int ccp_register_rsa_alg(struct list_head *head, const struct ccp_rsa_def *def)
252{
253 struct ccp_crypto_akcipher_alg *ccp_alg;
254 struct akcipher_alg *alg;
255 int ret;
256
257 ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
258 if (!ccp_alg)
259 return -ENOMEM;
260
261 INIT_LIST_HEAD(&ccp_alg->entry);
262
263 alg = &ccp_alg->alg;
264 *alg = *def->alg_defaults;
265 snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
266 snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
267 def->driver_name);
268 ret = crypto_register_akcipher(alg);
269 if (ret) {
270 pr_err("%s akcipher algorithm registration error (%d)\n",
271 alg->base.cra_name, ret);
272 kfree(ccp_alg);
273 return ret;
274 }
275
276 list_add(&ccp_alg->entry, head);
277
278 return 0;
279}
280
281int ccp_register_rsa_algs(struct list_head *head)
282{
283 int i, ret;
284 unsigned int ccpversion = ccp_version();
285
286 /* Register the RSA algorithm in standard mode
287 * This works for CCP v3 and later
288 */
289 for (i = 0; i < ARRAY_SIZE(rsa_algs); i++) {
290 if (rsa_algs[i].version > ccpversion)
291 continue;
292 ret = ccp_register_rsa_alg(head, &rsa_algs[i]);
293 if (ret)
294 return ret;
295 }
296
297 return 0;
298}
299