1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* In-software asymmetric public-key crypto subtype
3 *
4 * See Documentation/crypto/asymmetric-keys.txt
5 *
6 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
8 */
9
10 #define pr_fmt(fmt) "PKEY: "fmt
11 #ifdef __UBOOT__
12 #include <dm/devres.h>
13 #include <linux/bug.h>
14 #include <linux/compat.h>
15 #include <linux/err.h>
16 #include <linux/printk.h>
17 #else
18 #include <linux/module.h>
19 #include <linux/export.h>
20 #endif
21 #include <linux/kernel.h>
22 #ifndef __UBOOT__
23 #include <linux/slab.h>
24 #include <linux/seq_file.h>
25 #include <linux/scatterlist.h>
26 #include <keys/asymmetric-subtype.h>
27 #endif
28 #include <crypto/public_key.h>
29 #ifdef __UBOOT__
30 #include <image.h>
31 #include <u-boot/rsa.h>
32 #else
33 #include <crypto/akcipher.h>
34 #endif
35
36 MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
37 MODULE_AUTHOR("Red Hat, Inc.");
38 MODULE_LICENSE("GPL");
39
40 #ifndef __UBOOT__
41 /*
42 * Provide a part of a description of the key for /proc/keys.
43 */
public_key_describe(const struct key * asymmetric_key,struct seq_file * m)44 static void public_key_describe(const struct key *asymmetric_key,
45 struct seq_file *m)
46 {
47 struct public_key *key = asymmetric_key->payload.data[asym_crypto];
48
49 if (key)
50 seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
51 }
52 #endif
53
54 #ifdef __UBOOT__
55
56 /**
57 * public_key_verify_signature - Verify a signature using a public key.
58 *
59 * @pkey: Public key
60 * @sig: Signature
61 *
62 * Verify a signature, @sig, using a RSA public key, @pkey.
63 *
64 * Return: 0 - verified, non-zero error code - otherwise
65 */
public_key_verify_signature(const struct public_key * pkey,const struct public_key_signature * sig)66 int public_key_verify_signature(const struct public_key *pkey,
67 const struct public_key_signature *sig)
68 {
69 struct image_sign_info info;
70 char algo[256];
71 int ret;
72
73 pr_devel("==>%s()\n", __func__);
74
75 if (!pkey || !sig)
76 return -EINVAL;
77
78 if (pkey->key_is_private)
79 return -EINVAL;
80
81 memset(&info, '\0', sizeof(info));
82 memset(algo, 0, sizeof(algo));
83 info.padding = image_get_padding_algo("pkcs-1.5");
84 if (strcmp(sig->pkey_algo, "rsa")) {
85 pr_err("Encryption is not RSA: %s\n", sig->pkey_algo);
86 return -ENOPKG;
87 }
88 ret = snprintf(algo, sizeof(algo), "%s,%s%d", sig->hash_algo,
89 sig->pkey_algo, sig->s_size * 8);
90
91 if (ret >= sizeof(algo))
92 return -EINVAL;
93
94 info.checksum = image_get_checksum_algo((const char *)algo);
95 info.name = (const char *)algo;
96 info.crypto = image_get_crypto_algo(info.name);
97 if (!info.checksum || !info.crypto) {
98 pr_err("<%s> not supported on image_get_(checksum|crypto)_algo()\n",
99 algo);
100 return -ENOPKG;
101 }
102
103 info.key = pkey->key;
104 info.keylen = pkey->keylen;
105
106 if (rsa_verify_with_pkey(&info, sig->digest, sig->s, sig->s_size))
107 ret = -EKEYREJECTED;
108 else
109 ret = 0;
110
111 pr_devel("<==%s() = %d\n", __func__, ret);
112 return ret;
113 }
114 #else
115 /*
116 * Destroy a public key algorithm key.
117 */
public_key_destroy(void * payload0,void * payload3)118 static void public_key_destroy(void *payload0, void *payload3)
119 {
120 public_key_free(payload0);
121 public_key_signature_free(payload3);
122 }
123
124 /*
125 * Determine the crypto algorithm name.
126 */
127 static
software_key_determine_akcipher(const char * encoding,const char * hash_algo,const struct public_key * pkey,char alg_name[CRYPTO_MAX_ALG_NAME])128 int software_key_determine_akcipher(const char *encoding,
129 const char *hash_algo,
130 const struct public_key *pkey,
131 char alg_name[CRYPTO_MAX_ALG_NAME])
132 {
133 int n;
134
135 if (strcmp(encoding, "pkcs1") == 0) {
136 /* The data wangled by the RSA algorithm is typically padded
137 * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
138 * sec 8.2].
139 */
140 if (!hash_algo)
141 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
142 "pkcs1pad(%s)",
143 pkey->pkey_algo);
144 else
145 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
146 "pkcs1pad(%s,%s)",
147 pkey->pkey_algo, hash_algo);
148 return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
149 }
150
151 if (strcmp(encoding, "raw") == 0) {
152 strcpy(alg_name, pkey->pkey_algo);
153 return 0;
154 }
155
156 return -ENOPKG;
157 }
158
pkey_pack_u32(u8 * dst,u32 val)159 static u8 *pkey_pack_u32(u8 *dst, u32 val)
160 {
161 memcpy(dst, &val, sizeof(val));
162 return dst + sizeof(val);
163 }
164
165 /*
166 * Query information about a key.
167 */
software_key_query(const struct kernel_pkey_params * params,struct kernel_pkey_query * info)168 static int software_key_query(const struct kernel_pkey_params *params,
169 struct kernel_pkey_query *info)
170 {
171 struct crypto_akcipher *tfm;
172 struct public_key *pkey = params->key->payload.data[asym_crypto];
173 char alg_name[CRYPTO_MAX_ALG_NAME];
174 u8 *key, *ptr;
175 int ret, len;
176
177 ret = software_key_determine_akcipher(params->encoding,
178 params->hash_algo,
179 pkey, alg_name);
180 if (ret < 0)
181 return ret;
182
183 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
184 if (IS_ERR(tfm))
185 return PTR_ERR(tfm);
186
187 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
188 GFP_KERNEL);
189 if (!key)
190 goto error_free_tfm;
191 memcpy(key, pkey->key, pkey->keylen);
192 ptr = key + pkey->keylen;
193 ptr = pkey_pack_u32(ptr, pkey->algo);
194 ptr = pkey_pack_u32(ptr, pkey->paramlen);
195 memcpy(ptr, pkey->params, pkey->paramlen);
196
197 if (pkey->key_is_private)
198 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
199 else
200 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
201 if (ret < 0)
202 goto error_free_key;
203
204 len = crypto_akcipher_maxsize(tfm);
205 info->key_size = len * 8;
206 info->max_data_size = len;
207 info->max_sig_size = len;
208 info->max_enc_size = len;
209 info->max_dec_size = len;
210 info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
211 KEYCTL_SUPPORTS_VERIFY);
212 if (pkey->key_is_private)
213 info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
214 KEYCTL_SUPPORTS_SIGN);
215 ret = 0;
216
217 error_free_key:
218 kfree(key);
219 error_free_tfm:
220 crypto_free_akcipher(tfm);
221 pr_devel("<==%s() = %d\n", __func__, ret);
222 return ret;
223 }
224
225 /*
226 * Do encryption, decryption and signing ops.
227 */
software_key_eds_op(struct kernel_pkey_params * params,const void * in,void * out)228 static int software_key_eds_op(struct kernel_pkey_params *params,
229 const void *in, void *out)
230 {
231 const struct public_key *pkey = params->key->payload.data[asym_crypto];
232 struct akcipher_request *req;
233 struct crypto_akcipher *tfm;
234 struct crypto_wait cwait;
235 struct scatterlist in_sg, out_sg;
236 char alg_name[CRYPTO_MAX_ALG_NAME];
237 char *key, *ptr;
238 int ret;
239
240 pr_devel("==>%s()\n", __func__);
241
242 ret = software_key_determine_akcipher(params->encoding,
243 params->hash_algo,
244 pkey, alg_name);
245 if (ret < 0)
246 return ret;
247
248 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
249 if (IS_ERR(tfm))
250 return PTR_ERR(tfm);
251
252 req = akcipher_request_alloc(tfm, GFP_KERNEL);
253 if (!req)
254 goto error_free_tfm;
255
256 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
257 GFP_KERNEL);
258 if (!key)
259 goto error_free_req;
260
261 memcpy(key, pkey->key, pkey->keylen);
262 ptr = key + pkey->keylen;
263 ptr = pkey_pack_u32(ptr, pkey->algo);
264 ptr = pkey_pack_u32(ptr, pkey->paramlen);
265 memcpy(ptr, pkey->params, pkey->paramlen);
266
267 if (pkey->key_is_private)
268 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
269 else
270 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
271 if (ret)
272 goto error_free_key;
273
274 sg_init_one(&in_sg, in, params->in_len);
275 sg_init_one(&out_sg, out, params->out_len);
276 akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
277 params->out_len);
278 crypto_init_wait(&cwait);
279 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
280 CRYPTO_TFM_REQ_MAY_SLEEP,
281 crypto_req_done, &cwait);
282
283 /* Perform the encryption calculation. */
284 switch (params->op) {
285 case kernel_pkey_encrypt:
286 ret = crypto_akcipher_encrypt(req);
287 break;
288 case kernel_pkey_decrypt:
289 ret = crypto_akcipher_decrypt(req);
290 break;
291 case kernel_pkey_sign:
292 ret = crypto_akcipher_sign(req);
293 break;
294 default:
295 BUG();
296 }
297
298 ret = crypto_wait_req(ret, &cwait);
299 if (ret == 0)
300 ret = req->dst_len;
301
302 error_free_key:
303 kfree(key);
304 error_free_req:
305 akcipher_request_free(req);
306 error_free_tfm:
307 crypto_free_akcipher(tfm);
308 pr_devel("<==%s() = %d\n", __func__, ret);
309 return ret;
310 }
311
312 /*
313 * Verify a signature using a public key.
314 */
public_key_verify_signature(const struct public_key * pkey,const struct public_key_signature * sig)315 int public_key_verify_signature(const struct public_key *pkey,
316 const struct public_key_signature *sig)
317 {
318 struct crypto_wait cwait;
319 struct crypto_akcipher *tfm;
320 struct akcipher_request *req;
321 struct scatterlist src_sg[2];
322 char alg_name[CRYPTO_MAX_ALG_NAME];
323 char *key, *ptr;
324 int ret;
325
326 pr_devel("==>%s()\n", __func__);
327
328 BUG_ON(!pkey);
329 BUG_ON(!sig);
330 BUG_ON(!sig->s);
331
332 ret = software_key_determine_akcipher(sig->encoding,
333 sig->hash_algo,
334 pkey, alg_name);
335 if (ret < 0)
336 return ret;
337
338 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
339 if (IS_ERR(tfm))
340 return PTR_ERR(tfm);
341
342 ret = -ENOMEM;
343 req = akcipher_request_alloc(tfm, GFP_KERNEL);
344 if (!req)
345 goto error_free_tfm;
346
347 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
348 GFP_KERNEL);
349 if (!key)
350 goto error_free_req;
351
352 memcpy(key, pkey->key, pkey->keylen);
353 ptr = key + pkey->keylen;
354 ptr = pkey_pack_u32(ptr, pkey->algo);
355 ptr = pkey_pack_u32(ptr, pkey->paramlen);
356 memcpy(ptr, pkey->params, pkey->paramlen);
357
358 if (pkey->key_is_private)
359 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
360 else
361 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
362 if (ret)
363 goto error_free_key;
364
365 sg_init_table(src_sg, 2);
366 sg_set_buf(&src_sg[0], sig->s, sig->s_size);
367 sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
368 akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
369 sig->digest_size);
370 crypto_init_wait(&cwait);
371 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
372 CRYPTO_TFM_REQ_MAY_SLEEP,
373 crypto_req_done, &cwait);
374 ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
375
376 error_free_key:
377 kfree(key);
378 error_free_req:
379 akcipher_request_free(req);
380 error_free_tfm:
381 crypto_free_akcipher(tfm);
382 pr_devel("<==%s() = %d\n", __func__, ret);
383 if (WARN_ON_ONCE(ret > 0))
384 ret = -EINVAL;
385 return ret;
386 }
387 EXPORT_SYMBOL_GPL(public_key_verify_signature);
388
public_key_verify_signature_2(const struct key * key,const struct public_key_signature * sig)389 static int public_key_verify_signature_2(const struct key *key,
390 const struct public_key_signature *sig)
391 {
392 const struct public_key *pk = key->payload.data[asym_crypto];
393 return public_key_verify_signature(pk, sig);
394 }
395
396 /*
397 * Public key algorithm asymmetric key subtype
398 */
399 struct asymmetric_key_subtype public_key_subtype = {
400 .owner = THIS_MODULE,
401 .name = "public_key",
402 .name_len = sizeof("public_key") - 1,
403 .describe = public_key_describe,
404 .destroy = public_key_destroy,
405 .query = software_key_query,
406 .eds_op = software_key_eds_op,
407 .verify_signature = public_key_verify_signature_2,
408 };
409 EXPORT_SYMBOL_GPL(public_key_subtype);
410 #endif /* !__UBOOT__ */
411