1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* In-software asymmetric public-key crypto subtype
4 * See Documentation/crypto/asymmetric-keys.txt
6 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
10 #define pr_fmt(fmt) "PKEY: "fmt
12 #include <dm/devres.h>
13 #include <linux/bug.h>
14 #include <linux/compat.h>
15 #include <linux/err.h>
17 #include <linux/module.h>
18 #include <linux/export.h>
20 #include <linux/kernel.h>
22 #include <linux/slab.h>
23 #include <linux/seq_file.h>
24 #include <linux/scatterlist.h>
25 #include <keys/asymmetric-subtype.h>
27 #include <crypto/public_key.h>
29 #include <crypto/akcipher.h>
32 MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
33 MODULE_AUTHOR("Red Hat, Inc.");
34 MODULE_LICENSE("GPL");
38 * Provide a part of a description of the key for /proc/keys.
40 static void public_key_describe(const struct key *asymmetric_key,
43 struct public_key *key = asymmetric_key->payload.data[asym_crypto];
46 seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
51 * Destroy a public key algorithm key.
53 void public_key_free(struct public_key *key)
61 EXPORT_SYMBOL_GPL(public_key_free);
65 * from <linux>/crypto/asymmetric_keys/signature.c
67 * Destroy a public key signature.
69 void public_key_signature_free(struct public_key_signature *sig)
74 for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
75 free(sig->auth_ids[i]);
81 EXPORT_SYMBOL_GPL(public_key_signature_free);
85 * Destroy a public key algorithm key.
87 static void public_key_destroy(void *payload0, void *payload3)
89 public_key_free(payload0);
90 public_key_signature_free(payload3);
94 * Determine the crypto algorithm name.
97 int software_key_determine_akcipher(const char *encoding,
98 const char *hash_algo,
99 const struct public_key *pkey,
100 char alg_name[CRYPTO_MAX_ALG_NAME])
104 if (strcmp(encoding, "pkcs1") == 0) {
105 /* The data wangled by the RSA algorithm is typically padded
106 * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
110 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
114 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
116 pkey->pkey_algo, hash_algo);
117 return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
120 if (strcmp(encoding, "raw") == 0) {
121 strcpy(alg_name, pkey->pkey_algo);
128 static u8 *pkey_pack_u32(u8 *dst, u32 val)
130 memcpy(dst, &val, sizeof(val));
131 return dst + sizeof(val);
135 * Query information about a key.
137 static int software_key_query(const struct kernel_pkey_params *params,
138 struct kernel_pkey_query *info)
140 struct crypto_akcipher *tfm;
141 struct public_key *pkey = params->key->payload.data[asym_crypto];
142 char alg_name[CRYPTO_MAX_ALG_NAME];
146 ret = software_key_determine_akcipher(params->encoding,
152 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
156 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
160 memcpy(key, pkey->key, pkey->keylen);
161 ptr = key + pkey->keylen;
162 ptr = pkey_pack_u32(ptr, pkey->algo);
163 ptr = pkey_pack_u32(ptr, pkey->paramlen);
164 memcpy(ptr, pkey->params, pkey->paramlen);
166 if (pkey->key_is_private)
167 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
169 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
173 len = crypto_akcipher_maxsize(tfm);
174 info->key_size = len * 8;
175 info->max_data_size = len;
176 info->max_sig_size = len;
177 info->max_enc_size = len;
178 info->max_dec_size = len;
179 info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
180 KEYCTL_SUPPORTS_VERIFY);
181 if (pkey->key_is_private)
182 info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
183 KEYCTL_SUPPORTS_SIGN);
189 crypto_free_akcipher(tfm);
190 pr_devel("<==%s() = %d\n", __func__, ret);
195 * Do encryption, decryption and signing ops.
197 static int software_key_eds_op(struct kernel_pkey_params *params,
198 const void *in, void *out)
200 const struct public_key *pkey = params->key->payload.data[asym_crypto];
201 struct akcipher_request *req;
202 struct crypto_akcipher *tfm;
203 struct crypto_wait cwait;
204 struct scatterlist in_sg, out_sg;
205 char alg_name[CRYPTO_MAX_ALG_NAME];
209 pr_devel("==>%s()\n", __func__);
211 ret = software_key_determine_akcipher(params->encoding,
217 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
221 req = akcipher_request_alloc(tfm, GFP_KERNEL);
225 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
230 memcpy(key, pkey->key, pkey->keylen);
231 ptr = key + pkey->keylen;
232 ptr = pkey_pack_u32(ptr, pkey->algo);
233 ptr = pkey_pack_u32(ptr, pkey->paramlen);
234 memcpy(ptr, pkey->params, pkey->paramlen);
236 if (pkey->key_is_private)
237 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
239 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
243 sg_init_one(&in_sg, in, params->in_len);
244 sg_init_one(&out_sg, out, params->out_len);
245 akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
247 crypto_init_wait(&cwait);
248 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
249 CRYPTO_TFM_REQ_MAY_SLEEP,
250 crypto_req_done, &cwait);
252 /* Perform the encryption calculation. */
253 switch (params->op) {
254 case kernel_pkey_encrypt:
255 ret = crypto_akcipher_encrypt(req);
257 case kernel_pkey_decrypt:
258 ret = crypto_akcipher_decrypt(req);
260 case kernel_pkey_sign:
261 ret = crypto_akcipher_sign(req);
267 ret = crypto_wait_req(ret, &cwait);
274 akcipher_request_free(req);
276 crypto_free_akcipher(tfm);
277 pr_devel("<==%s() = %d\n", __func__, ret);
282 * Verify a signature using a public key.
284 int public_key_verify_signature(const struct public_key *pkey,
285 const struct public_key_signature *sig)
287 struct crypto_wait cwait;
288 struct crypto_akcipher *tfm;
289 struct akcipher_request *req;
290 struct scatterlist src_sg[2];
291 char alg_name[CRYPTO_MAX_ALG_NAME];
295 pr_devel("==>%s()\n", __func__);
301 ret = software_key_determine_akcipher(sig->encoding,
307 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
312 req = akcipher_request_alloc(tfm, GFP_KERNEL);
316 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
321 memcpy(key, pkey->key, pkey->keylen);
322 ptr = key + pkey->keylen;
323 ptr = pkey_pack_u32(ptr, pkey->algo);
324 ptr = pkey_pack_u32(ptr, pkey->paramlen);
325 memcpy(ptr, pkey->params, pkey->paramlen);
327 if (pkey->key_is_private)
328 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
330 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
334 sg_init_table(src_sg, 2);
335 sg_set_buf(&src_sg[0], sig->s, sig->s_size);
336 sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
337 akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
339 crypto_init_wait(&cwait);
340 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
341 CRYPTO_TFM_REQ_MAY_SLEEP,
342 crypto_req_done, &cwait);
343 ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
348 akcipher_request_free(req);
350 crypto_free_akcipher(tfm);
351 pr_devel("<==%s() = %d\n", __func__, ret);
352 if (WARN_ON_ONCE(ret > 0))
356 EXPORT_SYMBOL_GPL(public_key_verify_signature);
358 static int public_key_verify_signature_2(const struct key *key,
359 const struct public_key_signature *sig)
361 const struct public_key *pk = key->payload.data[asym_crypto];
362 return public_key_verify_signature(pk, sig);
366 * Public key algorithm asymmetric key subtype
368 struct asymmetric_key_subtype public_key_subtype = {
369 .owner = THIS_MODULE,
370 .name = "public_key",
371 .name_len = sizeof("public_key") - 1,
372 .describe = public_key_describe,
373 .destroy = public_key_destroy,
374 .query = software_key_query,
375 .eds_op = software_key_eds_op,
376 .verify_signature = public_key_verify_signature_2,
378 EXPORT_SYMBOL_GPL(public_key_subtype);
379 #endif /* !__UBOOT__ */