1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* In-software asymmetric public-key crypto subtype
4 * See Documentation/crypto/asymmetric-keys.rst
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
11 #include <linux/module.h>
12 #include <linux/export.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/seq_file.h>
16 #include <linux/scatterlist.h>
17 #include <linux/asn1.h>
18 #include <keys/asymmetric-subtype.h>
19 #include <crypto/public_key.h>
20 #include <crypto/akcipher.h>
21 #include <crypto/sm2.h>
22 #include <crypto/sm3_base.h>
24 MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
25 MODULE_AUTHOR("Red Hat, Inc.");
26 MODULE_LICENSE("GPL");
29 * Provide a part of a description of the key for /proc/keys.
31 static void public_key_describe(const struct key *asymmetric_key,
34 struct public_key *key = asymmetric_key->payload.data[asym_crypto];
37 seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
41 * Destroy a public key algorithm key.
43 void public_key_free(struct public_key *key)
51 EXPORT_SYMBOL_GPL(public_key_free);
54 * Destroy a public key algorithm key.
56 static void public_key_destroy(void *payload0, void *payload3)
58 public_key_free(payload0);
59 public_key_signature_free(payload3);
63 * Determine the crypto algorithm name.
66 int software_key_determine_akcipher(const char *encoding,
67 const char *hash_algo,
68 const struct public_key *pkey,
69 char alg_name[CRYPTO_MAX_ALG_NAME])
73 if (strcmp(encoding, "pkcs1") == 0) {
74 /* The data wangled by the RSA algorithm is typically padded
75 * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
79 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
83 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
85 pkey->pkey_algo, hash_algo);
86 return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
89 if (strcmp(encoding, "raw") == 0 ||
90 strcmp(encoding, "x962") == 0) {
91 strcpy(alg_name, pkey->pkey_algo);
98 static u8 *pkey_pack_u32(u8 *dst, u32 val)
100 memcpy(dst, &val, sizeof(val));
101 return dst + sizeof(val);
105 * Query information about a key.
107 static int software_key_query(const struct kernel_pkey_params *params,
108 struct kernel_pkey_query *info)
110 struct crypto_akcipher *tfm;
111 struct public_key *pkey = params->key->payload.data[asym_crypto];
112 char alg_name[CRYPTO_MAX_ALG_NAME];
116 ret = software_key_determine_akcipher(params->encoding,
122 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
127 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
131 memcpy(key, pkey->key, pkey->keylen);
132 ptr = key + pkey->keylen;
133 ptr = pkey_pack_u32(ptr, pkey->algo);
134 ptr = pkey_pack_u32(ptr, pkey->paramlen);
135 memcpy(ptr, pkey->params, pkey->paramlen);
137 if (pkey->key_is_private)
138 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
140 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
144 len = crypto_akcipher_maxsize(tfm);
145 info->key_size = len * 8;
146 info->max_data_size = len;
147 info->max_sig_size = len;
148 info->max_enc_size = len;
149 info->max_dec_size = len;
150 info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
151 KEYCTL_SUPPORTS_VERIFY);
152 if (pkey->key_is_private)
153 info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
154 KEYCTL_SUPPORTS_SIGN);
160 crypto_free_akcipher(tfm);
161 pr_devel("<==%s() = %d\n", __func__, ret);
166 * Do encryption, decryption and signing ops.
168 static int software_key_eds_op(struct kernel_pkey_params *params,
169 const void *in, void *out)
171 const struct public_key *pkey = params->key->payload.data[asym_crypto];
172 struct akcipher_request *req;
173 struct crypto_akcipher *tfm;
174 struct crypto_wait cwait;
175 struct scatterlist in_sg, out_sg;
176 char alg_name[CRYPTO_MAX_ALG_NAME];
180 pr_devel("==>%s()\n", __func__);
182 ret = software_key_determine_akcipher(params->encoding,
188 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
193 req = akcipher_request_alloc(tfm, GFP_KERNEL);
197 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
202 memcpy(key, pkey->key, pkey->keylen);
203 ptr = key + pkey->keylen;
204 ptr = pkey_pack_u32(ptr, pkey->algo);
205 ptr = pkey_pack_u32(ptr, pkey->paramlen);
206 memcpy(ptr, pkey->params, pkey->paramlen);
208 if (pkey->key_is_private)
209 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
211 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
215 sg_init_one(&in_sg, in, params->in_len);
216 sg_init_one(&out_sg, out, params->out_len);
217 akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
219 crypto_init_wait(&cwait);
220 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
221 CRYPTO_TFM_REQ_MAY_SLEEP,
222 crypto_req_done, &cwait);
224 /* Perform the encryption calculation. */
225 switch (params->op) {
226 case kernel_pkey_encrypt:
227 ret = crypto_akcipher_encrypt(req);
229 case kernel_pkey_decrypt:
230 ret = crypto_akcipher_decrypt(req);
232 case kernel_pkey_sign:
233 ret = crypto_akcipher_sign(req);
239 ret = crypto_wait_req(ret, &cwait);
246 akcipher_request_free(req);
248 crypto_free_akcipher(tfm);
249 pr_devel("<==%s() = %d\n", __func__, ret);
253 #if IS_REACHABLE(CONFIG_CRYPTO_SM2)
254 static int cert_sig_digest_update(const struct public_key_signature *sig,
255 struct crypto_akcipher *tfm_pkey)
257 struct crypto_shash *tfm;
258 struct shash_desc *desc;
260 unsigned char dgst[SM3_DIGEST_SIZE];
265 ret = sm2_compute_z_digest(tfm_pkey, SM2_DEFAULT_USERID,
266 SM2_DEFAULT_USERID_LEN, dgst);
270 tfm = crypto_alloc_shash(sig->hash_algo, 0, 0);
274 desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
275 desc = kzalloc(desc_size, GFP_KERNEL);
283 ret = crypto_shash_init(desc);
285 goto error_free_desc;
287 ret = crypto_shash_update(desc, dgst, SM3_DIGEST_SIZE);
289 goto error_free_desc;
291 ret = crypto_shash_finup(desc, sig->data, sig->data_size, sig->digest);
296 crypto_free_shash(tfm);
300 static inline int cert_sig_digest_update(
301 const struct public_key_signature *sig,
302 struct crypto_akcipher *tfm_pkey)
306 #endif /* ! IS_REACHABLE(CONFIG_CRYPTO_SM2) */
309 * Verify a signature using a public key.
311 int public_key_verify_signature(const struct public_key *pkey,
312 const struct public_key_signature *sig)
314 struct crypto_wait cwait;
315 struct crypto_akcipher *tfm;
316 struct akcipher_request *req;
317 struct scatterlist src_sg[2];
318 char alg_name[CRYPTO_MAX_ALG_NAME];
322 pr_devel("==>%s()\n", __func__);
328 ret = software_key_determine_akcipher(sig->encoding,
334 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
339 req = akcipher_request_alloc(tfm, GFP_KERNEL);
343 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
348 memcpy(key, pkey->key, pkey->keylen);
349 ptr = key + pkey->keylen;
350 ptr = pkey_pack_u32(ptr, pkey->algo);
351 ptr = pkey_pack_u32(ptr, pkey->paramlen);
352 memcpy(ptr, pkey->params, pkey->paramlen);
354 if (pkey->key_is_private)
355 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
357 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
361 if (sig->pkey_algo && strcmp(sig->pkey_algo, "sm2") == 0 &&
363 ret = cert_sig_digest_update(sig, tfm);
368 sg_init_table(src_sg, 2);
369 sg_set_buf(&src_sg[0], sig->s, sig->s_size);
370 sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
371 akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
373 crypto_init_wait(&cwait);
374 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
375 CRYPTO_TFM_REQ_MAY_SLEEP,
376 crypto_req_done, &cwait);
377 ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
382 akcipher_request_free(req);
384 crypto_free_akcipher(tfm);
385 pr_devel("<==%s() = %d\n", __func__, ret);
386 if (WARN_ON_ONCE(ret > 0))
390 EXPORT_SYMBOL_GPL(public_key_verify_signature);
392 static int public_key_verify_signature_2(const struct key *key,
393 const struct public_key_signature *sig)
395 const struct public_key *pk = key->payload.data[asym_crypto];
396 return public_key_verify_signature(pk, sig);
400 * Public key algorithm asymmetric key subtype
402 struct asymmetric_key_subtype public_key_subtype = {
403 .owner = THIS_MODULE,
404 .name = "public_key",
405 .name_len = sizeof("public_key") - 1,
406 .describe = public_key_describe,
407 .destroy = public_key_destroy,
408 .query = software_key_query,
409 .eds_op = software_key_eds_op,
410 .verify_signature = public_key_verify_signature_2,
412 EXPORT_SYMBOL_GPL(public_key_subtype);