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
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 <keys/asymmetric-subtype.h>
18 #include <crypto/public_key.h>
19 #include <crypto/akcipher.h>
21 MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
22 MODULE_AUTHOR("Red Hat, Inc.");
23 MODULE_LICENSE("GPL");
26 * Provide a part of a description of the key for /proc/keys.
28 static void public_key_describe(const struct key *asymmetric_key,
31 struct public_key *key = asymmetric_key->payload.data[asym_crypto];
34 seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
38 * Destroy a public key algorithm key.
40 void public_key_free(struct public_key *key)
48 EXPORT_SYMBOL_GPL(public_key_free);
51 * Destroy a public key algorithm key.
53 static void public_key_destroy(void *payload0, void *payload3)
55 public_key_free(payload0);
56 public_key_signature_free(payload3);
60 * Determine the crypto algorithm name.
63 int software_key_determine_akcipher(const char *encoding,
64 const char *hash_algo,
65 const struct public_key *pkey,
66 char alg_name[CRYPTO_MAX_ALG_NAME])
70 if (strcmp(encoding, "pkcs1") == 0) {
71 /* The data wangled by the RSA algorithm is typically padded
72 * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
76 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
80 n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
82 pkey->pkey_algo, hash_algo);
83 return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
86 if (strcmp(encoding, "raw") == 0) {
87 strcpy(alg_name, pkey->pkey_algo);
94 static u8 *pkey_pack_u32(u8 *dst, u32 val)
96 memcpy(dst, &val, sizeof(val));
97 return dst + sizeof(val);
101 * Query information about a key.
103 static int software_key_query(const struct kernel_pkey_params *params,
104 struct kernel_pkey_query *info)
106 struct crypto_akcipher *tfm;
107 struct public_key *pkey = params->key->payload.data[asym_crypto];
108 char alg_name[CRYPTO_MAX_ALG_NAME];
112 ret = software_key_determine_akcipher(params->encoding,
118 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
122 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
126 memcpy(key, pkey->key, pkey->keylen);
127 ptr = key + pkey->keylen;
128 ptr = pkey_pack_u32(ptr, pkey->algo);
129 ptr = pkey_pack_u32(ptr, pkey->paramlen);
130 memcpy(ptr, pkey->params, pkey->paramlen);
132 if (pkey->key_is_private)
133 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
135 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
139 len = crypto_akcipher_maxsize(tfm);
140 info->key_size = len * 8;
141 info->max_data_size = len;
142 info->max_sig_size = len;
143 info->max_enc_size = len;
144 info->max_dec_size = len;
145 info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
146 KEYCTL_SUPPORTS_VERIFY);
147 if (pkey->key_is_private)
148 info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
149 KEYCTL_SUPPORTS_SIGN);
155 crypto_free_akcipher(tfm);
156 pr_devel("<==%s() = %d\n", __func__, ret);
161 * Do encryption, decryption and signing ops.
163 static int software_key_eds_op(struct kernel_pkey_params *params,
164 const void *in, void *out)
166 const struct public_key *pkey = params->key->payload.data[asym_crypto];
167 struct akcipher_request *req;
168 struct crypto_akcipher *tfm;
169 struct crypto_wait cwait;
170 struct scatterlist in_sg, out_sg;
171 char alg_name[CRYPTO_MAX_ALG_NAME];
175 pr_devel("==>%s()\n", __func__);
177 ret = software_key_determine_akcipher(params->encoding,
183 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
187 req = akcipher_request_alloc(tfm, GFP_KERNEL);
191 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
196 memcpy(key, pkey->key, pkey->keylen);
197 ptr = key + pkey->keylen;
198 ptr = pkey_pack_u32(ptr, pkey->algo);
199 ptr = pkey_pack_u32(ptr, pkey->paramlen);
200 memcpy(ptr, pkey->params, pkey->paramlen);
202 if (pkey->key_is_private)
203 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
205 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
209 sg_init_one(&in_sg, in, params->in_len);
210 sg_init_one(&out_sg, out, params->out_len);
211 akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
213 crypto_init_wait(&cwait);
214 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
215 CRYPTO_TFM_REQ_MAY_SLEEP,
216 crypto_req_done, &cwait);
218 /* Perform the encryption calculation. */
219 switch (params->op) {
220 case kernel_pkey_encrypt:
221 ret = crypto_akcipher_encrypt(req);
223 case kernel_pkey_decrypt:
224 ret = crypto_akcipher_decrypt(req);
226 case kernel_pkey_sign:
227 ret = crypto_akcipher_sign(req);
233 ret = crypto_wait_req(ret, &cwait);
240 akcipher_request_free(req);
242 crypto_free_akcipher(tfm);
243 pr_devel("<==%s() = %d\n", __func__, ret);
248 * Verify a signature using a public key.
250 int public_key_verify_signature(const struct public_key *pkey,
251 const struct public_key_signature *sig)
253 struct crypto_wait cwait;
254 struct crypto_akcipher *tfm;
255 struct akcipher_request *req;
256 struct scatterlist src_sg[2];
257 char alg_name[CRYPTO_MAX_ALG_NAME];
261 pr_devel("==>%s()\n", __func__);
267 ret = software_key_determine_akcipher(sig->encoding,
273 tfm = crypto_alloc_akcipher(alg_name, 0, 0);
278 req = akcipher_request_alloc(tfm, GFP_KERNEL);
282 key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
287 memcpy(key, pkey->key, pkey->keylen);
288 ptr = key + pkey->keylen;
289 ptr = pkey_pack_u32(ptr, pkey->algo);
290 ptr = pkey_pack_u32(ptr, pkey->paramlen);
291 memcpy(ptr, pkey->params, pkey->paramlen);
293 if (pkey->key_is_private)
294 ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
296 ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
300 sg_init_table(src_sg, 2);
301 sg_set_buf(&src_sg[0], sig->s, sig->s_size);
302 sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
303 akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
305 crypto_init_wait(&cwait);
306 akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
307 CRYPTO_TFM_REQ_MAY_SLEEP,
308 crypto_req_done, &cwait);
309 ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
314 akcipher_request_free(req);
316 crypto_free_akcipher(tfm);
317 pr_devel("<==%s() = %d\n", __func__, ret);
318 if (WARN_ON_ONCE(ret > 0))
322 EXPORT_SYMBOL_GPL(public_key_verify_signature);
324 static int public_key_verify_signature_2(const struct key *key,
325 const struct public_key_signature *sig)
327 const struct public_key *pk = key->payload.data[asym_crypto];
328 return public_key_verify_signature(pk, sig);
332 * Public key algorithm asymmetric key subtype
334 struct asymmetric_key_subtype public_key_subtype = {
335 .owner = THIS_MODULE,
336 .name = "public_key",
337 .name_len = sizeof("public_key") - 1,
338 .describe = public_key_describe,
339 .destroy = public_key_destroy,
340 .query = software_key_query,
341 .eds_op = software_key_eds_op,
342 .verify_signature = public_key_verify_signature_2,
344 EXPORT_SYMBOL_GPL(public_key_subtype);