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471 lines
12 KiB
471 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* In-software asymmetric public-key crypto subtype |
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* |
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* See Documentation/crypto/asymmetric-keys.rst |
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* |
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* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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|
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#define pr_fmt(fmt) "PKEY: "fmt |
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#include <linux/module.h> |
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#include <linux/export.h> |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/seq_file.h> |
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#include <linux/scatterlist.h> |
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#include <linux/asn1.h> |
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#include <keys/asymmetric-subtype.h> |
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#include <crypto/public_key.h> |
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#include <crypto/akcipher.h> |
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#include <crypto/sm2.h> |
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#include <crypto/sm3_base.h> |
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|
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MODULE_DESCRIPTION("In-software asymmetric public-key subtype"); |
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MODULE_AUTHOR("Red Hat, Inc."); |
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MODULE_LICENSE("GPL"); |
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|
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/* |
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* Provide a part of a description of the key for /proc/keys. |
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*/ |
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static void public_key_describe(const struct key *asymmetric_key, |
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struct seq_file *m) |
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{ |
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struct public_key *key = asymmetric_key->payload.data[asym_crypto]; |
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|
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if (key) |
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seq_printf(m, "%s.%s", key->id_type, key->pkey_algo); |
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} |
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/* |
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* Destroy a public key algorithm key. |
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*/ |
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void public_key_free(struct public_key *key) |
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{ |
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if (key) { |
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kfree(key->key); |
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kfree(key->params); |
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kfree(key); |
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} |
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} |
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EXPORT_SYMBOL_GPL(public_key_free); |
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|
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/* |
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* Destroy a public key algorithm key. |
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*/ |
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static void public_key_destroy(void *payload0, void *payload3) |
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{ |
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public_key_free(payload0); |
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public_key_signature_free(payload3); |
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} |
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/* |
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* Given a public_key, and an encoding and hash_algo to be used for signing |
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* and/or verification with that key, determine the name of the corresponding |
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* akcipher algorithm. Also check that encoding and hash_algo are allowed. |
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*/ |
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static int |
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software_key_determine_akcipher(const struct public_key *pkey, |
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const char *encoding, const char *hash_algo, |
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char alg_name[CRYPTO_MAX_ALG_NAME]) |
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{ |
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int n; |
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|
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if (!encoding) |
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return -EINVAL; |
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if (strcmp(pkey->pkey_algo, "rsa") == 0) { |
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/* |
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* RSA signatures usually use EMSA-PKCS1-1_5 [RFC3447 sec 8.2]. |
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*/ |
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if (strcmp(encoding, "pkcs1") == 0) { |
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if (!hash_algo) |
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n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, |
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"pkcs1pad(%s)", |
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pkey->pkey_algo); |
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else |
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n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, |
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"pkcs1pad(%s,%s)", |
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pkey->pkey_algo, hash_algo); |
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return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0; |
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} |
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if (strcmp(encoding, "raw") != 0) |
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return -EINVAL; |
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/* |
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* Raw RSA cannot differentiate between different hash |
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* algorithms. |
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*/ |
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if (hash_algo) |
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return -EINVAL; |
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} else if (strncmp(pkey->pkey_algo, "ecdsa", 5) == 0) { |
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if (strcmp(encoding, "x962") != 0) |
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return -EINVAL; |
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/* |
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* ECDSA signatures are taken over a raw hash, so they don't |
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* differentiate between different hash algorithms. That means |
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* that the verifier should hard-code a specific hash algorithm. |
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* Unfortunately, in practice ECDSA is used with multiple SHAs, |
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* so we have to allow all of them and not just one. |
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*/ |
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if (!hash_algo) |
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return -EINVAL; |
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if (strcmp(hash_algo, "sha1") != 0 && |
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strcmp(hash_algo, "sha224") != 0 && |
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strcmp(hash_algo, "sha256") != 0 && |
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strcmp(hash_algo, "sha384") != 0 && |
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strcmp(hash_algo, "sha512") != 0) |
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return -EINVAL; |
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} else if (strcmp(pkey->pkey_algo, "sm2") == 0) { |
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if (strcmp(encoding, "raw") != 0) |
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return -EINVAL; |
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if (!hash_algo) |
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return -EINVAL; |
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if (strcmp(hash_algo, "sm3") != 0) |
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return -EINVAL; |
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} else if (strcmp(pkey->pkey_algo, "ecrdsa") == 0) { |
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if (strcmp(encoding, "raw") != 0) |
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return -EINVAL; |
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if (!hash_algo) |
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return -EINVAL; |
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if (strcmp(hash_algo, "streebog256") != 0 && |
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strcmp(hash_algo, "streebog512") != 0) |
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return -EINVAL; |
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} else { |
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/* Unknown public key algorithm */ |
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return -ENOPKG; |
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} |
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if (strscpy(alg_name, pkey->pkey_algo, CRYPTO_MAX_ALG_NAME) < 0) |
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return -EINVAL; |
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return 0; |
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} |
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static u8 *pkey_pack_u32(u8 *dst, u32 val) |
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{ |
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memcpy(dst, &val, sizeof(val)); |
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return dst + sizeof(val); |
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} |
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/* |
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* Query information about a key. |
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*/ |
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static int software_key_query(const struct kernel_pkey_params *params, |
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struct kernel_pkey_query *info) |
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{ |
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struct crypto_akcipher *tfm; |
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struct public_key *pkey = params->key->payload.data[asym_crypto]; |
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char alg_name[CRYPTO_MAX_ALG_NAME]; |
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u8 *key, *ptr; |
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int ret, len; |
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ret = software_key_determine_akcipher(pkey, params->encoding, |
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params->hash_algo, alg_name); |
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if (ret < 0) |
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return ret; |
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tfm = crypto_alloc_akcipher(alg_name, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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ret = -ENOMEM; |
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key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen, |
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GFP_KERNEL); |
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if (!key) |
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goto error_free_tfm; |
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memcpy(key, pkey->key, pkey->keylen); |
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ptr = key + pkey->keylen; |
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ptr = pkey_pack_u32(ptr, pkey->algo); |
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ptr = pkey_pack_u32(ptr, pkey->paramlen); |
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memcpy(ptr, pkey->params, pkey->paramlen); |
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if (pkey->key_is_private) |
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ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen); |
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else |
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ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen); |
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if (ret < 0) |
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goto error_free_key; |
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len = crypto_akcipher_maxsize(tfm); |
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info->key_size = len * 8; |
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info->max_data_size = len; |
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info->max_sig_size = len; |
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info->max_enc_size = len; |
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info->max_dec_size = len; |
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info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT | |
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KEYCTL_SUPPORTS_VERIFY); |
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if (pkey->key_is_private) |
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info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT | |
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KEYCTL_SUPPORTS_SIGN); |
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ret = 0; |
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error_free_key: |
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kfree(key); |
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error_free_tfm: |
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crypto_free_akcipher(tfm); |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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return ret; |
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} |
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/* |
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* Do encryption, decryption and signing ops. |
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*/ |
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static int software_key_eds_op(struct kernel_pkey_params *params, |
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const void *in, void *out) |
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{ |
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const struct public_key *pkey = params->key->payload.data[asym_crypto]; |
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struct akcipher_request *req; |
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struct crypto_akcipher *tfm; |
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struct crypto_wait cwait; |
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struct scatterlist in_sg, out_sg; |
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char alg_name[CRYPTO_MAX_ALG_NAME]; |
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char *key, *ptr; |
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int ret; |
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pr_devel("==>%s()\n", __func__); |
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ret = software_key_determine_akcipher(pkey, params->encoding, |
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params->hash_algo, alg_name); |
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if (ret < 0) |
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return ret; |
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tfm = crypto_alloc_akcipher(alg_name, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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ret = -ENOMEM; |
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req = akcipher_request_alloc(tfm, GFP_KERNEL); |
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if (!req) |
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goto error_free_tfm; |
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key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen, |
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GFP_KERNEL); |
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if (!key) |
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goto error_free_req; |
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memcpy(key, pkey->key, pkey->keylen); |
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ptr = key + pkey->keylen; |
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ptr = pkey_pack_u32(ptr, pkey->algo); |
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ptr = pkey_pack_u32(ptr, pkey->paramlen); |
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memcpy(ptr, pkey->params, pkey->paramlen); |
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if (pkey->key_is_private) |
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ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen); |
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else |
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ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen); |
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if (ret) |
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goto error_free_key; |
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sg_init_one(&in_sg, in, params->in_len); |
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sg_init_one(&out_sg, out, params->out_len); |
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akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len, |
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params->out_len); |
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crypto_init_wait(&cwait); |
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akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | |
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CRYPTO_TFM_REQ_MAY_SLEEP, |
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crypto_req_done, &cwait); |
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/* Perform the encryption calculation. */ |
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switch (params->op) { |
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case kernel_pkey_encrypt: |
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ret = crypto_akcipher_encrypt(req); |
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break; |
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case kernel_pkey_decrypt: |
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ret = crypto_akcipher_decrypt(req); |
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break; |
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case kernel_pkey_sign: |
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ret = crypto_akcipher_sign(req); |
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break; |
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default: |
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BUG(); |
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} |
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ret = crypto_wait_req(ret, &cwait); |
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if (ret == 0) |
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ret = req->dst_len; |
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error_free_key: |
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kfree(key); |
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error_free_req: |
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akcipher_request_free(req); |
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error_free_tfm: |
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crypto_free_akcipher(tfm); |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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return ret; |
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} |
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#if IS_REACHABLE(CONFIG_CRYPTO_SM2) |
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static int cert_sig_digest_update(const struct public_key_signature *sig, |
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struct crypto_akcipher *tfm_pkey) |
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{ |
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struct crypto_shash *tfm; |
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struct shash_desc *desc; |
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size_t desc_size; |
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unsigned char dgst[SM3_DIGEST_SIZE]; |
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int ret; |
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BUG_ON(!sig->data); |
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/* SM2 signatures always use the SM3 hash algorithm */ |
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if (!sig->hash_algo || strcmp(sig->hash_algo, "sm3") != 0) |
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return -EINVAL; |
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ret = sm2_compute_z_digest(tfm_pkey, SM2_DEFAULT_USERID, |
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SM2_DEFAULT_USERID_LEN, dgst); |
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if (ret) |
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return ret; |
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tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); |
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desc = kzalloc(desc_size, GFP_KERNEL); |
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if (!desc) { |
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ret = -ENOMEM; |
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goto error_free_tfm; |
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} |
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desc->tfm = tfm; |
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ret = crypto_shash_init(desc); |
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if (ret < 0) |
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goto error_free_desc; |
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ret = crypto_shash_update(desc, dgst, SM3_DIGEST_SIZE); |
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if (ret < 0) |
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goto error_free_desc; |
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ret = crypto_shash_finup(desc, sig->data, sig->data_size, sig->digest); |
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error_free_desc: |
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kfree(desc); |
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error_free_tfm: |
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crypto_free_shash(tfm); |
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return ret; |
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} |
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#else |
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static inline int cert_sig_digest_update( |
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const struct public_key_signature *sig, |
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struct crypto_akcipher *tfm_pkey) |
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{ |
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return -ENOTSUPP; |
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} |
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#endif /* ! IS_REACHABLE(CONFIG_CRYPTO_SM2) */ |
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/* |
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* Verify a signature using a public key. |
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*/ |
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int public_key_verify_signature(const struct public_key *pkey, |
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const struct public_key_signature *sig) |
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{ |
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struct crypto_wait cwait; |
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struct crypto_akcipher *tfm; |
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struct akcipher_request *req; |
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struct scatterlist src_sg[2]; |
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char alg_name[CRYPTO_MAX_ALG_NAME]; |
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char *key, *ptr; |
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int ret; |
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pr_devel("==>%s()\n", __func__); |
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BUG_ON(!pkey); |
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BUG_ON(!sig); |
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BUG_ON(!sig->s); |
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/* |
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* If the signature specifies a public key algorithm, it *must* match |
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* the key's actual public key algorithm. |
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* |
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* Small exception: ECDSA signatures don't specify the curve, but ECDSA |
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* keys do. So the strings can mismatch slightly in that case: |
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* "ecdsa-nist-*" for the key, but "ecdsa" for the signature. |
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*/ |
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if (sig->pkey_algo) { |
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if (strcmp(pkey->pkey_algo, sig->pkey_algo) != 0 && |
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(strncmp(pkey->pkey_algo, "ecdsa-", 6) != 0 || |
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strcmp(sig->pkey_algo, "ecdsa") != 0)) |
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return -EKEYREJECTED; |
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} |
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ret = software_key_determine_akcipher(pkey, sig->encoding, |
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sig->hash_algo, alg_name); |
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if (ret < 0) |
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return ret; |
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tfm = crypto_alloc_akcipher(alg_name, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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ret = -ENOMEM; |
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req = akcipher_request_alloc(tfm, GFP_KERNEL); |
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if (!req) |
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goto error_free_tfm; |
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key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen, |
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GFP_KERNEL); |
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if (!key) |
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goto error_free_req; |
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memcpy(key, pkey->key, pkey->keylen); |
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ptr = key + pkey->keylen; |
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ptr = pkey_pack_u32(ptr, pkey->algo); |
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ptr = pkey_pack_u32(ptr, pkey->paramlen); |
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memcpy(ptr, pkey->params, pkey->paramlen); |
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if (pkey->key_is_private) |
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ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen); |
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else |
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ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen); |
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if (ret) |
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goto error_free_key; |
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if (strcmp(pkey->pkey_algo, "sm2") == 0 && sig->data_size) { |
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ret = cert_sig_digest_update(sig, tfm); |
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if (ret) |
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goto error_free_key; |
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} |
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sg_init_table(src_sg, 2); |
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sg_set_buf(&src_sg[0], sig->s, sig->s_size); |
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sg_set_buf(&src_sg[1], sig->digest, sig->digest_size); |
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akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, |
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sig->digest_size); |
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crypto_init_wait(&cwait); |
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akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | |
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CRYPTO_TFM_REQ_MAY_SLEEP, |
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crypto_req_done, &cwait); |
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ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait); |
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error_free_key: |
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kfree(key); |
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error_free_req: |
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akcipher_request_free(req); |
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error_free_tfm: |
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crypto_free_akcipher(tfm); |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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if (WARN_ON_ONCE(ret > 0)) |
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ret = -EINVAL; |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(public_key_verify_signature); |
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static int public_key_verify_signature_2(const struct key *key, |
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const struct public_key_signature *sig) |
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{ |
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const struct public_key *pk = key->payload.data[asym_crypto]; |
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return public_key_verify_signature(pk, sig); |
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} |
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/* |
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* Public key algorithm asymmetric key subtype |
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*/ |
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struct asymmetric_key_subtype public_key_subtype = { |
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.owner = THIS_MODULE, |
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.name = "public_key", |
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.name_len = sizeof("public_key") - 1, |
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.describe = public_key_describe, |
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.destroy = public_key_destroy, |
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.query = software_key_query, |
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.eds_op = software_key_eds_op, |
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.verify_signature = public_key_verify_signature_2, |
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}; |
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EXPORT_SYMBOL_GPL(public_key_subtype);
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