347 lines
8.5 KiB
C
347 lines
8.5 KiB
C
// 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 (dhowells@redhat.com)
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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 <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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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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* 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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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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* 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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* Determine the crypto algorithm name.
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*/
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static
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int software_key_determine_akcipher(const char *encoding,
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const char *hash_algo,
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const struct public_key *pkey,
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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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if (strcmp(encoding, "pkcs1") == 0) {
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/* The data wangled by the RSA algorithm is typically padded
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* and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
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* sec 8.2].
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*/
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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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strcpy(alg_name, pkey->pkey_algo);
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return 0;
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}
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return -ENOPKG;
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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(params->encoding,
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params->hash_algo,
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pkey, 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(params->encoding,
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params->hash_algo,
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pkey, 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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/*
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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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ret = software_key_determine_akcipher(sig->encoding,
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sig->hash_algo,
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pkey, 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_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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