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- // SPDX-License-Identifier: GPL-2.0-or-later
- /* In-software asymmetric public-key crypto subtype
- *
- * See Documentation/crypto/asymmetric-keys.txt
- *
- * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
- #define pr_fmt(fmt) "PKEY: "fmt
- #ifdef __UBOOT__
- #include <linux/compat.h>
- #else
- #include <linux/module.h>
- #include <linux/export.h>
- #endif
- #include <linux/kernel.h>
- #ifndef __UBOOT__
- #include <linux/slab.h>
- #include <linux/seq_file.h>
- #include <linux/scatterlist.h>
- #include <keys/asymmetric-subtype.h>
- #endif
- #include <crypto/public_key.h>
- #ifndef __UBOOT__
- #include <crypto/akcipher.h>
- #endif
- MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
- MODULE_AUTHOR("Red Hat, Inc.");
- MODULE_LICENSE("GPL");
- #ifndef __UBOOT__
- /*
- * Provide a part of a description of the key for /proc/keys.
- */
- static void public_key_describe(const struct key *asymmetric_key,
- struct seq_file *m)
- {
- struct public_key *key = asymmetric_key->payload.data[asym_crypto];
- if (key)
- seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
- }
- #endif
- /*
- * Destroy a public key algorithm key.
- */
- void public_key_free(struct public_key *key)
- {
- if (key) {
- kfree(key->key);
- kfree(key->params);
- kfree(key);
- }
- }
- EXPORT_SYMBOL_GPL(public_key_free);
- #ifdef __UBOOT__
- /*
- * from <linux>/crypto/asymmetric_keys/signature.c
- *
- * Destroy a public key signature.
- */
- void public_key_signature_free(struct public_key_signature *sig)
- {
- int i;
- if (sig) {
- for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
- free(sig->auth_ids[i]);
- free(sig->s);
- free(sig->digest);
- free(sig);
- }
- }
- EXPORT_SYMBOL_GPL(public_key_signature_free);
- #else
- /*
- * Destroy a public key algorithm key.
- */
- static void public_key_destroy(void *payload0, void *payload3)
- {
- public_key_free(payload0);
- public_key_signature_free(payload3);
- }
- /*
- * Determine the crypto algorithm name.
- */
- static
- int software_key_determine_akcipher(const char *encoding,
- const char *hash_algo,
- const struct public_key *pkey,
- char alg_name[CRYPTO_MAX_ALG_NAME])
- {
- int n;
- if (strcmp(encoding, "pkcs1") == 0) {
- /* The data wangled by the RSA algorithm is typically padded
- * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
- * sec 8.2].
- */
- if (!hash_algo)
- n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
- "pkcs1pad(%s)",
- pkey->pkey_algo);
- else
- n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
- "pkcs1pad(%s,%s)",
- pkey->pkey_algo, hash_algo);
- return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
- }
- if (strcmp(encoding, "raw") == 0) {
- strcpy(alg_name, pkey->pkey_algo);
- return 0;
- }
- return -ENOPKG;
- }
- static u8 *pkey_pack_u32(u8 *dst, u32 val)
- {
- memcpy(dst, &val, sizeof(val));
- return dst + sizeof(val);
- }
- /*
- * Query information about a key.
- */
- static int software_key_query(const struct kernel_pkey_params *params,
- struct kernel_pkey_query *info)
- {
- struct crypto_akcipher *tfm;
- struct public_key *pkey = params->key->payload.data[asym_crypto];
- char alg_name[CRYPTO_MAX_ALG_NAME];
- u8 *key, *ptr;
- int ret, len;
- ret = software_key_determine_akcipher(params->encoding,
- params->hash_algo,
- pkey, alg_name);
- if (ret < 0)
- return ret;
- tfm = crypto_alloc_akcipher(alg_name, 0, 0);
- if (IS_ERR(tfm))
- return PTR_ERR(tfm);
- key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
- GFP_KERNEL);
- if (!key)
- goto error_free_tfm;
- memcpy(key, pkey->key, pkey->keylen);
- ptr = key + pkey->keylen;
- ptr = pkey_pack_u32(ptr, pkey->algo);
- ptr = pkey_pack_u32(ptr, pkey->paramlen);
- memcpy(ptr, pkey->params, pkey->paramlen);
- if (pkey->key_is_private)
- ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
- else
- ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
- if (ret < 0)
- goto error_free_key;
- len = crypto_akcipher_maxsize(tfm);
- info->key_size = len * 8;
- info->max_data_size = len;
- info->max_sig_size = len;
- info->max_enc_size = len;
- info->max_dec_size = len;
- info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
- KEYCTL_SUPPORTS_VERIFY);
- if (pkey->key_is_private)
- info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
- KEYCTL_SUPPORTS_SIGN);
- ret = 0;
- error_free_key:
- kfree(key);
- error_free_tfm:
- crypto_free_akcipher(tfm);
- pr_devel("<==%s() = %d\n", __func__, ret);
- return ret;
- }
- /*
- * Do encryption, decryption and signing ops.
- */
- static int software_key_eds_op(struct kernel_pkey_params *params,
- const void *in, void *out)
- {
- const struct public_key *pkey = params->key->payload.data[asym_crypto];
- struct akcipher_request *req;
- struct crypto_akcipher *tfm;
- struct crypto_wait cwait;
- struct scatterlist in_sg, out_sg;
- char alg_name[CRYPTO_MAX_ALG_NAME];
- char *key, *ptr;
- int ret;
- pr_devel("==>%s()\n", __func__);
- ret = software_key_determine_akcipher(params->encoding,
- params->hash_algo,
- pkey, alg_name);
- if (ret < 0)
- return ret;
- tfm = crypto_alloc_akcipher(alg_name, 0, 0);
- if (IS_ERR(tfm))
- return PTR_ERR(tfm);
- req = akcipher_request_alloc(tfm, GFP_KERNEL);
- if (!req)
- goto error_free_tfm;
- key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
- GFP_KERNEL);
- if (!key)
- goto error_free_req;
- memcpy(key, pkey->key, pkey->keylen);
- ptr = key + pkey->keylen;
- ptr = pkey_pack_u32(ptr, pkey->algo);
- ptr = pkey_pack_u32(ptr, pkey->paramlen);
- memcpy(ptr, pkey->params, pkey->paramlen);
- if (pkey->key_is_private)
- ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
- else
- ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
- if (ret)
- goto error_free_key;
- sg_init_one(&in_sg, in, params->in_len);
- sg_init_one(&out_sg, out, params->out_len);
- akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
- params->out_len);
- crypto_init_wait(&cwait);
- akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
- CRYPTO_TFM_REQ_MAY_SLEEP,
- crypto_req_done, &cwait);
- /* Perform the encryption calculation. */
- switch (params->op) {
- case kernel_pkey_encrypt:
- ret = crypto_akcipher_encrypt(req);
- break;
- case kernel_pkey_decrypt:
- ret = crypto_akcipher_decrypt(req);
- break;
- case kernel_pkey_sign:
- ret = crypto_akcipher_sign(req);
- break;
- default:
- BUG();
- }
- ret = crypto_wait_req(ret, &cwait);
- if (ret == 0)
- ret = req->dst_len;
- error_free_key:
- kfree(key);
- error_free_req:
- akcipher_request_free(req);
- error_free_tfm:
- crypto_free_akcipher(tfm);
- pr_devel("<==%s() = %d\n", __func__, ret);
- return ret;
- }
- /*
- * Verify a signature using a public key.
- */
- int public_key_verify_signature(const struct public_key *pkey,
- const struct public_key_signature *sig)
- {
- struct crypto_wait cwait;
- struct crypto_akcipher *tfm;
- struct akcipher_request *req;
- struct scatterlist src_sg[2];
- char alg_name[CRYPTO_MAX_ALG_NAME];
- char *key, *ptr;
- int ret;
- pr_devel("==>%s()\n", __func__);
- BUG_ON(!pkey);
- BUG_ON(!sig);
- BUG_ON(!sig->s);
- ret = software_key_determine_akcipher(sig->encoding,
- sig->hash_algo,
- pkey, alg_name);
- if (ret < 0)
- return ret;
- tfm = crypto_alloc_akcipher(alg_name, 0, 0);
- if (IS_ERR(tfm))
- return PTR_ERR(tfm);
- ret = -ENOMEM;
- req = akcipher_request_alloc(tfm, GFP_KERNEL);
- if (!req)
- goto error_free_tfm;
- key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
- GFP_KERNEL);
- if (!key)
- goto error_free_req;
- memcpy(key, pkey->key, pkey->keylen);
- ptr = key + pkey->keylen;
- ptr = pkey_pack_u32(ptr, pkey->algo);
- ptr = pkey_pack_u32(ptr, pkey->paramlen);
- memcpy(ptr, pkey->params, pkey->paramlen);
- if (pkey->key_is_private)
- ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
- else
- ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
- if (ret)
- goto error_free_key;
- sg_init_table(src_sg, 2);
- sg_set_buf(&src_sg[0], sig->s, sig->s_size);
- sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
- akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
- sig->digest_size);
- crypto_init_wait(&cwait);
- akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
- CRYPTO_TFM_REQ_MAY_SLEEP,
- crypto_req_done, &cwait);
- ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
- error_free_key:
- kfree(key);
- error_free_req:
- akcipher_request_free(req);
- error_free_tfm:
- crypto_free_akcipher(tfm);
- pr_devel("<==%s() = %d\n", __func__, ret);
- if (WARN_ON_ONCE(ret > 0))
- ret = -EINVAL;
- return ret;
- }
- EXPORT_SYMBOL_GPL(public_key_verify_signature);
- static int public_key_verify_signature_2(const struct key *key,
- const struct public_key_signature *sig)
- {
- const struct public_key *pk = key->payload.data[asym_crypto];
- return public_key_verify_signature(pk, sig);
- }
- /*
- * Public key algorithm asymmetric key subtype
- */
- struct asymmetric_key_subtype public_key_subtype = {
- .owner = THIS_MODULE,
- .name = "public_key",
- .name_len = sizeof("public_key") - 1,
- .describe = public_key_describe,
- .destroy = public_key_destroy,
- .query = software_key_query,
- .eds_op = software_key_eds_op,
- .verify_signature = public_key_verify_signature_2,
- };
- EXPORT_SYMBOL_GPL(public_key_subtype);
- #endif /* !__UBOOT__ */
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