| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* In-software asymmetric public-key crypto subtype |
| * |
| * See Documentation/crypto/asymmetric-keys.rst |
| * |
| * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #define pr_fmt(fmt) "PKEY: "fmt |
| #include <linux/module.h> |
| #include <linux/export.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/seq_file.h> |
| #include <linux/scatterlist.h> |
| #include <linux/asn1.h> |
| #include <keys/asymmetric-subtype.h> |
| #include <crypto/public_key.h> |
| #include <crypto/akcipher.h> |
| #include <crypto/sm2.h> |
| #include <crypto/sm3_base.h> |
| |
| MODULE_DESCRIPTION("In-software asymmetric public-key subtype"); |
| MODULE_AUTHOR("Red Hat, Inc."); |
| MODULE_LICENSE("GPL"); |
| |
| /* |
| * 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); |
| } |
| |
| /* |
| * 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); |
| |
| /* |
| * Destroy a public key algorithm key. |
| */ |
| static void public_key_destroy(void *payload0, void *payload3) |
| { |
| public_key_free(payload0); |
| public_key_signature_free(payload3); |
| } |
| |
| /* |
| * Given a public_key, and an encoding and hash_algo to be used for signing |
| * and/or verification with that key, determine the name of the corresponding |
| * akcipher algorithm. Also check that encoding and hash_algo are allowed. |
| */ |
| static int |
| software_key_determine_akcipher(const struct public_key *pkey, |
| const char *encoding, const char *hash_algo, |
| char alg_name[CRYPTO_MAX_ALG_NAME]) |
| { |
| int n; |
| |
| if (!encoding) |
| return -EINVAL; |
| |
| if (strcmp(pkey->pkey_algo, "rsa") == 0) { |
| /* |
| * RSA signatures usually use EMSA-PKCS1-1_5 [RFC3447 sec 8.2]. |
| */ |
| if (strcmp(encoding, "pkcs1") == 0) { |
| 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) |
| return -EINVAL; |
| /* |
| * Raw RSA cannot differentiate between different hash |
| * algorithms. |
| */ |
| if (hash_algo) |
| return -EINVAL; |
| } else if (strncmp(pkey->pkey_algo, "ecdsa", 5) == 0) { |
| if (strcmp(encoding, "x962") != 0) |
| return -EINVAL; |
| /* |
| * ECDSA signatures are taken over a raw hash, so they don't |
| * differentiate between different hash algorithms. That means |
| * that the verifier should hard-code a specific hash algorithm. |
| * Unfortunately, in practice ECDSA is used with multiple SHAs, |
| * so we have to allow all of them and not just one. |
| */ |
| if (!hash_algo) |
| return -EINVAL; |
| if (strcmp(hash_algo, "sha1") != 0 && |
| strcmp(hash_algo, "sha224") != 0 && |
| strcmp(hash_algo, "sha256") != 0 && |
| strcmp(hash_algo, "sha384") != 0 && |
| strcmp(hash_algo, "sha512") != 0) |
| return -EINVAL; |
| } else if (strcmp(pkey->pkey_algo, "sm2") == 0) { |
| if (strcmp(encoding, "raw") != 0) |
| return -EINVAL; |
| if (!hash_algo) |
| return -EINVAL; |
| if (strcmp(hash_algo, "sm3") != 0) |
| return -EINVAL; |
| } else if (strcmp(pkey->pkey_algo, "ecrdsa") == 0) { |
| if (strcmp(encoding, "raw") != 0) |
| return -EINVAL; |
| if (!hash_algo) |
| return -EINVAL; |
| if (strcmp(hash_algo, "streebog256") != 0 && |
| strcmp(hash_algo, "streebog512") != 0) |
| return -EINVAL; |
| } else { |
| /* Unknown public key algorithm */ |
| return -ENOPKG; |
| } |
| if (strscpy(alg_name, pkey->pkey_algo, CRYPTO_MAX_ALG_NAME) < 0) |
| return -EINVAL; |
| return 0; |
| } |
| |
| 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(pkey, params->encoding, |
| params->hash_algo, 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; |
| 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(pkey, params->encoding, |
| params->hash_algo, 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_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; |
| } |
| |
| #if IS_REACHABLE(CONFIG_CRYPTO_SM2) |
| static int cert_sig_digest_update(const struct public_key_signature *sig, |
| struct crypto_akcipher *tfm_pkey) |
| { |
| struct crypto_shash *tfm; |
| struct shash_desc *desc; |
| size_t desc_size; |
| unsigned char dgst[SM3_DIGEST_SIZE]; |
| int ret; |
| |
| BUG_ON(!sig->data); |
| |
| /* SM2 signatures always use the SM3 hash algorithm */ |
| if (!sig->hash_algo || strcmp(sig->hash_algo, "sm3") != 0) |
| return -EINVAL; |
| |
| ret = sm2_compute_z_digest(tfm_pkey, SM2_DEFAULT_USERID, |
| SM2_DEFAULT_USERID_LEN, dgst); |
| if (ret) |
| return ret; |
| |
| tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); |
| if (IS_ERR(tfm)) |
| return PTR_ERR(tfm); |
| |
| desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); |
| desc = kzalloc(desc_size, GFP_KERNEL); |
| if (!desc) { |
| ret = -ENOMEM; |
| goto error_free_tfm; |
| } |
| |
| desc->tfm = tfm; |
| |
| ret = crypto_shash_init(desc); |
| if (ret < 0) |
| goto error_free_desc; |
| |
| ret = crypto_shash_update(desc, dgst, SM3_DIGEST_SIZE); |
| if (ret < 0) |
| goto error_free_desc; |
| |
| ret = crypto_shash_finup(desc, sig->data, sig->data_size, sig->digest); |
| |
| error_free_desc: |
| kfree(desc); |
| error_free_tfm: |
| crypto_free_shash(tfm); |
| return ret; |
| } |
| #else |
| static inline int cert_sig_digest_update( |
| const struct public_key_signature *sig, |
| struct crypto_akcipher *tfm_pkey) |
| { |
| return -ENOTSUPP; |
| } |
| #endif /* ! IS_REACHABLE(CONFIG_CRYPTO_SM2) */ |
| |
| /* |
| * 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); |
| |
| /* |
| * If the signature specifies a public key algorithm, it *must* match |
| * the key's actual public key algorithm. |
| * |
| * Small exception: ECDSA signatures don't specify the curve, but ECDSA |
| * keys do. So the strings can mismatch slightly in that case: |
| * "ecdsa-nist-*" for the key, but "ecdsa" for the signature. |
| */ |
| if (sig->pkey_algo) { |
| if (strcmp(pkey->pkey_algo, sig->pkey_algo) != 0 && |
| (strncmp(pkey->pkey_algo, "ecdsa-", 6) != 0 || |
| strcmp(sig->pkey_algo, "ecdsa") != 0)) |
| return -EKEYREJECTED; |
| } |
| |
| ret = software_key_determine_akcipher(pkey, sig->encoding, |
| sig->hash_algo, 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; |
| |
| if (strcmp(pkey->pkey_algo, "sm2") == 0 && sig->data_size) { |
| ret = cert_sig_digest_update(sig, tfm); |
| 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); |