| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* RSA asymmetric public-key algorithm [RFC3447] |
| * |
| * Copyright (c) 2015, Intel Corporation |
| * Authors: Tadeusz Struk <tadeusz.struk@intel.com> |
| */ |
| |
| #include <linux/fips.h> |
| #include <linux/module.h> |
| #include <linux/mpi.h> |
| #include <crypto/internal/rsa.h> |
| #include <crypto/internal/akcipher.h> |
| #include <crypto/akcipher.h> |
| #include <crypto/algapi.h> |
| |
| struct rsa_mpi_key { |
| MPI n; |
| MPI e; |
| MPI d; |
| MPI p; |
| MPI q; |
| MPI dp; |
| MPI dq; |
| MPI qinv; |
| }; |
| |
| /* |
| * RSAEP function [RFC3447 sec 5.1.1] |
| * c = m^e mod n; |
| */ |
| static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m) |
| { |
| /* (1) Validate 0 <= m < n */ |
| if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0) |
| return -EINVAL; |
| |
| /* (2) c = m^e mod n */ |
| return mpi_powm(c, m, key->e, key->n); |
| } |
| |
| /* |
| * RSADP function [RFC3447 sec 5.1.2] |
| * m_1 = c^dP mod p; |
| * m_2 = c^dQ mod q; |
| * h = (m_1 - m_2) * qInv mod p; |
| * m = m_2 + q * h; |
| */ |
| static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c) |
| { |
| MPI m2, m12_or_qh; |
| int ret = -ENOMEM; |
| |
| /* (1) Validate 0 <= c < n */ |
| if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0) |
| return -EINVAL; |
| |
| m2 = mpi_alloc(0); |
| m12_or_qh = mpi_alloc(0); |
| if (!m2 || !m12_or_qh) |
| goto err_free_mpi; |
| |
| /* (2i) m_1 = c^dP mod p */ |
| ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p); |
| if (ret) |
| goto err_free_mpi; |
| |
| /* (2i) m_2 = c^dQ mod q */ |
| ret = mpi_powm(m2, c, key->dq, key->q); |
| if (ret) |
| goto err_free_mpi; |
| |
| /* (2iii) h = (m_1 - m_2) * qInv mod p */ |
| mpi_sub(m12_or_qh, m_or_m1_or_h, m2); |
| mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p); |
| |
| /* (2iv) m = m_2 + q * h */ |
| mpi_mul(m12_or_qh, key->q, m_or_m1_or_h); |
| mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n); |
| |
| ret = 0; |
| |
| err_free_mpi: |
| mpi_free(m12_or_qh); |
| mpi_free(m2); |
| return ret; |
| } |
| |
| static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm) |
| { |
| return akcipher_tfm_ctx(tfm); |
| } |
| |
| static int rsa_enc(struct akcipher_request *req) |
| { |
| struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); |
| const struct rsa_mpi_key *pkey = rsa_get_key(tfm); |
| MPI m, c = mpi_alloc(0); |
| int ret = 0; |
| int sign; |
| |
| if (!c) |
| return -ENOMEM; |
| |
| if (unlikely(!pkey->n || !pkey->e)) { |
| ret = -EINVAL; |
| goto err_free_c; |
| } |
| |
| ret = -ENOMEM; |
| m = mpi_read_raw_from_sgl(req->src, req->src_len); |
| if (!m) |
| goto err_free_c; |
| |
| ret = _rsa_enc(pkey, c, m); |
| if (ret) |
| goto err_free_m; |
| |
| ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign); |
| if (ret) |
| goto err_free_m; |
| |
| if (sign < 0) |
| ret = -EBADMSG; |
| |
| err_free_m: |
| mpi_free(m); |
| err_free_c: |
| mpi_free(c); |
| return ret; |
| } |
| |
| static int rsa_dec(struct akcipher_request *req) |
| { |
| struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); |
| const struct rsa_mpi_key *pkey = rsa_get_key(tfm); |
| MPI c, m = mpi_alloc(0); |
| int ret = 0; |
| int sign; |
| |
| if (!m) |
| return -ENOMEM; |
| |
| if (unlikely(!pkey->n || !pkey->d)) { |
| ret = -EINVAL; |
| goto err_free_m; |
| } |
| |
| ret = -ENOMEM; |
| c = mpi_read_raw_from_sgl(req->src, req->src_len); |
| if (!c) |
| goto err_free_m; |
| |
| ret = _rsa_dec_crt(pkey, m, c); |
| if (ret) |
| goto err_free_c; |
| |
| ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign); |
| if (ret) |
| goto err_free_c; |
| |
| if (sign < 0) |
| ret = -EBADMSG; |
| err_free_c: |
| mpi_free(c); |
| err_free_m: |
| mpi_free(m); |
| return ret; |
| } |
| |
| static void rsa_free_mpi_key(struct rsa_mpi_key *key) |
| { |
| mpi_free(key->d); |
| mpi_free(key->e); |
| mpi_free(key->n); |
| mpi_free(key->p); |
| mpi_free(key->q); |
| mpi_free(key->dp); |
| mpi_free(key->dq); |
| mpi_free(key->qinv); |
| key->d = NULL; |
| key->e = NULL; |
| key->n = NULL; |
| key->p = NULL; |
| key->q = NULL; |
| key->dp = NULL; |
| key->dq = NULL; |
| key->qinv = NULL; |
| } |
| |
| static int rsa_check_key_length(unsigned int len) |
| { |
| switch (len) { |
| case 512: |
| case 1024: |
| case 1536: |
| if (fips_enabled) |
| return -EINVAL; |
| fallthrough; |
| case 2048: |
| case 3072: |
| case 4096: |
| return 0; |
| } |
| |
| return -EINVAL; |
| } |
| |
| static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, |
| unsigned int keylen) |
| { |
| struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm); |
| struct rsa_key raw_key = {0}; |
| int ret; |
| |
| /* Free the old MPI key if any */ |
| rsa_free_mpi_key(mpi_key); |
| |
| ret = rsa_parse_pub_key(&raw_key, key, keylen); |
| if (ret) |
| return ret; |
| |
| mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz); |
| if (!mpi_key->e) |
| goto err; |
| |
| mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz); |
| if (!mpi_key->n) |
| goto err; |
| |
| if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) { |
| rsa_free_mpi_key(mpi_key); |
| return -EINVAL; |
| } |
| |
| return 0; |
| |
| err: |
| rsa_free_mpi_key(mpi_key); |
| return -ENOMEM; |
| } |
| |
| static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key, |
| unsigned int keylen) |
| { |
| struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm); |
| struct rsa_key raw_key = {0}; |
| int ret; |
| |
| /* Free the old MPI key if any */ |
| rsa_free_mpi_key(mpi_key); |
| |
| ret = rsa_parse_priv_key(&raw_key, key, keylen); |
| if (ret) |
| return ret; |
| |
| mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz); |
| if (!mpi_key->d) |
| goto err; |
| |
| mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz); |
| if (!mpi_key->e) |
| goto err; |
| |
| mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz); |
| if (!mpi_key->n) |
| goto err; |
| |
| mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz); |
| if (!mpi_key->p) |
| goto err; |
| |
| mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz); |
| if (!mpi_key->q) |
| goto err; |
| |
| mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz); |
| if (!mpi_key->dp) |
| goto err; |
| |
| mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz); |
| if (!mpi_key->dq) |
| goto err; |
| |
| mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz); |
| if (!mpi_key->qinv) |
| goto err; |
| |
| if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) { |
| rsa_free_mpi_key(mpi_key); |
| return -EINVAL; |
| } |
| |
| return 0; |
| |
| err: |
| rsa_free_mpi_key(mpi_key); |
| return -ENOMEM; |
| } |
| |
| static unsigned int rsa_max_size(struct crypto_akcipher *tfm) |
| { |
| struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm); |
| |
| return mpi_get_size(pkey->n); |
| } |
| |
| static void rsa_exit_tfm(struct crypto_akcipher *tfm) |
| { |
| struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm); |
| |
| rsa_free_mpi_key(pkey); |
| } |
| |
| static struct akcipher_alg rsa = { |
| .encrypt = rsa_enc, |
| .decrypt = rsa_dec, |
| .set_priv_key = rsa_set_priv_key, |
| .set_pub_key = rsa_set_pub_key, |
| .max_size = rsa_max_size, |
| .exit = rsa_exit_tfm, |
| .base = { |
| .cra_name = "rsa", |
| .cra_driver_name = "rsa-generic", |
| .cra_priority = 100, |
| .cra_module = THIS_MODULE, |
| .cra_ctxsize = sizeof(struct rsa_mpi_key), |
| }, |
| }; |
| |
| static int __init rsa_init(void) |
| { |
| int err; |
| |
| err = crypto_register_akcipher(&rsa); |
| if (err) |
| return err; |
| |
| err = crypto_register_template(&rsa_pkcs1pad_tmpl); |
| if (err) { |
| crypto_unregister_akcipher(&rsa); |
| return err; |
| } |
| |
| return 0; |
| } |
| |
| static void __exit rsa_exit(void) |
| { |
| crypto_unregister_template(&rsa_pkcs1pad_tmpl); |
| crypto_unregister_akcipher(&rsa); |
| } |
| |
| subsys_initcall(rsa_init); |
| module_exit(rsa_exit); |
| MODULE_ALIAS_CRYPTO("rsa"); |
| MODULE_LICENSE("GPL"); |
| MODULE_DESCRIPTION("RSA generic algorithm"); |