diff options
Diffstat (limited to 'crypto/rsa.c')
| -rw-r--r-- | crypto/rsa.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/crypto/rsa.c b/crypto/rsa.c new file mode 100644 index 000000000..752af0656 --- /dev/null +++ b/crypto/rsa.c @@ -0,0 +1,315 @@ +/* RSA asymmetric public-key algorithm [RFC3447] + * + * Copyright (c) 2015, Intel Corporation + * Authors: Tadeusz Struk <tadeusz.struk@intel.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <crypto/internal/rsa.h> +#include <crypto/internal/akcipher.h> +#include <crypto/akcipher.h> + +/* + * RSAEP function [RFC3447 sec 5.1.1] + * c = m^e mod n; + */ +static int _rsa_enc(const struct rsa_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 = c^d mod n; + */ +static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c) +{ + /* (1) Validate 0 <= c < n */ + if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0) + return -EINVAL; + + /* (2) m = c^d mod n */ + return mpi_powm(m, c, key->d, key->n); +} + +/* + * RSASP1 function [RFC3447 sec 5.2.1] + * s = m^d mod n + */ +static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m) +{ + /* (1) Validate 0 <= m < n */ + if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0) + return -EINVAL; + + /* (2) s = m^d mod n */ + return mpi_powm(s, m, key->d, key->n); +} + +/* + * RSAVP1 function [RFC3447 sec 5.2.2] + * m = s^e mod n; + */ +static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s) +{ + /* (1) Validate 0 <= s < n */ + if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0) + return -EINVAL; + + /* (2) m = s^e mod n */ + return mpi_powm(m, s, key->e, key->n); +} + +static inline struct rsa_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_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; + } + + if (req->dst_len < mpi_get_size(pkey->n)) { + req->dst_len = mpi_get_size(pkey->n); + ret = -EOVERFLOW; + goto err_free_c; + } + + m = mpi_read_raw_data(req->src, req->src_len); + if (!m) { + ret = -ENOMEM; + goto err_free_c; + } + + ret = _rsa_enc(pkey, c, m); + if (ret) + goto err_free_m; + + ret = mpi_read_buffer(c, req->dst, req->dst_len, &req->dst_len, &sign); + if (ret) + goto err_free_m; + + if (sign < 0) { + ret = -EBADMSG; + goto err_free_m; + } + +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_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; + } + + if (req->dst_len < mpi_get_size(pkey->n)) { + req->dst_len = mpi_get_size(pkey->n); + ret = -EOVERFLOW; + goto err_free_m; + } + + c = mpi_read_raw_data(req->src, req->src_len); + if (!c) { + ret = -ENOMEM; + goto err_free_m; + } + + ret = _rsa_dec(pkey, m, c); + if (ret) + goto err_free_c; + + ret = mpi_read_buffer(m, req->dst, req->dst_len, &req->dst_len, &sign); + if (ret) + goto err_free_c; + + if (sign < 0) { + ret = -EBADMSG; + goto err_free_c; + } + +err_free_c: + mpi_free(c); +err_free_m: + mpi_free(m); + return ret; +} + +static int rsa_sign(struct akcipher_request *req) +{ + struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); + const struct rsa_key *pkey = rsa_get_key(tfm); + MPI m, s = mpi_alloc(0); + int ret = 0; + int sign; + + if (!s) + return -ENOMEM; + + if (unlikely(!pkey->n || !pkey->d)) { + ret = -EINVAL; + goto err_free_s; + } + + if (req->dst_len < mpi_get_size(pkey->n)) { + req->dst_len = mpi_get_size(pkey->n); + ret = -EOVERFLOW; + goto err_free_s; + } + + m = mpi_read_raw_data(req->src, req->src_len); + if (!m) { + ret = -ENOMEM; + goto err_free_s; + } + + ret = _rsa_sign(pkey, s, m); + if (ret) + goto err_free_m; + + ret = mpi_read_buffer(s, req->dst, req->dst_len, &req->dst_len, &sign); + if (ret) + goto err_free_m; + + if (sign < 0) { + ret = -EBADMSG; + goto err_free_m; + } + +err_free_m: + mpi_free(m); +err_free_s: + mpi_free(s); + return ret; +} + +static int rsa_verify(struct akcipher_request *req) +{ + struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); + const struct rsa_key *pkey = rsa_get_key(tfm); + MPI s, m = mpi_alloc(0); + int ret = 0; + int sign; + + if (!m) + return -ENOMEM; + + if (unlikely(!pkey->n || !pkey->e)) { + ret = -EINVAL; + goto err_free_m; + } + + if (req->dst_len < mpi_get_size(pkey->n)) { + req->dst_len = mpi_get_size(pkey->n); + ret = -EOVERFLOW; + goto err_free_m; + } + + s = mpi_read_raw_data(req->src, req->src_len); + if (!s) { + ret = -ENOMEM; + goto err_free_m; + } + + ret = _rsa_verify(pkey, m, s); + if (ret) + goto err_free_s; + + ret = mpi_read_buffer(m, req->dst, req->dst_len, &req->dst_len, &sign); + if (ret) + goto err_free_s; + + if (sign < 0) { + ret = -EBADMSG; + goto err_free_s; + } + +err_free_s: + mpi_free(s); +err_free_m: + mpi_free(m); + return ret; +} + +static int rsa_setkey(struct crypto_akcipher *tfm, const void *key, + unsigned int keylen) +{ + struct rsa_key *pkey = akcipher_tfm_ctx(tfm); + + return rsa_parse_key(pkey, key, keylen); +} + +static void rsa_exit_tfm(struct crypto_akcipher *tfm) +{ + struct rsa_key *pkey = akcipher_tfm_ctx(tfm); + + rsa_free_key(pkey); +} + +static struct akcipher_alg rsa = { + .encrypt = rsa_enc, + .decrypt = rsa_dec, + .sign = rsa_sign, + .verify = rsa_verify, + .setkey = rsa_setkey, + .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_key), + }, +}; + +static int rsa_init(void) +{ + return crypto_register_akcipher(&rsa); +} + +static void rsa_exit(void) +{ + crypto_unregister_akcipher(&rsa); +} + +module_init(rsa_init); +module_exit(rsa_exit); +MODULE_ALIAS_CRYPTO("rsa"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("RSA generic algorithm"); |