![Tudor Ambarus](/assets/img/avatar_default.png)
Return the raw key with no other processing so that the caller can copy it or MPI parse it, etc. The scope is to have only one ANS.1 parser for all RSA implementations. Update the RSA software implementation so that it does the MPI conversion on top. Signed-off-by: Tudor Ambarus <tudor-dan.ambarus@nxp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
400 lines
7.5 KiB
C
400 lines
7.5 KiB
C
/* RSA asymmetric public-key algorithm [RFC3447]
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*
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* Copyright (c) 2015, Intel Corporation
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* Authors: Tadeusz Struk <tadeusz.struk@intel.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/mpi.h>
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#include <crypto/internal/rsa.h>
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#include <crypto/internal/akcipher.h>
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#include <crypto/akcipher.h>
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#include <crypto/algapi.h>
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struct rsa_mpi_key {
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MPI n;
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MPI e;
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MPI d;
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};
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/*
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* RSAEP function [RFC3447 sec 5.1.1]
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* c = m^e mod n;
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*/
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static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
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{
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/* (1) Validate 0 <= m < n */
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if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
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return -EINVAL;
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/* (2) c = m^e mod n */
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return mpi_powm(c, m, key->e, key->n);
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}
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/*
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* RSADP function [RFC3447 sec 5.1.2]
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* m = c^d mod n;
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*/
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static int _rsa_dec(const struct rsa_mpi_key *key, MPI m, MPI c)
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{
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/* (1) Validate 0 <= c < n */
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if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
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return -EINVAL;
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/* (2) m = c^d mod n */
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return mpi_powm(m, c, key->d, key->n);
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}
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/*
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* RSASP1 function [RFC3447 sec 5.2.1]
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* s = m^d mod n
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*/
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static int _rsa_sign(const struct rsa_mpi_key *key, MPI s, MPI m)
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{
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/* (1) Validate 0 <= m < n */
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if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
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return -EINVAL;
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/* (2) s = m^d mod n */
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return mpi_powm(s, m, key->d, key->n);
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}
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/*
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* RSAVP1 function [RFC3447 sec 5.2.2]
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* m = s^e mod n;
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*/
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static int _rsa_verify(const struct rsa_mpi_key *key, MPI m, MPI s)
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{
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/* (1) Validate 0 <= s < n */
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if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0)
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return -EINVAL;
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/* (2) m = s^e mod n */
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return mpi_powm(m, s, key->e, key->n);
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}
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static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
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{
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return akcipher_tfm_ctx(tfm);
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}
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static int rsa_enc(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
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MPI m, c = mpi_alloc(0);
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int ret = 0;
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int sign;
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if (!c)
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return -ENOMEM;
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if (unlikely(!pkey->n || !pkey->e)) {
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ret = -EINVAL;
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goto err_free_c;
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}
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ret = -ENOMEM;
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m = mpi_read_raw_from_sgl(req->src, req->src_len);
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if (!m)
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goto err_free_c;
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ret = _rsa_enc(pkey, c, m);
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if (ret)
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goto err_free_m;
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ret = mpi_write_to_sgl(c, req->dst, &req->dst_len, &sign);
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if (ret)
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goto err_free_m;
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if (sign < 0)
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ret = -EBADMSG;
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err_free_m:
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mpi_free(m);
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err_free_c:
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mpi_free(c);
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return ret;
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}
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static int rsa_dec(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
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MPI c, m = mpi_alloc(0);
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int ret = 0;
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int sign;
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if (!m)
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return -ENOMEM;
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if (unlikely(!pkey->n || !pkey->d)) {
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ret = -EINVAL;
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goto err_free_m;
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}
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ret = -ENOMEM;
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c = mpi_read_raw_from_sgl(req->src, req->src_len);
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if (!c)
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goto err_free_m;
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ret = _rsa_dec(pkey, m, c);
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if (ret)
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goto err_free_c;
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ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
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if (ret)
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goto err_free_c;
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if (sign < 0)
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ret = -EBADMSG;
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err_free_c:
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mpi_free(c);
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err_free_m:
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mpi_free(m);
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return ret;
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}
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static int rsa_sign(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
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MPI m, s = mpi_alloc(0);
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int ret = 0;
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int sign;
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if (!s)
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return -ENOMEM;
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if (unlikely(!pkey->n || !pkey->d)) {
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ret = -EINVAL;
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goto err_free_s;
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}
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ret = -ENOMEM;
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m = mpi_read_raw_from_sgl(req->src, req->src_len);
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if (!m)
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goto err_free_s;
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ret = _rsa_sign(pkey, s, m);
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if (ret)
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goto err_free_m;
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ret = mpi_write_to_sgl(s, req->dst, &req->dst_len, &sign);
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if (ret)
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goto err_free_m;
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if (sign < 0)
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ret = -EBADMSG;
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err_free_m:
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mpi_free(m);
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err_free_s:
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mpi_free(s);
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return ret;
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}
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static int rsa_verify(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
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MPI s, m = mpi_alloc(0);
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int ret = 0;
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int sign;
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if (!m)
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return -ENOMEM;
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if (unlikely(!pkey->n || !pkey->e)) {
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ret = -EINVAL;
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goto err_free_m;
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}
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ret = -ENOMEM;
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s = mpi_read_raw_from_sgl(req->src, req->src_len);
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if (!s) {
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ret = -ENOMEM;
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goto err_free_m;
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}
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ret = _rsa_verify(pkey, m, s);
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if (ret)
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goto err_free_s;
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ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
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if (ret)
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goto err_free_s;
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if (sign < 0)
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ret = -EBADMSG;
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err_free_s:
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mpi_free(s);
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err_free_m:
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mpi_free(m);
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return ret;
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}
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static void rsa_free_mpi_key(struct rsa_mpi_key *key)
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{
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mpi_free(key->d);
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mpi_free(key->e);
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mpi_free(key->n);
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key->d = NULL;
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key->e = NULL;
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key->n = NULL;
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}
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static int rsa_check_key_length(unsigned int len)
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{
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switch (len) {
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case 512:
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case 1024:
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case 1536:
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case 2048:
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case 3072:
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case 4096:
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return 0;
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}
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return -EINVAL;
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}
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static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
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unsigned int keylen)
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{
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struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
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struct rsa_key raw_key = {0};
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int ret;
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/* Free the old MPI key if any */
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rsa_free_mpi_key(mpi_key);
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ret = rsa_parse_pub_key(&raw_key, key, keylen);
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if (ret)
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return ret;
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mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
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if (!mpi_key->e)
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goto err;
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mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
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if (!mpi_key->n)
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goto err;
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if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
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rsa_free_mpi_key(mpi_key);
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return -EINVAL;
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}
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return 0;
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err:
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rsa_free_mpi_key(mpi_key);
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return -ENOMEM;
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}
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static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
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unsigned int keylen)
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{
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struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
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struct rsa_key raw_key = {0};
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int ret;
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/* Free the old MPI key if any */
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rsa_free_mpi_key(mpi_key);
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ret = rsa_parse_priv_key(&raw_key, key, keylen);
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if (ret)
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return ret;
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mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
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if (!mpi_key->d)
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goto err;
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mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
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if (!mpi_key->e)
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goto err;
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mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
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if (!mpi_key->n)
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goto err;
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if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
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rsa_free_mpi_key(mpi_key);
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return -EINVAL;
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}
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return 0;
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err:
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rsa_free_mpi_key(mpi_key);
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return -ENOMEM;
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}
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static int rsa_max_size(struct crypto_akcipher *tfm)
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{
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struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
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return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
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}
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static void rsa_exit_tfm(struct crypto_akcipher *tfm)
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{
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struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
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rsa_free_mpi_key(pkey);
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}
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static struct akcipher_alg rsa = {
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.encrypt = rsa_enc,
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.decrypt = rsa_dec,
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.sign = rsa_sign,
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.verify = rsa_verify,
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.set_priv_key = rsa_set_priv_key,
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.set_pub_key = rsa_set_pub_key,
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.max_size = rsa_max_size,
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.exit = rsa_exit_tfm,
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.base = {
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.cra_name = "rsa",
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.cra_driver_name = "rsa-generic",
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.cra_priority = 100,
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.cra_module = THIS_MODULE,
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.cra_ctxsize = sizeof(struct rsa_mpi_key),
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},
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};
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static int rsa_init(void)
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{
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int err;
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err = crypto_register_akcipher(&rsa);
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if (err)
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return err;
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err = crypto_register_template(&rsa_pkcs1pad_tmpl);
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if (err) {
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crypto_unregister_akcipher(&rsa);
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return err;
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}
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return 0;
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}
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static void rsa_exit(void)
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{
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crypto_unregister_template(&rsa_pkcs1pad_tmpl);
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crypto_unregister_akcipher(&rsa);
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}
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module_init(rsa_init);
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module_exit(rsa_exit);
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MODULE_ALIAS_CRYPTO("rsa");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("RSA generic algorithm");
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