crypto/rsa_helper.c

   1 /*
   2  * RSA key extract helper
   3  *
   4  * Copyright (c) 2015, Intel Corporation
   5  * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the Free
   9  * Software Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/export.h>
  15 #include <linux/err.h>
  16 #include <linux/fips.h>
  17 #include <crypto/internal/rsa.h>
  18 #include "rsapubkey-asn1.h"
  19 #include "rsaprivkey-asn1.h"
  20
  21 int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
  22               const void *value, size_t vlen)
  23 {
  24         struct rsa_key *key = context;
  25         const u8 *ptr = value;
  26         size_t n_sz = vlen;
  27
  28         /* invalid key provided */
  29         if (!value || !vlen)
  30                 return -EINVAL;
  31
  32         if (fips_enabled) {
  33                 while (!*ptr && n_sz) {
  34                         ptr++;
  35                         n_sz--;
  36                 }
  37
  38                 /* In FIPS mode only allow key size 2K & 3K */
  39                 if (n_sz != 256 && n_sz != 384) {
  40                         pr_err("RSA: key size not allowed in FIPS mode\n");
  41                         return -EINVAL;
  42                 }
  43         }
  44
  45         key->n = value;
  46         key->n_sz = vlen;
  47
  48         return 0;
  49 }
  50
  51 int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
  52               const void *value, size_t vlen)
  53 {
  54         struct rsa_key *key = context;
  55
  56         /* invalid key provided */
  57         if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
  58                 return -EINVAL;
  59
  60         key->e = value;
  61         key->e_sz = vlen;
  62
  63         return 0;
  64 }
  65
  66 int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
  67               const void *value, size_t vlen)
  68 {
  69         struct rsa_key *key = context;
  70
  71         /* invalid key provided */
  72         if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
  73                 return -EINVAL;
  74
  75         key->d = value;
  76         key->d_sz = vlen;
  77
  78         return 0;
  79 }
  80
  81 /**
  82  * rsa_parse_pub_key() - decodes the BER encoded buffer and stores in the
  83  *                       provided struct rsa_key, pointers to the raw key as is,
  84  *                       so that the caller can copy it or MPI parse it, etc.
  85  *
  86  * @rsa_key:    struct rsa_key key representation
  87  * @key:        key in BER format
  88  * @key_len:    length of key
  89  *
  90  * Return:      0 on success or error code in case of error
  91  */
  92 int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
  93                       unsigned int key_len)
  94 {
  95         return asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
  96 }
  97 EXPORT_SYMBOL_GPL(rsa_parse_pub_key);
  98
  99 /**
 100  * rsa_parse_priv_key() - decodes the BER encoded buffer and stores in the
 101  *                        provided struct rsa_key, pointers to the raw key
 102  *                        as is, so that the caller can copy it or MPI parse it,
 103  *                        etc.
 104  *
 105  * @rsa_key:    struct rsa_key key representation
 106  * @key:        key in BER format
 107  * @key_len:    length of key
 108  *
 109  * Return:      0 on success or error code in case of error
 110  */
 111 int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
 112                        unsigned int key_len)
 113 {
 114         return asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
 115 }
 116 EXPORT_SYMBOL_GPL(rsa_parse_priv_key);