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 "rsakey-asn1.h" 19 20 int rsa_get_n(void *context, size_t hdrlen, unsigned char tag, 21 const void *value, size_t vlen) 22 { 23 struct rsa_key *key = context; 24 25 key->n = mpi_read_raw_data(value, vlen); 26 27 if (!key->n) 28 return -ENOMEM; 29 30 /* In FIPS mode only allow key size 2K & 3K */ 31 if (fips_enabled && (mpi_get_size(key->n) != 256 || 32 mpi_get_size(key->n) != 384)) { 33 pr_err("RSA: key size not allowed in FIPS mode\n"); 34 mpi_free(key->n); 35 key->n = NULL; 36 return -EINVAL; 37 } 38 return 0; 39 } 40 41 int rsa_get_e(void *context, size_t hdrlen, unsigned char tag, 42 const void *value, size_t vlen) 43 { 44 struct rsa_key *key = context; 45 46 key->e = mpi_read_raw_data(value, vlen); 47 48 if (!key->e) 49 return -ENOMEM; 50 51 return 0; 52 } 53 54 int rsa_get_d(void *context, size_t hdrlen, unsigned char tag, 55 const void *value, size_t vlen) 56 { 57 struct rsa_key *key = context; 58 59 key->d = mpi_read_raw_data(value, vlen); 60 61 if (!key->d) 62 return -ENOMEM; 63 64 /* In FIPS mode only allow key size 2K & 3K */ 65 if (fips_enabled && (mpi_get_size(key->d) != 256 || 66 mpi_get_size(key->d) != 384)) { 67 pr_err("RSA: key size not allowed in FIPS mode\n"); 68 mpi_free(key->d); 69 key->d = NULL; 70 return -EINVAL; 71 } 72 return 0; 73 } 74 75 static void free_mpis(struct rsa_key *key) 76 { 77 mpi_free(key->n); 78 mpi_free(key->e); 79 mpi_free(key->d); 80 key->n = NULL; 81 key->e = NULL; 82 key->d = NULL; 83 } 84 85 /** 86 * rsa_free_key() - frees rsa key allocated by rsa_parse_key() 87 * 88 * @rsa_key: struct rsa_key key representation 89 */ 90 void rsa_free_key(struct rsa_key *key) 91 { 92 free_mpis(key); 93 } 94 EXPORT_SYMBOL_GPL(rsa_free_key); 95 96 /** 97 * rsa_parse_key() - extracts an rsa key from BER encoded buffer 98 * and stores it in the provided struct rsa_key 99 * 100 * @rsa_key: struct rsa_key key representation 101 * @key: key in BER format 102 * @key_len: length of key 103 * 104 * Return: 0 on success or error code in case of error 105 */ 106 int rsa_parse_key(struct rsa_key *rsa_key, const void *key, 107 unsigned int key_len) 108 { 109 int ret; 110 111 free_mpis(rsa_key); 112 ret = asn1_ber_decoder(&rsakey_decoder, rsa_key, key, key_len); 113 if (ret < 0) 114 goto error; 115 116 return 0; 117 error: 118 free_mpis(rsa_key); 119 return ret; 120 } 121 EXPORT_SYMBOL_GPL(rsa_parse_key); 122