crypto/rsa/rsa_x931.c

   1 /*
   2  * Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/bn.h>
  13 #include <openssl/rsa.h>
  14 #include <openssl/rand.h>
  15 #include <openssl/objects.h>
  16
  17 int RSA_padding_add_X931(unsigned char *to, int tlen,
  18                          const unsigned char *from, int flen)
  19 {
  20     int j;
  21     unsigned char *p;
  22
  23     /*
  24      * Absolute minimum amount of padding is 1 header nibble, 1 padding
  25      * nibble and 2 trailer bytes: but 1 hash if is already in 'from'.
  26      */
  27
  28     j = tlen - flen - 2;
  29
  30     if (j < 0) {
  31         RSAerr(RSA_F_RSA_PADDING_ADD_X931, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
  32         return -1;
  33     }
  34
  35     p = (unsigned char *)to;
  36
  37     /* If no padding start and end nibbles are in one byte */
  38     if (j == 0)
  39         *p++ = 0x6A;
  40     else {
  41         *p++ = 0x6B;
  42         if (j > 1) {
  43             memset(p, 0xBB, j - 1);
  44             p += j - 1;
  45         }
  46         *p++ = 0xBA;
  47     }
  48     memcpy(p, from, (unsigned int)flen);
  49     p += flen;
  50     *p = 0xCC;
  51     return (1);
  52 }
  53
  54 int RSA_padding_check_X931(unsigned char *to, int tlen,
  55                            const unsigned char *from, int flen, int num)
  56 {
  57     int i = 0, j;
  58     const unsigned char *p;
  59
  60     p = from;
  61     if ((num != flen) || ((*p != 0x6A) && (*p != 0x6B))) {
  62         RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_HEADER);
  63         return -1;
  64     }
  65
  66     if (*p++ == 0x6B) {
  67         j = flen - 3;
  68         for (i = 0; i < j; i++) {
  69             unsigned char c = *p++;
  70             if (c == 0xBA)
  71                 break;
  72             if (c != 0xBB) {
  73                 RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
  74                 return -1;
  75             }
  76         }
  77
  78         j -= i;
  79
  80         if (i == 0) {
  81             RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
  82             return -1;
  83         }
  84
  85     } else
  86         j = flen - 2;
  87
  88     if (p[j] != 0xCC) {
  89         RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_TRAILER);
  90         return -1;
  91     }
  92
  93     memcpy(to, p, (unsigned int)j);
  94
  95     return (j);
  96 }
  97
  98 /* Translate between X931 hash ids and NIDs */
  99
 100 int RSA_X931_hash_id(int nid)
 101 {
 102     switch (nid) {
 103     case NID_sha1:
 104         return 0x33;
 105
 106     case NID_sha256:
 107         return 0x34;
 108
 109     case NID_sha384:
 110         return 0x36;
 111
 112     case NID_sha512:
 113         return 0x35;
 114
 115     }
 116     return -1;
 117 }