rsa_x931.c
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/*
* Copyright 2005-2017 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/objects.h>
int RSA_padding_add_X931(unsigned char *to, int tlen,
const unsigned char *from, int flen)
{
int j;
unsigned char *p;
/*
* Absolute minimum amount of padding is 1 header nibble, 1 padding
* nibble and 2 trailer bytes: but 1 hash if is already in 'from'.
*/
j = tlen - flen - 2;
if (j < 0) {
RSAerr(RSA_F_RSA_PADDING_ADD_X931, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
return -1;
}
p = (unsigned char *)to;
/* If no padding start and end nibbles are in one byte */
if (j == 0) {
*p++ = 0x6A;
} else {
*p++ = 0x6B;
if (j > 1) {
memset(p, 0xBB, j - 1);
p += j - 1;
}
*p++ = 0xBA;
}
memcpy(p, from, (unsigned int)flen);
p += flen;
*p = 0xCC;
return 1;
}
int RSA_padding_check_X931(unsigned char *to, int tlen,
const unsigned char *from, int flen, int num)
{
int i = 0, j;
const unsigned char *p;
p = from;
if ((num != flen) || ((*p != 0x6A) && (*p != 0x6B))) {
RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_HEADER);
return -1;
}
if (*p++ == 0x6B) {
j = flen - 3;
for (i = 0; i < j; i++) {
unsigned char c = *p++;
if (c == 0xBA)
break;
if (c != 0xBB) {
RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
return -1;
}
}
j -= i;
if (i == 0) {
RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
return -1;
}
} else {
j = flen - 2;
}
if (p[j] != 0xCC) {
RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_TRAILER);
return -1;
}
memcpy(to, p, (unsigned int)j);
return j;
}
/* Translate between X931 hash ids and NIDs */
int RSA_X931_hash_id(int nid)
{
switch (nid) {
case NID_sha1:
return 0x33;
case NID_sha256:
return 0x34;
case NID_sha384:
return 0x36;
case NID_sha512:
return 0x35;
}
return -1;
}