1/*
2 * Copyright 2005-2017 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (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/objects.h>
15
16int RSA_padding_add_X931(unsigned char *to, int tlen,
17 const unsigned char *from, int flen)
18{
19 int j;
20 unsigned char *p;
21
22 /*
23 * Absolute minimum amount of padding is 1 header nibble, 1 padding
24 * nibble and 2 trailer bytes: but 1 hash if is already in 'from'.
25 */
26
27 j = tlen - flen - 2;
28
29 if (j < 0) {
30 RSAerr(RSA_F_RSA_PADDING_ADD_X931, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
31 return -1;
32 }
33
34 p = (unsigned char *)to;
35
36 /* If no padding start and end nibbles are in one byte */
37 if (j == 0) {
38 *p++ = 0x6A;
39 } else {
40 *p++ = 0x6B;
41 if (j > 1) {
42 memset(p, 0xBB, j - 1);
43 p += j - 1;
44 }
45 *p++ = 0xBA;
46 }
47 memcpy(p, from, (unsigned int)flen);
48 p += flen;
49 *p = 0xCC;
50 return 1;
51}
52
53int RSA_padding_check_X931(unsigned char *to, int tlen,
54 const unsigned char *from, int flen, int num)
55{
56 int i = 0, j;
57 const unsigned char *p;
58
59 p = from;
60 if ((num != flen) || ((*p != 0x6A) && (*p != 0x6B))) {
61 RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_HEADER);
62 return -1;
63 }
64
65 if (*p++ == 0x6B) {
66 j = flen - 3;
67 for (i = 0; i < j; i++) {
68 unsigned char c = *p++;
69 if (c == 0xBA)
70 break;
71 if (c != 0xBB) {
72 RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
73 return -1;
74 }
75 }
76
77 j -= i;
78
79 if (i == 0) {
80 RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_PADDING);
81 return -1;
82 }
83
84 } else {
85 j = flen - 2;
86 }
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
100int 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}
118