1 /* $OpenBSD: rsa_x931.c,v 1.8 2014/07/11 08:44:49 jsing Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3  * project 2005.
4  */
5 /* ====================================================================
6  * Copyright (c) 2005 The OpenSSL Project.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    licensing@OpenSSL.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58 
59 #include <stdio.h>
60 #include <string.h>
61 
62 #include <openssl/bn.h>
63 #include <openssl/err.h>
64 #include <openssl/objects.h>
65 #include <openssl/rsa.h>
66 
67 int
68 RSA_padding_add_X931(unsigned char *to, int tlen, const unsigned char *from,
69     int flen)
70 {
71 	int j;
72 	unsigned char *p;
73 
74 	/*
75 	 * Absolute minimum amount of padding is 1 header nibble, 1 padding
76 	 * nibble and 2 trailer bytes: but 1 hash if is already in 'from'.
77 	 */
78 	j = tlen - flen - 2;
79 
80 	if (j < 0) {
81 		RSAerr(RSA_F_RSA_PADDING_ADD_X931,
82 		    RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
83 		return -1;
84 	}
85 
86 	p = (unsigned char *)to;
87 
88 	/* If no padding start and end nibbles are in one byte */
89 	if (j == 0)
90 		*p++ = 0x6A;
91 	else {
92 		*p++ = 0x6B;
93 		if (j > 1) {
94 			memset(p, 0xBB, j - 1);
95 			p += j - 1;
96 		}
97 		*p++ = 0xBA;
98 	}
99 	memcpy(p, from, flen);
100 	p += flen;
101 	*p = 0xCC;
102 	return 1;
103 }
104 
105 int
106 RSA_padding_check_X931(unsigned char *to, int tlen, const unsigned char *from,
107     int flen, int num)
108 {
109 	int i = 0, j;
110 	const unsigned char *p = from;
111 
112 	if (num != flen || (*p != 0x6A && *p != 0x6B)) {
113 		RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_HEADER);
114 		return -1;
115 	}
116 
117 	if (*p++ == 0x6B) {
118 		j = flen - 3;
119 		for (i = 0; i < j; i++) {
120 			unsigned char c = *p++;
121 			if (c == 0xBA)
122 				break;
123 			if (c != 0xBB) {
124 				RSAerr(RSA_F_RSA_PADDING_CHECK_X931,
125 				    RSA_R_INVALID_PADDING);
126 				return -1;
127 			}
128 		}
129 
130 		if (i == 0) {
131 			RSAerr(RSA_F_RSA_PADDING_CHECK_X931,
132 			    RSA_R_INVALID_PADDING);
133 			return -1;
134 		}
135 
136 		j -= i;
137 	} else
138 		j = flen - 2;
139 
140 	if (j < 0 || p[j] != 0xCC) {
141 		RSAerr(RSA_F_RSA_PADDING_CHECK_X931, RSA_R_INVALID_TRAILER);
142 		return -1;
143 	}
144 
145 	memcpy(to, p, j);
146 
147 	return j;
148 }
149 
150 /* Translate between X931 hash ids and NIDs */
151 
152 int
153 RSA_X931_hash_id(int nid)
154 {
155 	switch (nid) {
156 	case NID_sha1:
157 		return 0x33;
158 	case NID_sha256:
159 		return 0x34;
160 	case NID_sha384:
161 		return 0x36;
162 	case NID_sha512:
163 		return 0x35;
164 	}
165 
166 	return -1;
167 }
168