1/* $OpenBSD: rsa_x931.c,v 1.12 2023/05/05 12:19:37 tb 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
67int
68RSA_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		RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
82		return -1;
83	}
84
85	p = (unsigned char *)to;
86
87	/* If no padding start and end nibbles are in one byte */
88	if (j == 0)
89		*p++ = 0x6A;
90	else {
91		*p++ = 0x6B;
92		if (j > 1) {
93			memset(p, 0xBB, j - 1);
94			p += j - 1;
95		}
96		*p++ = 0xBA;
97	}
98	memcpy(p, from, flen);
99	p += flen;
100	*p = 0xCC;
101	return 1;
102}
103
104int
105RSA_padding_check_X931(unsigned char *to, int tlen, const unsigned char *from,
106    int flen, int num)
107{
108	int i = 0, j;
109	const unsigned char *p = from;
110
111	if (num != flen || (*p != 0x6A && *p != 0x6B)) {
112		RSAerror(RSA_R_INVALID_HEADER);
113		return -1;
114	}
115
116	if (*p++ == 0x6B) {
117		j = flen - 3;
118		for (i = 0; i < j; i++) {
119			unsigned char c = *p++;
120			if (c == 0xBA)
121				break;
122			if (c != 0xBB) {
123				RSAerror(RSA_R_INVALID_PADDING);
124				return -1;
125			}
126		}
127
128		if (i == 0) {
129			RSAerror(RSA_R_INVALID_PADDING);
130			return -1;
131		}
132
133		j -= i;
134	} else
135		j = flen - 2;
136
137	if (j < 0 || p[j] != 0xCC) {
138		RSAerror(RSA_R_INVALID_TRAILER);
139		return -1;
140	}
141
142	memcpy(to, p, j);
143
144	return j;
145}
146
147/* Translate between X931 hash ids and NIDs */
148
149int
150RSA_X931_hash_id(int nid)
151{
152	switch (nid) {
153	case NID_sha1:
154		return 0x33;
155	case NID_sha256:
156		return 0x34;
157	case NID_sha384:
158		return 0x36;
159	case NID_sha512:
160		return 0x35;
161	}
162
163	return -1;
164}
165