1 /*
2 * Copyright 2005-2020 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 /*
11 * RSA low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdio.h>
17 #include "internal/cryptlib.h"
18 #include <openssl/bn.h>
19 #include <openssl/rsa.h>
20 #include <openssl/objects.h>
21
RSA_padding_add_X931(unsigned char * to,int tlen,const unsigned char * from,int flen)22 int RSA_padding_add_X931(unsigned char *to, int tlen,
23 const unsigned char *from, int flen)
24 {
25 int j;
26 unsigned char *p;
27
28 /*
29 * Absolute minimum amount of padding is 1 header nibble, 1 padding
30 * nibble and 2 trailer bytes: but 1 hash if is already in 'from'.
31 */
32
33 j = tlen - flen - 2;
34
35 if (j < 0) {
36 ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
37 return -1;
38 }
39
40 p = (unsigned char *)to;
41
42 /* If no padding start and end nibbles are in one byte */
43 if (j == 0) {
44 *p++ = 0x6A;
45 } else {
46 *p++ = 0x6B;
47 if (j > 1) {
48 memset(p, 0xBB, j - 1);
49 p += j - 1;
50 }
51 *p++ = 0xBA;
52 }
53 memcpy(p, from, (unsigned int)flen);
54 p += flen;
55 *p = 0xCC;
56 return 1;
57 }
58
RSA_padding_check_X931(unsigned char * to,int tlen,const unsigned char * from,int flen,int num)59 int RSA_padding_check_X931(unsigned char *to, int tlen,
60 const unsigned char *from, int flen, int num)
61 {
62 int i = 0, j;
63 const unsigned char *p;
64
65 p = from;
66 if ((num != flen) || ((*p != 0x6A) && (*p != 0x6B))) {
67 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_HEADER);
68 return -1;
69 }
70
71 if (*p++ == 0x6B) {
72 j = flen - 3;
73 for (i = 0; i < j; i++) {
74 unsigned char c = *p++;
75 if (c == 0xBA)
76 break;
77 if (c != 0xBB) {
78 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_PADDING);
79 return -1;
80 }
81 }
82
83 j -= i;
84
85 if (i == 0) {
86 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_PADDING);
87 return -1;
88 }
89
90 } else {
91 j = flen - 2;
92 }
93
94 if (p[j] != 0xCC) {
95 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_TRAILER);
96 return -1;
97 }
98
99 memcpy(to, p, (unsigned int)j);
100
101 return j;
102 }
103
104 /* Translate between X931 hash ids and NIDs */
105
RSA_X931_hash_id(int nid)106 int RSA_X931_hash_id(int nid)
107 {
108 switch (nid) {
109 case NID_sha1:
110 return 0x33;
111
112 case NID_sha256:
113 return 0x34;
114
115 case NID_sha384:
116 return 0x36;
117
118 case NID_sha512:
119 return 0x35;
120
121 }
122 return -1;
123 }
124