1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file base64_decode.c
15 Compliant base64 code donated by Wayne Scott (wscott@bitmover.com)
16 base64 URL Safe variant (RFC 4648 section 5) by Karel Miko
17 */
18
19
20 #if defined(LTC_BASE64) || defined (LTC_BASE64_URL)
21
22 #if defined(LTC_BASE64)
23 static const unsigned char map_base64[256] = {
24 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
25 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
26 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
27 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
28 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
29 255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
30 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
31 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255,
32 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
33 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
34 49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
35 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
36 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
37 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
38 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
39 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
40 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
41 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
42 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
43 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
44 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
45 255, 255, 255, 255 };
46 #endif /* LTC_BASE64 */
47
48 #if defined(LTC_BASE64_URL)
49 static const unsigned char map_base64url[256] = {
50 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
51 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
52 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
53 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255,
54 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
55 255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
56 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
57 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 63,
58 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
59 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
60 49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
61 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
62 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
63 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
64 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
65 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
66 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
67 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
68 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
69 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
70 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
71 255, 255, 255, 255 };
72 #endif /* LTC_BASE64_URL */
73
_base64_decode_internal(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen,const unsigned char * map)74 static int _base64_decode_internal(const unsigned char *in, unsigned long inlen,
75 unsigned char *out, unsigned long *outlen,
76 const unsigned char *map)
77 {
78 unsigned long t, x, y, z;
79 unsigned char c;
80 int g;
81
82 LTC_ARGCHK(in != NULL);
83 LTC_ARGCHK(out != NULL);
84 LTC_ARGCHK(outlen != NULL);
85
86 g = 3;
87 for (x = y = z = t = 0; x < inlen; x++) {
88 c = map[in[x]&0xFF];
89 if (c == 255) continue;
90 /* the final = symbols are read and used to trim the remaining bytes */
91 if (c == 254) {
92 c = 0;
93 /* prevent g < 0 which would potentially allow an overflow later */
94 if (--g < 0) {
95 return CRYPT_INVALID_PACKET;
96 }
97 } else if (g != 3) {
98 /* we only allow = to be at the end */
99 return CRYPT_INVALID_PACKET;
100 }
101
102 t = (t<<6)|c;
103
104 if (++y == 4) {
105 if (z + g > *outlen) {
106 return CRYPT_BUFFER_OVERFLOW;
107 }
108 out[z++] = (unsigned char)((t>>16)&255);
109 if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
110 if (g > 2) out[z++] = (unsigned char)(t&255);
111 y = t = 0;
112 }
113 }
114 if (y != 0) {
115 return CRYPT_INVALID_PACKET;
116 }
117 *outlen = z;
118 return CRYPT_OK;
119 }
120
121 #if defined(LTC_BASE64)
122 /**
123 base64 decode a block of memory
124 @param in The base64 data to decode
125 @param inlen The length of the base64 data
126 @param out [out] The destination of the binary decoded data
127 @param outlen [in/out] The max size and resulting size of the decoded data
128 @return CRYPT_OK if successful
129 */
base64_decode(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen)130 int base64_decode(const unsigned char *in, unsigned long inlen,
131 unsigned char *out, unsigned long *outlen)
132 {
133 return _base64_decode_internal(in, inlen, out, outlen, map_base64);
134 }
135 #endif /* LTC_BASE64 */
136
137 #if defined(LTC_BASE64_URL)
138 /**
139 base64 (URL Safe, RFC 4648 section 5) decode a block of memory
140 @param in The base64 data to decode
141 @param inlen The length of the base64 data
142 @param out [out] The destination of the binary decoded data
143 @param outlen [in/out] The max size and resulting size of the decoded data
144 @return CRYPT_OK if successful
145 */
base64url_decode(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen)146 int base64url_decode(const unsigned char *in, unsigned long inlen,
147 unsigned char *out, unsigned long *outlen)
148 {
149 return _base64_decode_internal(in, inlen, out, outlen, map_base64url);
150 }
151 #endif /* LTC_BASE64_URL */
152
153 #endif
154
155
156 /* $Source$ */
157 /* $Revision$ */
158 /* $Date$ */
159