1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3 #include "tomcrypt_private.h"
4
5 /**
6 @file base64_encode.c
7 Compliant base64 encoder donated by Wayne Scott (wscott@bitmover.com)
8 base64 URL Safe variant (RFC 4648 section 5) by Karel Miko
9 */
10
11
12 #if defined(LTC_BASE64) || defined (LTC_BASE64_URL)
13
14 #if defined(LTC_BASE64)
15 static const char * const codes_base64 =
16 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
17 #endif /* LTC_BASE64 */
18
19 #if defined(LTC_BASE64_URL)
20 static const char * const codes_base64url =
21 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
22 #endif /* LTC_BASE64_URL */
23
24 enum mode {
25 nopad = 0,
26 pad = 1,
27 lf = 2,
28 cr = 4,
29 ssh = 8,
30 crlf = lf | cr,
31 };
32
s_base64_encode_internal(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen,const char * codes,unsigned int mode)33 static int s_base64_encode_internal(const unsigned char *in, unsigned long inlen,
34 char *out, unsigned long *outlen,
35 const char *codes, unsigned int mode)
36 {
37 unsigned long i, len2, leven, linelen;
38 char *p;
39
40 LTC_ARGCHK(outlen != NULL);
41
42 linelen = (mode & ssh) ? 72 : 64;
43
44 /* valid output size ? */
45 len2 = 4 * ((inlen + 2) / 3);
46 if ((mode & crlf) == lf) {
47 len2 += len2 / linelen;
48 } else if ((mode & crlf) == crlf) {
49 len2 += (len2 / linelen) * 2;
50 }
51 if (*outlen < len2 + 1) {
52 *outlen = len2 + 1;
53 return CRYPT_BUFFER_OVERFLOW;
54 }
55
56 LTC_ARGCHK(in != NULL);
57 LTC_ARGCHK(out != NULL);
58
59 if ((void*)in == out) {
60 return CRYPT_INVALID_ARG;
61 }
62
63 p = out;
64 leven = 3*(inlen / 3);
65 for (i = 0; i < leven; i += 3) {
66 *p++ = codes[(in[0] >> 2) & 0x3F];
67 *p++ = codes[(((in[0] & 3) << 4) + (in[1] >> 4)) & 0x3F];
68 *p++ = codes[(((in[1] & 0xf) << 2) + (in[2] >> 6)) & 0x3F];
69 *p++ = codes[in[2] & 0x3F];
70 in += 3;
71 if ((p - out) % linelen == 0) {
72 if (mode & cr) *p++ = '\r';
73 if (mode & lf) *p++ = '\n';
74 }
75 }
76 /* Pad it if necessary... */
77 if (i < inlen) {
78 unsigned a = in[0];
79 unsigned b = (i+1 < inlen) ? in[1] : 0;
80
81 *p++ = codes[(a >> 2) & 0x3F];
82 *p++ = codes[(((a & 3) << 4) + (b >> 4)) & 0x3F];
83 if (mode & pad) {
84 *p++ = (i+1 < inlen) ? codes[(((b & 0xf) << 2)) & 0x3F] : '=';
85 *p++ = '=';
86 }
87 else {
88 if (i+1 < inlen) *p++ = codes[(((b & 0xf) << 2)) & 0x3F];
89 }
90 }
91
92 /* append a NULL byte */
93 *p = '\0';
94
95 /* return ok */
96 *outlen = (unsigned long)(p - out); /* the length without terminating NUL */
97 return CRYPT_OK;
98 }
99
100 #if defined(LTC_BASE64)
101 /**
102 base64 Encode a buffer (NUL terminated)
103 @param in The input buffer to encode
104 @param inlen The length of the input buffer
105 @param out [out] The destination of the base64 encoded data
106 @param outlen [in/out] The max size and resulting size
107 @return CRYPT_OK if successful
108 */
base64_encode(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen)109 int base64_encode(const unsigned char *in, unsigned long inlen,
110 char *out, unsigned long *outlen)
111 {
112 return s_base64_encode_internal(in, inlen, out, outlen, codes_base64, pad);
113 }
114
115 /**
116 base64 Encode a buffer for PEM output
117 (NUL terminated with line-break at 64 chars)
118 @param in The input buffer to encode
119 @param inlen The length of the input buffer
120 @param out [out] The destination of the base64 encoded data
121 @param outlen [in/out] The max size and resulting size
122 @param flags \ref base64_pem_flags
123 @return CRYPT_OK if successful
124 */
base64_encode_pem(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen,unsigned int flags)125 int base64_encode_pem(const unsigned char *in, unsigned long inlen,
126 char *out, unsigned long *outlen,
127 unsigned int flags)
128 {
129 int use_crlf = flags & BASE64_PEM_CRLF ? pad | crlf : pad | lf;
130 int ssh_style = flags & BASE64_PEM_SSH ? ssh : 0;
131 return s_base64_encode_internal(in, inlen, out, outlen, codes_base64, ssh_style | use_crlf);
132 }
133 #endif /* LTC_BASE64 */
134
135
136 #if defined(LTC_BASE64_URL)
137 /**
138 base64 (URL Safe, RFC 4648 section 5) Encode a buffer (NUL terminated)
139 @param in The input buffer to encode
140 @param inlen The length of the input buffer
141 @param out [out] The destination of the base64 encoded data
142 @param outlen [in/out] The max size and resulting size
143 @return CRYPT_OK if successful
144 */
base64url_encode(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen)145 int base64url_encode(const unsigned char *in, unsigned long inlen,
146 char *out, unsigned long *outlen)
147 {
148 return s_base64_encode_internal(in, inlen, out, outlen, codes_base64url, nopad);
149 }
150
base64url_strict_encode(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen)151 int base64url_strict_encode(const unsigned char *in, unsigned long inlen,
152 char *out, unsigned long *outlen)
153 {
154 return s_base64_encode_internal(in, inlen, out, outlen, codes_base64url, pad);
155 }
156 #endif /* LTC_BASE64_URL */
157
158 #endif
159
160