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1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #ifndef OPENSSL_HEADER_BASE64_H
58 #define OPENSSL_HEADER_BASE64_H
59 
60 #include <openssl/base.h>
61 
62 #if defined(__cplusplus)
63 extern "C" {
64 #endif
65 
66 
67 // base64 functions.
68 //
69 // For historical reasons, these functions have the EVP_ prefix but just do
70 // base64 encoding and decoding. Note that BoringSSL is a cryptography library,
71 // so these functions are implemented with side channel protections, at a
72 // performance cost. For other base64 uses, use a general-purpose base64
73 // implementation.
74 
75 
76 // Encoding
77 
78 // EVP_EncodeBlock encodes |src_len| bytes from |src| and writes the
79 // result to |dst| with a trailing NUL. It returns the number of bytes
80 // written, not including this trailing NUL.
81 OPENSSL_EXPORT size_t EVP_EncodeBlock(uint8_t *dst, const uint8_t *src,
82                                       size_t src_len);
83 
84 // EVP_EncodedLength sets |*out_len| to the number of bytes that will be needed
85 // to call |EVP_EncodeBlock| on an input of length |len|. This includes the
86 // final NUL that |EVP_EncodeBlock| writes. It returns one on success or zero
87 // on error.
88 OPENSSL_EXPORT int EVP_EncodedLength(size_t *out_len, size_t len);
89 
90 
91 // Decoding
92 
93 // EVP_DecodedLength sets |*out_len| to the maximum number of bytes that will
94 // be needed to call |EVP_DecodeBase64| on an input of length |len|. It returns
95 // one on success or zero if |len| is not a valid length for a base64-encoded
96 // string.
97 OPENSSL_EXPORT int EVP_DecodedLength(size_t *out_len, size_t len);
98 
99 // EVP_DecodeBase64 decodes |in_len| bytes from base64 and writes
100 // |*out_len| bytes to |out|. |max_out| is the size of the output
101 // buffer. If it is not enough for the maximum output size, the
102 // operation fails. It returns one on success or zero on error.
103 OPENSSL_EXPORT int EVP_DecodeBase64(uint8_t *out, size_t *out_len,
104                                     size_t max_out, const uint8_t *in,
105                                     size_t in_len);
106 
107 
108 // Deprecated functions.
109 //
110 // OpenSSL provides a streaming base64 implementation, however its behavior is
111 // very specific to PEM. It is also very lenient of invalid input. Use of any of
112 // these functions is thus deprecated.
113 
114 // EVP_EncodeInit initialises |*ctx|, which is typically stack
115 // allocated, for an encoding operation.
116 //
117 // NOTE: The encoding operation breaks its output with newlines every
118 // 64 characters of output (48 characters of input). Use
119 // EVP_EncodeBlock to encode raw base64.
120 OPENSSL_EXPORT void EVP_EncodeInit(EVP_ENCODE_CTX *ctx);
121 
122 // EVP_EncodeUpdate encodes |in_len| bytes from |in| and writes an encoded
123 // version of them to |out| and sets |*out_len| to the number of bytes written.
124 // Some state may be contained in |ctx| so |EVP_EncodeFinal| must be used to
125 // flush it before using the encoded data.
126 OPENSSL_EXPORT void EVP_EncodeUpdate(EVP_ENCODE_CTX *ctx, uint8_t *out,
127                                      int *out_len, const uint8_t *in,
128                                      size_t in_len);
129 
130 // EVP_EncodeFinal flushes any remaining output bytes from |ctx| to |out| and
131 // sets |*out_len| to the number of bytes written.
132 OPENSSL_EXPORT void EVP_EncodeFinal(EVP_ENCODE_CTX *ctx, uint8_t *out,
133                                     int *out_len);
134 
135 // EVP_DecodeInit initialises |*ctx|, which is typically stack allocated, for
136 // a decoding operation.
137 //
138 // TODO(davidben): This isn't a straight-up base64 decode either. Document
139 // and/or fix exactly what's going on here; maximum line length and such.
140 OPENSSL_EXPORT void EVP_DecodeInit(EVP_ENCODE_CTX *ctx);
141 
142 // EVP_DecodeUpdate decodes |in_len| bytes from |in| and writes the decoded
143 // data to |out| and sets |*out_len| to the number of bytes written. Some state
144 // may be contained in |ctx| so |EVP_DecodeFinal| must be used to flush it
145 // before using the encoded data.
146 //
147 // It returns -1 on error, one if a full line of input was processed and zero
148 // if the line was short (i.e. it was the last line).
149 OPENSSL_EXPORT int EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx, uint8_t *out,
150                                     int *out_len, const uint8_t *in,
151                                     size_t in_len);
152 
153 // EVP_DecodeFinal flushes any remaining output bytes from |ctx| to |out| and
154 // sets |*out_len| to the number of bytes written. It returns one on success
155 // and minus one on error.
156 OPENSSL_EXPORT int EVP_DecodeFinal(EVP_ENCODE_CTX *ctx, uint8_t *out,
157                                    int *out_len);
158 
159 // EVP_DecodeBlock encodes |src_len| bytes from |src| and writes the result to
160 // |dst|. It returns the number of bytes written or -1 on error.
161 //
162 // WARNING: EVP_DecodeBlock's return value does not take padding into
163 // account. It also strips leading whitespace and trailing
164 // whitespace and minuses.
165 OPENSSL_EXPORT int EVP_DecodeBlock(uint8_t *dst, const uint8_t *src,
166                                    size_t src_len);
167 
168 
169 struct evp_encode_ctx_st {
170   // data_used indicates the number of bytes of |data| that are valid. When
171   // encoding, |data| will be filled and encoded as a lump. When decoding, only
172   // the first four bytes of |data| will be used.
173   unsigned data_used;
174   uint8_t data[48];
175 
176   // eof_seen indicates that the end of the base64 data has been seen when
177   // decoding. Only whitespace can follow.
178   char eof_seen;
179 
180   // error_encountered indicates that invalid base64 data was found. This will
181   // cause all future calls to fail.
182   char error_encountered;
183 };
184 
185 
186 #if defined(__cplusplus)
187 }  // extern C
188 #endif
189 
190 #endif  // OPENSSL_HEADER_BASE64_H
191