Botan 3.0.0-alpha0
Crypto and TLS for C&
base64.cpp
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1/*
2* Base64 Encoding and Decoding
3* (C) 2010,2015,2020 Jack Lloyd
4*
5* Botan is released under the Simplified BSD License (see license.txt)
6*/
7
8#include <botan/base64.h>
9#include <botan/internal/codec_base.h>
10#include <botan/exceptn.h>
11#include <botan/internal/rounding.h>
12#include <botan/internal/ct_utils.h>
13
14namespace Botan {
15
16namespace {
17
18class Base64 final
19 {
20 public:
21 static inline std::string name() noexcept
22 {
23 return "base64";
24 }
25
26 static inline size_t encoding_bytes_in() noexcept
27 {
28 return m_encoding_bytes_in;
29 }
30 static inline size_t encoding_bytes_out() noexcept
31 {
32 return m_encoding_bytes_out;
33 }
34
35 static inline size_t decoding_bytes_in() noexcept
36 {
37 return m_encoding_bytes_out;
38 }
39 static inline size_t decoding_bytes_out() noexcept
40 {
41 return m_encoding_bytes_in;
42 }
43
44 static inline size_t bits_consumed() noexcept
45 {
46 return m_encoding_bits;
47 }
48 static inline size_t remaining_bits_before_padding() noexcept
49 {
50 return m_remaining_bits_before_padding;
51 }
52
53 static inline size_t encode_max_output(size_t input_length)
54 {
55 return (round_up(input_length, m_encoding_bytes_in) / m_encoding_bytes_in) * m_encoding_bytes_out;
56 }
57 static inline size_t decode_max_output(size_t input_length)
58 {
59 return (round_up(input_length, m_encoding_bytes_out) * m_encoding_bytes_in) / m_encoding_bytes_out;
60 }
61
62 static void encode(char out[8], const uint8_t in[5]) noexcept;
63
64 static uint8_t lookup_binary_value(char input) noexcept;
65
66 static bool check_bad_char(uint8_t bin, char input, bool ignore_ws);
67
68 static void decode(uint8_t* out_ptr, const uint8_t decode_buf[4])
69 {
70 out_ptr[0] = (decode_buf[0] << 2) | (decode_buf[1] >> 4);
71 out_ptr[1] = (decode_buf[1] << 4) | (decode_buf[2] >> 2);
72 out_ptr[2] = (decode_buf[2] << 6) | decode_buf[3];
73 }
74
75 static inline size_t bytes_to_remove(size_t final_truncate)
76 {
77 return final_truncate;
78 }
79
80 private:
81 static const size_t m_encoding_bits = 6;
82 static const size_t m_remaining_bits_before_padding = 8;
83
84 static const size_t m_encoding_bytes_in = 3;
85 static const size_t m_encoding_bytes_out = 4;
86 };
87
88char lookup_base64_char(uint8_t x)
89 {
90 BOTAN_DEBUG_ASSERT(x < 64);
91
92 const auto in_az = CT::Mask<uint8_t>::is_within_range(x, 26, 51);
93 const auto in_09 = CT::Mask<uint8_t>::is_within_range(x, 52, 61);
94 const auto eq_plus = CT::Mask<uint8_t>::is_equal(x, 62);
95 const auto eq_slash = CT::Mask<uint8_t>::is_equal(x, 63);
96
97 const char c_AZ = 'A' + x;
98 const char c_az = 'a' + (x - 26);
99 const char c_09 = '0' + (x - 2*26);
100 const char c_plus = '+';
101 const char c_slash = '/';
102
103 char ret = c_AZ;
104 ret = in_az.select(c_az, ret);
105 ret = in_09.select(c_09, ret);
106 ret = eq_plus.select(c_plus, ret);
107 ret = eq_slash.select(c_slash, ret);
108
109 return ret;
110 }
111
112//static
113void Base64::encode(char out[8], const uint8_t in[5]) noexcept
114 {
115 const uint8_t b0 = (in[0] & 0xFC) >> 2;
116 const uint8_t b1 = ((in[0] & 0x03) << 4) | (in[1] >> 4);
117 const uint8_t b2 = ((in[1] & 0x0F) << 2) | (in[2] >> 6);
118 const uint8_t b3 = in[2] & 0x3F;
119 out[0] = lookup_base64_char(b0);
120 out[1] = lookup_base64_char(b1);
121 out[2] = lookup_base64_char(b2);
122 out[3] = lookup_base64_char(b3);
123 }
124
125//static
126uint8_t Base64::lookup_binary_value(char input) noexcept
127 {
128 const uint8_t c = static_cast<uint8_t>(input);
129
130 const auto is_alpha_upper = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('Z'));
131 const auto is_alpha_lower = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('z'));
132 const auto is_decimal = CT::Mask<uint8_t>::is_within_range(c, uint8_t('0'), uint8_t('9'));
133
134 const auto is_plus = CT::Mask<uint8_t>::is_equal(c, uint8_t('+'));
135 const auto is_slash = CT::Mask<uint8_t>::is_equal(c, uint8_t('/'));
136 const auto is_equal = CT::Mask<uint8_t>::is_equal(c, uint8_t('='));
137
138 const auto is_whitespace = CT::Mask<uint8_t>::is_any_of(c, {
139 uint8_t(' '), uint8_t('\t'), uint8_t('\n'), uint8_t('\r')
140 });
141
142 const uint8_t c_upper = c - uint8_t('A');
143 const uint8_t c_lower = c - uint8_t('a') + 26;
144 const uint8_t c_decim = c - uint8_t('0') + 2*26;
145
146 uint8_t ret = 0xFF; // default value
147
148 ret = is_alpha_upper.select(c_upper, ret);
149 ret = is_alpha_lower.select(c_lower, ret);
150 ret = is_decimal.select(c_decim, ret);
151 ret = is_plus.select(62, ret);
152 ret = is_slash.select(63, ret);
153 ret = is_equal.select(0x81, ret);
154 ret = is_whitespace.select(0x80, ret);
155
156 return ret;
157 }
158
159//static
160bool Base64::check_bad_char(uint8_t bin, char input, bool ignore_ws)
161 {
162 if(bin <= 0x3F)
163 {
164 return true;
165 }
166 else if(!(bin == 0x81 || (bin == 0x80 && ignore_ws)))
167 {
168 std::string bad_char(1, input);
169 if(bad_char == "\t")
170 { bad_char = "\\t"; }
171 else if(bad_char == "\n")
172 { bad_char = "\\n"; }
173 else if(bad_char == "\r")
174 { bad_char = "\\r"; }
175
176 throw Invalid_Argument(
177 std::string("base64_decode: invalid base64 character '") +
178 bad_char + "'");
179 }
180 return false;
181 }
182
183}
184
185size_t base64_encode(char out[],
186 const uint8_t in[],
187 size_t input_length,
188 size_t& input_consumed,
189 bool final_inputs)
190 {
191 return base_encode(Base64(), out, in, input_length, input_consumed, final_inputs);
192 }
193
194std::string base64_encode(const uint8_t input[],
195 size_t input_length)
196 {
197 return base_encode_to_string(Base64(), input, input_length);
198 }
199
200size_t base64_decode(uint8_t out[],
201 const char in[],
202 size_t input_length,
203 size_t& input_consumed,
204 bool final_inputs,
205 bool ignore_ws)
206 {
207 return base_decode(Base64(), out, in, input_length, input_consumed, final_inputs, ignore_ws);
208 }
209
210size_t base64_decode(uint8_t output[],
211 const char input[],
212 size_t input_length,
213 bool ignore_ws)
214 {
215 return base_decode_full(Base64(), output, input, input_length, ignore_ws);
216 }
217
218size_t base64_decode(uint8_t output[],
219 const std::string& input,
220 bool ignore_ws)
221 {
222 return base64_decode(output, input.data(), input.length(), ignore_ws);
223 }
224
226 size_t input_length,
227 bool ignore_ws)
228 {
229 return base_decode_to_vec<secure_vector<uint8_t>>(Base64(), input, input_length, ignore_ws);
230 }
231
232secure_vector<uint8_t> base64_decode(const std::string& input,
233 bool ignore_ws)
234 {
235 return base64_decode(input.data(), input.size(), ignore_ws);
236 }
237
238size_t base64_encode_max_output(size_t input_length)
239 {
240 return Base64::encode_max_output(input_length);
241 }
242
243size_t base64_decode_max_output(size_t input_length)
244 {
245 return Base64::decode_max_output(input_length);
246 }
247
248}
#define BOTAN_DEBUG_ASSERT(expr)
Definition: assert.h:122
static Mask< T > is_equal(T x, T y)
Definition: ct_utils.h:147
static Mask< T > is_any_of(T v, std::initializer_list< T > accepted)
Definition: ct_utils.h:194
static Mask< T > is_within_range(T v, T l, T u)
Definition: ct_utils.h:184
std::string name
int(* final)(unsigned char *, CTX *)
std::string encode(const uint8_t der[], size_t length, const std::string &label, size_t width)
Definition: pem.cpp:41
secure_vector< uint8_t > decode(DataSource &source, std::string &label)
Definition: pem.cpp:66
Definition: alg_id.cpp:13
size_t base64_encode(char out[], const uint8_t in[], size_t input_length, size_t &input_consumed, bool final_inputs)
Definition: base64.cpp:185
size_t base64_decode(uint8_t out[], const char in[], size_t input_length, size_t &input_consumed, bool final_inputs, bool ignore_ws)
Definition: base64.cpp:200
size_t base_encode(Base &&base, char output[], const uint8_t input[], size_t input_length, size_t &input_consumed, bool final_inputs)
Definition: codec_base.h:34
size_t base64_encode_max_output(size_t input_length)
Definition: base64.cpp:238
size_t base64_decode_max_output(size_t input_length)
Definition: base64.cpp:243
size_t base_decode(Base &&base, uint8_t output[], const char input[], size_t input_length, size_t &input_consumed, bool final_inputs, bool ignore_ws=true)
Definition: codec_base.h:124
std::string base_encode_to_string(Base &&base, const uint8_t input[], size_t input_length)
Definition: codec_base.h:86
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65
size_t round_up(size_t n, size_t align_to)
Definition: rounding.h:21
size_t base_decode_full(Base &&base, uint8_t output[], const char input[], size_t input_length, bool ignore_ws)
Definition: codec_base.h:189