Line data Source code
1 : /*
2 : *
3 : * Copyright 2015, Google Inc.
4 : * All rights reserved.
5 : *
6 : * Redistribution and use in source and binary forms, with or without
7 : * modification, are permitted provided that the following conditions are
8 : * met:
9 : *
10 : * * Redistributions of source code must retain the above copyright
11 : * notice, this list of conditions and the following disclaimer.
12 : * * Redistributions in binary form must reproduce the above
13 : * copyright notice, this list of conditions and the following disclaimer
14 : * in the documentation and/or other materials provided with the
15 : * distribution.
16 : * * Neither the name of Google Inc. nor the names of its
17 : * contributors may be used to endorse or promote products derived from
18 : * this software without specific prior written permission.
19 : *
20 : * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 : * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 : * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 : * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 : * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 : * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 : * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 : * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 : * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 : * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 : * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 : *
32 : */
33 :
34 : #include "src/core/security/base64.h"
35 :
36 : #include <string.h>
37 :
38 : #include <grpc/support/alloc.h>
39 : #include <grpc/support/log.h>
40 : #include <grpc/support/useful.h>
41 :
42 : /* --- Constants. --- */
43 :
44 : static const char base64_bytes[] = {
45 : -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
46 : -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
47 : -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
48 : -1, -1, -1, -1, -1, -1, -1, 0x3E, -1, -1, -1, 0x3F,
49 : 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, -1, -1,
50 : -1, 0x7F, -1, -1, -1, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
51 : 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12,
52 : 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, -1, -1, -1, -1, -1,
53 : -1, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
54 : 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
55 : 0x31, 0x32, 0x33, -1, -1, -1, -1, -1};
56 :
57 : static const char base64_url_unsafe_chars[] =
58 : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
59 : static const char base64_url_safe_chars[] =
60 : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
61 :
62 : #define GRPC_BASE64_PAD_CHAR '='
63 : #define GRPC_BASE64_PAD_BYTE 0x7F
64 : #define GRPC_BASE64_MULTILINE_LINE_LEN 76
65 : #define GRPC_BASE64_MULTILINE_NUM_BLOCKS (GRPC_BASE64_MULTILINE_LINE_LEN / 4)
66 :
67 : /* --- base64 functions. --- */
68 :
69 50 : char *grpc_base64_encode(const void *vdata, size_t data_size, int url_safe,
70 : int multiline) {
71 50 : const unsigned char *data = vdata;
72 50 : const char *base64_chars =
73 50 : url_safe ? base64_url_safe_chars : base64_url_unsafe_chars;
74 50 : size_t result_projected_size =
75 100 : 4 * ((data_size + 3) / 3) +
76 50 : 2 * (multiline ? (data_size / (3 * GRPC_BASE64_MULTILINE_NUM_BLOCKS))
77 : : 0) +
78 : 1;
79 50 : char *result = gpr_malloc(result_projected_size);
80 50 : char *current = result;
81 50 : size_t num_blocks = 0;
82 50 : size_t i = 0;
83 :
84 : /* Encode each block. */
85 2284 : while (data_size >= 3) {
86 2184 : *current++ = base64_chars[(data[i] >> 2) & 0x3F];
87 4368 : *current++ =
88 2184 : base64_chars[((data[i] & 0x03) << 4) | ((data[i + 1] >> 4) & 0x0F)];
89 4368 : *current++ =
90 2184 : base64_chars[((data[i + 1] & 0x0F) << 2) | ((data[i + 2] >> 6) & 0x03)];
91 2184 : *current++ = base64_chars[data[i + 2] & 0x3F];
92 :
93 2184 : data_size -= 3;
94 2184 : i += 3;
95 2184 : if (multiline && (++num_blocks == GRPC_BASE64_MULTILINE_NUM_BLOCKS)) {
96 24 : *current++ = '\r';
97 24 : *current++ = '\n';
98 24 : num_blocks = 0;
99 : }
100 : }
101 :
102 : /* Take care of the tail. */
103 50 : if (data_size == 2) {
104 19 : *current++ = base64_chars[(data[i] >> 2) & 0x3F];
105 38 : *current++ =
106 19 : base64_chars[((data[i] & 0x03) << 4) | ((data[i + 1] >> 4) & 0x0F)];
107 19 : *current++ = base64_chars[(data[i + 1] & 0x0F) << 2];
108 19 : *current++ = GRPC_BASE64_PAD_CHAR;
109 31 : } else if (data_size == 1) {
110 20 : *current++ = base64_chars[(data[i] >> 2) & 0x3F];
111 20 : *current++ = base64_chars[(data[i] & 0x03) << 4];
112 20 : *current++ = GRPC_BASE64_PAD_CHAR;
113 20 : *current++ = GRPC_BASE64_PAD_CHAR;
114 : }
115 :
116 50 : GPR_ASSERT(current >= result);
117 50 : GPR_ASSERT((gpr_uintptr)(current - result) < result_projected_size);
118 50 : result[current - result] = '\0';
119 50 : return result;
120 : }
121 :
122 44 : gpr_slice grpc_base64_decode(const char *b64, int url_safe) {
123 44 : return grpc_base64_decode_with_len(b64, strlen(b64), url_safe);
124 : }
125 :
126 18 : static void decode_one_char(const unsigned char *codes, unsigned char *result,
127 : size_t *result_offset) {
128 18 : gpr_uint32 packed = ((gpr_uint32)codes[0] << 2) | ((gpr_uint32)codes[1] >> 4);
129 18 : result[(*result_offset)++] = (unsigned char)packed;
130 18 : }
131 :
132 22 : static void decode_two_chars(const unsigned char *codes, unsigned char *result,
133 : size_t *result_offset) {
134 66 : gpr_uint32 packed = ((gpr_uint32)codes[0] << 10) |
135 44 : ((gpr_uint32)codes[1] << 4) | ((gpr_uint32)codes[2] >> 2);
136 22 : result[(*result_offset)++] = (unsigned char)(packed >> 8);
137 22 : result[(*result_offset)++] = (unsigned char)(packed);
138 22 : }
139 :
140 2223 : static int decode_group(const unsigned char *codes, size_t num_codes,
141 : unsigned char *result, size_t *result_offset) {
142 2223 : GPR_ASSERT(num_codes <= 4);
143 :
144 : /* Short end groups that may not have padding. */
145 2223 : if (num_codes == 1) {
146 0 : gpr_log(GPR_ERROR, "Invalid group. Must be at least 2 bytes.");
147 0 : return 0;
148 : }
149 2223 : if (num_codes == 2) {
150 2 : decode_one_char(codes, result, result_offset);
151 2 : return 1;
152 : }
153 2221 : if (num_codes == 3) {
154 2 : decode_two_chars(codes, result, result_offset);
155 2 : return 1;
156 : }
157 :
158 : /* Regular 4 byte groups with padding or not. */
159 2219 : GPR_ASSERT(num_codes == 4);
160 2219 : if (codes[0] == GRPC_BASE64_PAD_BYTE || codes[1] == GRPC_BASE64_PAD_BYTE) {
161 0 : gpr_log(GPR_ERROR, "Invalid padding detected.");
162 0 : return 0;
163 : }
164 2219 : if (codes[2] == GRPC_BASE64_PAD_BYTE) {
165 16 : if (codes[3] == GRPC_BASE64_PAD_BYTE) {
166 16 : decode_one_char(codes, result, result_offset);
167 : } else {
168 0 : gpr_log(GPR_ERROR, "Invalid padding detected.");
169 0 : return 0;
170 : }
171 2203 : } else if (codes[3] == GRPC_BASE64_PAD_BYTE) {
172 20 : decode_two_chars(codes, result, result_offset);
173 : } else {
174 : /* No padding. */
175 6549 : gpr_uint32 packed = ((gpr_uint32)codes[0] << 18) |
176 4366 : ((gpr_uint32)codes[1] << 12) |
177 4366 : ((gpr_uint32)codes[2] << 6) | codes[3];
178 2183 : result[(*result_offset)++] = (unsigned char)(packed >> 16);
179 2183 : result[(*result_offset)++] = (unsigned char)(packed >> 8);
180 2183 : result[(*result_offset)++] = (unsigned char)(packed);
181 : }
182 2219 : return 1;
183 : }
184 :
185 56 : gpr_slice grpc_base64_decode_with_len(const char *b64, size_t b64_len,
186 : int url_safe) {
187 56 : gpr_slice result = gpr_slice_malloc(b64_len);
188 56 : unsigned char *current = GPR_SLICE_START_PTR(result);
189 56 : size_t result_size = 0;
190 : unsigned char codes[4];
191 56 : size_t num_codes = 0;
192 :
193 9052 : while (b64_len--) {
194 8942 : unsigned char c = (unsigned char)(*b64++);
195 : signed char code;
196 8942 : if (c >= GPR_ARRAY_SIZE(base64_bytes)) continue;
197 8942 : if (url_safe) {
198 6740 : if (c == '+' || c == '/') {
199 1 : gpr_log(GPR_ERROR, "Invalid character for url safe base64 %c", c);
200 1 : goto fail;
201 : }
202 6739 : if (c == '-') {
203 68 : c = '+';
204 6671 : } else if (c == '_') {
205 66 : c = '/';
206 : }
207 : }
208 8941 : code = base64_bytes[c];
209 8941 : if (code == -1) {
210 49 : if (c != '\r' && c != '\n') {
211 1 : gpr_log(GPR_ERROR, "Invalid character %c", c);
212 1 : goto fail;
213 : }
214 : } else {
215 8892 : codes[num_codes++] = (unsigned char)code;
216 8892 : if (num_codes == 4) {
217 2219 : if (!decode_group(codes, num_codes, current, &result_size)) goto fail;
218 2219 : num_codes = 0;
219 : }
220 : }
221 : }
222 :
223 58 : if (num_codes != 0 &&
224 4 : !decode_group(codes, num_codes, current, &result_size)) {
225 0 : goto fail;
226 : }
227 54 : GPR_SLICE_SET_LENGTH(result, result_size);
228 54 : return result;
229 :
230 : fail:
231 2 : gpr_slice_unref(result);
232 2 : return gpr_empty_slice();
233 : }
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