1 /*
2  * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * @brief Base64 encode/decode
24  * @author Ryan Martell <rdm4@martellventures.com> (with lots of Michael)
25  */
26 
27 #include "common.h"
28 #include "base64.h"
29 #include "intreadwrite.h"
30 #include "timer.h"
31 
32 /* ---------------- private code */
33 static const uint8_t map2[256] =
34 {
35     0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
36     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
37     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
38     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
39     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
40     0xff, 0xff, 0xff,
41 
42     0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
43     0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
44     0xff, 0xff, 0xfe, 0xff, 0xff, 0xff, 0x00, 0x01,
45     0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
46     0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
47     0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
48     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
49     0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
50     0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
51     0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33,
52 
53                       0xff, 0xff, 0xff, 0xff, 0xff,
54     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
55     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
56     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
57     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
58     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
59     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
60     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
61     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
62     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
63     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
64     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
65     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
66     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
67     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
68     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
69     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
70 };
71 
72 #define BASE64_DEC_STEP(i) do { \
73     bits = map2[in[i]]; \
74     if (bits & 0x80) \
75         goto out ## i; \
76     v = i ? (v << 6) + bits : bits; \
77 } while(0)
78 
av_base64_decode(uint8_t * out,const char * in_str,int out_size)79 int av_base64_decode(uint8_t *out, const char *in_str, int out_size)
80 {
81     uint8_t *dst = out;
82     uint8_t *end = out + out_size;
83     // no sign extension
84     const uint8_t *in = in_str;
85     unsigned bits = 0xff;
86     unsigned v;
87 
88     while (end - dst > 3) {
89         BASE64_DEC_STEP(0);
90         BASE64_DEC_STEP(1);
91         BASE64_DEC_STEP(2);
92         BASE64_DEC_STEP(3);
93         // Using AV_WB32 directly confuses compiler
94         v = av_be2ne32(v << 8);
95         AV_WN32(dst, v);
96         dst += 3;
97         in += 4;
98     }
99     if (end - dst) {
100         BASE64_DEC_STEP(0);
101         BASE64_DEC_STEP(1);
102         BASE64_DEC_STEP(2);
103         BASE64_DEC_STEP(3);
104         *dst++ = v >> 16;
105         if (end - dst)
106             *dst++ = v >> 8;
107         if (end - dst)
108             *dst++ = v;
109         in += 4;
110     }
111     while (1) {
112         BASE64_DEC_STEP(0);
113         in++;
114         BASE64_DEC_STEP(0);
115         in++;
116         BASE64_DEC_STEP(0);
117         in++;
118         BASE64_DEC_STEP(0);
119         in++;
120     }
121 
122 out3:
123     *dst++ = v >> 10;
124     v <<= 2;
125 out2:
126     *dst++ = v >> 4;
127 out1:
128 out0:
129     return bits & 1 ? AVERROR_INVALIDDATA : dst - out;
130 }
131 
132 /*****************************************************************************
133 * b64_encode: Stolen from VLC's http.c.
134 * Simplified by Michael.
135 * Fixed edge cases and made it work from data (vs. strings) by Ryan.
136 *****************************************************************************/
137 
av_base64_encode(char * out,int out_size,const uint8_t * in,int in_size)138 char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)
139 {
140     static const char b64[] =
141         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
142     char *ret, *dst;
143     unsigned i_bits = 0;
144     int i_shift = 0;
145     int bytes_remaining = in_size;
146 
147     if (in_size >= UINT_MAX / 4 ||
148         out_size < AV_BASE64_SIZE(in_size))
149         return NULL;
150     ret = dst = out;
151     while (bytes_remaining > 3) {
152         i_bits = AV_RB32(in);
153         in += 3; bytes_remaining -= 3;
154         *dst++ = b64[ i_bits>>26        ];
155         *dst++ = b64[(i_bits>>20) & 0x3F];
156         *dst++ = b64[(i_bits>>14) & 0x3F];
157         *dst++ = b64[(i_bits>>8 ) & 0x3F];
158     }
159     i_bits = 0;
160     while (bytes_remaining) {
161         i_bits = (i_bits << 8) + *in++;
162         bytes_remaining--;
163         i_shift += 8;
164     }
165     while (i_shift > 0) {
166         *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
167         i_shift -= 6;
168     }
169     while ((dst - ret) & 3)
170         *dst++ = '=';
171     *dst = '\0';
172 
173     return ret;
174 }
175 
176 #ifdef TEST
177 // LCOV_EXCL_START
178 
179 #define MAX_DATA_SIZE    1024
180 #define MAX_ENCODED_SIZE 2048
181 
test_encode_decode(const uint8_t * data,unsigned int data_size,const char * encoded_ref)182 static int test_encode_decode(const uint8_t *data, unsigned int data_size,
183                               const char *encoded_ref)
184 {
185     char  encoded[MAX_ENCODED_SIZE];
186     uint8_t data2[MAX_DATA_SIZE];
187     int data2_size, max_data2_size = MAX_DATA_SIZE;
188 
189     if (!av_base64_encode(encoded, MAX_ENCODED_SIZE, data, data_size)) {
190         printf("Failed: cannot encode the input data\n");
191         return 1;
192     }
193     if (encoded_ref && strcmp(encoded, encoded_ref)) {
194         printf("Failed: encoded string differs from reference\n"
195                "Encoded:\n%s\nReference:\n%s\n", encoded, encoded_ref);
196         return 1;
197     }
198 
199     if ((data2_size = av_base64_decode(data2, encoded, max_data2_size)) != data_size) {
200         printf("Failed: cannot decode the encoded string\n"
201                "Encoded:\n%s\n", encoded);
202         return 1;
203     }
204     if ((data2_size = av_base64_decode(data2, encoded, data_size)) != data_size) {
205         printf("Failed: cannot decode with minimal buffer\n"
206                "Encoded:\n%s\n", encoded);
207         return 1;
208     }
209     if (memcmp(data2, data, data_size)) {
210         printf("Failed: encoded/decoded data differs from original data\n");
211         return 1;
212     }
213     if (av_base64_decode(NULL, encoded, 0) != 0) {
214         printf("Failed: decode to NULL buffer\n");
215         return 1;
216     }
217     if (strlen(encoded)) {
218         char *end = strchr(encoded, '=');
219         if (!end)
220             end = encoded + strlen(encoded) - 1;
221         *end = '%';
222         if (av_base64_decode(NULL, encoded, 0) >= 0) {
223             printf("Failed: error detection\n");
224             return 1;
225         }
226     }
227 
228     printf("Passed!\n");
229     return 0;
230 }
231 
main(int argc,char ** argv)232 int main(int argc, char ** argv)
233 {
234     int i, error_count = 0;
235     struct test {
236         const uint8_t *data;
237         const char *encoded_ref;
238     } tests[] = {
239         { "",        ""},
240         { "1",       "MQ=="},
241         { "22",      "MjI="},
242         { "333",     "MzMz"},
243         { "4444",    "NDQ0NA=="},
244         { "55555",   "NTU1NTU="},
245         { "666666",  "NjY2NjY2"},
246         { "abc:def", "YWJjOmRlZg=="},
247     };
248     char in[1024], out[2048];
249 
250     printf("Encoding/decoding tests\n");
251     for (i = 0; i < FF_ARRAY_ELEMS(tests); i++)
252         error_count += test_encode_decode(tests[i].data, strlen(tests[i].data), tests[i].encoded_ref);
253 
254     if (argc>1 && !strcmp(argv[1], "-t")) {
255         memset(in, 123, sizeof(in));
256         for(i=0; i<10000; i++){
257             START_TIMER
258             av_base64_encode(out, sizeof(out), in, sizeof(in));
259             STOP_TIMER("encode")
260         }
261         for(i=0; i<10000; i++){
262             START_TIMER
263             av_base64_decode(in, out, sizeof(in));
264             STOP_TIMER("decode")
265         }
266 
267         for(i=0; i<10000; i++){
268             START_TIMER
269             av_base64_decode(NULL, out, 0);
270             STOP_TIMER("syntax check")
271         }
272     }
273 
274     if (error_count)
275         printf("Error Count: %d.\n", error_count);
276 
277     return !!error_count;
278 }
279 
280 // LCOV_EXCL_STOP
281 #endif
282