xref: /PHP-7.2/ext/standard/base64.c (revision 7a7ec01a)
1 /*
2    +----------------------------------------------------------------------+
3    | PHP Version 7                                                        |
4    +----------------------------------------------------------------------+
5    | Copyright (c) 1997-2018 The PHP Group                                |
6    +----------------------------------------------------------------------+
7    | This source file is subject to version 3.01 of the PHP license,      |
8    | that is bundled with this package in the file LICENSE, and is        |
9    | available through the world-wide-web at the following url:           |
10    | http://www.php.net/license/3_01.txt                                  |
11    | If you did not receive a copy of the PHP license and are unable to   |
12    | obtain it through the world-wide-web, please send a note to          |
13    | license@php.net so we can mail you a copy immediately.               |
14    +----------------------------------------------------------------------+
15    | Author: Jim Winstead <jimw@php.net>                                  |
16    +----------------------------------------------------------------------+
17  */
18 /* $Id$ */
19 
20 #include <string.h>
21 
22 #include "php.h"
23 #include "base64.h"
24 
25 /* {{{ base64 tables */
26 static const char base64_table[] = {
27 	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
28 	'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
29 	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
30 	'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
31 	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/', '\0'
32 };
33 
34 static const char base64_pad = '=';
35 
36 static const short base64_reverse_table[256] = {
37 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1, -2, -2, -1, -2, -2,
38 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
39 	-1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, 62, -2, -2, -2, 63,
40 	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -2, -2, -2, -2, -2, -2,
41 	-2,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
42 	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -2, -2, -2, -2, -2,
43 	-2, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
44 	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -2, -2, -2, -2, -2,
45 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
46 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
47 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
48 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
49 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
50 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
51 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
52 	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2
53 };
54 /* }}} */
55 
php_base64_encode(const unsigned char * str,size_t length)56 PHPAPI zend_string *php_base64_encode(const unsigned char *str, size_t length) /* {{{ */
57 {
58 	const unsigned char *current = str;
59 	unsigned char *p;
60 	zend_string *result;
61 
62 	result = zend_string_safe_alloc(((length + 2) / 3), 4 * sizeof(char), 0, 0);
63 	p = (unsigned char *)ZSTR_VAL(result);
64 
65 	while (length > 2) { /* keep going until we have less than 24 bits */
66 		*p++ = base64_table[current[0] >> 2];
67 		*p++ = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
68 		*p++ = base64_table[((current[1] & 0x0f) << 2) + (current[2] >> 6)];
69 		*p++ = base64_table[current[2] & 0x3f];
70 
71 		current += 3;
72 		length -= 3; /* we just handle 3 octets of data */
73 	}
74 
75 	/* now deal with the tail end of things */
76 	if (length != 0) {
77 		*p++ = base64_table[current[0] >> 2];
78 		if (length > 1) {
79 			*p++ = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
80 			*p++ = base64_table[(current[1] & 0x0f) << 2];
81 			*p++ = base64_pad;
82 		} else {
83 			*p++ = base64_table[(current[0] & 0x03) << 4];
84 			*p++ = base64_pad;
85 			*p++ = base64_pad;
86 		}
87 	}
88 	*p = '\0';
89 
90 	ZSTR_LEN(result) = (p - (unsigned char *)ZSTR_VAL(result));
91 
92 	return result;
93 }
94 /* }}} */
95 
96 /* {{{ */
97 /* generate reverse table (do not set index 0 to 64)
98 static unsigned short base64_reverse_table[256];
99 #define rt base64_reverse_table
100 void php_base64_init(void)
101 {
102 	char *s = emalloc(10240), *sp;
103 	char *chp;
104 	short idx;
105 
106 	for(ch = 0; ch < 256; ch++) {
107 		chp = strchr(base64_table, ch);
108 		if(ch && chp) {
109 			idx = chp - base64_table;
110 			if (idx >= 64) idx = -1;
111 			rt[ch] = idx;
112 		} else {
113 			rt[ch] = -1;
114 		}
115 	}
116 	sp = s;
117 	sprintf(sp, "static const short base64_reverse_table[256] = {\n");
118 	for(ch =0; ch < 256;) {
119 		sp = s+strlen(s);
120 		sprintf(sp, "\t% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,% 3d,\n", rt[ch+0], rt[ch+1], rt[ch+2], rt[ch+3], rt[ch+4], rt[ch+5], rt[ch+6], rt[ch+7], rt[ch+8], rt[ch+9], rt[ch+10], rt[ch+11], rt[ch+12], rt[ch+13], rt[ch+14], rt[ch+15]);
121 		ch += 16;
122 	}
123 	sprintf(sp, "};");
124 	php_error_docref(NULL, E_NOTICE, "Reverse_table:\n%s", s);
125 	efree(s);
126 }
127 */
128 /* }}} */
129 
php_base64_decode_ex(const unsigned char * str,size_t length,zend_bool strict)130 PHPAPI zend_string *php_base64_decode_ex(const unsigned char *str, size_t length, zend_bool strict) /* {{{ */
131 {
132 	const unsigned char *current = str;
133 	int ch, i = 0, j = 0, padding = 0;
134 	zend_string *result;
135 
136 	result = zend_string_alloc(length, 0);
137 
138 	/* run through the whole string, converting as we go */
139 	while (length-- > 0) {
140 		ch = *current++;
141 		if (ch == base64_pad) {
142 			padding++;
143 			continue;
144 		}
145 
146 		ch = base64_reverse_table[ch];
147 		if (!strict) {
148 			/* skip unknown characters and whitespace */
149 			if (ch < 0) {
150 				continue;
151 			}
152 		} else {
153 			/* skip whitespace */
154 			if (ch == -1) {
155 				continue;
156 			}
157 			/* fail on bad characters or if any data follows padding */
158 			if (ch == -2 || padding) {
159 				goto fail;
160 			}
161 		}
162 
163 		switch(i % 4) {
164 		case 0:
165 			ZSTR_VAL(result)[j] = ch << 2;
166 			break;
167 		case 1:
168 			ZSTR_VAL(result)[j++] |= ch >> 4;
169 			ZSTR_VAL(result)[j] = (ch & 0x0f) << 4;
170 			break;
171 		case 2:
172 			ZSTR_VAL(result)[j++] |= ch >>2;
173 			ZSTR_VAL(result)[j] = (ch & 0x03) << 6;
174 			break;
175 		case 3:
176 			ZSTR_VAL(result)[j++] |= ch;
177 			break;
178 		}
179 		i++;
180 	}
181 	/* fail if the input is truncated (only one char in last group) */
182 	if (strict && i % 4 == 1) {
183 		goto fail;
184 	}
185 	/* fail if the padding length is wrong (not VV==, VVV=), but accept zero padding
186 	 * RFC 4648: "In some circumstances, the use of padding [--] is not required" */
187 	if (strict && padding && (padding > 2 || (i + padding) % 4 != 0)) {
188 		goto fail;
189 	}
190 
191 	ZSTR_LEN(result) = j;
192 	ZSTR_VAL(result)[ZSTR_LEN(result)] = '\0';
193 
194 	return result;
195 
196 fail:
197 	zend_string_free(result);
198 	return NULL;
199 }
200 /* }}} */
201 
202 /* {{{ proto string base64_encode(string str)
203    Encodes string using MIME base64 algorithm */
PHP_FUNCTION(base64_encode)204 PHP_FUNCTION(base64_encode)
205 {
206 	char *str;
207 	size_t str_len;
208 	zend_string *result;
209 
210 	ZEND_PARSE_PARAMETERS_START(1, 1)
211 		Z_PARAM_STRING(str, str_len)
212 	ZEND_PARSE_PARAMETERS_END();
213 
214 	result = php_base64_encode((unsigned char*)str, str_len);
215 	if (result != NULL) {
216 		RETURN_STR(result);
217 	} else {
218 		RETURN_FALSE;
219 	}
220 }
221 /* }}} */
222 
223 /* {{{ proto string base64_decode(string str[, bool strict])
224    Decodes string using MIME base64 algorithm */
PHP_FUNCTION(base64_decode)225 PHP_FUNCTION(base64_decode)
226 {
227 	char *str;
228 	zend_bool strict = 0;
229 	size_t str_len;
230 	zend_string *result;
231 
232 	ZEND_PARSE_PARAMETERS_START(1, 2)
233 		Z_PARAM_STRING(str, str_len)
234 		Z_PARAM_OPTIONAL
235 		Z_PARAM_BOOL(strict)
236 	ZEND_PARSE_PARAMETERS_END();
237 
238 	result = php_base64_decode_ex((unsigned char*)str, str_len, strict);
239 	if (result != NULL) {
240 		RETURN_STR(result);
241 	} else {
242 		RETURN_FALSE;
243 	}
244 }
245 /* }}} */
246 
247 /*
248  * Local variables:
249  * tab-width: 4
250  * c-basic-offset: 4
251  * End:
252  * vim600: sw=4 ts=4 fdm=marker
253  * vim<600: sw=4 ts=4
254  */
255