1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.haxx.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 ***************************************************************************/
22
23 /* Escape and unescape URL encoding in strings. The functions return a new
24 * allocated string or NULL if an error occurred. */
25
26 #include "curl_setup.h"
27
28 #include <curl/curl.h>
29
30 #include "urldata.h"
31 #include "warnless.h"
32 #include "non-ascii.h"
33 #include "escape.h"
34 #include "strdup.h"
35 /* The last 3 #include files should be in this order */
36 #include "curl_printf.h"
37 #include "curl_memory.h"
38 #include "memdebug.h"
39
40 /* Portable character check (remember EBCDIC). Do not use isalnum() because
41 its behavior is altered by the current locale.
42 See https://tools.ietf.org/html/rfc3986#section-2.3
43 */
Curl_isunreserved(unsigned char in)44 bool Curl_isunreserved(unsigned char in)
45 {
46 switch(in) {
47 case '0': case '1': case '2': case '3': case '4':
48 case '5': case '6': case '7': case '8': case '9':
49 case 'a': case 'b': case 'c': case 'd': case 'e':
50 case 'f': case 'g': case 'h': case 'i': case 'j':
51 case 'k': case 'l': case 'm': case 'n': case 'o':
52 case 'p': case 'q': case 'r': case 's': case 't':
53 case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
54 case 'A': case 'B': case 'C': case 'D': case 'E':
55 case 'F': case 'G': case 'H': case 'I': case 'J':
56 case 'K': case 'L': case 'M': case 'N': case 'O':
57 case 'P': case 'Q': case 'R': case 'S': case 'T':
58 case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
59 case '-': case '.': case '_': case '~':
60 return TRUE;
61 default:
62 break;
63 }
64 return FALSE;
65 }
66
67 /* for ABI-compatibility with previous versions */
curl_escape(const char * string,int inlength)68 char *curl_escape(const char *string, int inlength)
69 {
70 return curl_easy_escape(NULL, string, inlength);
71 }
72
73 /* for ABI-compatibility with previous versions */
curl_unescape(const char * string,int length)74 char *curl_unescape(const char *string, int length)
75 {
76 return curl_easy_unescape(NULL, string, length, NULL);
77 }
78
curl_easy_escape(struct Curl_easy * data,const char * string,int inlength)79 char *curl_easy_escape(struct Curl_easy *data, const char *string,
80 int inlength)
81 {
82 size_t alloc;
83 char *ns;
84 char *testing_ptr = NULL;
85 size_t newlen;
86 size_t strindex = 0;
87 size_t length;
88 CURLcode result;
89
90 if(inlength < 0)
91 return NULL;
92
93 alloc = (inlength?(size_t)inlength:strlen(string)) + 1;
94 newlen = alloc;
95
96 ns = malloc(alloc);
97 if(!ns)
98 return NULL;
99
100 length = alloc-1;
101 while(length--) {
102 unsigned char in = *string; /* we need to treat the characters unsigned */
103
104 if(Curl_isunreserved(in))
105 /* just copy this */
106 ns[strindex++] = in;
107 else {
108 /* encode it */
109 newlen += 2; /* the size grows with two, since this'll become a %XX */
110 if(newlen > alloc) {
111 alloc *= 2;
112 testing_ptr = Curl_saferealloc(ns, alloc);
113 if(!testing_ptr)
114 return NULL;
115 ns = testing_ptr;
116 }
117
118 result = Curl_convert_to_network(data, (char *)&in, 1);
119 if(result) {
120 /* Curl_convert_to_network calls failf if unsuccessful */
121 free(ns);
122 return NULL;
123 }
124
125 msnprintf(&ns[strindex], 4, "%%%02X", in);
126
127 strindex += 3;
128 }
129 string++;
130 }
131 ns[strindex] = 0; /* terminate it */
132 return ns;
133 }
134
135 /*
136 * Curl_urldecode() URL decodes the given string.
137 *
138 * Optionally detects control characters (byte codes lower than 32) in the
139 * data and rejects such data.
140 *
141 * Returns a pointer to a malloced string in *ostring with length given in
142 * *olen. If length == 0, the length is assumed to be strlen(string).
143 *
144 * 'data' can be set to NULL but then this function can't convert network
145 * data to host for non-ascii.
146 */
Curl_urldecode(struct Curl_easy * data,const char * string,size_t length,char ** ostring,size_t * olen,bool reject_ctrl)147 CURLcode Curl_urldecode(struct Curl_easy *data,
148 const char *string, size_t length,
149 char **ostring, size_t *olen,
150 bool reject_ctrl)
151 {
152 size_t alloc = (length?length:strlen(string)) + 1;
153 char *ns = malloc(alloc);
154 size_t strindex = 0;
155 unsigned long hex;
156 CURLcode result = CURLE_OK;
157
158 if(!ns)
159 return CURLE_OUT_OF_MEMORY;
160
161 while(--alloc > 0) {
162 unsigned char in = *string;
163 if(('%' == in) && (alloc > 2) &&
164 ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
165 /* this is two hexadecimal digits following a '%' */
166 char hexstr[3];
167 char *ptr;
168 hexstr[0] = string[1];
169 hexstr[1] = string[2];
170 hexstr[2] = 0;
171
172 hex = strtoul(hexstr, &ptr, 16);
173
174 in = curlx_ultouc(hex); /* this long is never bigger than 255 anyway */
175
176 if(data) {
177 result = Curl_convert_from_network(data, (char *)&in, 1);
178 if(result) {
179 /* Curl_convert_from_network calls failf if unsuccessful */
180 free(ns);
181 return result;
182 }
183 }
184
185 string += 2;
186 alloc -= 2;
187 }
188
189 if(reject_ctrl && (in < 0x20)) {
190 free(ns);
191 return CURLE_URL_MALFORMAT;
192 }
193
194 ns[strindex++] = in;
195 string++;
196 }
197 ns[strindex] = 0; /* terminate it */
198
199 if(olen)
200 /* store output size */
201 *olen = strindex;
202
203 /* store output string */
204 *ostring = ns;
205
206 return CURLE_OK;
207 }
208
209 /*
210 * Unescapes the given URL escaped string of given length. Returns a
211 * pointer to a malloced string with length given in *olen.
212 * If length == 0, the length is assumed to be strlen(string).
213 * If olen == NULL, no output length is stored.
214 */
curl_easy_unescape(struct Curl_easy * data,const char * string,int length,int * olen)215 char *curl_easy_unescape(struct Curl_easy *data, const char *string,
216 int length, int *olen)
217 {
218 char *str = NULL;
219 if(length >= 0) {
220 size_t inputlen = length;
221 size_t outputlen;
222 CURLcode res = Curl_urldecode(data, string, inputlen, &str, &outputlen,
223 FALSE);
224 if(res)
225 return NULL;
226
227 if(olen) {
228 if(outputlen <= (size_t) INT_MAX)
229 *olen = curlx_uztosi(outputlen);
230 else
231 /* too large to return in an int, fail! */
232 Curl_safefree(str);
233 }
234 }
235 return str;
236 }
237
238 /* For operating systems/environments that use different malloc/free
239 systems for the app and for this library, we provide a free that uses
240 the library's memory system */
curl_free(void * p)241 void curl_free(void *p)
242 {
243 free(p);
244 }
245