1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2016, 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 /* The last 3 #include files should be in this order */
35 #include "curl_printf.h"
36 #include "curl_memory.h"
37 #include "memdebug.h"
38
39 /* Portable character check (remember EBCDIC). Do not use isalnum() because
40 its behavior is altered by the current locale.
41 See https://tools.ietf.org/html/rfc3986#section-2.3
42 */
Curl_isunreserved(unsigned char in)43 static bool Curl_isunreserved(unsigned char in)
44 {
45 switch (in) {
46 case '0': case '1': case '2': case '3': case '4':
47 case '5': case '6': case '7': case '8': case '9':
48 case 'a': case 'b': case 'c': case 'd': case 'e':
49 case 'f': case 'g': case 'h': case 'i': case 'j':
50 case 'k': case 'l': case 'm': case 'n': case 'o':
51 case 'p': case 'q': case 'r': case 's': case 't':
52 case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
53 case 'A': case 'B': case 'C': case 'D': case 'E':
54 case 'F': case 'G': case 'H': case 'I': case 'J':
55 case 'K': case 'L': case 'M': case 'N': case 'O':
56 case 'P': case 'Q': case 'R': case 'S': case 'T':
57 case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
58 case '-': case '.': case '_': case '~':
59 return TRUE;
60 default:
61 break;
62 }
63 return FALSE;
64 }
65
66 /* for ABI-compatibility with previous versions */
curl_escape(const char * string,int inlength)67 char *curl_escape(const char *string, int inlength)
68 {
69 return curl_easy_escape(NULL, string, inlength);
70 }
71
72 /* for ABI-compatibility with previous versions */
curl_unescape(const char * string,int length)73 char *curl_unescape(const char *string, int length)
74 {
75 return curl_easy_unescape(NULL, string, length, NULL);
76 }
77
curl_easy_escape(CURL * handle,const char * string,int inlength)78 char *curl_easy_escape(CURL *handle, const char *string, int inlength)
79 {
80 size_t alloc = (inlength?(size_t)inlength:strlen(string))+1;
81 char *ns;
82 char *testing_ptr = NULL;
83 unsigned char in; /* we need to treat the characters unsigned */
84 size_t newlen = alloc;
85 size_t strindex=0;
86 size_t length;
87 CURLcode result;
88
89 ns = malloc(alloc);
90 if(!ns)
91 return NULL;
92
93 length = alloc-1;
94 while(length--) {
95 in = *string;
96
97 if(Curl_isunreserved(in))
98 /* just copy this */
99 ns[strindex++]=in;
100 else {
101 /* encode it */
102 newlen += 2; /* the size grows with two, since this'll become a %XX */
103 if(newlen > alloc) {
104 alloc *= 2;
105 testing_ptr = realloc(ns, alloc);
106 if(!testing_ptr) {
107 free(ns);
108 return NULL;
109 }
110 else {
111 ns = testing_ptr;
112 }
113 }
114
115 result = Curl_convert_to_network(handle, &in, 1);
116 if(result) {
117 /* Curl_convert_to_network calls failf if unsuccessful */
118 free(ns);
119 return NULL;
120 }
121
122 snprintf(&ns[strindex], 4, "%%%02X", in);
123
124 strindex+=3;
125 }
126 string++;
127 }
128 ns[strindex]=0; /* terminate it */
129 return ns;
130 }
131
132 /*
133 * Curl_urldecode() URL decodes the given string.
134 *
135 * Optionally detects control characters (byte codes lower than 32) in the
136 * data and rejects such data.
137 *
138 * Returns a pointer to a malloced string in *ostring with length given in
139 * *olen. If length == 0, the length is assumed to be strlen(string).
140 *
141 */
Curl_urldecode(struct SessionHandle * data,const char * string,size_t length,char ** ostring,size_t * olen,bool reject_ctrl)142 CURLcode Curl_urldecode(struct SessionHandle *data,
143 const char *string, size_t length,
144 char **ostring, size_t *olen,
145 bool reject_ctrl)
146 {
147 size_t alloc = (length?length:strlen(string))+1;
148 char *ns = malloc(alloc);
149 unsigned char in;
150 size_t strindex=0;
151 unsigned long hex;
152 CURLcode result;
153
154 if(!ns)
155 return CURLE_OUT_OF_MEMORY;
156
157 while(--alloc > 0) {
158 in = *string;
159 if(('%' == in) && (alloc > 2) &&
160 ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
161 /* this is two hexadecimal digits following a '%' */
162 char hexstr[3];
163 char *ptr;
164 hexstr[0] = string[1];
165 hexstr[1] = string[2];
166 hexstr[2] = 0;
167
168 hex = strtoul(hexstr, &ptr, 16);
169
170 in = curlx_ultouc(hex); /* this long is never bigger than 255 anyway */
171
172 result = Curl_convert_from_network(data, &in, 1);
173 if(result) {
174 /* Curl_convert_from_network calls failf if unsuccessful */
175 free(ns);
176 return result;
177 }
178
179 string+=2;
180 alloc-=2;
181 }
182
183 if(reject_ctrl && (in < 0x20)) {
184 free(ns);
185 return CURLE_URL_MALFORMAT;
186 }
187
188 ns[strindex++] = in;
189 string++;
190 }
191 ns[strindex]=0; /* terminate it */
192
193 if(olen)
194 /* store output size */
195 *olen = strindex;
196
197 /* store output string */
198 *ostring = ns;
199
200 return CURLE_OK;
201 }
202
203 /*
204 * Unescapes the given URL escaped string of given length. Returns a
205 * pointer to a malloced string with length given in *olen.
206 * If length == 0, the length is assumed to be strlen(string).
207 * If olen == NULL, no output length is stored.
208 */
curl_easy_unescape(CURL * handle,const char * string,int length,int * olen)209 char *curl_easy_unescape(CURL *handle, const char *string, int length,
210 int *olen)
211 {
212 char *str = NULL;
213 size_t inputlen = length;
214 size_t outputlen;
215 CURLcode res = Curl_urldecode(handle, string, inputlen, &str, &outputlen,
216 FALSE);
217 if(res)
218 return NULL;
219 if(olen)
220 *olen = curlx_uztosi(outputlen);
221 return str;
222 }
223
224 /* For operating systems/environments that use different malloc/free
225 systems for the app and for this library, we provide a free that uses
226 the library's memory system */
curl_free(void * p)227 void curl_free(void *p)
228 {
229 free(p);
230 }
231