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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
/* Escape and unescape URL encoding in strings. The functions return a new
* allocated string or NULL if an error occurred. */
#include "curl_setup.h"
#include <curl/curl.h>
#include "urldata.h"
#include "warnless.h"
#include "escape.h"
#include "strdup.h"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
/* Portable character check (remember EBCDIC). Do not use isalnum() because
its behavior is altered by the current locale.
See https://datatracker.ietf.org/doc/html/rfc3986#section-2.3
*/
bool Curl_isunreserved(unsigned char in)
{
switch(in) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
case 'a': case 'b': case 'c': case 'd': case 'e':
case 'f': case 'g': case 'h': case 'i': case 'j':
case 'k': case 'l': case 'm': case 'n': case 'o':
case 'p': case 'q': case 'r': case 's': case 't':
case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
case 'A': case 'B': case 'C': case 'D': case 'E':
case 'F': case 'G': case 'H': case 'I': case 'J':
case 'K': case 'L': case 'M': case 'N': case 'O':
case 'P': case 'Q': case 'R': case 'S': case 'T':
case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
case '-': case '.': case '_': case '~':
return TRUE;
default:
break;
}
return FALSE;
}
/* for ABI-compatibility with previous versions */
char *curl_escape(const char *string, int inlength)
{
return curl_easy_escape(NULL, string, inlength);
}
/* for ABI-compatibility with previous versions */
char *curl_unescape(const char *string, int length)
{
return curl_easy_unescape(NULL, string, length, NULL);
}
/* Escapes for URL the given unescaped string of given length.
* 'data' is ignored since 7.82.0.
*/
char *curl_easy_escape(struct Curl_easy *data, const char *string,
int inlength)
{
size_t length;
struct dynbuf d;
(void)data;
if(inlength < 0)
return NULL;
Curl_dyn_init(&d, CURL_MAX_INPUT_LENGTH * 3);
length = (inlength?(size_t)inlength:strlen(string));
if(!length)
return strdup("");
while(length--) {
unsigned char in = *string++; /* treat the characters unsigned */
if(Curl_isunreserved(in)) {
/* append this */
if(Curl_dyn_addn(&d, &in, 1))
return NULL;
}
else {
/* encode it */
const char hex[] = "0123456789ABCDEF";
char out[3]={'%'};
out[1] = hex[in>>4];
out[2] = hex[in & 0xf];
if(Curl_dyn_addn(&d, out, 3))
return NULL;
}
}
return Curl_dyn_ptr(&d);
}
static const unsigned char hextable[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0, /* 0x30 - 0x3f */
0, 10, 11, 12, 13, 14, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x40 - 0x4f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50 - 0x5f */
0, 10, 11, 12, 13, 14, 15 /* 0x60 - 0x66 */
};
/* the input is a single hex digit */
#define onehex2dec(x) hextable[x - '0']
/*
* Curl_urldecode() URL decodes the given string.
*
* Returns a pointer to a malloced string in *ostring with length given in
* *olen. If length == 0, the length is assumed to be strlen(string).
*
* ctrl options:
* - REJECT_NADA: accept everything
* - REJECT_CTRL: rejects control characters (byte codes lower than 32) in
* the data
* - REJECT_ZERO: rejects decoded zero bytes
*
* The values for the enum starts at 2, to make the assert detect legacy
* invokes that used TRUE/FALSE (0 and 1).
*/
CURLcode Curl_urldecode(const char *string, size_t length,
char **ostring, size_t *olen,
enum urlreject ctrl)
{
size_t alloc;
char *ns;
DEBUGASSERT(string);
DEBUGASSERT(ctrl >= REJECT_NADA); /* crash on TRUE/FALSE */
alloc = (length?length:strlen(string));
ns = malloc(alloc + 1);
if(!ns)
return CURLE_OUT_OF_MEMORY;
/* store output string */
*ostring = ns;
while(alloc) {
unsigned char in = *string;
if(('%' == in) && (alloc > 2) &&
ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
/* this is two hexadecimal digits following a '%' */
in = (unsigned char)(onehex2dec(string[1]) << 4) | onehex2dec(string[2]);
string += 3;
alloc -= 3;
}
else {
string++;
alloc--;
}
if(((ctrl == REJECT_CTRL) && (in < 0x20)) ||
((ctrl == REJECT_ZERO) && (in == 0))) {
Curl_safefree(*ostring);
return CURLE_URL_MALFORMAT;
}
*ns++ = in;
}
*ns = 0; /* terminate it */
if(olen)
/* store output size */
*olen = ns - *ostring;
return CURLE_OK;
}
/*
* Unescapes the given URL escaped string of given length. Returns a
* pointer to a malloced string with length given in *olen.
* If length == 0, the length is assumed to be strlen(string).
* If olen == NULL, no output length is stored.
* 'data' is ignored since 7.82.0.
*/
char *curl_easy_unescape(struct Curl_easy *data, const char *string,
int length, int *olen)
{
char *str = NULL;
(void)data;
if(length >= 0) {
size_t inputlen = (size_t)length;
size_t outputlen;
CURLcode res = Curl_urldecode(string, inputlen, &str, &outputlen,
REJECT_NADA);
if(res)
return NULL;
if(olen) {
if(outputlen <= (size_t) INT_MAX)
*olen = curlx_uztosi(outputlen);
else
/* too large to return in an int, fail! */
Curl_safefree(str);
}
}
return str;
}
/* For operating systems/environments that use different malloc/free
systems for the app and for this library, we provide a free that uses
the library's memory system */
void curl_free(void *p)
{
free(p);
}
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