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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2018, 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.haxx.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.
*
***************************************************************************/
/* Escape and unescape URL encoding in strings. The functions return a new
* allocated string or NULL if an error occurred. */
#include <ctype.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "escape.h"
/* Portable character check (remember EBCDIC). Do not use isalnum() because
its behavior is altered by the current locale.
See https://tools.ietf.org/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(string, inlength);
}
/* for ABI-compatibility with previous versions */
char *curl_unescape(const char *string, int length)
{
return curl_easy_unescape(string, length, NULL);
}
char *curl_easy_escape(const char *string, int inlength)
{
size_t alloc;
char *ns;
char *testing_ptr = NULL;
size_t newlen;
size_t strindex = 0;
size_t length;
if(inlength < 0)
return NULL;
alloc = (inlength?(size_t)inlength:strlen(string)) + 1;
newlen = alloc;
ns = malloc(alloc);
if(!ns)
return NULL;
length = alloc-1;
while(length--) {
unsigned char in = *string; /* we need to treat the characters unsigned */
if(Curl_isunreserved(in))
/* just copy this */
ns[strindex++] = in;
else {
/* encode it */
newlen += 2; /* the size grows with two, since this'll become a %XX */
if(newlen > alloc) {
alloc *= 2;
testing_ptr = realloc(ns, alloc);
if(!testing_ptr)
return NULL;
ns = testing_ptr;
}
snprintf(&ns[strindex], 4, "%%%02X", in);
strindex += 3;
}
string++;
}
ns[strindex] = 0; /* terminate it */
return ns;
}
/*
* Curl_urldecode() URL decodes the given string.
*
* Optionally detects control characters (byte codes lower than 32) in the
* data and rejects such data.
*
* 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).
*/
CURLcode Curl_urldecode(const char *string, size_t length,
char **ostring, size_t *olen,
bool reject_ctrl)
{
size_t alloc = (length?length:strlen(string)) + 1;
char *ns = malloc(alloc);
size_t strindex = 0;
unsigned long hex;
if(!ns)
return CURLE_OUT_OF_MEMORY;
while(--alloc > 0) {
unsigned char in = *string;
if(('%' == in) && (alloc > 2) &&
isxdigit(string[1]) && isxdigit(string[2])) {
/* this is two hexadecimal digits following a '%' */
char hexstr[3];
char *ptr;
hexstr[0] = string[1];
hexstr[1] = string[2];
hexstr[2] = 0;
hex = strtoul(hexstr, &ptr, 16);
in = (unsigned char)hex; /* this long is never bigger than 255 anyway */
string += 2;
alloc -= 2;
}
if(reject_ctrl && (in < 0x20)) {
free(ns);
return CURLE_URL_MALFORMAT;
}
ns[strindex++] = in;
string++;
}
ns[strindex] = 0; /* terminate it */
if(olen)
/* store output size */
*olen = strindex;
/* store output string */
*ostring = ns;
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.
*/
char *curl_easy_unescape(const char *string, int length, int *olen)
{
char *str = NULL;
if(length >= 0) {
size_t inputlen = length;
size_t outputlen;
CURLcode res = Curl_urldecode(string, inputlen, &str, &outputlen, false);
if(res)
return NULL;
if(olen) {
if(outputlen <= (size_t) INT_MAX)
*olen = (int)outputlen;
else
/* too large to return in an int, fail! */
free(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);
}