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mirror of https://github.com/moparisthebest/curl synced 2024-12-23 16:48:49 -05:00
curl/lib/escape.c
Daniel Stenberg dcd6f81025
snprintf: renamed and we now only use msnprintf()
The function does not return the same value as snprintf() normally does,
so readers may be mislead into thinking the code works differently than
it actually does. A different function name makes this easier to detect.

Reported-by: Tomas Hoger
Assisted-by: Daniel Gustafsson
Fixes #3296
Closes #3297
2018-11-23 08:26:51 +01:00

245 lines
6.8 KiB
C

/***************************************************************************
* _ _ ____ _
* 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 "curl_setup.h"
#include <curl/curl.h>
#include "urldata.h"
#include "warnless.h"
#include "non-ascii.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://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(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);
}
char *curl_easy_escape(struct Curl_easy *data, const char *string,
int inlength)
{
size_t alloc;
char *ns;
char *testing_ptr = NULL;
size_t newlen;
size_t strindex = 0;
size_t length;
CURLcode result;
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 = Curl_saferealloc(ns, alloc);
if(!testing_ptr)
return NULL;
ns = testing_ptr;
}
result = Curl_convert_to_network(data, (char *)&in, 1);
if(result) {
/* Curl_convert_to_network calls failf if unsuccessful */
free(ns);
return NULL;
}
msnprintf(&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).
*
* 'data' can be set to NULL but then this function can't convert network
* data to host for non-ascii.
*/
CURLcode Curl_urldecode(struct Curl_easy *data,
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;
CURLcode result = CURLE_OK;
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 = curlx_ultouc(hex); /* this long is never bigger than 255 anyway */
if(data) {
result = Curl_convert_from_network(data, (char *)&in, 1);
if(result) {
/* Curl_convert_from_network calls failf if unsuccessful */
free(ns);
return result;
}
}
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(struct Curl_easy *data, const char *string,
int length, int *olen)
{
char *str = NULL;
if(length >= 0) {
size_t inputlen = length;
size_t outputlen;
CURLcode res = Curl_urldecode(data, string, inputlen, &str, &outputlen,
FALSE);
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);
}