curl/lib/noproxy.c
Daniel Gustafsson 60453483b5 noproxy: guard against empty hostnames in noproxy check
When checking for a noproxy setting we need to ensure that we get
a hostname passed in. If there is no hostname then there cannot be
a matching noproxy rule for it by definition.

Closes: #10057
Reported-by: Geeknik Labs
Reviewed-by: Daniel Stenberg <daniel@haxx.se>
2022-12-08 23:37:32 +01:00

256 lines
7.0 KiB
C

/***************************************************************************
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* Copyright (C) 1998 - 2022, 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
*
***************************************************************************/
#include "curl_setup.h"
#ifndef CURL_DISABLE_PROXY
#include "inet_pton.h"
#include "strcase.h"
#include "noproxy.h"
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
/*
* Curl_cidr4_match() returns TRUE if the given IPv4 address is within the
* specified CIDR address range.
*/
UNITTEST bool Curl_cidr4_match(const char *ipv4, /* 1.2.3.4 address */
const char *network, /* 1.2.3.4 address */
unsigned int bits)
{
unsigned int address = 0;
unsigned int check = 0;
if(bits > 32)
/* strange input */
return FALSE;
if(1 != Curl_inet_pton(AF_INET, ipv4, &address))
return FALSE;
if(1 != Curl_inet_pton(AF_INET, network, &check))
return FALSE;
if(bits && (bits != 32)) {
unsigned int mask = 0xffffffff << (32 - bits);
unsigned int haddr = htonl(address);
unsigned int hcheck = htonl(check);
#if 0
fprintf(stderr, "Host %s (%x) network %s (%x) bits %u mask %x => %x\n",
ipv4, haddr, network, hcheck, bits, mask,
(haddr ^ hcheck) & mask);
#endif
if((haddr ^ hcheck) & mask)
return FALSE;
return TRUE;
}
return (address == check);
}
UNITTEST bool Curl_cidr6_match(const char *ipv6,
const char *network,
unsigned int bits)
{
#ifdef ENABLE_IPV6
int bytes;
int rest;
unsigned char address[16];
unsigned char check[16];
if(!bits)
bits = 128;
bytes = bits/8;
rest = bits & 0x07;
if(1 != Curl_inet_pton(AF_INET6, ipv6, address))
return FALSE;
if(1 != Curl_inet_pton(AF_INET6, network, check))
return FALSE;
if((bytes > 16) || ((bytes == 16) && rest))
return FALSE;
if(bytes && memcmp(address, check, bytes))
return FALSE;
if(rest && !((address[bytes] ^ check[bytes]) & (0xff << (8 - rest))))
return FALSE;
return TRUE;
#else
(void)ipv6;
(void)network;
(void)bits;
return FALSE;
#endif
}
enum nametype {
TYPE_HOST,
TYPE_IPV4,
TYPE_IPV6
};
/****************************************************************
* Checks if the host is in the noproxy list. returns TRUE if it matches and
* therefore the proxy should NOT be used.
****************************************************************/
bool Curl_check_noproxy(const char *name, const char *no_proxy)
{
/*
* If we don't have a hostname at all, like for example with a FILE
* transfer, we have nothing to interrogate the noproxy list with.
*/
if(!name || name[0] == '\0')
return FALSE;
/* no_proxy=domain1.dom,host.domain2.dom
* (a comma-separated list of hosts which should
* not be proxied, or an asterisk to override
* all proxy variables)
*/
if(no_proxy && no_proxy[0]) {
const char *p = no_proxy;
size_t namelen;
enum nametype type = TYPE_HOST;
char hostip[128];
if(!strcmp("*", no_proxy))
return TRUE;
/* NO_PROXY was specified and it wasn't just an asterisk */
if(name[0] == '[') {
char *endptr;
/* IPv6 numerical address */
endptr = strchr(name, ']');
if(!endptr)
return FALSE;
name++;
namelen = endptr - name;
if(namelen >= sizeof(hostip))
return FALSE;
memcpy(hostip, name, namelen);
hostip[namelen] = 0;
name = hostip;
type = TYPE_IPV6;
}
else {
unsigned int address;
namelen = strlen(name);
if(1 == Curl_inet_pton(AF_INET, name, &address))
type = TYPE_IPV4;
else {
/* ignore trailing dots in the host name */
if(name[namelen - 1] == '.')
namelen--;
}
}
while(*p) {
const char *token;
size_t tokenlen = 0;
bool match = FALSE;
/* pass blanks */
while(*p && ISBLANK(*p))
p++;
token = p;
/* pass over the pattern */
while(*p && !ISBLANK(*p) && (*p != ',')) {
p++;
tokenlen++;
}
if(tokenlen) {
switch(type) {
case TYPE_HOST:
/* ignore trailing dots in the token to check */
if(token[tokenlen - 1] == '.')
tokenlen--;
if(tokenlen && (*token == '.')) {
/* ignore leading token dot as well */
token++;
tokenlen--;
}
/* A: example.com matches 'example.com'
B: www.example.com matches 'example.com'
C: nonexample.com DOES NOT match 'example.com'
*/
if(tokenlen == namelen)
/* case A, exact match */
match = strncasecompare(token, name, namelen);
else if(tokenlen < namelen) {
/* case B, tailmatch domain */
match = (name[namelen - tokenlen - 1] == '.') &&
strncasecompare(token, name + (namelen - tokenlen),
tokenlen);
}
/* case C passes through, not a match */
break;
case TYPE_IPV4:
/* FALLTHROUGH */
case TYPE_IPV6: {
const char *check = token;
char *slash;
unsigned int bits = 0;
char checkip[128];
if(tokenlen >= sizeof(checkip))
/* this cannot match */
break;
/* copy the check name to a temp buffer */
memcpy(checkip, check, tokenlen);
checkip[tokenlen] = 0;
check = checkip;
slash = strchr(check, '/');
/* if the slash is part of this token, use it */
if(slash) {
bits = atoi(slash + 1);
*slash = 0; /* null terminate there */
}
if(type == TYPE_IPV6)
match = Curl_cidr6_match(name, check, bits);
else
match = Curl_cidr4_match(name, check, bits);
break;
}
}
if(match)
return TRUE;
} /* if(tokenlen) */
while(*p == ',')
p++;
} /* while(*p) */
} /* NO_PROXY was specified and it wasn't just an asterisk */
return FALSE;
}
#endif /* CURL_DISABLE_PROXY */