albino
/
ngircd-tor
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
ngircd-tor/src/ngircd/resolve.c

546 lines
12 KiB
C
Raw Blame History

/*
* ngIRCd -- The Next Generation IRC Daemon
* Copyright (c)2001-2003 by Alexander Barton (alex@barton.de)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* Please read the file COPYING, README and AUTHORS for more information.
*
* Asynchronous resolver
*/
#include "portab.h"
static char UNUSED id[] = "$Id: resolve.c,v 1.29 2008/02/26 22:04:17 fw Exp $";
#include "imp.h"
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#ifdef IDENTAUTH
#ifdef HAVE_IDENT_H
#include <ident.h>
#endif
#endif
#include "conn.h"
#include "defines.h"
#include "log.h"
#include "exp.h"
#include "resolve.h"
#include "io.h"
static void Do_ResolveAddr PARAMS(( const ng_ipaddr_t *Addr, int Sock, int w_fd ));
static void Do_ResolveName PARAMS(( const char *Host, int w_fd ));
static bool register_callback PARAMS((RES_STAT *s, void (*cbfunc)(int, short)));
#ifdef WANT_IPV6
extern bool Conf_ConnectIPv4;
extern bool Conf_ConnectIPv6;
#endif
static pid_t
Resolver_fork(int *pipefds)
{
pid_t pid;
if (pipe(pipefds) != 0) {
Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
return -1;
}
pid = fork();
switch(pid) {
case -1:
Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
close(pipefds[0]);
close(pipefds[1]);
return -1;
case 0: /* child */
close(pipefds[0]);
Log_Init_Resolver( );
return 0;
}
/* parent */
close(pipefds[1]);
return pid;
}
/**
* Resolve IP (asynchronous!).
*/
GLOBAL bool
Resolve_Addr(RES_STAT * s, const ng_ipaddr_t *Addr, int identsock,
void (*cbfunc) (int, short))
{
int pipefd[2];
pid_t pid;
assert(s != NULL);
pid = Resolver_fork(pipefd);
if (pid > 0) {
Log(LOG_DEBUG, "Resolver for %s created (PID %d).", ng_ipaddr_tostr(Addr), pid);
s->pid = pid;
s->resolver_fd = pipefd[0];
return register_callback(s, cbfunc);
} else if( pid == 0 ) {
/* Sub process */
Do_ResolveAddr( Addr, identsock, pipefd[1]);
Log_Exit_Resolver( );
exit(0);
}
return false;
} /* Resolve_Addr */
/**
* Resolve hostname (asynchronous!).
*/
GLOBAL bool
Resolve_Name( RES_STAT *s, const char *Host, void (*cbfunc)(int, short))
{
int pipefd[2];
pid_t pid;
assert(s != NULL);
pid = Resolver_fork(pipefd);
if (pid > 0) {
/* Main process */
#ifdef DEBUG
Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
#endif
s->pid = pid;
s->resolver_fd = pipefd[0];
return register_callback(s, cbfunc);
} else if( pid == 0 ) {
/* Sub process */
Do_ResolveName(Host, pipefd[1]);
Log_Exit_Resolver( );
exit(0);
}
return false;
} /* Resolve_Name */
GLOBAL void
Resolve_Init(RES_STAT *s)
{
assert(s != NULL);
s->resolver_fd = -1;
s->pid = 0;
}
#ifndef WANT_IPV6
#ifdef h_errno
static char *
Get_Error( int H_Error )
{
/* Get error message for H_Error */
switch( H_Error ) {
case HOST_NOT_FOUND:
return "host not found";
case NO_DATA:
return "name valid but no IP address defined";
case NO_RECOVERY:
return "name server error";
case TRY_AGAIN:
return "name server temporary not available";
}
return "unknown error";
}
#endif /* h_errno */
#endif /* WANT_IPV6 */
/* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
static void
Do_IdentQuery(int identsock, array *resolved_addr)
{
#ifdef IDENTAUTH
char *res;
assert(identsock >= 0);
#ifdef DEBUG
Log_Resolver(LOG_DEBUG, "Doing IDENT lookup on socket %d ...", identsock);
#endif
if (identsock < 0)
return;
res = ident_id( identsock, 10 );
#ifdef DEBUG
Log_Resolver(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
identsock, res ? res : "(NULL)" );
#endif
if (!res) /* no result */
return;
if (!array_cats(resolved_addr, res))
Log_Resolver(LOG_WARNING, "Resolver: Cannot copy IDENT result: %s!", strerror(errno));
free(res);
#else
(void) identsock;
(void) resolved_addr;
#endif
}
/**
* perform reverse DNS lookup and put result string into resbuf.
* If no hostname could be obtained, this function stores the string representation of
* the IP address in resbuf and returns false.
* @param IpAddr ip address to resolve
* @param resbuf result buffer to store DNS name/string representation of ip address
* @reslen size of result buffer (must be >= NGT_INET_ADDRSTRLEN)
* @return true if reverse lookup successful, false otherwise
*/
static bool
ReverseLookup(const ng_ipaddr_t *IpAddr, char *resbuf, size_t reslen)
{
char tmp_ip_str[NG_INET_ADDRSTRLEN];
const char *errmsg;
#ifdef HAVE_GETNAMEINFO
static const char funcname[]="getnameinfo";
int res;
*resbuf = 0;
res = getnameinfo((struct sockaddr *) IpAddr, ng_ipaddr_salen(IpAddr),
resbuf, reslen, NULL, 0, NI_NAMEREQD);
if (res == 0)
return true;
if (res == EAI_SYSTEM)
errmsg = strerror(errno);
else
errmsg = gai_strerror(res);
#else
const struct sockaddr_in *Addr = (const struct sockaddr_in *) IpAddr;
struct hostent *h;
static const char funcname[]="gethostbyaddr";
h = gethostbyaddr((char *)&Addr->sin_addr, sizeof(Addr->sin_addr), AF_INET);
if (h) {
if (strlcpy(resbuf, h->h_name, reslen) < reslen)
return true;
errmsg = "hostname too long";
} else {
# ifdef h_errno
errmsg = Get_Error(h_errno);
# else
errmsg = "unknown error";
# endif /* h_errno */
}
#endif /* HAVE_GETNAMEINFO */
assert(errmsg);
assert(reslen >= NG_INET_ADDRSTRLEN);
ng_ipaddr_tostr_r(IpAddr, tmp_ip_str);
Log_Resolver(LOG_WARNING, "%s: Can't resolve address \"%s\": %s",
funcname, tmp_ip_str, errmsg);
strlcpy(resbuf, tmp_ip_str, reslen);
return false;
}
/**
* perform DNS lookup of given host name and fill IpAddr with a list of
* ip addresses associated with that name.
* ip addresses found are stored in the "array *IpAddr" argument (type ng_ipaddr_t)
* @param hostname The domain name to look up.
* @param IpAddr pointer to empty and initialized array to store results
* @return true if lookup successful, false if domain name not found
*/
static bool
ForwardLookup(const char *hostname, array *IpAddr)
{
ng_ipaddr_t addr;
#ifdef HAVE_GETADDRINFO
int res;
struct addrinfo *a, *ai_results;
static struct addrinfo hints = {
#ifndef WANT_IPV6
.ai_family = AF_INET,
#endif
#ifdef AI_ADDRCONFIG /* glibc has this, but not e.g. netbsd 4.0 */
.ai_flags = AI_ADDRCONFIG,
#endif
.ai_socktype = SOCK_STREAM,
.ai_protocol = IPPROTO_TCP
};
#ifdef WANT_IPV6
assert(Conf_ConnectIPv6 || Conf_ConnectIPv4);
if (!Conf_ConnectIPv6)
hints.ai_family = AF_INET;
if (!Conf_ConnectIPv4)
hints.ai_family = AF_INET6;
#endif
res = getaddrinfo(hostname, NULL, &hints, &ai_results);
switch (res) {
case 0: break;
case EAI_SYSTEM:
Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, strerror(errno));
return false;
default:
Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, gai_strerror(res));
return false;
}
for (a = ai_results; a != NULL; a = a->ai_next) {
assert(a->ai_addrlen <= sizeof(addr));
if (a->ai_addrlen > sizeof(addr))
continue;
memcpy(&addr, a->ai_addr, a->ai_addrlen);
if (!array_catb(IpAddr, (char *)&addr, sizeof(addr)))
break;
}
freeaddrinfo(ai_results);
return a == NULL;
#else
struct hostent *h = gethostbyname(hostname);
if (!h) {
#ifdef h_errno
Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, Get_Error(h_errno));
#else
Log_Resolver(LOG_WARNING, "Can't resolve \"%s\"", hostname);
#endif
return false;
}
memset(&addr, 0, sizeof(addr));
addr.sin4.sin_family = AF_INET;
memcpy(&addr.sin4.sin_addr, h->h_addr, sizeof(struct in_addr));
return array_copyb(IpAddr, (char *)&addr, sizeof(addr));
#endif /* HAVE_GETADDRINFO */
}
static bool
Addr_in_list(const array *resolved_addr, const ng_ipaddr_t *Addr)
{
char tmp_ip_str[NG_INET_ADDRSTRLEN];
const ng_ipaddr_t *tmpAddrs = array_start(resolved_addr);
size_t len = array_length(resolved_addr, sizeof(*tmpAddrs));
assert(len > 0);
assert(tmpAddrs);
while (len > 0) {
if (ng_ipaddr_ipequal(Addr, tmpAddrs))
return true;
tmpAddrs++;
len--;
}
/* failed; print list of addresses */
ng_ipaddr_tostr_r(Addr, tmp_ip_str);
len = array_length(resolved_addr, sizeof(*tmpAddrs));
tmpAddrs = array_start(resolved_addr);
while (len > 0) {
Log_Resolver(LOG_WARNING, "Address mismatch: %s != %s",
tmp_ip_str, ng_ipaddr_tostr(tmpAddrs));
tmpAddrs++;
len--;
}
return false;
}
static void
Log_Forgery_NoIP(const char *ip, const char *host)
{
Log_Resolver(LOG_WARNING, "Possible forgery: %s resolved to %s "
"(which has no ip address)", ip, host);
}
static void
Log_Forgery_WrongIP(const char *ip, const char *host)
{
Log_Resolver(LOG_WARNING,"Possible forgery: %s resolved to %s "
"(which points to different address)", ip, host);
}
static void
ArrayWrite(int fd, const array *a)
{
size_t len = array_bytes(a);
const char *data = array_start(a);
assert(data);
if( (size_t)write(fd, data, len) != len )
Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!",
strerror(errno));
}
static void
Do_ResolveAddr(const ng_ipaddr_t *Addr, int identsock, int w_fd)
{
/* Resolver sub-process: resolve IP address and write result into
* pipe to parent. */
char hostname[CLIENT_HOST_LEN];
char tmp_ip_str[NG_INET_ADDRSTRLEN];
size_t len;
array resolved_addr;
array_init(&resolved_addr);
ng_ipaddr_tostr_r(Addr, tmp_ip_str);
#ifdef DEBUG
Log_Resolver(LOG_DEBUG, "Now resolving %s ...", tmp_ip_str);
#endif
if (!ReverseLookup(Addr, hostname, sizeof(hostname)))
goto dns_done;
if (ForwardLookup(hostname, &resolved_addr)) {
if (!Addr_in_list(&resolved_addr, Addr)) {
Log_Forgery_WrongIP(tmp_ip_str, hostname);
strlcpy(hostname, tmp_ip_str, sizeof(hostname));
}
} else {
Log_Forgery_NoIP(tmp_ip_str, hostname);
strlcpy(hostname, tmp_ip_str, sizeof(hostname));
}
#ifdef DEBUG
Log_Resolver(LOG_DEBUG, "Ok, translated %s to \"%s\".", tmp_ip_str, hostname);
#endif
dns_done:
len = strlen(hostname);
hostname[len] = '\n';
if (!array_copyb(&resolved_addr, hostname, ++len)) {
Log_Resolver(LOG_CRIT, "Resolver: Can't copy resolved name: %s!", strerror(errno));
array_free(&resolved_addr);
return;
}
Do_IdentQuery(identsock, &resolved_addr);
ArrayWrite(w_fd, &resolved_addr);
array_free(&resolved_addr);
} /* Do_ResolveAddr */
static void
Do_ResolveName( const char *Host, int w_fd )
{
/* Resolver sub-process: resolve name and write result into pipe
* to parent. */
array IpAddrs;
#ifdef DEBUG
ng_ipaddr_t *addr;
size_t len;
#endif
Log_Resolver(LOG_DEBUG, "Now resolving \"%s\" ...", Host);
array_init(&IpAddrs);
/* Resolve hostname */
if (!ForwardLookup(Host, &IpAddrs)) {
close(w_fd);
return;
}
#ifdef DEBUG
len = array_length(&IpAddrs, sizeof(*addr));
assert(len > 0);
addr = array_start(&IpAddrs);
assert(addr);
for (; len > 0; --len,addr++) {
Log_Resolver(LOG_DEBUG, "translated \"%s\" to %s.",
Host, ng_ipaddr_tostr(addr));
}
#endif
/* Write result into pipe to parent */
ArrayWrite(w_fd, &IpAddrs);
array_free(&IpAddrs);
} /* Do_ResolveName */
static bool
register_callback( RES_STAT *s, void (*cbfunc)(int, short))
{
assert(cbfunc != NULL);
assert(s != NULL);
assert(s->resolver_fd >= 0);
if (io_setnonblock(s->resolver_fd) &&
io_event_create(s->resolver_fd, IO_WANTREAD, cbfunc))
return true;
Log( LOG_CRIT, "Resolver: Could not register callback function: %s!", strerror(errno));
close(s->resolver_fd);
Resolve_Init(s);
return false;
}
GLOBAL bool
Resolve_Shutdown( RES_STAT *s)
{
bool ret = false;
assert(s != NULL);
assert(s->resolver_fd >= 0);
if (s->resolver_fd >= 0)
ret = io_close(s->resolver_fd);
Resolve_Init(s);
return ret;
}
/**
* Read result of resolver sub-process from pipe
*/
GLOBAL size_t
Resolve_Read( RES_STAT *s, void* readbuf, size_t buflen)
{
ssize_t bytes_read;
assert(buflen > 0);
/* Read result from pipe */
bytes_read = read(s->resolver_fd, readbuf, buflen);
if (bytes_read < 0) {
if (errno == EAGAIN)
return 0;
Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(errno));
bytes_read = 0;
}
#ifdef DEBUG
else if (bytes_read == 0)
Log( LOG_DEBUG, "Resolver: Can't read result: EOF");
#endif
Resolve_Shutdown(s);
return (size_t)bytes_read;
}
/* -eof- */
Reference in New Issue View Git Blame Copy Permalink