add support for "proxy_dns_old" to use old 3.1 DNS lookup method

some lamer on IRC by the name of annoner/R3M0RS3/penis was complaining
that 3.1 is a lot better than proxychains-ng, because it happens to
work with the browser he's interested in.
since this wasn't the first time this is requested, let's give this
those lamers what they want: lame code!

5 files changed, 115 insertions, 13 deletions

diff --git a/src/core.c b/src/core.c
index 9e5f93c..42bd3e9 100644
--- a/src/core.c
+++ b/src/core.c
@@ -745,6 +745,86 @@ static void gethostbyname_data_setstring(struct gethostbyname_data* data, char*
 }
 
 extern ip_type4 hostsreader_get_numeric_ip_for_name(const char* name);
+struct hostent* proxy_gethostbyname_old(const char *name)
+{
+	static struct hostent hostent_space;
+	static in_addr_t resolved_addr;
+	static char* resolved_addr_p;
+	static char addr_name[1024*8];
+
+	int pipe_fd[2];
+	char buff[256];
+	in_addr_t addr;
+	pid_t pid;
+	int status;
+	size_t l;
+	struct hostent* hp;
+
+	hostent_space.h_addr_list = &resolved_addr_p;
+	*hostent_space.h_addr_list = (char*)&resolved_addr;
+	resolved_addr = 0;
+
+	gethostname(buff,sizeof(buff));
+	if(!strcmp(buff,name))
+		goto got_buff;
+
+	memset(buff, 0, sizeof(buff));
+
+	// TODO: this works only once, so cache it  ...
+	// 	 later
+	while ((hp=gethostent()))
+		if (!strcmp(hp->h_name,name))
+			return hp;
+
+	if(pipe(pipe_fd))
+		goto err;
+	pid = fork();
+	switch(pid) {
+
+		case 0: // child
+			proxychains_write_log("|DNS-request| %s \n", name);
+			close(pipe_fd[0]);
+			dup2(pipe_fd[1],1);
+			close(pipe_fd[1]);
+
+		//	putenv("LD_PRELOAD=");
+			execlp("proxyresolv","proxyresolv",name,NULL);
+			perror("can't exec proxyresolv");
+			exit(2);
+
+		case -1: //error
+			close(pipe_fd[0]);
+			close(pipe_fd[1]);
+			perror("can't fork");
+			goto err;
+
+		default:
+			close(pipe_fd[1]);
+			waitpid(pid, &status, 0);
+			buff[0] = 0;
+			read(pipe_fd[0],&buff,sizeof(buff));
+			close(pipe_fd[0]);
+got_buff:
+			l = strlen(buff);
+			if(l && buff[l-1] == '\n') buff[l-1] = 0;
+			addr = inet_addr(buff);
+			if (addr == (in_addr_t) (-1))
+				goto err_dns;
+			memcpy(*(hostent_space.h_addr_list),
+						&addr ,sizeof(struct in_addr));
+			hostent_space.h_name = addr_name;
+			hostent_space.h_length = sizeof (in_addr_t);
+	}
+	proxychains_write_log("|DNS-response| %s is %s\n",
+			name, inet_ntoa(*(struct in_addr*)&addr));
+	return &hostent_space;
+err_dns:
+	proxychains_write_log("|DNS-response|: %s does not exist\n", name);
+	perror("err_dns");
+err:
+	return NULL;
+}
+
 struct hostent *proxy_gethostbyname(const char *name, struct gethostbyname_data* data) {
 	PFUNC();
 	char buff[256];
@@ -872,7 +952,11 @@ int proxy_getaddrinfo(const char *node, const char *service, const struct addrin
 			free(space);
 			return EAI_NONAME;
 		}
-		hp = proxy_gethostbyname(node, &ghdata);
+		if(proxychains_resolver == 2)
+			hp = proxy_gethostbyname_old(node);
+		else
+			hp = proxy_gethostbyname(node, &ghdata);
+
 		if(hp)
 			memcpy(&((struct sockaddr_in *) &space->sockaddr_space)->sin_addr,
 			       *(hp->h_addr_list), sizeof(in_addr_t));
diff --git a/src/core.h b/src/core.h
index a9ad88b..d54806d 100644
--- a/src/core.h
+++ b/src/core.h
@@ -121,6 +121,7 @@ struct gethostbyname_data {
 };
 
 struct hostent* proxy_gethostbyname(const char *name, struct gethostbyname_data *data);
+struct hostent* proxy_gethostbyname_old(const char *name);
 
 int proxy_getaddrinfo(const char *node, const char *service, 
 		      const struct addrinfo *hints, struct addrinfo **res);
diff --git a/src/libproxychains.c b/src/libproxychains.c
index 513351e..ad75636 100644
--- a/src/libproxychains.c
+++ b/src/libproxychains.c
@@ -146,7 +146,7 @@ static void do_init(void) {
 	while(close_fds_cnt) true_close(close_fds[--close_fds_cnt]);
 	init_l = 1;
 
-	if(proxychains_resolver) rdns_init();
+	if(proxychains_resolver == 1) rdns_init();
 }
 
 static void init_lib_wrapper(const char* caller) {
@@ -328,7 +328,7 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 				pd[count].port = htons((unsigned short) port_n);
 				ip_type* host_ip = &pd[count].ip;
 				if(1 != inet_pton(host_ip->is_v6 ? AF_INET6 : AF_INET, host, host_ip->addr.v6)) {
-					if(*ct == STRICT_TYPE && proxychains_resolver && count > 0) {
+					if(*ct == STRICT_TYPE && proxychains_resolver == 1 && count > 0) {
 						/* we can allow dns hostnames for all but the first proxy in the list if chaintype is strict, as remote lookup can be done */
 						rdns_init();
 						ip_type4 internal_ip = at_get_ip_for_host(host, strlen(host));
@@ -431,6 +431,8 @@ inv_host:
 					proxychains_max_chain = (len ? len : 1);
 				} else if(strstr(buff, "quiet_mode")) {
 					proxychains_quiet_mode = 1;
+				} else if(strstr(buff, "proxy_dns_old")) {
+					proxychains_resolver = 2;
 				} else if(strstr(buff, "proxy_dns")) {
 					proxychains_resolver = 1;
 				} else if(strstr(buff, "dnat")) {
@@ -495,7 +497,7 @@ inv_host:
 	}
 	*proxy_count = count;
 	proxychains_got_chain_data = 1;
-	PDEBUG("proxy_dns: %s\n", proxychains_resolver ? "ON" : "OFF");
+	PDEBUG("proxy_dns: %s\n", proxychains_resolver ? (proxychains_resolver == 2 ? "OLD" : "ON") : "OFF");
 }
 
 /*******  HOOK FUNCTIONS  *******/
@@ -507,7 +509,7 @@ int close(int fd) {
 		errno = 0;
 		return 0;
 	}
-	if(!proxychains_resolver) return true_close(fd);
+	if(proxychains_resolver != 1) return true_close(fd);
 
 	/* prevent rude programs (like ssh) from closing our pipes */
 	if(fd != req_pipefd[0]  && fd != req_pipefd[1] &&
@@ -622,8 +624,10 @@ struct hostent *gethostbyname(const char *name) {
 	INIT();
 	PDEBUG("gethostbyname: %s\n", name);
 
-	if(proxychains_resolver)
+	if(proxychains_resolver == 1)
 		return proxy_gethostbyname(name, &ghbndata);
+	else if(proxychains_resolver == 2)
+		return proxy_gethostbyname_old(name);
 	else
 		return true_gethostbyname(name);
 
diff --git a/src/proxychains.conf b/src/proxychains.conf
index 65c04ad..fb08ae1 100644
--- a/src/proxychains.conf
+++ b/src/proxychains.conf
@@ -49,7 +49,15 @@ strict_chain
 #quiet_mode
 
 # Proxy DNS requests - no leak for DNS data
-proxy_dns 
+# this uses the proxychains4 style method to do remote dns
+proxy_dns
+
+# use the old proxyresolv script to proxy DNS requests
+# in proxychains 3.1 style. requires proxyresolv in $PATH
+# plus a dynamically linked `dig` binary.
+# this is a lot slower than `proxy_dns`, doesn't support .onion URLs,
+# but might be more compatible with complex software like webbrowsers.
+#proxy_dns_old
 
 # set the class A subnet number to use for the internal remote DNS mapping
 # we use the reserved 224.x.x.x range by default,
diff --git a/src/proxyresolv b/src/proxyresolv
index ae932c2..f10a412 100755
--- a/src/proxyresolv
+++ b/src/proxyresolv
@@ -1,10 +1,8 @@
 #!/bin/sh
-# This is a legacy script that uses "dig" to do DNS lookups via TCP.
-# it is not actively maintained since proxychains no longer depends
-# on it. i leave it here as a bonus.
+# This is a legacy script that uses "dig" or "drill" to do DNS lookups via TCP.
 
 # DNS server used to resolve names
-DNS_SERVER=8.8.8.8
+test -z "$DNS_SERVER" && DNS_SERVER=8.8.8.8
 
 
 if [ $# = 0 ] ; then
@@ -14,5 +12,12 @@ if [ $# = 0 ] ; then
 fi
 
 
-export LD_PRELOAD=libproxychains4.so
-dig $1 @$DNS_SERVER +tcp | awk '/A.?[0-9]+\.[0-9]+\.[0-9]/{print $5;}'
+test -z $LD_PRELOAD && export LD_PRELOAD=libproxychains4.so
+
+if type dig 1>/dev/null 2>&1 ; then
+dig       $1 @$DNS_SERVER +tcp | awk '/A.?[0-9]+\.[0-9]+\.[0-9]/{print $5;}'
+elif type drill 1>/dev/null 2>&1 ; then
+drill -t4 $1 @$DNS_SERVER      | awk '/A.+[0-9]+\.[0-9]+\.[0-9]/{print $5;}'
+else
+echo "error: neither dig nor drill found" >&2
+fi