overhaul README

especially mentioning that proxychains is a HACK so it may not work.
it is a hack because it modifies existing programs in a way not
originally intended by its authors.
additionally it relies on a very complicated and fragile dynamic
linker infrastructure which can easily break, as is the case with
glibc-linked programs that use dlopen() (see issue #10).

Makefile

@@ -15,12 +15,15 @@ sysconfdir=$(prefix)/etc
 
 SRCS = $(sort $(wildcard src/*.c))
 OBJS = $(SRCS:.c=.o)
-LOBJS = src/core.o src/common.o src/libproxychains.o src/shm.o \
+LOBJS = src/nameinfo.o \
+        src/core.o src/common.o src/libproxychains.o src/shm.o \
         src/allocator_thread.o src/ip_type.o src/stringdump.o \
         src/hostentdb.o src/hash.o
 
 CFLAGS  += -Wall -O0 -g -std=c99 -D_GNU_SOURCE -pipe
-LDFLAGS = -shared -fPIC -Wl,--no-as-needed -ldl -lpthread
+NO_AS_NEEDED = -Wl,--no-as-needed
+LIBDL   = -ldl
+LDFLAGS = -shared -fPIC $(NO_AS_NEEDED) $(LIBDL) -lpthread
 INC     = 
 PIC     = -fPIC
 AR      = $(CROSS_COMPILE)ar
@@ -30,8 +33,6 @@ LDSO_SUFFIX = so
 LD_SET_SONAME = -Wl,-soname=
 INSTALL_FLAGS = -D -m
 
--include config.mak
-
 LDSO_PATHNAME = libproxychains4.$(LDSO_SUFFIX)
 
 SHARED_LIBS = $(LDSO_PATHNAME)
@@ -39,6 +40,7 @@ ALL_LIBS = $(SHARED_LIBS)
 PXCHAINS = proxychains4
 ALL_TOOLS = $(PXCHAINS)
 
+-include config.mak
 
 CFLAGS+=$(USER_CFLAGS) $(MAC_CFLAGS)
 CFLAGS_MAIN=-DLIB_DIR=\"$(libdir)\" -DSYSCONFDIR=\"$(sysconfdir)\" -DDLL_NAME=\"$(LDSO_PATHNAME)\"
@@ -70,4 +72,4 @@ $(ALL_TOOLS): $(OBJS)
 	$(CC) src/main.o src/common.o -o $(PXCHAINS)
 
 
-.PHONY: all clean install
+.PHONY: all clean install install-config

README

@@ -1,27 +1,51 @@
-ProxyChains ver 4.3 README
-==========================
+ProxyChains-NG ver 4.5 README
+=============================
 
   ProxyChains is a UNIX program, that hooks network-related libc functions
-  in dynamically linked programs via a preloaded DLL and redirects the
-  connections through SOCKS4a/5 or HTTP proxies.
+  in DYNAMICALLY LINKED programs via a preloaded DLL (dlsym(), LD_PRELOAD)
+  and redirects the connections through SOCKS4a/5 or HTTP proxies.
+  It supports TCP only (no UDP/ICMP etc).
+
+  The way it works is basically a HACK; so it is possible that it doesn't
+  work with your program, especially when it's a script, or starts 
+  numerous processes like background daemons or uses dlopen() to load
+  "modules" (bug in glibc dynlinker).
+  It should work with simple compiled (C/C++) dynamically linked programs
+  though.
+
+  If your program doesn't work with proxychains, consider using an 
+  iptables based solution instead; this is much more robust.
+
+  Supported Platforms: Linux, BSD, Mac.
+
 
 *********** ATTENTION ***********
 
-  this program works only on dynamically linked programs.
-  also both proxychains and the program to call must use
-  the same dynamic linker (i.e. same libc).
-  why ? because in order to hook to libc functions like
-  connect(), dynamic loader facilities are used, namely
-  dl_sym() and LD_PRELOAD.
+  this program can be used to circumvent censorship.
+  doing so can be VERY DANGEROUS in certain countries.
 
-*********************************
+  ALWAYS MAKE SURE THAT PROXYCHAINS WORKS AS EXPECTED
+  BEFORE USING IT FOR ANYTHING SERIOUS.
+
+  this involves both the program and the proxy that you're going to
+  use.
+
+  for example, you can connect to some "what is my ip" service
+  like ifconfig.me to make sure that it's not using your real ip.
+
+  ONLY USE PROXYCHAINS IF YOU KNOW WHAT YOU'RE DOING.
+
+  THE AUTHORS AND MAINTAINERS OF PROXYCHAINS DO NOT TAKE ANY 
+  RESPONSIBILITY FOR ANY ABUSE OR MISUSE OF THIS SOFTWARE AND 
+  THE RESULTING CONSEQUENCES.
 
 *** Installation ***
 
   # needs a working C compiler, preferably gcc
-  ./configure
+  ./configure --prefix=/usr --sysconfdir=/etc
   make
   [optional] sudo make install
+  [optional] sudo make install-config (installs proxychains.conf)
 
   if you dont install, you can use proxychains from the build directory
   like this: ./proxychains4 -f src/proxychains.conf telnet google.com 80
@@ -29,6 +53,14 @@ ProxyChains ver 4.3 README
 Changelog:
 ----------
 
+Version 4.5:
+- hook close() to prevent OpenSSH from messing with internal infrastructure.
+  this caused ssh client to segfault when proxified.
+
+Version 4.4:
+- FreeBSD port
+- fixes some installation issues on Debian and Mac.
+
 Version 4.3:
 - fixes programs that do dns-lookups in child processes (fork()ed),
   like irssi. to achieve this, support for compilation without pthreads
@@ -78,10 +110,9 @@ Some cool features:
 	random order from the list ( user defined length of chain ).
 	exact order  (as they appear in the list )
 	dynamic order (smart exclude dead proxies from chain)
-* You can use it with any TCP client application, even network scanners
-	yes, yes - you can make portscan via proxy (or chained proxies)
-	for example with Nmap scanner by fyodor (www.insecire.org/nmap).
-	proxychains nmap -sT -PO -p 80 -iR  (find some webservers through proxy)
+* You can use it with most TCP client applications, possibly even network 
+	scanners, as long as they use standard libc functionality.
+	pcap based scanning does not work.
 * You can use it with servers, like squid, sendmail, or whatever.
 * DNS resolving through proxy.
 
@@ -90,13 +121,13 @@ Configuration:
 --------------
 
 proxychains looks for config file in following order:
-1)	file listed in environment variable ${PROXYCHAINS_CONF_FILE} or
+1)	file listed in environment variable PROXYCHAINS_CONF_FILE or
 	provided as a -f argument to proxychains script or binary.
 2)	./proxychains.conf
 3)	$(HOME)/.proxychains/proxychains.conf
-4)	/etc/proxychains.conf  **
+4)	$(sysconfdir)/proxychains.conf  **
 
-**see more in /etc/proxychains.conf
+** usually /etc/proxychains.conf
 
 Usage Example:
 

configure

@@ -34,7 +34,11 @@ parsearg() {
 }
 
 ismac() {
-	uname -s | grep Darwin
+	uname -s | grep Darwin >/dev/null
+}
+
+isbsd() {
+	uname -s | grep BSD >/dev/null
 }
 
 while true ; do
@@ -78,10 +82,15 @@ echo libdir=$libdir>>config.mak
 echo includedir=$includedir>>config.mak
 echo sysconfdir=$sysconfdir>>config.mak
 if ismac ; then
+	echo NO_AS_NEEDED=>>config.mak
 	echo LDSO_SUFFIX=dylib>>config.mak
 	echo MAC_CFLAGS+=-DIS_MAC=1>>config.mak
 	echo LD_SET_SONAME=-Wl,-install_name,>>config.mak
 	echo INSTALL_FLAGS=-m>>config.mak
+elif isbsd ; then
+	echo LIBDL=>>config.mak
+	echo "CFLAGS+=-DIS_BSD">>config.mak
+	echo INSTALL_FLAGS=-m>>config.mak
 fi
 
 echo done, now run make \&\& make install

src/allocator_thread.c

@@ -8,6 +8,7 @@
 #include <string.h>
 #include <stdint.h>
 #include <stddef.h>
+#include <errno.h>
 #include "allocator_thread.h"
 #include "shm.h"
 #include "debug.h"
@@ -147,8 +148,8 @@ struct at_msghdr {
 
 static pthread_t allocator_thread;
 static pthread_attr_t allocator_thread_attr;
-static int req_pipefd[2];
-static int resp_pipefd[2];
+int req_pipefd[2];
+int resp_pipefd[2];
 
 static int wait_data(int readfd) {
 	PFUNC();
@@ -158,7 +159,13 @@ static int wait_data(int readfd) {
 	int ret;
 	while((ret = select(readfd+1, &fds, NULL, NULL, NULL)) <= 0) {
 		if(ret < 0) {
-			perror("select2");
+			int e = errno;
+			if(e == EINTR) continue;
+#ifdef __GLIBC__
+			char emsg[1024];
+			char* x = strerror_r(errno, emsg, sizeof emsg);
+			dprintf(2, "select2: %s\n", x);
+#endif
 			return 0;
 		}
 	}

src/allocator_thread.h

@@ -6,10 +6,14 @@
 
 #define MSG_LEN_MAX 256
 
+extern int req_pipefd[2];
+extern int resp_pipefd[2];
+
 void at_init(void);
 void at_close(void);
 size_t at_get_host_for_ip(ip_type ip, char* readbuf);
 ip_type at_get_ip_for_host(char* host, size_t len);
 
 //RcB: DEP "allocator_thread.c"
-#endif
+#endif
+

src/core.h

@@ -82,6 +82,7 @@ int connect_proxy_chain (int sock, ip_type target_ip, unsigned short target_port
 
 void proxychains_write_log(char *str, ...);
 
+typedef int (*close_t)(int);
 typedef int (*connect_t)(int, const struct sockaddr *, socklen_t);
 typedef struct hostent* (*gethostbyname_t)(const char *);
 typedef int (*freeaddrinfo_t)(struct addrinfo *);
@@ -123,4 +124,5 @@ void core_unload(void);
 
 //RcB: DEP "core.c"
 //RcB: DEP "libproxychains.c"
-//RcB: LINK "-Wl,--no-as-needed -ldl -lpthread"
+//RcB: LINK "-Wl,--no-as-needed -ldl -lpthread"
+

src/debug.h

@@ -10,4 +10,5 @@
 
 # define PFUNC() do { PDEBUG("pid[%d]:%s\n", getpid(), __FUNCTION__); } while(0)
 
-#endif
+#endif
+

src/hostentdb.c

@@ -2,6 +2,8 @@
 #include <string.h>
 #include <netdb.h>
 #include <stdlib.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
 
 #include "ip_type.h"
 #include "hash.h"
@@ -26,11 +28,16 @@ static void hdb_add(struct hostent_list* hl, char* host, ip_type ip) {
 }
 
 static void hdb_fill(struct hostent_list *hl) {
+#ifndef IS_BSD
 	struct hostent* hp;
 	while((hp = gethostent()))
 		if(hp->h_addrtype == AF_INET && hp->h_length == sizeof(in_addr_t)) {
 			hdb_add(hl, hp->h_name, (ip_type) { .as_int = *((in_addr_t*)(hp->h_addr_list[0])) });
 		}
+#else
+	/* FreeBSD hangs on gethostent(). since this feature is not crucial, we just do nothing */
+	(void) hl;
+#endif
 }
 
 void hdb_init(struct hostent_list *hl) {
@@ -53,4 +60,4 @@ ip_type hdb_get(struct hostent_list *hl, char* host) {
 		}
 	}
 	return ip_type_invalid;
-}
+}

src/libproxychains.c

@@ -45,6 +45,7 @@
 #define     SOCKFAMILY(x)     (satosin(x)->sin_family)
 #define     MAX_CHAIN 512
 
+close_t true_close;
 connect_t true_connect;
 gethostbyname_t true_gethostbyname;
 getaddrinfo_t true_getaddrinfo;
@@ -113,6 +114,7 @@ static void do_init(void) {
 	SETUP_SYM(freeaddrinfo);
 	SETUP_SYM(gethostbyaddr);
 	SETUP_SYM(getnameinfo);
+	SETUP_SYM(close);
 	
 	init_l = 1;
 }
@@ -282,6 +284,16 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 
 /*******  HOOK FUNCTIONS  *******/
 
+int close(int fd) {
+	/* prevent rude programs (like ssh) from closing our pipes */
+	if(fd != req_pipefd[0]  && fd != req_pipefd[1] &&
+	   fd != resp_pipefd[0] && fd != resp_pipefd[1]) {
+		return true_close(fd);
+	}
+	errno = EINTR;
+	return -1;
+}
+
 int connect(int sock, const struct sockaddr *addr, unsigned int len) {
 	PFUNC();
 	int socktype = 0, flags = 0, ret = 0;
@@ -381,32 +393,31 @@ void freeaddrinfo(struct addrinfo *res) {
 	return;
 }
 
-// work around a buggy prototype in GLIBC. according to the bugtracker it has been fixed in git at 02 May 2011.
-// 2.14 came out in June 2011 so that should be the first fixed version
-#if defined(__GLIBC__) && (__GLIBC__ < 3) && (__GLIBC_MINOR__ < 14)
-int getnameinfo(const struct sockaddr *sa,
-		socklen_t salen, char *host, socklen_t hostlen, char *serv, socklen_t servlen, unsigned int flags)
-#else
-int getnameinfo(const struct sockaddr *sa,
-		socklen_t salen, char *host, socklen_t hostlen, char *serv, socklen_t servlen, int flags)
-#endif
+int pc_getnameinfo(const struct sockaddr *sa, socklen_t salen, 
+	           char *host, socklen_t hostlen, char *serv, 
+	           socklen_t servlen, int flags)
 {
 	char ip_buf[16];
 	int ret = 0;
 
 	INIT();
 	
-	PDEBUG("getnameinfo: %s %s\n", host, serv);
+	PFUNC();
 
 	if(!proxychains_resolver) {
 		ret = true_getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
 	} else {
+		if(salen < sizeof(struct sockaddr_in) || SOCKFAMILY(*sa) != AF_INET)
+			return EAI_FAMILY;
 		if(hostlen) {
 			pc_stringfromipv4((unsigned char*) &(SOCKADDR_2(*sa)), ip_buf);
-			strncpy(host, ip_buf, hostlen);
+			if(snprintf(host, hostlen, "%s", ip_buf) >= hostlen)
+				return EAI_OVERFLOW;
+		}
+		if(servlen) {
+			if(snprintf(serv, servlen, "%d", ntohs(SOCKPORT(*sa))) >= servlen)
+				return EAI_OVERFLOW;
 		}
-		if(servlen)
-			snprintf(serv, servlen, "%d", ntohs(SOCKPORT(*sa)));
 	}
 	return ret;
 }

src/nameinfo.c

@@ -0,0 +1,13 @@
+#include <sys/socket.h>
+
+extern int pc_getnameinfo(const void *sa, socklen_t salen, 
+                   char *host, socklen_t hostlen, char *serv, 
+                   socklen_t servlen, int flags);
+
+
+int getnameinfo(const void *sa, socklen_t salen, 
+                   char *host, socklen_t hostlen, char *serv, 
+                   socklen_t servlen, int flags) {
+	return pc_getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
+}
+

src/proxychains

@@ -1,26 +0,0 @@
-#!/bin/sh
-echo "ProxyChains-3.1 (http://proxychains.sf.net)"
-
-usage() {
-
-	echo "	usage:"
-	echo "		$0 [h] [f config-file] <prog> [args]"
-	exit
-}
-
-if [ $# = 0 ] ; then
-	usage
-fi
-
-if [ $1 = "-h" ]; then
-	usage
-fi
-
-if [ "$1" = "-f" ]; then
-	export PROXYCHAINS_CONF_FILE=$2;
-	shift;
-	shift;
-fi
-
-export LD_PRELOAD=libproxychains.so.3
-exec "$@"

src/proxyresolv

@@ -1,8 +1,10 @@
 #!/bin/sh
-# This script is called by proxychains to resolve DNS names
+# 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.
 
 # DNS server used to resolve names
-DNS_SERVER=4.2.2.2
+DNS_SERVER=8.8.8.8
 
 
 if [ $# = 0 ] ; then
@@ -12,5 +14,5 @@ if [ $# = 0 ] ; then
 fi
 
 
-export LD_PRELOAD=libproxychains.so
-dig $1 @$DNS_SERVER +tcp | awk '/A.+[0-9]+\.[0-9]+\.[0-9]/{print $5;}'
+export LD_PRELOAD=libproxychains4.so
+dig $1 @$DNS_SERVER +tcp | awk '/A.?[0-9]+\.[0-9]+\.[0-9]/{print $5;}'

tests/test_getnameinfo.c

@@ -0,0 +1,83 @@
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#define     satosin(x)      ((struct sockaddr_in *) &(x))
+#define     SOCKADDR(x)     (satosin(x)->sin_addr.s_addr)
+#define     SOCKADDR_2(x)     (satosin(x)->sin_addr)
+#define     SOCKPORT(x)     (satosin(x)->sin_port)
+#define     SOCKFAMILY(x)     (satosin(x)->sin_family)
+
+int main() {
+	struct sockaddr a = {0}, *sa = &a;
+	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
+	SOCKPORT(a) = htons(80);
+	memcpy(  &( (struct sockaddr_in*) sa ) ->sin_addr   , (char[]) {127,0,0,1}, 4);
+
+	int ret;
+
+	if ((ret = getnameinfo(sa, 0, hbuf, sizeof(hbuf), sbuf,
+	    sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == EAI_FAMILY);
+
+	if ((ret = getnameinfo(sa, sizeof a, hbuf, sizeof(hbuf), sbuf,
+	    sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == EAI_FAMILY);
+
+	SOCKFAMILY(a) = AF_INET;
+
+	if ((ret = getnameinfo(sa, sizeof a, hbuf, 1, sbuf,
+	    sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == EAI_OVERFLOW);
+
+	if ((ret = getnameinfo(sa, sizeof a, hbuf, 0, sbuf,
+	    1, NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == EAI_OVERFLOW);
+
+	if ((ret = getnameinfo(sa, sizeof a, hbuf, 0, sbuf,
+	    sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == 0);
+
+	if ((ret = getnameinfo(sa, sizeof a, hbuf, sizeof hbuf, sbuf,
+	    0, NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == 0);
+
+
+	if ((ret = getnameinfo(sa, sizeof a, hbuf, sizeof(hbuf), sbuf,
+	    sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV)) == 0)
+		printf("host=%s, serv=%s\n", hbuf, sbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	assert(ret == 0);
+
+		
+	return 0;
+}