preliminary support for new DYLD hooking method for OSX Monterey

there's currently no build system support yet. after ./configure
was executed, add -DMONTEREY_HOOKING to CFLAGS/CPPFLAGS in config.mak
to activate this.

addressing #409

Makefile

@@ -19,7 +19,7 @@ DOBJS = src/daemon/hsearch.o \
         src/daemon/sblist.o src/daemon/sblist_delete.o \
         src/daemon/daemon.o src/daemon/udpserver.o
 
-LOBJS = src/nameinfo.o src/version.o \
+LOBJS = src/version.o \
         src/core.o src/common.o src/libproxychains.o \
         src/allocator_thread.o src/rdns.o \
         src/hostsreader.o src/hash.o src/debug.o

configure

@@ -50,8 +50,10 @@ check_compile_run() {
 
 check_link_silent() {
 	printf "$2" > "$tmpc"
-	$CC $OUR_CPPFLAGS $CPPFLAGS $1 $CFLAGS "$tmpc" -o "$tmpc".out  >/dev/null 2>&1
+	local res=0
+	$CC $OUR_CPPFLAGS $CPPFLAGS $1 $CFLAGS "$tmpc" -o "$tmpc".out  >/dev/null 2>&1 || res=1
 	rm -f "$tmpc".out
+	return $res
 }
 
 check_link() {

src/libproxychains.c

@@ -104,25 +104,12 @@ static void* load_sym(char* symname, void* proxyfunc) {
 
 #define INIT() init_lib_wrapper(__FUNCTION__)
 
-#define SETUP_SYM(X) do { if (! true_ ## X ) true_ ## X = load_sym( # X, X ); } while(0)
 
 #include "allocator_thread.h"
 
 const char *proxychains_get_version(void);
 
-static void setup_hooks(void) {
-	SETUP_SYM(connect);
-	SETUP_SYM(sendto);
-	SETUP_SYM(gethostbyname);
-	SETUP_SYM(getaddrinfo);
-	SETUP_SYM(freeaddrinfo);
-	SETUP_SYM(gethostbyaddr);
-	SETUP_SYM(getnameinfo);
-#ifdef IS_SOLARIS
-	SETUP_SYM(__xnet_connect);
-#endif
-	SETUP_SYM(close);
-}
+static void setup_hooks(void);
 
 static int close_fds[16];
 static int close_fds_cnt = 0;
@@ -537,7 +524,14 @@ inv_host:
 
 /*******  HOOK FUNCTIONS  *******/
 
-int close(int fd) {
+#define EXPAND( args...) args
+#ifdef MONTEREY_HOOKING
+#define HOOKFUNC(R, N, args...) R pxcng_ ## N ( EXPAND(args) )
+#else
+#define HOOKFUNC(R, N, args...) R N ( EXPAND(args) )
+#endif
+
+HOOKFUNC(int, close, int fd) {
 	if(!init_l) {
 		if(close_fds_cnt>=(sizeof close_fds/sizeof close_fds[0])) goto err;
 		close_fds[close_fds_cnt++] = fd;
@@ -558,7 +552,8 @@ int close(int fd) {
 static int is_v4inv6(const struct in6_addr *a) {
 	return !memcmp(a->s6_addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
 }
-int connect(int sock, const struct sockaddr *addr, unsigned int len) {
+
+HOOKFUNC(int, connect, int sock, const struct sockaddr *addr, unsigned int len) {
 	INIT();
 	PFUNC();
 
@@ -649,13 +644,13 @@ int connect(int sock, const struct sockaddr *addr, unsigned int len) {
 }
 
 #ifdef IS_SOLARIS
-int __xnet_connect(int sock, const struct sockaddr *addr, unsigned int len) {
+HOOKFUNC(int, __xnet_connect, int sock, const struct sockaddr *addr, unsigned int len)
 	return connect(sock, addr, len);
 }
 #endif
 
 static struct gethostbyname_data ghbndata;
-struct hostent *gethostbyname(const char *name) {
+HOOKFUNC(struct hostent*, gethostbyname, const char *name) {
 	INIT();
 	PDEBUG("gethostbyname: %s\n", name);
 
@@ -669,7 +664,7 @@ struct hostent *gethostbyname(const char *name) {
 	return NULL;
 }
 
-int getaddrinfo(const char *node, const char *service, const struct addrinfo *hints, struct addrinfo **res) {
+HOOKFUNC(int, getaddrinfo, const char *node, const char *service, const struct addrinfo *hints, struct addrinfo **res) {
 	INIT();
 	PDEBUG("getaddrinfo: %s %s\n", node ? node : "null", service ? service : "null");
 
@@ -679,7 +674,7 @@ int getaddrinfo(const char *node, const char *service, const struct addrinfo *hi
 		return true_getaddrinfo(node, service, hints, res);
 }
 
-void freeaddrinfo(struct addrinfo *res) {
+HOOKFUNC(void, freeaddrinfo, struct addrinfo *res) {
 	INIT();
 	PDEBUG("freeaddrinfo %p \n", (void *) res);
 
@@ -689,7 +684,7 @@ void freeaddrinfo(struct addrinfo *res) {
 		proxy_freeaddrinfo(res);
 }
 
-int pc_getnameinfo(const struct sockaddr *sa, socklen_t salen,
+HOOKFUNC(int, getnameinfo, const struct sockaddr *sa, socklen_t salen,
 	           char *host, socklen_t hostlen, char *serv,
 	           socklen_t servlen, int flags)
 {
@@ -733,7 +728,7 @@ int pc_getnameinfo(const struct sockaddr *sa, socklen_t salen,
 	return 0;
 }
 
-struct hostent *gethostbyaddr(const void *addr, socklen_t len, int type) {
+HOOKFUNC(struct hostent*, gethostbyaddr, const void *addr, socklen_t len, int type) {
 	INIT();
 	PDEBUG("TODO: proper gethostbyaddr hook\n");
 
@@ -769,7 +764,7 @@ struct hostent *gethostbyaddr(const void *addr, socklen_t len, int type) {
 #   define MSG_FASTOPEN 0x20000000
 #endif
 
-ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,
+HOOKFUNC(ssize_t, sendto, int sockfd, const void *buf, size_t len, int flags,
 	       const struct sockaddr *dest_addr, socklen_t addrlen) {
 	INIT();
 	PFUNC();
@@ -783,3 +778,41 @@ ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,
 	}
 	return true_sendto(sockfd, buf, len, flags, dest_addr, addrlen);
 }
+
+#ifdef MONTEREY_HOOKING
+#define SETUP_SYM(X) do { if (! true_ ## X ) true_ ## X = &X; } while(0)
+#else
+#define SETUP_SYM(X) do { if (! true_ ## X ) true_ ## X = load_sym( # X, X ); } while(0)
+#endif
+
+static void setup_hooks(void) {
+	SETUP_SYM(connect);
+	SETUP_SYM(sendto);
+	SETUP_SYM(gethostbyname);
+	SETUP_SYM(getaddrinfo);
+	SETUP_SYM(freeaddrinfo);
+	SETUP_SYM(gethostbyaddr);
+	SETUP_SYM(getnameinfo);
+#ifdef IS_SOLARIS
+	SETUP_SYM(__xnet_connect);
+#endif
+	SETUP_SYM(close);
+}
+
+#ifdef MONTEREY_HOOKING
+
+#define DYLD_INTERPOSE(_replacement,_replacee) \
+   __attribute__((used)) static struct{ const void* replacement; const void* replacee; } _interpose_##_replacee \
+   __attribute__((section ("__DATA,__interpose"))) = { (const void*)(unsigned long)&_replacement, (const void*)(unsigned long)&_replacee };
+#define DYLD_HOOK(F) DYLD_INTERPOSE(pxcng_ ## F, F)
+
+DYLD_HOOK(connect);
+DYLD_HOOK(sendto);
+DYLD_HOOK(gethostbyname);
+DYLD_HOOK(getaddrinfo);
+DYLD_HOOK(freeaddrinfo);
+DYLD_HOOK(gethostbyaddr);
+DYLD_HOOK(getnameinfo);
+DYLD_HOOK(close);
+
+#endif

src/nameinfo.c

@@ -1,13 +0,0 @@
-#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);
-}
-

tests/test_getaddrinfo.c

@@ -3,6 +3,8 @@
 #include <netdb.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
+#include <assert.h>
+#include <string.h>
 
 #ifndef   NI_MAXHOST
 #define   NI_MAXHOST 1025
@@ -43,9 +45,42 @@ static int doit(const char* host, const char* service) {
 	return EXIT_SUCCESS;
 }
 
+/* reproduce use of getaddrinfo as used by nmap 7.91's canonicalize_address */
+int canonicalize_address(struct sockaddr_storage *ss, struct sockaddr_storage *output) {
+	char canonical_ip_string[NI_MAXHOST];
+	struct addrinfo *ai;
+	int rc;
+	/* Convert address to string. */
+	rc = getnameinfo((struct sockaddr *) ss, sizeof(*ss),
+		canonical_ip_string, sizeof(canonical_ip_string), NULL, 0, NI_NUMERICHOST);
+	assert(rc == 0);
+	struct addrinfo hints = {
+		.ai_family = ss->ss_family,
+		.ai_socktype = SOCK_DGRAM,
+		.ai_flags = AI_NUMERICHOST,
+	};
+	rc = getaddrinfo(canonical_ip_string, NULL, &hints, &ai);
+	if (rc != 0 || ai == NULL)
+		return -1;
+	assert(ai->ai_addrlen > 0 && ai->ai_addrlen <= (int) sizeof(*output));
+	memcpy(output, ai->ai_addr, ai->ai_addrlen);
+	freeaddrinfo(ai);
+	return 0;
+}
+
 int main(void) {
 	int ret;
 	ret = doit("www.example.com", NULL);
 	ret = doit("www.example.com", "80");
+	struct sockaddr_storage o, ss = {.ss_family = PF_INET};
+	struct sockaddr_in *v4 = &ss;
+	struct sockaddr_in6 *v6 = &ss;
+	memcpy(&v4->sin_addr, "\x7f\0\0\1", 4);
+	ret = canonicalize_address(&ss, &o);
+	assert (ret == 0);
+	ss.ss_family = PF_INET6;
+	memcpy(&v6->sin6_addr, "\0\0\0\0" "\0\0\0\0" "\0\0\0\0""\0\0\0\1", 16);
+	ret = canonicalize_address(&ss, &o);
+	assert (ret == 0);
 	return ret;
 }

tests/test_getnameinfo.c

@@ -123,5 +123,17 @@ int main() {
 
 	ASSERT(ret == 0);
 
+	b.sin6_port = 0;
+	b.sin6_scope_id = 0;
+	memcpy(&b.sin6_addr,"\0\0\0\0" "\0\0\0\0" "\0\0\0\0" "\0\0\0\1", 16);
+
+	if ((ret = getnameinfo((void*)sb, sizeof b, hbuf, sizeof(hbuf), NULL,
+	    0, NI_NUMERICHOST)) == 0)
+		printf("host=%s\n", hbuf);
+	else
+		printf("%s\n", gai_strerror(ret));
+
+	ASSERT(ret == 0);
+
 	return 0;
 }