hook read and write

src/allocator_thread.c

@@ -174,7 +174,7 @@ static int trywrite(int fd, void* buf, size_t bytes) {
 	ssize_t ret;
 	unsigned char *out = buf;
 again:
-	ret = write(fd, out, bytes);
+	ret = true_write(fd, out, bytes);
 	switch(ret) {
 		case -1:
 			if(errno == EINTR) goto again;
@@ -200,7 +200,7 @@ static int tryread(int fd, void* buf, size_t bytes) {
 	ssize_t ret;
 	unsigned char *out = buf;
 again:
-	ret = read(fd, out, bytes);
+	ret = true_read(fd, out, bytes);
 	switch(ret) {
 		case -1:
 			if(errno == EINTR) goto again;
@@ -350,7 +350,7 @@ void at_init(void) {
 void at_close(void) {
 	PFUNC();
 	const int msg = ATM_EXIT;
-	write(req_pipefd[1], &msg, sizeof(int));
+	true_write(req_pipefd[1], &msg, sizeof(int));
 	pthread_join(allocator_thread, NULL);
 	close(req_pipefd[0]);
 	close(req_pipefd[1]);

src/core.c

@@ -122,7 +122,7 @@ static int write_n_bytes(int fd, char *buff, size_t size) {
 	int i = 0;
 	size_t wrote = 0;
 	for(;;) {
-		i = write(fd, &buff[wrote], size - wrote);
+		i = true_write(fd, &buff[wrote], size - wrote);
 		if(i <= 0)
 			return i;
 		wrote += i;
@@ -141,7 +141,7 @@ static int read_n_bytes(int fd, char *buff, size_t size) {
 	for(i = 0; i < size; i++) {
 		pfd[0].revents = 0;
 		ready = poll_retry(pfd, 1, tcp_read_time_out);
-		if(ready != 1 || !(pfd[0].revents & POLLIN) || 1 != read(fd, &buff[i], 1))
+		if(ready != 1 || !(pfd[0].revents & POLLIN) || 1 != true_read(fd, &buff[i], 1))
 			return -1;
 	}
 	return (int) size;
@@ -934,7 +934,8 @@ int socksify_udp_packet(void* udp_data, size_t udp_data_len, udp_relay_chain cha
 
 
 	// Append UDP data in the remaining space of the buffer
-	int min = (udp_data_len>(buffer_len-tmp_buffer_len))?(buffer_len-tmp_buffer_len):udp_data_len;
+	size_t min = (udp_data_len>(buffer_len-tmp_buffer_len))?(buffer_len-tmp_buffer_len):udp_data_len;
+	PDEBUG("test, min = %lu\n", min);
 	memcpy(buffer + tmp_buffer_len, udp_data, min);
 
 	*buffer_len = tmp_buffer_len + min;
@@ -1628,7 +1629,7 @@ struct hostent* proxy_gethostbyname_old(const char *name)
 			close(pipe_fd[1]);
 			waitpid(pid, &status, 0);
 			buff[0] = 0;
-			read(pipe_fd[0],&buff,sizeof(buff));
+			true_read(pipe_fd[0],&buff,sizeof(buff));
 			close(pipe_fd[0]);
 got_buff:
 			l = strlen(buff);

src/core.h

@@ -176,6 +176,8 @@ typedef ssize_t (*sendmsg_t) (int sockfd, const struct msghdr *msg, int flags);
 typedef int (*sendmmsg_t) (int sockfd, struct mmsghdr* msgvec, unsigned int vlen, int flags);
 typedef ssize_t (*recvmsg_t) (int sockfd, struct msghdr *msg, int flags);
 typedef int (*getpeername_t) (int sockfd, struct sockaddr *restrict addr, socklen_t *restrict addrlen);
+typedef ssize_t (*read_t)(int fd, void* buf, size_t count);
+typedef ssize_t (*write_t)(int fd, const void* buf, size_t count);
 
 
 extern connect_t true_connect;
@@ -192,6 +194,8 @@ extern sendmsg_t true_sendmsg;
 extern sendmmsg_t true_sendmmsg;
 extern recvmsg_t true_recvmsg;
 extern getpeername_t true_getpeername;
+extern read_t true_read;
+extern write_t true_write;
 
 struct gethostbyname_data {
 	struct hostent hostent_space;

src/debug.c

@@ -24,7 +24,7 @@ void dump_proxy_chain(proxy_data *pchain, unsigned int count) {
 
 void dump_buffer(unsigned char * data, size_t len){
 	printf("buffer_dump[");
-	for(int i=0; i<len; i++){
+	for(size_t i=0; i<len; i++){
 		printf("%d ", *(data+i));
 	}
 	printf("]\n");

src/libproxychains.c

@@ -36,6 +36,10 @@
 #include <dlfcn.h>
 #include <pthread.h>
 
+#include <sys/stat.h>
+
+
+
 
 #include "core.h"
 #include "common.h"
@@ -72,6 +76,8 @@ sendmsg_t true_sendmsg;
 recvmsg_t true_recvmsg;
 sendmmsg_t true_sendmmsg;
 getpeername_t true_getpeername;
+read_t true_read;
+write_t true_write;
 
 int tcp_read_time_out;
 int tcp_connect_time_out;
@@ -1080,6 +1086,8 @@ HOOKFUNC(ssize_t, sendto, int sockfd, const void *buf, size_t len, int flags,
 	PDEBUG("target: %s\n", inet_ntop(v6 ? AF_INET6 : AF_INET, v6 ? (void*)p_addr_in6 : (void*)p_addr_in, str, sizeof(str)));
 	PDEBUG("port: %d\n", port);
 	PDEBUG("client socket: %d\n", sockfd);
+	PDEBUG("trying to send %lu bytes : ", len);
+	DUMP_BUFFER(buf, len);
 
 	// check if connect called from proxydns
     remote_dns_connect = !v6 && (ntohl(p_addr_in->s_addr) >> 24 == remote_dns_subnet);
@@ -1184,7 +1192,7 @@ HOOKFUNC(ssize_t, sendto, int sockfd, const void *buf, size_t len, int flags,
 		return -1;
 	}
 
-	int sent = 0;
+	ssize_t sent = 0;
 	sent = true_sendto(sockfd, send_buffer, send_buffer_len, flags, (struct sockaddr*)(v6?(void*)&addr6:(void*)&addr), v6?sizeof(addr6):sizeof(addr));
 
 	if(sent == -1){
@@ -2094,6 +2102,40 @@ HOOKFUNC(ssize_t, send, int sockfd, const void *buf, size_t len, int flags){
 	return sendto(sockfd, buf, len, flags, (struct sockaddr*)&addr, addr_len);
 }
 
+
+HOOKFUNC(ssize_t, read,int fd, void* buf, size_t count){
+	
+	// If fd is a socket, call recv() with no flags as it is equivalent to read()
+	// WARNING: As stated in https://man7.org/linux/man-pages/man2/recv.2.html in NOTES, 
+	//"If a zero-length datagram is pending, read(2) and recv() with a
+    // flags argument of zero provide different behavior.  In this
+	// circumstance, read(2) has no effect (the datagram remains
+	// pending), while recv() consumes the pending datagram."
+
+	struct stat statbuf;
+	fstat(fd, &statbuf);
+	if(S_ISSOCK(statbuf.st_mode)){
+		PDEBUG("hooked read() on a socket file descriptor, calling recv() with 0 flags\n");
+		return recv(fd, buf, count, 0);
+	}
+	return true_read(fd, buf, count);
+}
+
+HOOKFUNC(ssize_t, write, int fd, const void* buf, size_t count ){
+
+	PDEBUG("fd : %d, count: %zu, buf: %p\n", fd, count, buf);
+	DUMP_BUFFER(buf, count);
+
+	// If fd is a socket, call send() with no flags as it is equivalent to write()
+	struct stat statbuf;
+	fstat(fd, &statbuf);
+	if(S_ISSOCK(statbuf.st_mode)){
+		PDEBUG("hooked write() on a socket file descriptor, calling send() with 0 flags\n");
+		return send(fd, buf,count, 0);
+	}
+	return true_write(fd, buf, count);
+}
+
 #ifdef MONTEREY_HOOKING
 #define SETUP_SYM(X) do { if (! true_ ## X ) true_ ## X = &X; } while(0)
 #define SETUP_SYM_OPTIONAL(X)
@@ -2118,6 +2160,8 @@ static void setup_hooks(void) {
 	SETUP_SYM(freeaddrinfo);
 	SETUP_SYM(gethostbyaddr);
 	SETUP_SYM(getnameinfo);
+	SETUP_SYM(write);
+	SETUP_SYM(read);
 #ifdef IS_SOLARIS
 	SETUP_SYM(__xnet_connect);
 #endif