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#include "vnc.h"
#include <libsec.h>
#include <auth.h>
char *serveraddr;
/*
* Encrypt n bytes using the password
* as key, padded with zeros to 8 bytes.
*/
enum
{
VerLen = 12
};
static char version[VerLen+1] = "RFB 003.003\n";
static uchar tab[256];
/* VNC reverses the bits of each byte before using as a des key */
static void
mktab(void)
{
int i, j, k;
static int once;
if(once)
return;
once = 1;
for(i=0; i<256; i++){
j=i;
tab[i] = 0;
for(k=0; k<8; k++){
tab[i] = (tab[i]<<1) | (j&1);
j >>= 1;
}
}
}
static void
vncencrypt(uchar *buf, int n, char *pw)
{
uchar *p;
uchar key[9];
DESstate s;
mktab();
memset(key, 0, sizeof key);
strncpy((char*)key, pw, 8);
for(p=key; *p; p++)
*p = tab[*p];
setupDESstate(&s, key, nil);
desECBencrypt(buf, n, &s);
}
static int
readln(char *prompt, char *line, int len)
{
char *p;
int fd, ctl, n, nr;
fd = open("/dev/cons", ORDWR);
if(fd < 0)
sysfatal("couldn't open cons");
ctl = open("/dev/consctl", OWRITE);
if(ctl < 0)
sysfatal("couldn't open consctl");
write(ctl, "rawon", 5);
fprint(fd, "%s", prompt);
nr = 0;
p = line;
for(;;){
n = read(fd, p, 1);
if(n < 0){
close(fd);
close(ctl);
return -1;
}
if(n == 0 || *p == '\n' || *p == '\r'){
*p = '\0';
write(fd, "\n", 1);
close(fd);
close(ctl);
return nr;
}
if(*p == '\b'){
if(nr > 0){
nr--;
p--;
}
}else if(*p == 21){ /* cntrl-u */
fprint(fd, "\n%s", prompt);
nr = 0;
p = line;
}else{
nr++;
p++;
}
if(nr == len){
fprint(fd, "line too long; try again\n%s", prompt);
nr = 0;
p = line;
}
}
}
int
vncsrvhandshake(Vnc *v)
{
char msg[VerLen+1];
strecpy(msg, msg+sizeof msg, version);
if(verbose)
fprint(2, "server version: %s\n", msg);
vncwrbytes(v, msg, VerLen);
vncflush(v);
vncrdbytes(v, msg, VerLen);
if(verbose)
fprint(2, "client version: %s\n", msg);
return 0;
}
int
vnchandshake(Vnc *v)
{
char msg[VerLen+1];
msg[VerLen] = 0;
vncrdbytes(v, msg, VerLen);
if(strncmp(msg, "RFB ", 4) != 0){
werrstr("bad rfb version \"%s\"", msg);
return -1;
}
if(verbose)
fprint(2, "server version: %s\n", msg);
strcpy(msg, version);
vncwrbytes(v, msg, VerLen);
vncflush(v);
return 0;
}
int
vncauth(Vnc *v, char *keypattern)
{
char pw[128], *reason;
uchar chal[VncChalLen];
ulong auth;
char *p, *server;
if(keypattern == nil)
keypattern = "";
auth = vncrdlong(v);
switch(auth){
default:
werrstr("unknown auth type 0x%lux", auth);
if(verbose)
fprint(2, "unknown auth type 0x%lux\n", auth);
return -1;
case AFailed:
reason = vncrdstring(v);
werrstr("%s", reason);
if(verbose)
fprint(2, "auth failed: %s\n", reason);
return -1;
case ANoAuth:
if(verbose)
fprint(2, "no auth needed\n");
break;
case AVncAuth:
vncrdbytes(v, chal, VncChalLen);
server = strdup(serveraddr);
p = strrchr(server, ':');
if(p)
*p = 0;
if(auth_respond(chal, VncChalLen, nil, 0, chal, VncChalLen, auth_getkey,
"proto=vnc role=client server=%s %s", server, keypattern) != VncChalLen){
/* BUG This is for drawterm users who don't start their own factotums */
readln("password: ", pw, sizeof(pw));
vncencrypt(chal, VncChalLen, pw);
memset(pw, 0, sizeof pw);
}
free(server);
vncwrbytes(v, chal, VncChalLen);
vncflush(v);
auth = vncrdlong(v);
switch(auth){
default:
werrstr("unknown server response 0x%lux", auth);
return -1;
case VncAuthFailed:
werrstr("server says authentication failed");
return -1;
case VncAuthTooMany:
werrstr("server says too many tries");
return -1;
case VncAuthOK:
break;
}
break;
}
return 0;
}
int
vncsrvauth(Vnc *v)
{
Chalstate *c;
AuthInfo *ai;
if((c = auth_challenge("proto=vnc role=server user=%q", getuser()))==nil)
sysfatal("vncchal: %r");
if(c->nchal != VncChalLen)
sysfatal("vncchal got %d bytes wanted %d", c->nchal, VncChalLen);
vncwrlong(v, AVncAuth);
vncwrbytes(v, c->chal, VncChalLen);
vncflush(v);
vncrdbytes(v, c->chal, VncChalLen);
c->resp = c->chal;
c->nresp = VncChalLen;
ai = auth_response(c);
auth_freechal(c);
if(ai == nil){
fprint(2, "vnc auth failed: server factotum: %r\n");
vncwrlong(v, VncAuthFailed);
vncflush(v);
return -1;
}
auth_freeAI(ai);
vncwrlong(v, VncAuthOK);
vncflush(v);
return 0;
}
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