ref: 0f8168038af32828fcdc39575dea0e4de0c01122
dir: /sys/src/cmd/vnc/auth.c/
#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; }