1 #include "vnc.h" 2 #include <libsec.h> 3 #include <auth.h> 4 5 char *serveraddr; 6 7 /* 8 * Encrypt n bytes using the password 9 * as key, padded with zeros to 8 bytes. 10 */ 11 enum 12 { 13 VerLen = 12 14 }; 15 16 static char version[VerLen+1] = "RFB 003.003\n"; 17 18 static uchar tab[256]; 19 20 /* VNC reverses the bits of each byte before using as a des key */ 21 static void 22 mktab(void) 23 { 24 int i, j, k; 25 static int once; 26 27 if(once) 28 return; 29 once = 1; 30 31 for(i=0; i<256; i++){ 32 j=i; 33 tab[i] = 0; 34 for(k=0; k<8; k++){ 35 tab[i] = (tab[i]<<1) | (j&1); 36 j >>= 1; 37 } 38 } 39 } 40 41 static void 42 vncencrypt(uchar *buf, int n, char *pw) 43 { 44 uchar *p; 45 uchar key[9]; 46 DESstate s; 47 48 mktab(); 49 memset(key, 0, sizeof key); 50 strncpy((char*)key, pw, 8); 51 for(p=key; *p; p++) 52 *p = tab[*p]; 53 54 setupDESstate(&s, key, nil); 55 desECBencrypt(buf, n, &s); 56 } 57 58 static int 59 readln(char *prompt, char *line, int len) 60 { 61 char *p; 62 int fd, ctl, n, nr; 63 64 fd = open("/dev/cons", ORDWR); 65 if(fd < 0) 66 sysfatal("couldn't open cons"); 67 ctl = open("/dev/consctl", OWRITE); 68 if(ctl < 0) 69 sysfatal("couldn't open consctl"); 70 write(ctl, "rawon", 5); 71 fprint(fd, "%s", prompt); 72 nr = 0; 73 p = line; 74 for(;;){ 75 n = read(fd, p, 1); 76 if(n < 0){ 77 close(fd); 78 close(ctl); 79 return -1; 80 } 81 if(n == 0 || *p == '\n' || *p == '\r'){ 82 *p = '\0'; 83 write(fd, "\n", 1); 84 close(fd); 85 close(ctl); 86 return nr; 87 } 88 if(*p == '\b'){ 89 if(nr > 0){ 90 nr--; 91 p--; 92 } 93 }else if(*p == 21){ /* cntrl-u */ 94 fprint(fd, "\n%s", prompt); 95 nr = 0; 96 p = line; 97 }else{ 98 nr++; 99 p++; 100 } 101 if(nr == len){ 102 fprint(fd, "line too long; try again\n%s", prompt); 103 nr = 0; 104 p = line; 105 } 106 } 107 return -1; 108 } 109 110 int 111 vncsrvhandshake(Vnc *v) 112 { 113 char msg[VerLen+1]; 114 115 strecpy(msg, msg+sizeof msg, version); 116 if(verbose) 117 fprint(2, "server version: %s", msg); 118 vncwrbytes(v, msg, VerLen); 119 vncflush(v); 120 121 vncrdbytes(v, msg, VerLen); 122 if(verbose) 123 fprint(2, "client version: %s", msg); 124 return 0; 125 } 126 127 int 128 vnchandshake(Vnc *v) 129 { 130 char msg[VerLen+1]; 131 132 msg[VerLen] = 0; 133 vncrdbytes(v, msg, VerLen); 134 if(strncmp(msg, "RFB ", 4) != 0){ 135 werrstr("bad rfb version \"%s\"", msg); 136 return -1; 137 } 138 if(verbose) 139 fprint(2, "server version: %s", msg); 140 strcpy(msg, version); 141 vncwrbytes(v, msg, VerLen); 142 vncflush(v); 143 return 0; 144 } 145 146 int 147 vncauth(Vnc *v) 148 { 149 char pw[128], *reason; 150 uchar chal[VncChalLen]; 151 ulong auth; 152 char *p, *server; 153 154 auth = vncrdlong(v); 155 switch(auth){ 156 default: 157 werrstr("unknown auth type 0x%lux", auth); 158 if(verbose) 159 fprint(2, "unknown auth type 0x%lux", auth); 160 return -1; 161 162 case AFailed: 163 reason = vncrdstring(v); 164 werrstr("%s", reason); 165 if(verbose) 166 fprint(2, "auth failed: %s\n", reason); 167 return -1; 168 169 case ANoAuth: 170 if(verbose) 171 fprint(2, "no auth needed"); 172 break; 173 174 case AVncAuth: 175 vncrdbytes(v, chal, VncChalLen); 176 server = strdup(serveraddr); 177 p = strrchr(server, ':'); 178 if(p) 179 *p = 0; 180 if(auth_respond(chal, VncChalLen, nil, 0, chal, VncChalLen, auth_getkey, 181 "proto=vnc role=client server=%s", server) != VncChalLen){ 182 /* BUG This is for drawterm users who don't start their own factotums */ 183 readln("password: ", pw, sizeof(pw)); 184 vncencrypt(chal, VncChalLen, pw); 185 memset(pw, 0, sizeof pw); 186 } 187 free(server); 188 vncwrbytes(v, chal, VncChalLen); 189 vncflush(v); 190 191 auth = vncrdlong(v); 192 switch(auth){ 193 default: 194 werrstr("unknown server response 0x%lux", auth); 195 return -1; 196 case VncAuthFailed: 197 werrstr("server says authentication failed"); 198 return -1; 199 case VncAuthTooMany: 200 werrstr("server says too many tries"); 201 return -1; 202 case VncAuthOK: 203 break; 204 } 205 break; 206 } 207 return 0; 208 } 209 210 int 211 vncsrvauth(Vnc *v) 212 { 213 Chalstate *c; 214 AuthInfo *ai; 215 216 if((c = auth_challenge("proto=vnc role=server user=%q", getuser()))==nil) 217 sysfatal("vncchal: %r"); 218 if(c->nchal != VncChalLen) 219 sysfatal("vncchal got %d bytes wanted %d", c->nchal, VncChalLen); 220 vncwrlong(v, AVncAuth); 221 vncwrbytes(v, c->chal, VncChalLen); 222 vncflush(v); 223 224 vncrdbytes(v, c->chal, VncChalLen); 225 c->resp = c->chal; 226 c->nresp = VncChalLen; 227 ai = auth_response(c); 228 auth_freechal(c); 229 if(ai == nil){ 230 fprint(2, "vnc auth failed: server factotum: %r\n"); 231 vncwrlong(v, VncAuthFailed); 232 vncflush(v); 233 return -1; 234 } 235 auth_freeAI(ai); 236 vncwrlong(v, VncAuthOK); 237 vncflush(v); 238 239 return 0; 240 } 241 242