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wpa: cleanup, pad eap-ttls/pap password, zero passwords and key material after use

--- a/sys/src/cmd/aux/wpa.c

+++ b/sys/src/cmd/aux/wpa.c

@@ -446,14 +446,22 @@

 factotumctl(char *fmt, ...)

 {

 	va_list list;

-	int r, fd;

+	int fd, r, n;

+	char *s;

-	if((fd = open("/mnt/factotum/ctl", OWRITE)) < 0)

-		return -1;

-	va_start(list, fmt);

-	r = vfprint(fd, fmt, list);

-	va_end(list);

-	close(fd);

+	r = -1;

+	if((fd = open("/mnt/factotum/ctl", OWRITE)) >= 0){

+		va_start(list, fmt);

+		s = vsmprint(fmt, list);

+		va_end(list);

+		if(s != nil){

+			n = strlen(s);

+			r = write(fd, s, n);

+			memset(s, 0, n);

+			free(s);

+		}

+		close(fd);

+	}

 	return r;

 }

@@ -462,7 +470,7 @@

 {

 	if(getessid() == nil)

 		return -1;

-	return factotumctl("key proto=wpapsk role=client essid=%q !password=%.32H\n", essid, pmk);

+	return factotumctl("key proto=wpapsk role=client essid=%q !password=%.*H\n", essid, PMKlen, pmk);

 }

 int

@@ -842,9 +850,10 @@

 		tls->sessionKeylen = 128;

 		tls->sessionKey = emalloc(tls->sessionKeylen);

 	}

-	if((fd = tlsClient(fd, tls)) < 0)

+	fd = tlsClient(fd, tls);

+	if(fd < 0)

 		sysfatal("tlsClient: %r");

-	if(label != nil){

+	if(label != nil && tls->sessionKey != nil){

 		/*

 		 * PMK is derived from MSK by taking the first 256 bits.

 		 * we store the PMK into factotum with setpmk() associated

@@ -852,7 +861,14 @@

 		 */

 		if(setpmk(tls->sessionKey) < 0)

 			sysfatal("setpmk: %r");

+

+		/* destroy session key */

+		memset(tls->sessionKey, 0, tls->sessionKeylen);

 	}

+	free(tls->cert);	/* TODO: check cert */

+	free(tls->sessionID);

+	free(tls->sessionKey);

+	free(tls);

 	return fd;

 }

@@ -874,12 +890,16 @@

 		eapreset(conn);

 		if(code == 4 || debug)

 			fprint(2, "%s: eap code %s\n", argv0, code == 3 ? "Success" : "NAK");

+		return;

 	default:

+	unhandled:

+		if(debug)

+			fprint(2, "unhandled: %.*H\n", datalen < 0 ? 0 : datalen, data);

 		return;

 	}

-

 	if(datalen < 1)

-		return;

+		goto unhandled;

+

 	tp = data[0];

 	switch(tp){

 	case 1:		/* Identity */

@@ -887,15 +907,15 @@

 		datalen = 1+strlen(user);

 		memmove(data+1, user, datalen-1);

 		eapresp(conn, 2, id, data, datalen);

-		break;

+		return;

 	case 2:

 		fprint(2, "%s: eap error: %.*s\n", argv0, datalen-1, (char*)data+1);

-		break;

+		return;

 	case 33:	/* EAP Extensions (AVP) */

 		if(debug)

 			fprint(2, "eap extension: %.*H\n", datalen, data);

 		eapresp(conn, 2, id, data, datalen);

-		break;

+		return;

 	case 26:	/* MS-CHAP-V2 */

 		data++;

 		datalen--;

@@ -936,6 +956,7 @@

 				*(--data) = tp, len++;

 				eapresp(conn, 2, id, data, len);

+				return;

 			}

 			break;

@@ -947,7 +968,7 @@

 					datalen < 4 ? 0 : datalen-4, (char*)data+4);

 			*(--data) = tp;

 			eapresp(conn, 2, id, data, 2);

-			break;

+			return;

 		}

 		break;

@@ -992,8 +1013,7 @@

 			if((pid = rfork(RFPROC|RFMEM)) == -1)

 				sysfatal("fork: %r");

 			if(pid == 0){

-				pid = getpid();

-				tunn->readerpid = pid;

+				tunn->readerpid = getpid();

 				tlsreader(tunn, conn);

 				if(conn->tunn == tunn)

 					conn->tunn = nil;

@@ -1001,7 +1021,7 @@

 				free(tunn);

 				exits(nil);

 			}

-			break;

+			return;

 		}

 		if(tunn == nil)

 			break;

@@ -1014,10 +1034,8 @@

 			data += 4;

 		}

 		data++;

-		if(datalen <= 0)

-			break;

-		if(write(tunn->fd, data, datalen) != datalen)

-			break;

+		if(datalen > 0)

+			write(tunn->fd, data, datalen);

 		if(frag || (tp == 25 && data[0] == 20)){	/* ack change cipher spec */

 			data -= 2;

 			data[0] = tp;

@@ -1024,33 +1042,30 @@

 			data[1] = 0;

 			eapresp(conn, 2, id, data, 2);

 		}

-		break;

+		return;

 	}

+	goto unhandled;

 }

 int

-avp(uchar *p, int code, void *val, int len)

+avp(uchar *p, int n, int code, void *val, int len, int pad)

 {

-	int n;

-

-	n = 4 + 4 + len;

-

-	*p++ = code >> 24;

-	*p++ = code >> 16;

-	*p++ = code >> 8;

-	*p++ = code;

-	*p++ = 2;

-

-	*p++ = n >> 16;

-	*p++ = n >> 8;

-	*p++ = n;

-

-	memmove(p, val, len);

-	p += len;

-

-	n = (n + 3) & ~3;

-	memset(p, 0, n - len);

-

+	len += 8;

+	if(len > n){

+		len = n - 8;

+		pad = 0;

+	}

+	p[0] = code >> 24;

+	p[1] = code >> 16;

+	p[2] = code >> 8;

+	p[3] = code;

+	p[4] = 2;

+	p[5] = len >> 16;

+	p[6] = len >> 8;

+	p[7] = len;

+	memmove(p+8, val, len-8);

+	n = (len + pad) & ~pad;

+	memset(p + len, 0, n - len);

 	return n;

 }

@@ -1070,21 +1085,19 @@

 	int n;

 	fd = tlswrap(fd, "ttls keying material");

-

-	/* we should really do challenge response here */

 	if((up = auth_getuserpasswd(nil, "proto=pass service=wpa essid=%q", essid)) == nil)

-		sysfatal("ttlsclient %d: no user/pass for essid=%q", getpid(), essid);

-

-	n = avp(buf, AvpUserName, up->user, strlen(up->user));

-	n += avp(buf+n, AvpUserPass, up->passwd, strlen(up->passwd));

+		sysfatal("auth_getuserpasswd: %r");

+	n = avp(buf, sizeof(buf), AvpUserName, up->user, strlen(up->user), 3);

+	n += avp(buf+n, sizeof(buf)-n, AvpUserPass, up->passwd, strlen(up->passwd), 15);

 	freeup(up);

-	if(write(fd, buf, n) != n)

-		sysfatal("ttlsclient write: %r");

+	write(fd, buf, n);

+	memset(buf, 0, n);

 }

 void

 peapwrite(Eapconn *conn, uchar *data, int len)

 {

+	assert(len >= 4);

 	fdwrite(conn, data + 4, len - 4);

 }