1 files changed, 545 insertions, 0 deletions
diff --git a/src/cmd/auth/factotum/p9cr.c b/src/cmd/auth/factotum/p9cr.c
new file mode 100644
index 00000000..7f53e447
--- /dev/null
+++ b/src/cmd/auth/factotum/p9cr.c
@@ -0,0 +1,545 @@
+/*
+ * p9cr, vnc - one-sided challenge/response authentication
+ *
+ * Protocol:
+ *
+ *	C -> S: user
+ *	S -> C: challenge
+ *	C -> S: response
+ *	S -> C: ok or bad
+ *
+ * Note that this is the protocol between factotum and the local
+ * program, not between the two factotums.  The information 
+ * exchanged here is wrapped in other protocols by the local
+ * programs.
+ */
+
+#include "std.h"
+#include "dat.h"
+
+static int
+p9crcheck(Key *k)
+{
+	if(!strfindattr(k->attr, "user") || !strfindattr(k->privattr, "!password")){
+		werrstr("need user and !password attributes");
+		return -1;
+	}
+	return 0;
+}
+
+static int
+p9crclient(Conv *c)
+{
+	char *chal, *pw, *res, *user;
+	int astype, nchal, npw, ntry, ret;
+	uchar resp[MD5dlen];
+	Attr *attr;
+	DigestState *ds;
+	Key *k;
+	
+	chal = nil;
+	k = nil;
+	res = nil;
+	ret = -1;
+	attr = c->attr;
+
+	if(c->proto == &p9cr){
+		astype = AuthChal;
+		challen = NETCHLEN;
+	}else if(c->proto == &vnc){
+		astype = AuthVnc;
+		challen = MAXCHAL;
+	}else{
+		werrstr("bad proto");
+		goto out;
+	}
+
+	c->state = "find key";
+	k = keyfetch(c, "%A %s", attr, c->proto->keyprompt);
+	if(k == nil)
+		goto out;
+
+	for(ntry=1;; ntry++){
+		if(c->attr != attr)
+			freeattr(c->attr);
+		c->attr = addattrs(copyattr(attr), k->attr);
+		if((pw = strfindattr(k->privattr, "!password")) == nil){
+			werrstr("key has no !password (cannot happen)");
+			goto out;
+		}
+		npw = strlen(pw);
+
+		if((user = strfindattr(k->attr, "user")) == nil){
+			werrstr("key has no user (cannot happen)");
+			goto out;
+		}
+
+		if(convprint(c, "%s", user) < 0)
+			goto out;
+
+		if(convreadm(c, &chal) < 0)
+			goto out;
+
+		if((nresp = (*response)(chal, resp)) < 0)
+			goto out;
+
+		if(convwrite(c, resp, nresp) < 0)
+			goto out;
+
+		if(convreadm(c, &res) < 0)
+			goto out;
+
+		if(strcmp(res, "ok") == 0)
+			break;
+
+		if((k = keyreplace(c, k, "%s", res)) == nil){
+			c->state = "auth failed";
+			werrstr("%s", res);
+			goto out;
+		}
+	}
+
+	werrstr("succeeded");
+	ret = 0;
+
+out:
+	keyclose(k);
+	free(chal);
+	if(c->attr != attr)
+		freeattr(attr);
+	return ret;
+}
+
+static int
+p9crserver(Conv *c)
+{
+	char chal[APOPCHALLEN], *user, *resp;
+	ServerState s;
+	int astype, ret;
+	Attr *a;
+
+	ret = -1;
+	user = nil;
+	resp = nil;
+	memset(&s, 0, sizeof s);
+	s.asfd = -1;
+
+	if(c->proto == &apop)
+		astype = AuthApop;
+	else if(c->proto == &cram)
+		astype = AuthCram;
+	else{
+		werrstr("bad proto");
+		goto out;
+	}
+
+	c->state = "find key";
+	if((s.k = plan9authkey(c->attr)) == nil)
+		goto out;
+
+	a = copyattr(s.k->attr);
+	a = delattr(a, "proto");
+	c->attr = addattrs(c->attr, a);
+	freeattr(a);
+
+	c->state = "authdial";
+	s.hostid = strfindattr(s.k->attr, "user");
+	s.dom = strfindattr(s.k->attr, "dom");
+	if((s.asfd = xioauthdial(nil, s.dom)) < 0){
+		werrstr("authdial %s: %r", s.dom);
+		goto out;
+	}
+
+	c->state = "authchal";
+	if(p9crchal(&s, astype, chal) < 0)
+		goto out;
+
+	c->state = "write challenge";
+	if(convprint(c, "%s", chal) < 0)
+		goto out;
+
+	for(;;){
+		c->state = "read user";
+		if(convreadm(c, &user) < 0)
+			goto out;
+
+		c->state = "read response";
+		if(convreadm(c, &resp) < 0)
+			goto out;
+
+		c->state = "authwrite";
+		switch(apopresp(&s, user, resp)){
+		case -1:
+			goto out;
+		case 0:
+			c->state = "write status";
+			if(convprint(c, "bad authentication failed") < 0)
+				goto out;
+			break;
+		case 1:
+			c->state = "write status";
+			if(convprint(c, "ok") < 0)
+				goto out;
+			goto ok;
+		}
+		free(user);
+		free(resp);
+		user = nil;
+		resp = nil;
+	}
+
+ok:
+	ret = 0;
+	c->attr = addcap(c->attr, c->sysuser, &s.t);
+
+out:
+	keyclose(s.k);
+	free(user);
+	free(resp);
+//	xioclose(s.asfd);
+	return ret;
+}
+
+enum
+{
+	MAXCHAL = 64,
+};
+
+typedef struct State State;
+struct State
+{
+	Key	*key;
+	int	astype;
+	int	asfd;
+	Ticket	t;
+	Ticketreq tr;
+	char	chal[MAXCHAL];
+	int	challen;
+	char	resp[MAXCHAL];
+	int	resplen;
+};
+
+enum
+{
+	CNeedChal,
+	CHaveResp,
+
+	SHaveChal,
+	SNeedResp,
+
+	Maxphase,
+};
+
+static char *phasenames[Maxphase] =
+{
+[CNeedChal]	"CNeedChal",
+[CHaveResp]	"CHaveResp",
+
+[SHaveChal]	"SHaveChal",
+[SNeedResp]	"SNeedResp",
+};
+
+static void
+p9crclose(Fsstate *fss)
+{
+	State *s;
+
+	s = fss->ps;
+	if(s->asfd >= 0){
+		close(s->asfd);
+		s->asfd = -1;
+	}
+	free(s);
+}
+
+static int getchal(State*, Fsstate*);
+
+static int
+p9crinit(Proto *p, Fsstate *fss)
+{
+	int iscli, ret;
+	char *user;
+	State *s;
+	Attr *attr;
+
+	if((iscli = isclient(_str_findattr(fss->attr, "role"))) < 0)
+		return failure(fss, nil);
+	
+	s = emalloc(sizeof(*s));
+	s->asfd = -1;
+	if(p == &p9cr){
+		s->astype = AuthChal;
+		s->challen = NETCHLEN;
+	}else if(p == &vnc){
+		s->astype = AuthVNC;
+		s->challen = Maxchal;
+	}else
+		abort();
+
+	if(iscli){
+		fss->phase = CNeedChal;
+		if(p == &p9cr)
+			attr = setattr(_copyattr(fss->attr), "proto=p9sk1");
+		else
+			attr = nil;
+		ret = findkey(&s->key, fss, Kuser, 0, attr ? attr : fss->attr,
+			"role=client %s", p->keyprompt);
+		_freeattr(attr);
+		if(ret != RpcOk){
+			free(s);
+			return ret;
+		}
+		fss->ps = s;
+	}else{
+		if((ret = findp9authkey(&s->key, fss)) != RpcOk){
+			free(s);
+			return ret;
+		}
+		if((user = _str_findattr(fss->attr, "user")) == nil){
+			free(s);
+			return failure(fss, "no user name specified in start msg");
+		}
+		if(strlen(user) >= sizeof s->tr.uid){
+			free(s);
+			return failure(fss, "user name too long");
+		}
+		fss->ps = s;
+		strcpy(s->tr.uid, user);
+		ret = getchal(s, fss);
+		if(ret != RpcOk){
+			p9crclose(fss);	/* frees s */
+			fss->ps = nil;
+		}
+	}
+	fss->phasename = phasenames;
+	fss->maxphase = Maxphase;
+	return ret;
+}
+
+static int
+p9crread(Fsstate *fss, void *va, uint *n)
+{
+	int m;
+	State *s;
+
+	s = fss->ps;
+	switch(fss->phase){
+	default:
+		return phaseerror(fss, "read");
+
+	case CHaveResp:
+		if(s->resplen < *n)
+			*n = s->resplen;
+		memmove(va, s->resp, *n);
+		fss->phase = Established;
+		return RpcOk;
+
+	case SHaveChal:
+		if(s->astype == AuthChal)
+			m = strlen(s->chal);	/* ascii string */
+		else
+			m = s->challen;		/* fixed length binary */
+		if(m > *n)
+			return toosmall(fss, m);
+		*n = m;
+		memmove(va, s->chal, m);
+		fss->phase = SNeedResp;
+		return RpcOk;
+	}
+}
+
+static int
+p9response(Fsstate *fss, State *s)
+{
+	char key[DESKEYLEN];
+	uchar buf[8];
+	ulong chal;
+	char *pw;
+
+	pw = _str_findattr(s->key->privattr, "!password");
+	if(pw == nil)
+		return failure(fss, "vncresponse cannot happen");
+	passtokey(key, pw);
+	memset(buf, 0, 8);
+	sprint((char*)buf, "%d", atoi(s->chal));
+	if(encrypt(key, buf, 8) < 0)
+		return failure(fss, "can't encrypt response");
+	chal = (buf[0]<<24)+(buf[1]<<16)+(buf[2]<<8)+buf[3];
+	s->resplen = snprint(s->resp, sizeof s->resp, "%.8lux", chal);
+	return RpcOk;
+}
+
+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 int
+vncaddkey(Key *k)
+{
+	uchar *p;
+	char *s;
+
+	k->priv = emalloc(8+1);
+	if(s = _str_findattr(k->privattr, "!password")){
+		mktab();
+		memset(k->priv, 0, 8+1);
+		strncpy((char*)k->priv, s, 8);
+		for(p=k->priv; *p; p++)
+			*p = tab[*p];
+	}else{
+		werrstr("no key data");
+		return -1;
+	}
+	return replacekey(k);
+}
+
+static void
+vncclosekey(Key *k)
+{
+	free(k->priv);
+}
+
+static int
+vncresponse(Fsstate*, State *s)
+{
+	DESstate des;
+
+	memmove(s->resp, s->chal, sizeof s->chal);
+	setupDESstate(&des, s->key->priv, nil);
+	desECBencrypt((uchar*)s->resp, s->challen, &des);
+	s->resplen = s->challen;
+	return RpcOk;
+}
+
+static int
+p9crwrite(Fsstate *fss, void *va, uint n)
+{
+	char tbuf[TICKETLEN+AUTHENTLEN];
+	State *s;
+	char *data = va;
+	Authenticator a;
+	char resp[Maxchal];
+	int ret;
+
+	s = fss->ps;
+	switch(fss->phase){
+	default:
+		return phaseerror(fss, "write");
+
+	case CNeedChal:
+		if(n >= sizeof(s->chal))
+			return failure(fss, Ebadarg);
+		memset(s->chal, 0, sizeof s->chal);
+		memmove(s->chal, data, n);
+		s->challen = n;
+
+		if(s->astype == AuthChal)
+			ret = p9response(fss, s);
+		else
+			ret = vncresponse(fss, s);
+		if(ret != RpcOk)
+			return ret;
+		fss->phase = CHaveResp;
+		return RpcOk;
+
+	case SNeedResp:
+		/* send response to auth server and get ticket */
+		if(n > sizeof(resp))
+			return failure(fss, Ebadarg);
+		memset(resp, 0, sizeof resp);
+		memmove(resp, data, n);
+		if(write(s->asfd, resp, s->challen) != s->challen)
+			return failure(fss, Easproto);
+
+		/* get ticket plus authenticator from auth server */
+		if(_asrdresp(s->asfd, tbuf, TICKETLEN+AUTHENTLEN) < 0)
+			return failure(fss, nil);
+
+		/* check ticket */
+		convM2T(tbuf, &s->t, s->key->priv);
+		if(s->t.num != AuthTs
+		|| memcmp(s->t.chal, s->tr.chal, sizeof(s->t.chal)) != 0)
+			return failure(fss, Easproto);
+		convM2A(tbuf+TICKETLEN, &a, s->t.key);
+		if(a.num != AuthAc
+		|| memcmp(a.chal, s->tr.chal, sizeof(a.chal)) != 0
+		|| a.id != 0)
+			return failure(fss, Easproto);
+
+		fss->haveai = 1;
+		fss->ai.cuid = s->t.cuid;
+		fss->ai.suid = s->t.suid;
+		fss->ai.nsecret = 0;
+		fss->ai.secret = nil;
+		fss->phase = Established;
+		return RpcOk;
+	}
+}
+
+static int
+getchal(State *s, Fsstate *fss)
+{
+	char trbuf[TICKREQLEN];
+	int n;
+
+	safecpy(s->tr.hostid, _str_findattr(s->key->attr, "user"), sizeof(s->tr.hostid));
+	safecpy(s->tr.authdom, _str_findattr(s->key->attr, "dom"), sizeof(s->tr.authdom));
+	s->tr.type = s->astype;
+	convTR2M(&s->tr, trbuf);
+
+	/* get challenge from auth server */
+	s->asfd = _authdial(nil, _str_findattr(s->key->attr, "dom"));
+	if(s->asfd < 0)
+		return failure(fss, Easproto);
+	if(write(s->asfd, trbuf, TICKREQLEN) != TICKREQLEN)
+		return failure(fss, Easproto);
+	n = _asrdresp(s->asfd, s->chal, s->challen);
+	if(n <= 0){
+		if(n == 0)
+			werrstr("_asrdresp short read");
+		return failure(fss, nil);
+	}
+	s->challen = n;
+	fss->phase = SHaveChal;
+	return RpcOk;
+}
+
+Proto p9cr =
+{
+.name=		"p9cr",
+.init=		p9crinit,
+.write=		p9crwrite,
+.read=		p9crread,
+.close=		p9crclose,
+.keyprompt=	"user? !password?",
+};
+
+Proto vnc =
+{
+.name=		"vnc",
+.init=		p9crinit,
+.write=		p9crwrite,
+.read=		p9crread,
+.close=		p9crclose,
+.keyprompt=	"!password?",
+.addkey=	vncaddkey,
+};