1 files changed, 353 insertions, 0 deletions
diff --git a/src/cmd/auth/factotum/p9sk1.c b/src/cmd/auth/factotum/p9sk1.c
new file mode 100644
index 00000000..92b055d0
--- /dev/null
+++ b/src/cmd/auth/factotum/p9sk1.c
@@ -0,0 +1,353 @@
+/*
+ * p9sk1, p9sk2 - Plan 9 secret (private) key authentication.
+ * p9sk2 is an incomplete flawed variant of p9sk1.
+ *
+ * Client protocol:
+ *	write challenge[challen]	(p9sk1 only)
+ *	read tickreq[tickreqlen]
+ *	write ticket[ticketlen]
+ *	read authenticator[authentlen]
+ *
+ * Server protocol:
+ * 	read challenge[challen]	(p9sk1 only)
+ *	write tickreq[tickreqlen]
+ *	read ticket[ticketlen]
+ *	write authenticator[authentlen]
+ */
+
+#include "std.h"
+#include "dat.h"
+
+extern Proto p9sk1, p9sk2;
+static int gettickets(Ticketreq*, char*, Key*);
+
+#define max(a, b) ((a) > (b) ? (a) : (b))
+enum
+{
+	MAXAUTH = max(TICKREQLEN, TICKETLEN+max(TICKETLEN, AUTHENTLEN))
+};
+
+static int
+p9skclient(Conv *c)
+{
+	char *user;
+	char cchal[CHALLEN];
+	uchar secret[8];
+	char buf[MAXAUTH];
+	int speakfor, ret;
+	Attr *a;
+	Authenticator au;
+	Key *k;
+	Ticket t;
+	Ticketreq tr;
+
+	ret = -1;
+	a = nil;
+	k = nil;
+
+	/* p9sk1: send client challenge */
+	if(c->proto == &p9sk1){
+		c->state = "write challenge";
+		memrandom(cchal, CHALLEN);
+		if(convwrite(c, cchal, CHALLEN) < 0)
+			goto out;
+	}
+
+	/* read ticket request */
+	c->state = "read tickreq";
+	if(convread(c, buf, TICKREQLEN) < 0)
+		goto out;
+	convM2TR(buf, &tr);
+
+	/* p9sk2: use server challenge as client challenge */
+	if(c->proto == &p9sk2)
+		memmove(cchal, tr.chal, CHALLEN);
+
+	/*
+	 * find a key.
+	 *
+	 * if the user is the factotum owner, any key will do.
+	 * if not, then if we have a speakfor key,
+	 * we will only vouch for the user's local identity.
+	 *
+	 * this logic is duplicated in p9any.c
+	 */
+	user = strfindattr(c->attr, "user");
+	a = delattr(copyattr(c->attr), "role");
+	a = addattr(a, "proto=p9sk1");
+
+	if(strcmp(c->sysuser, owner) == 0){
+		speakfor = 0;
+		a = addattr(a, "proto=p9sk1 user? dom=%q", tr.authdom);
+	}else if(user==nil || strcmp(c->sysuser, user)==0){
+		speakfor = 1;
+		a = delattr(a, "user");
+		a = addattr(a, "proto=p9sk1 user? dom=%q role=speakfor", tr.authdom);
+	}else{
+		werrstr("will not authenticate for %q as %q", c->sysuser, user);
+		goto out;
+	}
+
+	for(;;){
+		c->state = "find key";
+		k = keyfetch(c, "%A", a);
+		if(k == nil)
+			goto out;
+		
+		/* relay ticket request to auth server, get tickets */
+		strcpy(tr.hostid, strfindattr(k->attr, "user"));
+		if(speakfor)
+			strcpy(tr.uid, c->sysuser);
+		else
+			strcpy(tr.uid, tr.hostid);
+
+		c->state = "get tickets";
+		if(gettickets(&tr, buf, k) < 0)
+			goto out;
+
+		convM2T(buf, &t, k->priv);
+		if(t.num == AuthTc)
+			break;
+
+		/* we don't agree with the auth server about the key; try again */
+		c->state = "replace key";
+		if((k = keyreplace(c, k, "key mismatch with auth server")) == nil){
+			werrstr("key mismatch with auth server");
+			goto out;
+		}
+	}
+
+	/* send second ticket and authenticator to server */
+	c->state = "write ticket+auth";
+	memmove(buf, buf+TICKETLEN, TICKETLEN);
+	au.num = AuthAc;
+	memmove(au.chal, tr.chal, CHALLEN);
+	au.id = 0;
+	convA2M(&au, buf+TICKETLEN, t.key);
+	if(convwrite(c, buf, TICKETLEN+AUTHENTLEN) < 0)
+		goto out;
+
+	/* read authenticator from server */
+	c->state = "read auth";
+	if(convread(c, buf, AUTHENTLEN) < 0)
+		goto out;
+	convM2A(buf, &au, t.key);
+	if(au.num != AuthAs || memcmp(au.chal, cchal, CHALLEN) != 0 || au.id != 0){
+		werrstr("server lies through his teeth");
+		goto out;
+	}
+
+	/* success */
+	c->attr = addcap(c->attr, c->sysuser, &t);
+	des56to64((uchar*)t.key, secret);
+	c->attr = addattr(c->attr, "secret=%.8H", secret);
+	ret = 0;
+
+out:
+	freeattr(a);
+	keyclose(k);
+	return ret;
+}
+
+static int
+p9skserver(Conv *c)
+{
+	char cchal[CHALLEN], buf[MAXAUTH];
+	uchar secret[8];
+	int ret;
+	Attr *a;
+	Authenticator au;
+	Key *k;
+	Ticketreq tr;
+	Ticket t;
+
+	ret = -1;
+
+	a = addattr(copyattr(c->attr), "user? dom?");
+	a = addattr(a, "user? dom? proto=p9sk1");
+	if((k = keyfetch(c, "%A", a)) == nil)
+		goto out;
+
+	/* p9sk1: read client challenge */
+	if(c->proto == &p9sk1){
+		if(convread(c, cchal, CHALLEN) < 0)
+			goto out;
+	}
+
+	/* send ticket request */
+	memset(&tr, 0, sizeof tr);
+	tr.type = AuthTreq;
+	strcpy(tr.authid, strfindattr(k->attr, "user"));
+	strcpy(tr.authdom, strfindattr(k->attr, "dom"));
+	memrandom(tr.chal, sizeof tr.chal);
+	convTR2M(&tr, buf);
+	if(convwrite(c, buf, TICKREQLEN) < 0)
+		goto out;
+
+	/* p9sk2: use server challenge as client challenge */
+	if(c->proto == &p9sk2)
+		memmove(cchal, tr.chal, sizeof tr.chal);
+
+	/* read ticket+authenticator */
+	if(convread(c, buf, TICKETLEN+AUTHENTLEN) < 0)
+		goto out;
+
+	convM2T(buf, &t, k->priv);
+	if(t.num != AuthTs || memcmp(t.chal, tr.chal, CHALLEN) != 0){
+		/* BUG badkey */
+		werrstr("key mismatch with auth server");
+		goto out;
+	}
+
+	convM2A(buf+TICKETLEN, &au, t.key);
+	if(au.num != AuthAc || memcmp(au.chal, tr.chal, CHALLEN) != 0 || au.id != 0){
+		werrstr("client lies through his teeth");
+		goto out;
+	}
+
+	/* send authenticator */
+	au.num = AuthAs;
+	memmove(au.chal, cchal, CHALLEN);
+	convA2M(&au, buf, t.key);
+	if(convwrite(c, buf, AUTHENTLEN) < 0)
+		goto out;
+
+	/* success */
+	c->attr = addcap(c->attr, c->sysuser, &t);
+	des56to64((uchar*)t.key, secret);
+	c->attr = addattr(c->attr, "secret=%.8H", secret);
+	ret = 0;
+
+out:
+	freeattr(a);
+	keyclose(k);
+	return ret;
+}
+
+int
+_asgetticket(int fd, char *trbuf, char *tbuf)
+{
+	if(write(fd, trbuf, TICKREQLEN) < 0){
+		close(fd);
+		return -1;
+	}
+	return _asrdresp(fd, tbuf, 2*TICKETLEN);
+}
+static int
+getastickets(Ticketreq *tr, char *buf)
+{
+	int asfd;
+	int ret;
+
+	if((asfd = xioauthdial(nil, tr->authdom)) < 0)
+		return -1;
+	convTR2M(tr, buf);
+	ret = xioasgetticket(asfd, buf, buf);
+	xioclose(asfd);
+	return ret;
+}
+
+static int
+mktickets(Ticketreq *tr, char *buf, Key *k)
+{
+	Ticket t;
+
+	if(strcmp(tr->authid, tr->hostid) != 0)
+		return -1;
+
+	memset(&t, 0, sizeof t);
+	memmove(t.chal, tr->chal, CHALLEN);
+	strcpy(t.cuid, tr->uid);
+	strcpy(t.suid, tr->uid);
+	memrandom(t.key, DESKEYLEN);
+	t.num = AuthTc;
+	convT2M(&t, buf, k->priv);
+	t.num = AuthTs;
+	convT2M(&t, buf+TICKETLEN, k->priv);
+	return 0;
+}
+
+static int
+gettickets(Ticketreq *tr, char *buf, Key *k)
+{
+	if(getastickets(tr, buf) == 0)
+		return 0;
+	if(mktickets(tr, buf, k) == 0)
+		return 0;
+	werrstr("gettickets: %r");
+	return -1;
+}
+
+static int
+p9sk1check(Key *k)
+{
+	char *user, *dom, *pass;
+	Ticketreq tr;
+
+	user = strfindattr(k->attr, "user");
+	dom = strfindattr(k->attr, "dom");
+	if(user==nil || dom==nil){
+		werrstr("need user and dom attributes");
+		return -1;
+	}
+	if(strlen(user) >= sizeof tr.authid){
+		werrstr("user name too long");
+		return -1;
+	}
+	if(strlen(dom) >= sizeof tr.authdom){
+		werrstr("auth dom name too long");
+		return -1;
+	}
+
+	k->priv = emalloc(DESKEYLEN);
+	if(pass = strfindattr(k->privattr, "!password"))
+		passtokey(k->priv, pass);
+	else if(pass = strfindattr(k->privattr, "!hex")){
+		if(hexparse(pass, k->priv, 7) < 0){
+			werrstr("malformed !hex key data");
+			return -1;
+		}
+	}else{
+		werrstr("need !password or !hex attribute");
+		return -1;
+	}
+
+	return 0;
+}
+
+static void
+p9sk1close(Key *k)
+{
+	free(k->priv);
+	k->priv = nil;
+}
+
+static Role
+p9sk1roles[] = 
+{
+	"client",	p9skclient,
+	"server",	p9skserver,
+	0
+};
+
+static Role
+p9sk2roles[] = 
+{
+	"client",	p9skclient,
+	"server",	p9skserver,
+	0
+};
+
+Proto p9sk1 = {
+.name=		"p9sk1",
+.roles=		p9sk1roles,
+.checkkey=	p9sk1check,
+.closekey=	p9sk1close,
+.keyprompt=	"user? dom? !password?",
+};
+
+Proto p9sk2 = {
+.name=		"p9sk2",
+.roles=		p9sk2roles,
+};
+