libauthsrv: generalize ticket service, not hardcoding ticket format and DES encryption

this is in preparation for replacing DES ticket encryption with
something better. but first need to make the code stop making
assumptions.

the wire encoding of the Ticket might be variable length
with TICKETLEN just giving an upper bound. the details will be
handled by libauthsrv _asgetticket() and _asgetresp() funciotns.

the Authenticator and Passwordreq structures are encrypted
with the random ticket key. The encryption schmeme will depend
on the Ticket format used, so we pass the Ticket* structure
instead of the DES key.

introduce Authkey structure that will hold all the required
cryptographic keys instead of passing DES key.

12 files changed, 88 insertions, 46 deletions

diff --git a/sys/src/libauthsrv/_asgetticket.c b/sys/src/libauthsrv/_asgetticket.c
index 46283bd5a..11a344621 100644
--- a/sys/src/libauthsrv/_asgetticket.c
+++ b/sys/src/libauthsrv/_asgetticket.c
@@ -5,11 +5,13 @@
 static char *pbmsg = "AS protocol botch";
 
 int
-_asgetticket(int fd, char *trbuf, char *tbuf)
+_asgetticket(int fd, Ticketreq *tr, char *tbuf, int tbuflen)
 {
-	if(write(fd, trbuf, TICKREQLEN) < 0){
+	if(_asrequest(fd, tr) < 0){
 		werrstr(pbmsg);
 		return -1;
 	}
-	return _asrdresp(fd, tbuf, 2*TICKETLEN);
+	if(tbuflen > 2*TICKETLEN)
+		tbuflen = 2*TICKETLEN;
+	return _asrdresp(fd, tbuf, tbuflen);
 }
diff --git a/sys/src/libauthsrv/convA2M.c b/sys/src/libauthsrv/convA2M.c
index 2799cbf56..d285ad770 100644
--- a/sys/src/libauthsrv/convA2M.c
+++ b/sys/src/libauthsrv/convA2M.c
@@ -9,17 +9,19 @@
 #define	STRING(x,n)	memmove(p, f->x, n); p += n
 
 int
-convA2M(Authenticator *f, char *ap, char *key)
+convA2M(Authenticator *f, char *ap, int n, Ticket *t)
 {
-	int n;
 	uchar *p;
 
+	if(n < AUTHENTLEN)
+		return 0;
+
 	p = (uchar*)ap;
 	CHAR(num);
 	STRING(chal, CHALLEN);
 	LONG(id);
 	n = p - (uchar*)ap;
-	if(key)
-		encrypt(key, ap, n);
+	if(t)
+		encrypt(t->key, ap, n);
 	return n;
 }
diff --git a/sys/src/libauthsrv/convM2A.c b/sys/src/libauthsrv/convM2A.c
index 3d58f9b59..b0d6712ca 100644
--- a/sys/src/libauthsrv/convM2A.c
+++ b/sys/src/libauthsrv/convM2A.c
@@ -8,16 +8,24 @@
 #define	LONG(x)		VLONG(f->x)
 #define	STRING(x,n)	memmove(f->x, p, n); p += n
 
-void
-convM2A(char *ap, Authenticator *f, char *key)
+int
+convM2A(char *ap, int n, Authenticator *f, Ticket *t)
 {
-	uchar *p;
+	uchar *p, buf[AUTHENTLEN];
 
-	if(key)
-		decrypt(key, ap, AUTHENTLEN);
+	memset(f, 0, sizeof(Authenticator));
+	if(n < AUTHENTLEN)
+		return -AUTHENTLEN;
+
+	if(t) {
+		memmove(buf, ap, AUTHENTLEN);
+		ap = (char*)buf;
+		decrypt(t->key, ap, AUTHENTLEN);
+	}
 	p = (uchar*)ap;
 	CHAR(num);
 	STRING(chal, CHALLEN);
 	LONG(id);
-	USED(p);
+	n = p - (uchar*)ap;
+	return n;
 }
diff --git a/sys/src/libauthsrv/convM2PR.c b/sys/src/libauthsrv/convM2PR.c
index 21df5b508..c7bd4974d 100644
--- a/sys/src/libauthsrv/convM2PR.c
+++ b/sys/src/libauthsrv/convM2PR.c
@@ -8,14 +8,21 @@
 #define	LONG(x)		VLONG(f->x)
 #define	STRING(x,n)	memmove(f->x, p, n); p += n
 
-void
-convM2PR(char *ap, Passwordreq *f, char *key)
+int
+convM2PR(char *ap, int n, Passwordreq *f, Ticket *t)
 {
-	uchar *p;
+	uchar *p, buf[PASSREQLEN];
 
+	memset(f, 0, sizeof(Passwordreq));
+	if(n < PASSREQLEN)
+		return -PASSREQLEN;
+
+	if(t){
+		memmove(buf, ap, PASSREQLEN);
+		ap = (char*)buf;
+		decrypt(t->key, ap, PASSREQLEN);
+	}
 	p = (uchar*)ap;
-	if(key)
-		decrypt(key, ap, PASSREQLEN);
 	CHAR(num);
 	STRING(old, ANAMELEN);
 	f->old[ANAMELEN-1] = 0;
@@ -24,5 +31,6 @@ convM2PR(char *ap, Passwordreq *f, char *key)
 	CHAR(changesecret);
 	STRING(secret, SECRETLEN);
 	f->secret[SECRETLEN-1] = 0;
-	USED(p);
+	n = p - (uchar*)ap;
+	return n;
 }
diff --git a/sys/src/libauthsrv/convM2T.c b/sys/src/libauthsrv/convM2T.c
index 372825a87..425ebefdd 100644
--- a/sys/src/libauthsrv/convM2T.c
+++ b/sys/src/libauthsrv/convM2T.c
@@ -8,13 +8,20 @@
 #define	LONG(x)		VLONG(f->x)
 #define	STRING(x,n)	memmove(f->x, p, n); p += n
 
-void
-convM2T(char *ap, Ticket *f, char *key)
+int
+convM2T(char *ap, int n, Ticket *f, Authkey *key)
 {
-	uchar *p;
+	uchar *p, buf[TICKETLEN];
 
-	if(key)
-		decrypt(key, ap, TICKETLEN);
+	memset(f, 0, sizeof(Ticket));
+	if(n < TICKETLEN)
+		return -TICKETLEN;
+
+	if(key){
+		memmove(buf, ap, TICKETLEN);
+		ap = (char*)buf;
+		decrypt(key->des, ap, TICKETLEN);
+	}
 	p = (uchar*)ap;
 	CHAR(num);
 	STRING(chal, CHALLEN);
@@ -23,6 +30,6 @@ convM2T(char *ap, Ticket *f, char *key)
 	STRING(suid, ANAMELEN);
 	f->suid[ANAMELEN-1] = 0;
 	STRING(key, DESKEYLEN);
-	USED(p);
+	n = p - (uchar*)ap;
+	return n;
 }
-
diff --git a/sys/src/libauthsrv/convM2TR.c b/sys/src/libauthsrv/convM2TR.c
index ffad75c77..d6491705b 100644
--- a/sys/src/libauthsrv/convM2TR.c
+++ b/sys/src/libauthsrv/convM2TR.c
@@ -8,11 +8,15 @@
 #define	LONG(x)		VLONG(f->x)
 #define	STRING(x,n)	memmove(f->x, p, n); p += n
 
-void
-convM2TR(char *ap, Ticketreq *f)
+int
+convM2TR(char *ap, int n, Ticketreq *f)
 {
 	uchar *p;
 
+	memset(f, 0, sizeof(Ticketreq));
+	if(n < TICKREQLEN)
+		return -TICKREQLEN;
+
 	p = (uchar*)ap;
 	CHAR(type);
 	STRING(authid, ANAMELEN);
@@ -24,5 +28,6 @@ convM2TR(char *ap, Ticketreq *f)
 	f->hostid[ANAMELEN-1] = 0;
 	STRING(uid, ANAMELEN);
 	f->uid[ANAMELEN-1] = 0;
-	USED(p);
+	n = p - (uchar*)ap;
+	return n;
 }
diff --git a/sys/src/libauthsrv/convPR2M.c b/sys/src/libauthsrv/convPR2M.c
index 8b2422f1b..d5c0ee7ac 100644
--- a/sys/src/libauthsrv/convPR2M.c
+++ b/sys/src/libauthsrv/convPR2M.c
@@ -9,11 +9,13 @@
 #define	STRING(x,n)	memmove(p, f->x, n); p += n
 
 int
-convPR2M(Passwordreq *f, char *ap, char *key)
+convPR2M(Passwordreq *f, char *ap, int n, Ticket *t)
 {
-	int n;
 	uchar *p;
 
+	if(n < PASSREQLEN)
+		return 0;
+
 	p = (uchar*)ap;
 	CHAR(num);
 	STRING(old, ANAMELEN);
@@ -21,8 +23,8 @@ convPR2M(Passwordreq *f, char *ap, char *key)
 	CHAR(changesecret);
 	STRING(secret, SECRETLEN);
 	n = p - (uchar*)ap;
-	if(key)
-		encrypt(key, ap, n);
+	if(t)
+		encrypt(t->key, ap, n);
 	return n;
 }
 
diff --git a/sys/src/libauthsrv/convT2M.c b/sys/src/libauthsrv/convT2M.c
index 810ba5c67..77edcef1f 100644
--- a/sys/src/libauthsrv/convT2M.c
+++ b/sys/src/libauthsrv/convT2M.c
@@ -9,11 +9,13 @@
 #define	STRING(x,n)	memmove(p, f->x, n); p += n
 
 int
-convT2M(Ticket *f, char *ap, char *key)
+convT2M(Ticket *f, char *ap, int n, Authkey *key)
 {
-	int n;
 	uchar *p;
 
+	if(n < TICKETLEN)
+		return 0;
+
 	p = (uchar*)ap;
 	CHAR(num);
 	STRING(chal, CHALLEN);
@@ -22,6 +24,6 @@ convT2M(Ticket *f, char *ap, char *key)
 	STRING(key, DESKEYLEN);
 	n = p - (uchar*)ap;
 	if(key)
-		encrypt(key, ap, n);
+		encrypt(key->des, ap, n);
 	return n;
 }
diff --git a/sys/src/libauthsrv/convTR2M.c b/sys/src/libauthsrv/convTR2M.c
index 3a7610a71..0bbe9cb6f 100644
--- a/sys/src/libauthsrv/convTR2M.c
+++ b/sys/src/libauthsrv/convTR2M.c
@@ -9,11 +9,13 @@
 #define	STRING(x,n)	memmove(p, f->x, n); p += n
 
 int
-convTR2M(Ticketreq *f, char *ap)
+convTR2M(Ticketreq *f, char *ap, int n)
 {
-	int n;
 	uchar *p;
 
+	if(n < TICKREQLEN)
+		return 0;
+
 	p = (uchar*)ap;
 	CHAR(type);
 	STRING(authid, 28);	/* BUG */
@@ -24,4 +26,3 @@ convTR2M(Ticketreq *f, char *ap)
 	n = p - (uchar*)ap;
 	return n;
 }
-
diff --git a/sys/src/libauthsrv/mkfile b/sys/src/libauthsrv/mkfile
index b3e59b670..d46fa52d7 100644
--- a/sys/src/libauthsrv/mkfile
+++ b/sys/src/libauthsrv/mkfile
@@ -3,6 +3,8 @@
 LIB=/$objtype/lib/libauthsrv.a
 OFILES=\
 	_asgetticket.$O\
+	_asgetresp.$O\
+	_asrequest.$O\
 	_asrdresp.$O\
 	authdial.$O\
 	convA2M.$O\
diff --git a/sys/src/libauthsrv/passtokey.c b/sys/src/libauthsrv/passtokey.c
index cde9a2422..44963cec6 100644
--- a/sys/src/libauthsrv/passtokey.c
+++ b/sys/src/libauthsrv/passtokey.c
@@ -3,7 +3,7 @@
 #include <authsrv.h>
 
 int
-passtokey(char *key, char *p)
+passtokey(Authkey *key, char *p)
 {
 	uchar buf[ANAMELEN], *t;
 	int i, n;
@@ -15,10 +15,10 @@ passtokey(char *key, char *p)
 	t = buf;
 	strncpy((char*)t, p, n);
 	t[n] = 0;
-	memset(key, 0, DESKEYLEN);
+	memset(key, 0, sizeof(Authkey));
 	for(;;){
 		for(i = 0; i < DESKEYLEN; i++)
-			key[i] = (t[i] >> i) + (t[i+1] << (8 - (i+1)));
+			key->des[i] = (t[i] >> i) + (t[i+1] << (8 - (i+1)));
 		if(n <= 8)
 			return 1;
 		n -= 8;
@@ -27,6 +27,6 @@ passtokey(char *key, char *p)
 			t -= 8 - n;
 			n = 8;
 		}
-		encrypt(key, t, 8);
+		encrypt(key->des, t, 8);
 	}
 }
diff --git a/sys/src/libauthsrv/readnvram.c b/sys/src/libauthsrv/readnvram.c
index ef9c91249..5d054725d 100644
--- a/sys/src/libauthsrv/readnvram.c
+++ b/sys/src/libauthsrv/readnvram.c
@@ -292,11 +292,14 @@ readnvram(Nvrsafe *safep, int flag)
 			readcons("secstore key", nil, 1, safe->config,
 					sizeof safe->config);
 			for(;;){
-				if(readcons("password", nil, 1, in, sizeof in)
-				    == nil)
+				Authkey k;
+
+				if(readcons("password", nil, 1, in, sizeof in) == nil)
 					goto Out;
-				if(passtokey(safe->machkey, in))
+				if(passtokey(&k, in)){
+					memmove(safe->machkey, k.des, DESKEYLEN);
 					break;
+				}
 			}
 		}