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.

1 files changed, 43 insertions, 19 deletions

diff --git a/sys/man/2/authsrv b/sys/man/2/authsrv
index 9eec0a426..70b1e7057 100644
--- a/sys/man/2/authsrv
+++ b/sys/man/2/authsrv
@@ -1,6 +1,6 @@
 .TH AUTHSRV 2
 .SH NAME
-authdial, passtokey, nvcsum, readnvram, convT2M, convM2T, convTR2M, convM2TR, convA2M, convM2A, convPR2M, convM2PR, _asgetticket, _asrdresp \- routines for communicating with authentication servers
+authdial, passtokey, nvcsum, readnvram, convT2M, convM2T, convTR2M, convM2TR, convA2M, convM2A, convPR2M, convM2PR, _asgetticket, _asrequest, _asgetresp, _asrdresp \- routines for communicating with authentication servers
 .SH SYNOPSIS
 .nf
 .PP
@@ -15,7 +15,7 @@ authdial, passtokey, nvcsum, readnvram, convT2M, convM2T, convTR2M, convM2TR, co
 int	authdial(char *netroot, char *ad);
 .PP
 .B
-int	passtokey(char key[DESKEYLEN], char *password)
+int	passtokey(Authkey *key, char *password)
 .PP
 .B
 uchar	nvcsum(void *mem, int len)
@@ -24,34 +24,40 @@ uchar	nvcsum(void *mem, int len)
 int	readnvram(Nvrsafe *nv, int flag);
 .PPP
 .B
-int	convT2M(Ticket *t, char *msg, char *key)
+int	convT2M(Ticket *t, char *msg, int len, Authkey *key)
 .PP
 .B
-void	convM2T(char *msg, Ticket *t, char *key)
+int	convM2T(char *msg, int len, Ticket *t, Authkey *key)
 .PP
 .B
-int	convA2M(Authenticator *a, char *msg, char *key)
+int	convA2M(Authenticator *a, char *msg, int len, Ticket *t)
 .PP
 .B
-void	convM2A(char *msg, Authenticator *a, char *key)
+int	convM2A(char *msg, int len, Authenticator *a, Ticket *t)
 .PP
 .B
-int	convTR2M(Ticketreq *tr, char *msg)
+int	convTR2M(Ticketreq *tr, char *msg, int len)
 .PP
 .B
-void	convM2TR(char *msg, Ticketreq *tr)
+int	convM2TR(char *msg, int len, Ticketreq *tr)
 .PP
 .B
-int	convPR2M(Passwordreq *pr, char *msg, char *key)
+int	convPR2M(Passwordreq *pr, char *msg, int len, Ticket *t)
 .PP
 .B
-void	convM2PR(char *msg, Passwordreq *pr, char *key)
+int	convM2PR(char *msg, int len, Passwordreq *pr, Ticket *t)
 .PP
 .B
-int	_asgetticket(int fd, char *trbuf, char *tbuf);
+int	_asgetticket(int fd, Ticketreq *tr, char *buf, int len)
 .PP
 .B
-int	_asrdresp(int fd, char *buf, int len);
+int	_asrequest(int fd, Ticketreq *tr)
+.PP
+.B
+int	_asgetresp(int fd, Ticket *t, Authenticator *a, Authkey *key)
+.PP
+.B
+int	_asrdresp(int fd, char *buf, int len)
 .SH DESCRIPTION
 .I Authdial
 dials an authentication server over the
@@ -99,7 +105,9 @@ is used to make the call.
 .I Passtokey
 converts
 .I password
-into a DES key and stores the result in
+into a set of cryptographic keys and stores them in the
+.I Authkey
+structure
 .IR key .
 It returns 0 if
 .I password
@@ -213,18 +221,34 @@ are used to convert them back.
 .I Key
 is used for encrypting the message before transmission and decrypting
 after reception.
+.IR ConvA2M ,
+.IR convM2A ,
+.I convPR2M
+and
+.I convM2PR
+encrypt/decrypt the message with the random ticket key.
 .PP
 The routine
+.I _asgetticket
+sends a ticket request
+.I tr
+returning the two encrypted tickets in
+.IR buf .
+The routine
+.I _asrequest
+encodes the ticket request
+.I tr
+and sends it not waiting for a response.
+After sending a request,
 .I _asgetresp
+can be used to receive the response containing a ticket and an optional
+authenticator and decrypts the ticket and authenticator using
+.IR key .
+The routine
+.I _asrdresp
 receives either a character array or an error string.
 On error, it sets errstr and returns -1.  If successful,
 it returns the number of bytes received.
-.PP
-The routine
-.I _asgetticket
-sends a ticket request message and then uses
-.I _asgetresp
-to recieve an answer.
 .SH SOURCE
 .B /sys/src/libauthsrv
 .SH SEE ALSO