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# Inferno Encrypt Key Exchange Protocol
#
# Copyright © 1995-1999 Lucent Techologies Inc. All rights reserved.
#
# This code uses methods that are subject to one or more patents
# held by Lucent Technologies Inc. Its use outside Inferno
# requires a separate licence from Lucent.
#
implement Login;
include "sys.m";
sys: Sys;
include "keyring.m";
kr: Keyring;
IPint: import kr;
include "security.m";
include "string.m";
# see login(6)
login(id, password, dest: string): (string, ref Keyring->Authinfo)
{
sys = load Sys Sys->PATH;
kr = load Keyring Keyring->PATH;
if(kr == nil)
return nomod(Keyring->PATH);
ssl := load SSL SSL->PATH;
if(ssl == nil)
return nomod(SSL->PATH);
rand := load Random Random->PATH;
if(rand == nil)
return nomod(Random->PATH);
if(dest == nil)
dest = "$SIGNER";
for(j:=0; j<len dest && dest[j] != '!'; j++)
break;
if(j >= len dest)
dest = "net!"+dest+"!inflogin"; # BUG: must do better
(ok, lc) := sys->dial(dest, nil);
if(ok < 0)
return (sys->sprint("can't contact login service: %r"), nil);
# push ssl, leave in clear mode for now
(err, c) := ssl->connect(lc.dfd);
if(c == nil)
return ("can't push ssl: " + err, nil);
lc.dfd = nil;
lc.cfd = nil;
# user->CA name
if(kr->putstring(c.dfd, id) < 0)
return (sys->sprint("can't send user name: %r"), nil);
# CA->user ACK
(s, why) := kr->getstring(c.dfd);
if(why != nil)
return ("remote: " + why, nil);
if(s != id)
return ("unexpected reply from signer: " + s, nil);
# user->CA ivec
ivec := rand->randombuf(rand->ReallyRandom, 8);
if(kr->putbytearray(c.dfd, ivec, len ivec) < 0)
return (sys->sprint("can't send initialization vector: %r"), nil);
# start encrypting
pwbuf := array of byte password;
digest := array[Keyring->SHA1dlen] of byte;
kr->sha1(pwbuf, len pwbuf, digest, nil);
pwbuf = array[8] of byte;
for(i := 0; i < 8; i++)
pwbuf[i] = digest[i] ^ digest[8+i];
for(i = 0; i < 4; i++)
pwbuf[i] ^= digest[16+i];
for(i = 0; i < 8; i++)
pwbuf[i] ^= ivec[i];
err = ssl->secret(c, pwbuf, pwbuf);
if(err != nil)
return ("can't set secret: " + err, nil);
if(sys->fprint(c.cfd, "alg rc4") < 0)
return (sys->sprint("can't push alg rc4: %r"), nil);
#if(sys->fprint(c.cfd, "alg desebc") < 0)
# return (sys->sprint("can't push alg desecb: %r"), nil);
# CA -> user key(alpha**r0 mod p)
(s, err) = kr->getstring(c.dfd);
if(err != nil){
if(err == "failure") # calculated secret is wrong
return ("name or secret incorrect (alpha**r0 mod p)", nil);
return ("remote:" + err, nil);
}
# stop encrypting
if(sys->fprint(c.cfd, "alg clear") < 0)
return (sys->sprint("can't push alg clear: %r"), nil);
alphar0 := IPint.b64toip(s);
# CA->user alpha
(s, err) = kr->getstring(c.dfd);
if(err != nil){
if(err == "failure")
return ("name or secret incorrect (alpha)", nil);
return ("remote: " + err, nil);
}
info := ref Keyring->Authinfo;
info.alpha = IPint.b64toip(s);
# CA->user p
(s, err) = kr->getstring(c.dfd);
if(err != nil){
if(err == "failure")
return ("name or secret incorrect (p)", nil);
return ("remote: " + err, nil);
}
info.p = IPint.b64toip(s);
# sanity check
bits := info.p.bits();
abits := info.alpha.bits();
if(abits > bits || abits < 2)
return ("bogus diffie hellman constants", nil);
# generate our random diffie hellman part
r1 := kr->IPint.random(bits/4, bits);
alphar1 := info.alpha.expmod(r1, info.p);
# user->CA alpha**r1 mod p
if(kr->putstring(c.dfd, alphar1.iptob64()) < 0)
return (sys->sprint("can't send (alpha**r1 mod p): %r"), nil);
# compute alpha**(r0*r1) mod p
alphar0r1 := alphar0.expmod(r1, info.p);
# turn on digesting
secret := alphar0r1.iptobytes();
err = ssl->secret(c, secret, secret);
if(err != nil)
return ("can't set digesting: " + err, nil);
if(sys->fprint(c.cfd, "alg sha1") < 0)
return (sys->sprint("can't push alg sha1: %r"), nil);
# CA->user CA's public key, SHA(CA's public key + secret)
(s, err) = kr->getstring(c.dfd);
if(err != nil)
return ("can't get signer's public key: " + err, nil);
info.spk = kr->strtopk(s);
# generate a key pair
info.mysk = kr->genSKfromPK(info.spk, id);
info.mypk = kr->sktopk(info.mysk);
# user->CA user's public key, SHA(user's public key + secret)
if(kr->putstring(c.dfd, kr->pktostr(info.mypk)) < 0)
return (sys->sprint("can't send your public: %r"), nil);
# CA->user user's public key certificate
(s, err) = kr->getstring(c.dfd);
if(err != nil)
return ("can't get certificate: " + err, nil);
info.cert = kr->strtocert(s);
return(nil, info);
}
nomod(mod: string): (string, ref Keyring->Authinfo)
{
return (sys->sprint("can't load module %s: %r", mod), nil);
}
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