package plan9.auth; import java.math.BigInteger; import java.nio.ByteBuffer; import java.util.Date; import java.util.Arrays;import java.util.ArrayList; import plan9.lib.Attr;import plan9.lib.Attrs;import plan9.lib.Key;import plan9.lib.Keys;import plan9.lib.Packer;import plan9.lib.Strings;import plan9.lib.Base16;import plan9.lib.Encoding;import plan9.lib.Base64;import plan9.lib.Strings;import plan9.lib.Msgio;import plan9.lib.RemoteError; import plan9.Log;import plan9.LogFactory; import static plan9.auth.Pki.*; public class Verifier { 	static final Log log = LogFactory.logger(Verifier.class); 	ArrayList<Principal> keys = new ArrayList<Principal>(); 	public final Principal addkey(PK pk){		try{			Hash h = Pki.hash("sha1", pk);			Principal p = keybyhash(h);			if(p == null){				p = new Principal(pk, null, h);				keys.add(p);			}			return p;		}catch(CryptoError e){			// can't happen, but if it did, just ignore the key			return null;		}	} 	public final Principal addkey(Principal p){		Principal op = keybyhash(p.pkhash);		if(op != null)			return op;		keys.add(p);		return p;	} 	public final Principal keybyhash(Hash h) {		for(Principal p : keys)			if(p.eqhash(h))				return p;		return null;	} 	public Certificate verify(ArrayList<Object> seq) throws ValidationFailed {		ArrayList<Certificate> certs = new ArrayList<Certificate>();		Name n0 = null;		Certificate cn = null;		Tag tag = null;		long expires = 0; 		for(Object o : seq){			if(o instanceof Certificate){				Certificate cert = (Certificate)o;				if(cert.expires != 0 && cert.expires <= now())					throw new ValidationFailed("certificate expired: "+cert);				if(cn != null){					if(!cn.subject.principal.eq(cert.issuer.principal))						throw new ValidationFailed(String.format("certificate chain has mismatched principals: subject %s but next issuer %s", cn.subject, cert.issuer));					if(log.debugging())						log.debug("subject %s → issuer %s ok", cn.subject, cert.issuer.principal);				}				certs.add(cert);				if(n0 == null)					n0 = cert.issuer;				if(cert.expires != 0 && cert.expires < expires)					expires = cert.expires;				if(!cert.isNameCert()){					if(tag != null){						tag = tag.intersect(cert.tag);						if(tag.isnone())							throw new ValidationFailed("certificate chain gives no authority");					}else						tag = cert.tag;				}				cn = cert;			}else if(o instanceof Principal){				Principal p = (Principal)o;				if(p.pk != null){	// otherwise it's just a hash, and makes no difference					if(keybyhash(p.pkhash) == null)						keys.add(p);				}			}else if(o instanceof PK){				addkey((PK)o);			}else if(o instanceof SK){				addkey(((SK)o).pk());			}else if(o instanceof Signature){				Signature sig = (Signature)o; 				if(cn == null)					throw new ValidationFailed("invalid proof sequence: signature missing certificate: "+sig); 				Principal p = sig.signer;				if(p.pk == null){					// if needed, ought to appear earlier in the sequence					p = keybyhash(sig.signer.pkhash);					if(p == null)						throw new ValidationFailed("missing public key for signer "+sig.signer);					// could sig.signer.addkey(p.pk);				} 				// verify signature				if(!validsig(cn, sig, p))					throw new ValidationFailed("signature does not match certificate: "+sig.signer);			}		}		if(n0 == null || cn == null)			throw new ValidationFailed("proof sequence proved nothing"); 		if(log.debugging()){			String s = String.format("Verifier: %s speaks for %s", cn.subject, n0);			if(tag != null)				s += " regarding "+tag;			if(expires != 0)				s += String.format(" expires %d [%s]", expires, new Date(expires*1000));			log.debug("%s", s);		} 		return new Certificate(n0, cn.subject, expires, tag);	} 	private static int now(){		return (int)((new Date()).getTime()/1000);	} 	public final static boolean validsig(Certificate cert, Signature sig, Principal p) throws ValidationFailed {		try{			ByteBuffer b = ByteBuffer.allocate(8192);			cert.pack(b);			if(!sig.data.alg.equals("sha1"))				throw new ValidationFailed("unimplemented hash algorithm: "+sig.data.alg);			byte[] h = Aids.sha1(b.array(), 0, b.position(), null);			if(log.debugging())				log.debug("hash cert: %s", Aids.b16(h));			// TO DO: pkcs1			if(!sig.signer.pk.verify(sig.sig, new BigInteger(1, h)))				throw new ValidationFailed("signature verification failed: "+cert);			return true;		}catch(Exception e){			// any error causes validation to fail			throw new ValidationFailed(e.getMessage());		}	}}