add C-Keens tls-client-auth

This patch adds client TLS authentication to libsec in compliance with
rfc 4346.

A new -c flag has been introduced for tlsclient allowing the user to
specify a certificate in pem(8) format which will be provided to the
server upon request.

A -D debug flag has been introduced to enable debugging output.

The patch has been tested against OpenSSL 0.9.7j 04 May 2006.

It exists today because of the great (debugging) help and insight
provided by Matthias Bauer.

TODOs:

- specification of a certain client key in factotum is not possible at
	the moment
- tlssrv should support this too

These will get added in another patch.

The first try to submit this patch failed due to a network error.
Sorry for the duplication!

Kind regards,

Christian

2 files changed, 84 insertions, 11 deletions

diff --git a/sys/src/libsec/port/tlshand.c b/sys/src/libsec/port/tlshand.c
index 5ebd3d4e5..16a82ef65 100644
--- a/sys/src/libsec/port/tlshand.c
+++ b/sys/src/libsec/port/tlshand.c
@@ -112,6 +112,9 @@ typedef struct Msg{
 		struct {
 			Bytes *key;
 		} clientKeyExchange;
+ 		struct {
+ 			Bytes *signature;
+ 		} certificateVerify;		
 		Finished finished;
 	} u;
 } Msg;
@@ -249,8 +252,7 @@ static uchar compressors[] = {
 };
 
 static TlsConnection *tlsServer2(int ctl, int hand, uchar *cert, int ncert, int (*trace)(char*fmt, ...), PEMChain *chain);
-static TlsConnection *tlsClient2(int ctl, int hand, uchar *csid, int ncsid, int (*trace)(char*fmt, ...));
-
+static TlsConnection *tlsClient2(int ctl, int hand, uchar *csid, int ncsid, uchar *cert, int certlen,  int (*trace)(char*fmt, ...));
 static void	msgClear(Msg *m);
 static char* msgPrint(char *buf, int n, Msg *m);
 static int	msgRecv(TlsConnection *c, Msg *m);
@@ -301,11 +303,15 @@ static int get24(uchar *p);
 static int get16(uchar *p);
 static Bytes* newbytes(int len);
 static Bytes* makebytes(uchar* buf, int len);
+static Bytes* mptobytes(mpint* big);
 static void freebytes(Bytes* b);
 static Ints* newints(int len);
 static Ints* makeints(int* buf, int len);
 static void freeints(Ints* b);
 
+/* x509.c */
+extern mpint* pkcs1padbuf(uchar *buf, int len, mpint *modulus);
+
 //================= client/server ========================
 
 //	push TLS onto fd, returning new (application) file descriptor
@@ -398,7 +404,7 @@ tlsClient(int fd, TLSconn *conn)
 		return -1;
 	}
 	fprint(ctl, "fd %d 0x%x", fd, ProtocolVersion);
-	tls = tlsClient2(ctl, hand, conn->sessionID, conn->sessionIDlen, conn->trace);
+	tls = tlsClient2(ctl, hand, conn->sessionID, conn->sessionIDlen, conn->cert, conn->certlen, conn->trace);
 	close(hand);
 	close(ctl);
 	close(fd);
@@ -602,13 +608,14 @@ Err:
 }
 
 static TlsConnection *
-tlsClient2(int ctl, int hand, uchar *csid, int ncsid, int (*trace)(char*fmt, ...))
+tlsClient2(int ctl, int hand, uchar *csid, int ncsid, uchar *cert, int certlen, int (*trace)(char*fmt, ...))
 {
 	TlsConnection *c;
 	Msg m;
 	uchar kd[MaxKeyData], *epm;
 	char *secrets;
 	int creq, nepm, rv;
+	mpint *signedMP, *paddedHashes; 
 
 	if(!initCiphers())
 		return nil;
@@ -719,7 +726,9 @@ tlsClient2(int ctl, int hand, uchar *csid, int ncsid, int (*trace)(char*fmt, ...
 	}
 
 	if(creq) {
-		/* send a zero length certificate */
+ 		m.u.certificate.ncert = 1;
+ 		m.u.certificate.certs = emalloc(m.u.certificate.ncert * sizeof(Bytes));
+ 		m.u.certificate.certs[0] = makebytes(cert, certlen);		
 		m.tag = HCertificate;
 		if(!msgSend(c, &m, AFlush))
 			goto Err;
@@ -735,10 +744,55 @@ tlsClient2(int ctl, int hand, uchar *csid, int ncsid, int (*trace)(char*fmt, ...
 		tlsError(c, EHandshakeFailure, "can't set secret: %r");
 		goto Err;
 	}
+	 
 	if(!msgSend(c, &m, AFlush))
 		goto Err;
 	msgClear(&m);
 
+ 	/* CertificateVerify */
+ 	/*XXX I should only send this when it is not DH right? 
+ 		Also we need to know which TLS key 
+		we have to use in case there are more than one*/
+ 	if(cert) {
+ 		m.tag = HCertificateVerify;
+ 		uchar hshashes[MD5dlen+SHA1dlen]; /* content of signature */
+		MD5state	hsmd5_save;
+		SHAstate	hssha1_save;
+	
+		/* save the state for the Finish message */
+
+		hsmd5_save = c->hsmd5;
+		hssha1_save = c->hssha1;
+ 		md5(nil, 0, hshashes, &c->hsmd5);
+		sha1(nil, 0, hshashes+MD5dlen, &c->hssha1);
+	
+		c->hsmd5 = hsmd5_save;
+		c->hssha1 = hssha1_save;
+
+ 		c->sec->rpc = factotum_rsa_open(cert, certlen);
+ 		if(c->sec->rpc == nil){
+ 			tlsError(c, EHandshakeFailure, "factotum_rsa_open: %r");
+ 			goto Err;
+ 		}
+		c->sec->rsapub = X509toRSApub(cert, certlen, nil, 0);
+		
+		paddedHashes = pkcs1padbuf(hshashes, 36, c->sec->rsapub->n);
+		signedMP = factotum_rsa_decrypt(c->sec->rpc, paddedHashes);
+ 		m.u.certificateVerify.signature = mptobytes(signedMP);
+		free(signedMP);
+
+		if(m.u.certificateVerify.signature == nil){
+			msgClear(&m);	
+			goto Err;
+		}
+
+		if(!msgSend(c, &m, AFlush)){
+ 			msgClear(&m);
+ 			goto Err;
+ 		}
+ 		msgClear(&m);
+ 	} 
+
 	/* change cipher spec */
 	if(fprint(c->ctl, "changecipher") < 0){
 		tlsError(c, EInternalError, "can't enable cipher: %r");
@@ -892,6 +946,12 @@ msgSend(TlsConnection *c, Msg *m, int act)
 			p += m->u.certificate.certs[i]->len;
 		}
 		break;
+ 	case HCertificateVerify:
+		put16(p, m->u.certificateVerify.signature->len);
+		p += 2;
+ 		memmove(p, m->u.certificateVerify.signature->data, m->u.certificateVerify.signature->len);
+ 		p += m->u.certificateVerify.signature->len;
+ 		break;	
 	case HClientKeyExchange:
 		n = m->u.clientKeyExchange.key->len;
 		if(c->version != SSL3Version){
@@ -1116,7 +1176,7 @@ msgRecv(TlsConnection *c, Msg *m)
 		nn = get24(p);
 		p += 3;
 		n -= 3;
-		if(n != nn)
+		if(nn == 0 && n > 0)
 			goto Short;
 		/* certs */
 		i = 0;
@@ -1142,7 +1202,7 @@ msgRecv(TlsConnection *c, Msg *m)
 		nn = p[0];
 		p += 1;
 		n -= 1;
-		if(nn < 1 || nn > n)
+		if(nn > n)
 			goto Short;
 		m->u.certificateRequest.types = makebytes(p, nn);
 		p += nn;
@@ -1250,6 +1310,9 @@ msgClear(Msg *m)
 			freebytes(m->u.certificateRequest.cas[i]);
 		free(m->u.certificateRequest.cas);
 		break;
+ 	case HCertificateVerify:
+ 		freebytes(m->u.certificateVerify.signature);
+ 		break;
 	case HServerHelloDone:
 		break;
 	case HClientKeyExchange:
@@ -1343,6 +1406,10 @@ msgPrint(char *buf, int n, Msg *m)
 		for(i=0; i<m->u.certificateRequest.nca; i++)
 			bs = bytesPrint(bs, be, "\t\t", m->u.certificateRequest.cas[i], "\n");
 		break;
+ 	case HCertificateVerify:
+ 		bs = seprint(bs, be, "HCertificateVerify\n");
+ 		bs = bytesPrint(bs, be, "\tsignature: ", m->u.certificateVerify.signature,"\n");
+ 		break;	
 	case HServerHelloDone:
 		bs = seprint(bs, be, "ServerHelloDone\n");
 		break;
diff --git a/sys/src/libsec/port/x509.c b/sys/src/libsec/port/x509.c
index 103ab2933..77c2205f9 100644
--- a/sys/src/libsec/port/x509.c
+++ b/sys/src/libsec/port/x509.c
@@ -2036,27 +2036,33 @@ asn1mpint(Elem *e)
 	return nil;
 }
 
-static mpint*
-pkcs1pad(Bytes *b, mpint *modulus)
+mpint*
+pkcs1padbuf(uchar *buf, int len, mpint *modulus)
 {
 	int n = (mpsignif(modulus)+7)/8;
 	int pm1, i;
 	uchar *p;
 	mpint *mp;
 
-	pm1 = n - 1 - b->len;
+	pm1 = n - 1 - len;
 	p = (uchar*)emalloc(n);
 	p[0] = 0;
 	p[1] = 1;
 	for(i = 2; i < pm1; i++)
 		p[i] = 0xFF;
 	p[pm1] = 0;
-	memcpy(&p[pm1+1], b->data, b->len);
+	memcpy(&p[pm1+1], buf, len);
 	mp = betomp(p, n, nil);
 	free(p);
 	return mp;
 }
 
+static mpint*
+pkcs1pad(Bytes *b, mpint *modulus)
+{
+	return pkcs1padbuf(b->data, b->len, modulus);
+}
+
 RSApriv*
 asn1toRSApriv(uchar *kd, int kn)
 {