libsec: send sigature_algoritms extension for TLS1.2, order ciphers

TLS1.2 requires the client to send the list of supported
signature and hash algorithm pairs. some servers will simply
reject the client hello otherwise. note that we do not implement
any dh/ecdh param signature verification.

order the cipher list to strogest first. aes128 is actually more
secure than aes256.

1 files changed, 39 insertions, 6 deletions

diff --git a/sys/src/libsec/port/tlshand.c b/sys/src/libsec/port/tlshand.c
index e2f495a9d..3a190c96a 100644
--- a/sys/src/libsec/port/tlshand.c
+++ b/sys/src/libsec/port/tlshand.c
@@ -141,6 +141,7 @@ typedef struct Msg{
 			Bytes *dh_g;
 			Bytes *dh_Ys;
 			Bytes *dh_signature;
+			int sigalg;
 			int curve;
 		} serverKeyExchange;
 		struct {
@@ -283,16 +284,16 @@ enum {
 };
 
 static Algs cipherAlgs[] = {
-	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA},
 	{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA},
-	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA},
+	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA},
 	{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA},
-	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_DHE_RSA_WITH_AES_256_CBC_SHA},
+	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA},
 	{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_DHE_RSA_WITH_AES_128_CBC_SHA},
-	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_RSA_WITH_AES_256_CBC_SHA},
-	{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_RSA_WITH_AES_128_CBC_SHA},
+	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_DHE_RSA_WITH_AES_256_CBC_SHA},
 	{"aes_128_cbc", "sha256", 2*(16+16+SHA2_256dlen), TLS_RSA_WITH_AES_128_CBC_SHA256},
 	{"aes_256_cbc", "sha256", 2*(32+16+SHA2_256dlen), TLS_RSA_WITH_AES_256_CBC_SHA256},
+	{"aes_128_cbc", "sha1", 2*(16+16+SHA1dlen), TLS_RSA_WITH_AES_128_CBC_SHA},
+	{"aes_256_cbc", "sha1", 2*(32+16+SHA1dlen), TLS_RSA_WITH_AES_256_CBC_SHA},
 	{"3des_ede_cbc","sha1",	2*(4*8+SHA1dlen), TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA},
 	{"3des_ede_cbc","sha1",	2*(4*8+SHA1dlen), TLS_RSA_WITH_3DES_EDE_CBC_SHA},
 	{"rc4_128", "sha1",	2*(16+SHA1dlen), TLS_RSA_WITH_RC4_128_SHA},
@@ -317,6 +318,18 @@ static uchar pointformats[] = {
 	CompressionNull /* support of uncompressed point format is mandatory */
 };
 
+// signature algorithms
+static int sigalgs[] = {
+	0x0601,		/* SHA512 RSA */
+	0x0501,		/* SHA384 RSA */
+	0x0401,		/* SHA256 RSA */
+	0x0201,		/* SHA1 RSA */
+	0x0603,		/* SHA512 ECDSA */
+	0x0503,		/* SHA384 ECDSA */
+	0x0403,		/* SHA256 ECDSA */
+	0x0203,		/* SHA1 ECDSA */
+};
+
 static TlsConnection *tlsServer2(int ctl, int hand, uchar *cert, int certlen, int (*trace)(char*fmt, ...), PEMChain *chain);
 static TlsConnection *tlsClient2(int ctl, int hand, uchar *csid, int ncsid, uchar *cert, int certlen, uchar *ext, int extlen, int (*trace)(char*fmt, ...));
 static void	msgClear(Msg *m);
@@ -489,6 +502,23 @@ tlsClientExtensions(TLSconn *conn, int *plen)
 		for(i=0; i < n; i++)		/* Elliptic curves point formats */
 			*p++ = pointformats[i];
 	}
+
+	// signature algorithms
+	if(ProtocolVersion >= TLS12Version){
+		n = nelem(sigalgs);
+
+		m = p - b;
+		b = erealloc(b, m + 2+2+2+n*2);
+		p = b + m;
+
+		put16(p, 0x000d), p += 2;
+		put16(p, n*2 + 2), p += 2;
+		put16(p, n*2), p += 2;
+		for(i=0; i < n; i++){
+			put16(p, sigalgs[i]);
+			p += 2;
+		}
+	}
 	
 	*plen = p - b;
 	return b;
@@ -1703,8 +1733,9 @@ msgRecv(TlsConnection *c, Msg *m)
 			break;
 		}
 		if(n >= 2){
+			m->u.serverKeyExchange.sigalg = 0;
 			if(c->version >= TLS12Version){
-				/* signature hash algorithm */
+				m->u.serverKeyExchange.sigalg = get16(p);
 				p += 2, n -= 2;
 				if(n < 2)
 					goto Short;
@@ -1916,6 +1947,8 @@ msgPrint(char *buf, int n, Msg *m)
 			bs = bytesPrint(bs, be, "\tdh_g: ", m->u.serverKeyExchange.dh_g, "\n");
 		}
 		bs = bytesPrint(bs, be, "\tdh_Ys: ", m->u.serverKeyExchange.dh_Ys, "\n");
+		if(m->u.serverKeyExchange.sigalg != 0)
+			bs = seprint(bs, be, "\tsigalg: %.4x\n", m->u.serverKeyExchange.sigalg);
 		bs = bytesPrint(bs, be, "\tdh_signature: ", m->u.serverKeyExchange.dh_signature, "\n");
 		break;
 	case HClientKeyExchange: