[PATCH] sha256 tls mac

[PATCH] sha256 tls mac

[Nick Owens]

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this patch adds sha256 mac support and enables two ciphers that use
it, TLS_RSA_WITH_AES_128_CBC_SHA256 and
TLS_RSA_WITH_AES_256_CBC_SHA256.

i'm not sure if initsha2_256key is the right place to call error if
the tls version is wrong.

feedback welcome.

mischief

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diff -r 61e11ee59f83 -r 28e64a53383e sys/src/9/port/devtls.c
--- a/sys/src/9/port/devtls.c	Sun Aug 23 23:49:31 2015 +0200
+++ b/sys/src/9/port/devtls.c	Tue Aug 25 02:36:29 2015 -0700
@@ -21,12 +21,13 @@
 	MaxRecLen	= 1<<14,	/* max payload length of a record layer message */
 	MaxCipherRecLen	= MaxRecLen + 2048,
 	RecHdrLen	= 5,
-	MaxMacLen	= SHA1dlen,
+	MaxMacLen	= SHA2_256dlen,
 
 	/* protocol versions we can accept */
 	SSL3Version	= 0x0300,
 	TLS10Version	= 0x0301,
 	TLS11Version	= 0x0302,
+	TLS12Version	= 0x0303,
 	MinProtoVersion	= 0x0300,	/* limits on version we accept */
 	MaxProtoVersion	= 0x03ff,
 
@@ -1417,11 +1418,25 @@
 	memmove(s->mackey, p, ha->maclen);
 }
 
+static void
+initsha2_256key(Hashalg *ha, int version, Secret *s, uchar *p)
+{
+	s->maclen = ha->maclen;
+
+	/* only TLS 1.2 has SHA256. */
+	if(version != TLS12Version)
+		error("sha256 is TLS 1.2 only");
+
+	s->mac = hmac_sha2_256;
+	memmove(s->mackey, p, ha->maclen);
+}
+
 static Hashalg hashtab[] =
 {
-	{ "clear", 0, initclearmac, },
-	{ "md5", MD5dlen, initmd5key, },
-	{ "sha1", SHA1dlen, initsha1key, },
+	{ "clear",	0,		initclearmac, },
+	{ "md5",	MD5dlen,	initmd5key, },
+	{ "sha1",	SHA1dlen,	initsha1key, },
+	{ "sha256",	SHA2_256dlen,	initsha2_256key, },
 	{ 0 }
 };
 
diff -r 61e11ee59f83 -r 28e64a53383e sys/src/libsec/port/tlshand.c
--- a/sys/src/libsec/port/tlshand.c	Sun Aug 23 23:49:31 2015 +0200
+++ b/sys/src/libsec/port/tlshand.c	Tue Aug 25 02:36:29 2015 -0700
@@ -17,7 +17,7 @@
 enum {
 	TLSFinishedLen = 12,
 	SSL3FinishedLen = MD5dlen+SHA1dlen,
-	MaxKeyData = 136,	// amount of secret we may need
+	MaxKeyData = 160,	// amount of secret we may need
 	MaxChunk = 1<<15,
 	RandomSize = 32,
 	SidSize = 32,
@@ -224,14 +224,14 @@
 
 // cipher suites
 enum {
-	TLS_NULL_WITH_NULL_NULL	 		= 0x0000,
-	TLS_RSA_WITH_NULL_MD5 			= 0x0001,
-	TLS_RSA_WITH_NULL_SHA 			= 0x0002,
-	TLS_RSA_EXPORT_WITH_RC4_40_MD5 		= 0x0003,
-	TLS_RSA_WITH_RC4_128_MD5 		= 0x0004,
-	TLS_RSA_WITH_RC4_128_SHA 		= 0x0005,
+	TLS_NULL_WITH_NULL_NULL			= 0x0000,
+	TLS_RSA_WITH_NULL_MD5			= 0x0001,
+	TLS_RSA_WITH_NULL_SHA			= 0x0002,
+	TLS_RSA_EXPORT_WITH_RC4_40_MD5		= 0x0003,
+	TLS_RSA_WITH_RC4_128_MD5		= 0x0004,
+	TLS_RSA_WITH_RC4_128_SHA		= 0x0005,
 	TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5	= 0X0006,
-	TLS_RSA_WITH_IDEA_CBC_SHA 		= 0X0007,
+	TLS_RSA_WITH_IDEA_CBC_SHA		= 0X0007,
 	TLS_RSA_EXPORT_WITH_DES40_CBC_SHA	= 0X0008,
 	TLS_RSA_WITH_DES_CBC_SHA		= 0X0009,
 	TLS_RSA_WITH_3DES_EDE_CBC_SHA		= 0X000A,
@@ -248,7 +248,7 @@
 	TLS_DHE_RSA_WITH_DES_CBC_SHA		= 0X0015,
 	TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA	= 0X0016,
 	TLS_DH_anon_EXPORT_WITH_RC4_40_MD5	= 0x0017,
-	TLS_DH_anon_WITH_RC4_128_MD5 		= 0x0018,
+	TLS_DH_anon_WITH_RC4_128_MD5		= 0x0018,
 	TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA	= 0X0019,
 	TLS_DH_anon_WITH_DES_CBC_SHA		= 0X001A,
 	TLS_DH_anon_WITH_3DES_EDE_CBC_SHA	= 0X001B,
@@ -265,11 +265,14 @@
 	TLS_DHE_DSS_WITH_AES_256_CBC_SHA	= 0X0038,
 	TLS_DHE_RSA_WITH_AES_256_CBC_SHA	= 0X0039,
 	TLS_DH_anon_WITH_AES_256_CBC_SHA	= 0X003A,
-	
+
+	TLS_RSA_WITH_AES_128_CBC_SHA256		= 0X003C,
+	TLS_RSA_WITH_AES_256_CBC_SHA256		= 0X003D,
+
 	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA	= 0xC013,
 	TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA	= 0xC014,
-	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA  = 0xC009,
-	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA = 0xC00A,
+	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA	= 0xC009,
+	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA	= 0xC00A,
 	CipherMax
 };
 
@@ -288,6 +291,8 @@
 	{"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_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},
 	{"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},