--- libsmb/smb_signing.c.orig	2012-07-31 14:49:24.000000000 -0700
+++ libsmb/smb_signing.c	2012-07-31 15:37:11.000000000 -0700
@@ -45,6 +45,41 @@ struct smb_signing_state {
 	uint32_t seqnum;
 };
 
+static unsigned char const SSKeyHash[256] = {
+	0x53, 0x65, 0x63, 0x75, 0x72, 0x69, 0x74, 0x79,
+	0x20, 0x53, 0x69, 0x67, 0x6e, 0x61, 0x74, 0x75,
+	0x72, 0x65, 0x20, 0x4b, 0x65, 0x79, 0x20, 0x55,
+	0x70, 0x67, 0x72, 0x61, 0x64, 0x65, 0x79, 0x07,
+	0x6e, 0x28, 0x2e, 0x69, 0x88, 0x10, 0xb3, 0xdb,
+	0x01, 0x55, 0x72, 0xfb, 0x74, 0x14, 0xfb, 0xc4,
+	0xc5, 0xaf, 0x3b, 0x41, 0x65, 0x32, 0x17, 0xba,
+	0xa3, 0x29, 0x08, 0xc1, 0xde, 0x16, 0x61, 0x7e,
+	0x66, 0x98, 0xa4, 0x0b, 0xfe, 0x06, 0x83, 0x53,
+	0x4d, 0x05, 0xdf, 0x6d, 0xa7, 0x51, 0x10, 0x73,
+	0xc5, 0x50, 0xdc, 0x5e, 0xf8, 0x21, 0x46, 0xaa,
+	0x96, 0x14, 0x33, 0xd7, 0x52, 0xeb, 0xaf, 0x1f,
+	0xbf, 0x36, 0x6c, 0xfc, 0xb7, 0x1d, 0x21, 0x19,
+	0x81, 0xd0, 0x6b, 0xfa, 0x77, 0xad, 0xbe, 0x18,
+	0x78, 0xcf, 0x10, 0xbd, 0xd8, 0x78, 0xf7, 0xd3,
+	0xc6, 0xdf, 0x43, 0x32, 0x19, 0xd3, 0x9b, 0xa8,
+	0x4d, 0x9e, 0xaa, 0x41, 0xaf, 0xcb, 0xc6, 0xb9,
+	0x34, 0xe7, 0x48, 0x25, 0xd4, 0x88, 0xc4, 0x51,
+	0x60, 0x38, 0xd9, 0x62, 0xe8, 0x8d, 0x5b, 0x83,
+	0x92, 0x7f, 0xb5, 0x0e, 0x1c, 0x2d, 0x06, 0x91,
+	0xc3, 0x75, 0xb3, 0xcc, 0xf8, 0xf7, 0x92, 0x91,
+	0x0b, 0x3d, 0xa1, 0x10, 0x5b, 0xd5, 0x0f, 0xa8,
+	0x3f, 0x5d, 0x13, 0x83, 0x0a, 0x6b, 0x72, 0x93,
+	0x14, 0x59, 0xd5, 0xab, 0xde, 0x26, 0x15, 0x6d,
+	0x60, 0x67, 0x71, 0x06, 0x6e, 0x3d, 0x0d, 0xa7,
+	0xcb, 0x70, 0xe9, 0x08, 0x5c, 0x99, 0xfa, 0x0a,
+	0x5f, 0x3d, 0x44, 0xa3, 0x8b, 0xc0, 0x8d, 0xda,
+	0xe2, 0x68, 0xd0, 0x0d, 0xcd, 0x7f, 0x3d, 0xf8,
+	0x73, 0x7e, 0x35, 0x7f, 0x07, 0x02, 0x0a, 0xb5,
+	0xe9, 0xb7, 0x87, 0xfb, 0xa1, 0xbf, 0xcb, 0x32,
+	0x31, 0x66, 0x09, 0x48, 0x88, 0xcc, 0x18, 0xa3,
+	0xb2, 0x1f, 0x1f, 0x1b, 0x90, 0x4e, 0xd7, 0xe1
+};
+
 static void smb_signing_reset_info(struct smb_signing_state *si)
 {
 	si->active = false;
@@ -74,6 +109,42 @@ struct smb_signing_state *smb_signing_in
 	return si;
 }
 
+static bool smb_signing_protect_key(struct smb_signing_state *si)
+{
+	unsigned char digest[64];
+
+	/* If signing is not active, then this is wrong */
+	if (!si->active) {
+		return false;
+	}
+
+	/* The key cannot be more than 16 bytes in length */
+	if (si->mac_key.length > 16) {
+		si->mac_key.length = 16;
+	}
+
+	/* If the key is 8 bytes, zero fill to 16 */
+	if (si->mac_key.length == 8) {
+		int i = 0;
+
+		if (!data_blob_realloc(si, &si->mac_key, 16)) {
+			return false;
+		}
+
+		for (i = 8; i < 16; i++)
+			si->mac_key.data[i] = 0;
+
+		si->mac_key.length = 16;
+	}
+
+	hmac_md5(si->mac_key.data, SSKeyHash, sizeof(SSKeyHash), digest);
+
+	/* Replace the session key with the digest */
+	memcpy(si->mac_key.data, digest, 16);
+
+	return true;
+}
+
 static bool smb_signing_good(struct smb_signing_state *si,
 			     bool good, uint32_t seq)
 {