1 files changed, 133 insertions, 0 deletions
diff --git a/source4/libcli/auth/session.c b/source4/libcli/auth/session.c
new file mode 100644
index 0000000000..946b0fe62f
--- /dev/null
+++ b/source4/libcli/auth/session.c
@@ -0,0 +1,133 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   code to encrypt/decrypt data using the user session key
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+/*
+  encrypt or decrypt a blob of data using the user session key
+  as used in lsa_SetSecret
+
+  before calling, the out blob must be initialised to be the same size
+  as the in blob
+*/
+void sess_crypt_blob(DATA_BLOB *out, const DATA_BLOB *in, const uint8 session_key[16],
+		     BOOL forward)
+{
+	int i, k;
+
+	for (i=0,k=0;
+	     i<in->length;
+	     i += 8, k += 7) {
+		uint8 bin[8], bout[8], key[7];
+
+		memset(bin, 0, 8);
+		memcpy(bin,  &in->data[i], MIN(8, in->length-i));
+
+		if (k + 7 > 16) {
+			k = (16 - k);
+		}
+		memcpy(key, &session_key[k], 7);
+
+		smbhash(bout, bin, key, forward?1:0);
+
+		memcpy(&out->data[i], bout, MIN(8, in->length-i));
+	}
+}
+
+
+/*
+  a convenient wrapper around sess_crypt_blob() for strings, using the LSA convention
+
+  note that we round the length to a multiple of 8. This seems to be needed for 
+  compatibility with windows
+
+  caller should free using data_blob_free()
+*/
+DATA_BLOB sess_encrypt_string(const char *str, const uint8 session_key[16])
+{
+	DATA_BLOB ret, src;
+	int slen = strlen(str);
+	int dlen = (slen+7) & ~7;
+
+	src = data_blob(NULL, 8+dlen);
+	if (!src.data) {
+		return data_blob(NULL, 0);
+	}
+
+	ret = data_blob(NULL, 8+dlen);
+	if (!ret.data) {
+		data_blob_free(&src);
+		return data_blob(NULL, 0);
+	}
+
+	SIVAL(src.data, 0, slen);
+	SIVAL(src.data, 4, 1);
+	memset(src.data+8, 0,   dlen);
+	memcpy(src.data+8, str, slen);
+
+	sess_crypt_blob(&ret, &src, session_key, True);
+	
+	data_blob_free(&src);
+
+	return ret;
+}
+
+/*
+  a convenient wrapper around sess_crypt_blob() for strings, using the LSA convention
+
+  caller should free the returned string
+*/
+char *sess_decrypt_string(DATA_BLOB *blob, const uint8 session_key[16])
+{
+	DATA_BLOB out;
+	int slen;
+	char *ret;
+
+	if (blob->length < 8) {
+		return NULL;
+	}
+	
+	out = data_blob(NULL, blob->length);
+	if (!out.data) {
+		return NULL;
+	}
+
+	sess_crypt_blob(&out, blob, session_key, False);
+
+	slen = IVAL(out.data, 0);
+	if (slen > blob->length - 8) {
+		DEBUG(0,("Invalid crypt length %d\n", slen));
+		return NULL;
+	}
+
+	if (IVAL(out.data, 4) != 1) {
+		DEBUG(0,("Unexpected revision number %d in session crypted string\n",
+			 IVAL(out.data, 4)));
+		return NULL;
+	}
+		
+	ret = strndup(out.data+8, slen);
+
+	data_blob_free(&out);
+
+	return ret;
+}