Implement RFC 3961 PRF

Add krb5_c_prf, a function that implements the RFC 3961 PRF.


As part of this change, the krb5_init_keyblock and krb5 free routines
move to libk5crypto.  Public stubs remain in libkrb5, but the actual
implementation is an internal interface in libk5crypto

ticket: new
Tags: enhancement

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@17219 dc483132-0cff-0310-8789-dd5450dbe970

1 files changed, 87 insertions, 0 deletions

diff --git a/src/lib/crypto/prf.c b/src/lib/crypto/prf.c
new file mode 100644
index 000000000..f52564db4
--- /dev/null
+++ b/src/lib/crypto/prf.c
@@ -0,0 +1,87 @@
+/*
+ * lib/crypto/prf.c
+ *
+ * Copyright (C) 2004 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Export of this software from the United States of America may
+ *   require a specific license from the United States Government.
+ *   It is the responsibility of any person or organization contemplating
+ *   export to obtain such a license before exporting.
+ * 
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission.  Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ * 
+ * 
+ *
+ * This contains the implementation of krb5_c_prf, which  will find
+ *the enctype-specific PRF and then generate pseudo-random data.  This
+ *function yields krb5_c_prf_length bytes of output.
+ */
+
+
+#include "k5-int.h"
+#include "etypes.h"
+
+#include <assert.h>
+
+krb5_error_code KRB5_CALLCONV
+krb5_c_prf_length(krb5_context context, krb5_enctype enctype,
+		  size_t *len)
+{
+    int i;
+    assert (len);
+
+    for (i=0; i<krb5_enctypes_length; i++) {
+	if (krb5_enctypes_list[i].etype == enctype)
+	    break;
+    }
+
+    if (i == krb5_enctypes_length)
+	return(KRB5_BAD_ENCTYPE);
+
+    *len = krb5_enctypes_list[i].prf_length;
+    return 0;
+    
+}
+
+krb5_error_code KRB5_CALLCONV
+krb5_c_prf(krb5_context context, const krb5_keyblock *key,
+krb5_data *input, krb5_data *output)
+{
+    int i;
+    size_t len;
+    assert(input && output);
+    assert (output->data);
+
+
+    for (i=0; i<krb5_enctypes_length; i++) {
+	if (krb5_enctypes_list[i].etype == key->enctype)
+	    break;
+    }
+
+    if (i == krb5_enctypes_length)
+	return(KRB5_BAD_ENCTYPE);
+
+    output->magic = KV5M_DATA;
+    if (!krb5_enctypes_list[i].prf)
+	return (KRB5_CRYPTO_INTERNAL);
+    krb5_c_prf_length (context, key->enctype, &len);
+    if( len != output->length)
+	return (KRB5_CRYPTO_INTERNAL);
+            return((*(krb5_enctypes_list[i].prf))
+	   (krb5_enctypes_list[i].enc, krb5_enctypes_list[i].hash,
+	    key,  input, output));
+}
+