update krb5_c_keylength function, create krb5_c_random_to_key function

Modify the keylength function to return both keybytes and keylength.
Change the name of the function and source file to reflect this.

Add a function, krb5_c_random_to_key() that takes random input data
of the right length (keybytes) and produce a valid key for a given
enctype.

ticket: new
Target_Version: 1.6
Tags: pullup

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@18836 dc483132-0cff-0310-8789-dd5450dbe970

1 files changed, 61 insertions, 0 deletions

diff --git a/src/lib/crypto/keylengths.c b/src/lib/crypto/keylengths.c
new file mode 100644
index 000000000..acd1da81b
--- /dev/null
+++ b/src/lib/crypto/keylengths.c
@@ -0,0 +1,61 @@
+/*
+ * COPYRIGHT (c) 2006
+ * The Regents of the University of Michigan
+ * ALL RIGHTS RESERVED
+ * 
+ * Permission is granted to use, copy, create derivative works
+ * and redistribute this software and such derivative works
+ * for any purpose, so long as the name of The University of
+ * Michigan is not used in any advertising or publicity
+ * pertaining to the use of distribution of this software
+ * without specific, written prior authorization.  If the
+ * above copyright notice or any other identification of the
+ * University of Michigan is included in any copy of any
+ * portion of this software, then the disclaimer below must
+ * also be included.
+ * 
+ * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
+ * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
+ * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
+ * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
+ * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
+ * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
+ * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
+ * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
+ * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGES.
+ */
+
+#include "k5-int.h"
+#include "etypes.h"
+
+/*
+ * keybytes is the number of bytes required as input to make a key,
+ * keylength is the length of the final key in bytes
+ */
+krb5_error_code KRB5_CALLCONV
+krb5_c_keylengths(krb5_context context, krb5_enctype enctype,
+		  size_t *keybytes, size_t *keylength)
+{
+    int i;
+
+    if (keybytes == NULL && keylength == NULL)
+	return(EINVAL);
+
+    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);
+
+    if (keybytes)
+	*keybytes = krb5_enctypes_list[i].enc->keybytes;
+    if (keylength)
+	*keylength = krb5_enctypes_list[i].enc->keylength;
+
+    return(0);
+}