Triple DES support routines

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@7128 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/crypto/des3_md5.c b/src/lib/crypto/des3_md5.c
new file mode 100644 (file)
index 0000000..e93f7ad
--- /dev/null
+++ b/src/lib/crypto/des3_md5.c
@@ -0,0 +1,173 @@
+/*
+ * lib/crypto/des3-md5.32
+ *
+ * Copyright 1994 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.  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.
+ */
+
+#include "k5-int.h"
+#include "rsa-md5.h"
+#include "des_int.h"
+
+krb5_error_code mit_des3_md5_encrypt_func
+    PROTOTYPE(( krb5_const_pointer, krb5_pointer, const size_t,
+               krb5_encrypt_block *, krb5_pointer ));
+
+krb5_error_code mit_des3_md5_decrypt_func
+    PROTOTYPE(( krb5_const_pointer, krb5_pointer, const size_t,
+               krb5_encrypt_block *, krb5_pointer ));
+
+static mit_des_cblock zero_ivec = { 0 };
+
+static krb5_cryptosystem_entry mit_des3_md5_cryptosystem_entry = {
+    0,
+    mit_des3_md5_encrypt_func,
+    mit_des3_md5_decrypt_func, 
+    mit_des3_process_key,
+    mit_des_finish_key,
+    mit_des3_string_to_key,
+    mit_des_init_random_key,
+    mit_des_finish_random_key,
+    mit_des3_random_key,
+    sizeof(mit_des_cblock),
+    RSA_MD5_CKSUM_LENGTH+sizeof(mit_des_cblock),
+    3*sizeof(mit_des_cblock),
+    ENCTYPE_DES3_CBC_MD5
+    };
+
+krb5_cs_table_entry krb5_des3_md5_cst_entry = {
+    0,
+    &mit_des3_md5_cryptosystem_entry,
+    0
+    };
+
+
+krb5_error_code
+mit_des3_md5_encrypt_func(in, out, size, key, ivec)
+    krb5_const_pointer in;
+    krb5_pointer out;
+    const size_t size;
+    krb5_encrypt_block * key;
+    krb5_pointer ivec;
+{
+    krb5_checksum cksum;
+    krb5_octet         contents[RSA_MD5_CKSUM_LENGTH];
+    int sumsize;
+    krb5_error_code retval;
+
+/*    if ( size < sizeof(mit_des_cblock) )
+       return KRB5_BAD_MSIZE; */
+
+    /* caller passes data size, and saves room for the padding. */
+    /* format of ciphertext, per RFC is:
+      +-----------+----------+-------------+-----+
+      |confounder |   check  |   msg-seq   | pad |
+      +-----------+----------+-------------+-----+
+      
+      our confounder is 8 bytes (one cblock);
+      our checksum is RSA_MD5_CKSUM_LENGTH
+     */
+    sumsize =  krb5_roundup(size+RSA_MD5_CKSUM_LENGTH+sizeof(mit_des_cblock),
+                           sizeof(mit_des_cblock));
+
+    /* assemble crypto input into the output area, then encrypt in place. */
+
+    memset((char *)out, 0, sumsize);
+
+    /* put in the confounder */
+    if ((retval = krb5_random_confounder(sizeof(mit_des_cblock), out)))
+       return retval;
+
+    memcpy((char *)out+sizeof(mit_des_cblock)+RSA_MD5_CKSUM_LENGTH, (char *)in,
+          size);
+
+    cksum.contents = contents; 
+
+    /* This is equivalent to krb5_calculate_checksum(CKSUMTYPE_MD5,...)
+       but avoids use of the cryptosystem config table which can not be
+       referenced here if this object is to be included in a shared library.  */
+    if ((retval = rsa_md5_cksumtable_entry.sum_func((krb5_pointer) out,
+                                                   sumsize,
+                                                   (krb5_pointer)key->key->contents,
+                                                   key->key->length,
+                                                   &cksum)))
+       return retval;
+
+    memcpy((char *)out+sizeof(mit_des_cblock), (char *)contents,
+          RSA_MD5_CKSUM_LENGTH);
+
+    /* We depend here on the ability of this DES-3 implementation to
+       encrypt plaintext to ciphertext in-place. */
+    return (mit_des3_cbc_encrypt(out, 
+                               out,
+                               sumsize, 
+                               (struct mit_des_ks_struct *) key->priv, 
+                               ((struct mit_des_ks_struct *) key->priv) + 1, 
+                               ((struct mit_des_ks_struct *) key->priv) + 2, 
+                               ivec ? ivec : (krb5_pointer)zero_ivec,
+                               MIT_DES_ENCRYPT));
+    
+}
+
+krb5_error_code
+mit_des3_md5_decrypt_func(in, out, size, key, ivec)
+    krb5_const_pointer in;
+    krb5_pointer out;
+    const size_t size;
+    krb5_encrypt_block * key;
+    krb5_pointer ivec;
+{
+    krb5_checksum cksum;
+    krb5_octet         contents_prd[RSA_MD5_CKSUM_LENGTH];
+    krb5_octet  contents_get[RSA_MD5_CKSUM_LENGTH];
+    char       *p;
+    krb5_error_code   retval;
+
+    if ( size < 2*sizeof(mit_des_cblock) )
+       return KRB5_BAD_MSIZE;
+
+    retval = mit_des3_cbc_encrypt((const mit_des_cblock *) in,
+                                out,
+                                size,
+                                (struct mit_des_ks_struct *) key->priv,
+                                ((struct mit_des_ks_struct *) key->priv) + 1, 
+                                ((struct mit_des_ks_struct *) key->priv) + 2, 
+                                ivec ? ivec : (krb5_pointer)zero_ivec,
+                                MIT_DES_DECRYPT);
+    if (retval)
+       return retval;
+
+    cksum.contents = contents_prd;
+    p = (char *)out + sizeof(mit_des_cblock);
+    memcpy((char *)contents_get, p, RSA_MD5_CKSUM_LENGTH);
+    memset(p, 0, RSA_MD5_CKSUM_LENGTH);
+
+    if ((retval = rsa_md5_cksumtable_entry.sum_func(out, size,
+                                                   (krb5_pointer)key->key->contents,
+                                                   key->key->length,
+                                                   &cksum)))
+       return retval;
+
+    if (memcmp((char *)contents_get, (char *)contents_prd, RSA_MD5_CKSUM_LENGTH) )
+        return KRB5KRB_AP_ERR_BAD_INTEGRITY;
+    memmove((char *)out, (char *)out +
+          sizeof(mit_des_cblock) + RSA_MD5_CKSUM_LENGTH,
+          size - sizeof(mit_des_cblock) - RSA_MD5_CKSUM_LENGTH);
+    return 0;
+}