1 files changed, 131 insertions, 0 deletions
diff --git a/src/lib/crypto/hmac.c b/src/lib/crypto/hmac.c
new file mode 100644
index 0000000000..7cf11a6c70
--- /dev/null
+++ b/src/lib/crypto/hmac.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 1998 by the FundsXpress, INC.
+ * 
+ * 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 FundsXpress. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission.  FundsXpress makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ * 
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "k5-int.h"
+
+/*
+ * the HMAC transform looks like:
+ *
+ * H(K XOR opad, H(K XOR ipad, text))
+ *
+ * where H is a cryptographic hash
+ * K is an n byte key
+ * ipad is the byte 0x36 repeated blocksize times
+ * opad is the byte 0x5c repeated blocksize times
+ * and text is the data being protected
+ */
+
+krb5_error_code
+krb5_hmac(hash, key, icount, input, output)
+     krb5_const struct krb5_hash_provider *hash;
+     krb5_const krb5_keyblock *key;
+     unsigned int icount;
+     krb5_const krb5_data *input;
+     krb5_data *output;
+{
+    size_t hashsize, blocksize;
+    unsigned char *xorkey, *ihash;
+    int i;
+    krb5_data *hashin, hashout;
+    krb5_error_code ret;
+
+    (*(hash->hash_size))(&hashsize);
+    (*(hash->block_size))(&blocksize);
+
+    if (key->length > blocksize)
+	return(KRB5_CRYPTO_INTERNAL);
+    if (output->length < hashsize)
+	return(KRB5_BAD_MSIZE);
+    /* if this isn't > 0, then there won't be enough space in this
+       array to compute the outer hash */
+    if (icount == 0)
+	return(KRB5_CRYPTO_INTERNAL);
+
+    /* allocate space for the xor key, hash input vector, and inner hash */
+
+    if ((xorkey = (unsigned char *) malloc(blocksize)) == NULL)
+	return(ENOMEM);
+    if ((ihash = (unsigned char *) malloc(hashsize)) == NULL) {
+	free(xorkey);
+	return(ENOMEM);
+    }
+    if ((hashin = (krb5_data *)malloc(sizeof(krb5_data)*(icount+1))) == NULL) {
+	free(ihash);
+	free(xorkey);
+	return(ENOMEM);
+    }
+
+    /* create the inner padded key */
+
+    memset(xorkey, 0x36, blocksize);
+
+    for (i=0; i<key->length; i++)
+	xorkey[i] ^= key->contents[i];
+
+    /* compute the inner hash */
+
+    for (i=0; i<icount; i++) {
+	hashin[0].length = blocksize;
+	hashin[0].data = xorkey;
+	hashin[i+1] = input[i];
+    }
+
+    hashout.length = hashsize;
+    hashout.data = ihash;
+
+    if (ret = ((*(hash->hash))(icount+1, hashin, &hashout)))
+	goto cleanup;
+
+    /* create the outer padded key */
+
+    memset(xorkey, 0x5c, blocksize);
+
+    for (i=0; i<key->length; i++)
+	xorkey[i] ^= key->contents[i];
+
+    /* compute the outer hash */
+
+    hashin[0].length = blocksize;
+    hashin[0].data = xorkey;
+    hashin[1] = hashout;
+
+    output->length = hashsize;
+
+    if (ret = ((*(hash->hash))(2, hashin, output)))
+	memset(output->data, 0, output->length);
+
+    /* ret is set correctly by the prior call */
+
+cleanup:
+    memset(xorkey, 0, blocksize);
+    memset(ihash, 0, hashsize);
+
+    free(hashin);
+    free(ihash);
+    free(xorkey);
+
+    return(ret);
+}