Add some convenience/helper functions for RSA. Modify test utility to use the new function.
BUG=670
TEST=RSA verification test using the convenience function is passes.
Review URL: http://codereview.chromium.org/575019
diff --git a/crypto/rsa_utility.c b/crypto/rsa_utility.c
new file mode 100644
index 0000000..2215b7c
--- /dev/null
+++ b/crypto/rsa_utility.c
@@ -0,0 +1,46 @@
+/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Utility functions for message digest functions.
+ */
+
+#include "padding.h"
+#include "rsa_utility.h"
+#include "utility.h"
+
+int RSAProcessedKeySize(int algorithm) {
+ int key_len = siglen_map[algorithm] * sizeof(uint32_t); /* Key length in
+ * bytes. */
+ /* Total size needed by a RSAPublicKey structure is =
+ * 2 * key_len bytes for the n and rr arrays
+ * + sizeof len + sizeof n0inv.
+ */
+ return (2 * key_len + sizeof(int) + sizeof(uint32_t));
+}
+
+RSAPublicKey* RSAPublicKeyFromBuf(uint8_t* buf, int len) {
+ RSAPublicKey* key = (RSAPublicKey*) Malloc(sizeof(RSAPublicKey));
+ MemcpyState st;
+ int key_len;
+
+ st.remaining_buf = buf;
+ st.remaining_len = len;
+
+ StatefulMemcpy(&st, &key->len, sizeof(key->len));
+ key_len = key->len * sizeof(uint32_t); /* key length in bytes. */
+ key->n = (uint32_t*) Malloc(key_len);
+ key->rr = (uint32_t*) Malloc(key_len);
+
+ StatefulMemcpy(&st, &key->n0inv, sizeof(key->n0inv));
+ StatefulMemcpy(&st, key->n, key_len);
+ StatefulMemcpy(&st, key->rr, key_len);
+ if (st.remaining_len != 0) { /* Underrun or overrun. */
+ Free(key->n);
+ Free(key->rr);
+ Free(key);
+ return NULL;
+ }
+
+ return key;
+}