1 files changed, 81 insertions, 0 deletions
diff --git a/lib/libmpa/mpa_random.c b/lib/libmpa/mpa_random.c
new file mode 100644
index 0000000..2ee0031
--- /dev/null
+++ b/lib/libmpa/mpa_random.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2014, STMicroelectronics International N.V.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "mpa.h"
+#include <tee_api_types.h>
+
+static random_generator_cb get_rng_array;
+
+void mpa_set_random_generator(random_generator_cb callback)
+{
+	get_rng_array = callback;
+}
+
+static uint8_t get_random_byte(void)
+{
+	uint8_t buf;
+	while (get_rng_array(&buf, 1) != TEE_SUCCESS)
+	;
+
+	return buf;
+}
+
+/*------------------------------------------------------------
+ *
+ *  mpa_get_random
+ *
+ */
+void mpa_get_random(mpanum dest, mpanum limit)
+{
+	int done = 0;
+
+	mpa_wipe(dest);
+	if (__mpanum_alloced(dest) < __mpanum_size(limit))
+		dest->size = __mpanum_alloced(dest);
+	else
+		dest->size = __mpanum_size(limit);
+	while (!done) {
+		for (int idx = 0; idx < dest->size; idx++) {
+			mpa_word_t w = 0;
+			for (int j = 0; j < BYTES_PER_WORD; j++)
+				w = (w << 8) ^ get_random_byte();
+			dest->d[idx] = w;
+		}
+		if (dest->size < __mpanum_size(limit)) {
+			done = 1;
+		} else {
+			mpa_word_t hbi =
+			    (mpa_word_t) mpa_highest_bit_index(limit);
+			/* 1 <= hbi <= WORD_SIZE */
+			hbi = (hbi % WORD_SIZE) + 1;
+			if (hbi < WORD_SIZE) {
+				hbi = (1 << hbi) - 1;
+				dest->d[dest->size - 1] &= hbi;
+			}
+			done = (mpa_cmp(dest, limit) < 0) ? 1 : 0;
+		}
+	}
+}