From f6cefc91dac9daeca0b941e2d7591ae3da40e59f Mon Sep 17 00:00:00 2001
From: Dhruv Maroo <dhruvmaru007@gmail.com>
Date: Sat, 17 Feb 2024 10:37:36 +0530
Subject: [PATCH] Add a simple emulateme for floating point operations

    * Can be used to test floating point IL lifting
---
 src/rzil/emulatefloat.c | 75 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 src/rzil/emulatefloat.c

diff --git a/src/rzil/emulatefloat.c b/src/rzil/emulatefloat.c
new file mode 100644
index 0000000..6cf37ba
--- /dev/null
+++ b/src/rzil/emulatefloat.c
@@ -0,0 +1,75 @@
+/**
+ * \file
+ * Simple crackme-like program, which decrypts a string in memory, but uses floating point operations to do so.
+ * The decryption loop is implemented to not make any external calls, so it can be emulated nicely.
+ * See emulateme.c for the the non-floating point instruction counterpart.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#define LEN 0x10
+
+char seckrit[LEN + 1] = { 0xe, 0xf, 0x3, 0xd, 0x1a, 0x6d, 0xf, 0x1a, 0xa, 0x4, 0x62, 0x34, 0xf, 0x3d, 0x29, 0x52 };
+
+/* somewhat randomly generated numbers */
+const double secondary_key[LEN] = { 8.99833709175345e-10, -0.3846771547676213, 2112271980.5789769, -2496373494.813322, 0.8743511441461778, -0.7300930961653576, -9705324222.854767, 0.5248033950772337, -712026204.430174, -0.04255897245519691, -8.307435687809127e-10, -0.22546719870688525, -0.8951827579358256, -8272556172.013981, 8.200744604338547e-10, 0.7577483159942799 };
+
+int hash(double f) {
+	/* Get f to be >= 1 or >= -1, and then square it. */
+	if (f < 1 && f > -1) {
+		f = 1.0 / f;
+	}
+	f *= f;
+
+	/* Get the last byte of the rounded integer. */
+	int h = (int)f;
+	h &= 0xff;
+	return h;
+}
+
+void decrypt(const char *key) {
+	for (size_t i = 0; i < LEN; i++) {
+		double key_i = secondary_key[i];
+		int pad = hash(key_i);
+		seckrit[i] ^= (pad ^ key[i]);
+	}
+}
+
+#if INVERSE
+
+int main() {
+	const char *key = "FloatLikeAButter";
+	const char *result = "Hello from RzIL!";
+
+	printf("char seckrit[LEN + 1] = { ");
+	for (size_t i = 0; i < LEN; i++) {
+		double key_i = secondary_key[i];
+		int pad = hash(key_i);
+
+		printf("%#02x, ", pad ^ key[i] ^ result[i]);
+	}
+	printf("};\n");
+
+	return 0;
+}
+
+#else
+
+int main(int argc, const char *argv[]) {
+	if (argc != 2) {
+		printf("usage: %s [key]\n", argv[0]);
+		return 1;
+	}
+	const char *key = argv[1];
+	if (strlen(key) != LEN) {
+		printf("wrong length.\n");
+		return 1;
+	}
+	decrypt(key);
+	printf("Decrypted: %s\n", seckrit);
+	return 0;
+}
+
+#endif