initial commit

Signed-off-by: segfault <segfault@secmail.pro>

1 files changed, 77 insertions, 0 deletions

diff --git a/funccrypt.h b/funccrypt.h
new file mode 100644
index 0000000..6b1f95c
--- /dev/null
+++ b/funccrypt.h
@@ -0,0 +1,77 @@
+#ifndef FUNCCRYPT_H
+#define FUNCCRYPT_H 1
+
+#include <stdlib.h>
+#include <stdint.h>
+
+#if !defined(__GNUC__) || !defined(__GNUC_MINOR__)
+#error "This is only verified to work with GCC compiler!"
+#endif
+
+/* Force GCC struct for MingW compilers and pack them,
+ * which means the struct is 1-byte aligned.
+ */
+#define GCC_PACKED __attribute__((packed, gcc_struct))
+
+typedef struct crypt_header {
+    uint64_t key;
+    uint8_t crpyted;
+    uint32_t marker;
+    uint64_t func_body[0];
+} GCC_PACKED crypt_header;
+
+typedef enum crypt_return {
+    CRET_ERROR, CRET_PROLOGUE, CRET_EPILOGUE, CRET_CHECK, CRET_OK
+} crypt_return;
+
+#define CRYPT_FUNC_MAXSIZ 0x100
+#define CRYPT_FUNC(fn) \
+    crypt_func((void *)fn)
+#define CRYPT_PROLOGUE(fn) \
+    crypt_return __cr; \
+    { \
+        __cr = CRYPT_FUNC(fn); \
+        if (__cr != CRET_OK) \
+            asm volatile goto("jmp %l0          \n" \
+                : : : : cr_epilogue); \
+        asm volatile goto("jmp %l0          \n" \
+            : : : : cr_prologue); \
+        asm volatile( \
+            ".byte " \
+            /* key: */     "0x00, 0x00, 0x00, 0x00," \
+                           "0x00, 0x00, 0x00, 0x00," \
+            /* crypted: */ "0x00," \
+            /* marker: */  "0xDE, 0xC0, 0xDE, 0xC0;  \n" \
+        ); \
+    } \
+    cr_prologue: {
+#define CRYPT_EPILOGUE(fn) \
+    } { \
+        asm volatile goto("jmp %l0          \n" \
+            : : : : cr_epilogue); \
+        asm volatile( \
+            ".byte " \
+            /* Insert encryption pad, so we can find the end marker,
+             * while the function body is encrypted.
+             * (XOR 64 bit encryption == 8 byte)
+             */ \
+            "0x00, 0x00, 0x00, 0x00," \
+            "0x00, 0x00, 0x00, 0x00," \
+            /* marker: */   "0xFE, 0xCA, 0xFE, 0xCA;  \n" \
+        ); \
+    } \
+    cr_epilogue: \
+    CRYPT_FUNC(fn);
+
+#define CRYPT_FNDEF(name, ...) \
+    void name( __VA_ARGS__ ) { \
+        CRYPT_PROLOGUE( name );
+#define CRYPT_FNEND(name) \
+        CRYPT_EPILOGUE(name); \
+    }
+
+extern const char *crypt_strs[];
+extern void printHexBuf(uint8_t *buf, size_t siz, size_t chars_per_line);
+extern crypt_return crypt_func(void *fn_start);
+
+#endif