refactor: split into phases

phases/ctoasm.py

@@ -0,0 +1,85 @@
+from helper import *
+
+
+def make_c_to_asm(c_file, asm_file, payload_len):
+    print("--[ C to ASM: {} -> {} ]".format(c_file, asm_file))
+
+    asm = {
+        "initial": "",
+        "cleanup": "",
+        "fixup": "",
+    }
+
+    # Phase 1: Compile
+    print("---[ Compile: {} ]".format(c_file))
+    run_process_checkret([
+            path_cl,
+            "/c",
+            "/FA",
+            "/GS-",
+            "/Fa{}/".format(os.path.dirname(c_file)),
+            c_file,
+    ])
+    if not os.path.isfile(asm_file):
+        print("Error: Compiling failed")
+        return
+    asm["initial"] = file_readall_text(asm_file)
+
+    # Phase 2: Assembly cleanup
+    asm_clean_file = asm_file + ".clean"
+    print("---[ Cleanup: {} ]".format(asm_file))
+    run_process_checkret([
+        path_masmshc,
+        asm_file,
+        asm_clean_file,
+    ])
+    if not os.path.isfile(asm_clean_file):
+        print("Error: Cleanup filed")
+        return
+    else:
+        shutil.move(asm_clean_file, asm_file)
+        asm["cleanup"] = file_readall_text(asm_file)
+
+    # Phase 2: Assembly fixup
+    print("---[ Fixup  : {} ]".format(asm_file))
+    if not fixup_asm_file(asm_file, payload_len):
+        print("Error: Fixup failed")
+        return
+    else:
+        asm["fixup"] = file_readall_text(asm_file)
+
+    return asm
+
+
+def fixup_asm_file(filename, payload_len):
+    with open(filename, 'r') as asmfile:
+        lines = asmfile.readlines()
+
+    # replace external reference with shellcode reference
+    for idx, line in enumerate(lines): 
+        if "dobin" in lines[idx]:
+            print("    > Replace external reference at line: {}".format(idx))
+            lines[idx] = lines[idx].replace(
+                "mov	r8, QWORD PTR dobin",
+                "lea	r8, [shcstart]"
+            )
+
+    # replace payload length
+    for idx, line in enumerate(lines): 
+        if "11223344" in lines[idx]:
+            print("    > Replace payload length at line: {}".format(idx))
+            lines[idx] = lines[idx].replace("11223344", str(payload_len+1))
+            break
+            
+    # add label at end of code
+    for idx, line in enumerate(lines): 
+        if lines[idx].startswith("END"):
+            print("    > Add end of code label at line: {}".format(idx))
+            lines.insert(idx-1, "shcstart:\r\n")
+            lines.insert(idx, "\tnop\r\n")
+            break
+    
+    with open(filename, 'w') as asmfile:
+        asmfile.writelines(lines)
+
+    return True