From 85487b4a0243bcb40e0294d8d9f4a40f626c2f8a Mon Sep 17 00:00:00 2001
From: Mike Auty <mike.auty@gmail.com>
Date: Tue, 9 Feb 2016 00:20:55 +0000
Subject: [PATCH] Add in initial efforts at x64 dtb finding using the
 self-referential pointer.

---
 dtbfinder.py | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 dtbfinder.py

diff --git a/dtbfinder.py b/dtbfinder.py
new file mode 100644
index 000000000..e6c539045
--- /dev/null
+++ b/dtbfinder.py
@@ -0,0 +1,98 @@
+import binascii
+import struct
+import sys
+
+import volatility.framework
+from volatility.framework import layers
+from volatility.framework.symbols import native
+
+__author__ = 'mike'
+
+PAGE_SIZE = 0x1000
+POINTER_SIZE = 8
+STRUCT = "Q"
+BIT = 64
+
+
+def utils_load_as():
+    nativelst = native.x86NativeTable
+
+    #    virtual_types = xp_sp2_x86_vtypes.ntkrnlmp_types
+    #
+    #    ntkrnlmp = vtypes.VTypeSymbolTable('ntkrnlmp', virtual_types, nativelst)
+
+    ctx = volatility.framework.contexts.Context(nativelst)
+    # ctx.symbol_space.append(nativelst)
+    # ctx.symbol_space.append(ntkrnlmp)
+    return ctx
+
+
+class DTBFinderX64(object):
+    def __init__(self, ctx):
+        self.ctx = ctx
+        self.page_map = {}
+
+    def store_page_mappings(self, offset):
+        page = self.ctx.memory.read('data', offset, PAGE_SIZE)
+        self.page_map[offset] = [x & 0xFFFFFFFFFFFFF000 for x in
+                                 struct.unpack("<" + STRUCT * int(PAGE_SIZE / POINTER_SIZE), page) if (x & 1 == 1)]
+
+    def scan(self, magic = 0x1ED):
+        for offset in range(self.ctx.memory['data'].minimum_address, self.ctx.memory['data'].maximum_address,
+                            PAGE_SIZE):
+            null = struct.unpack("<" + STRUCT, self.ctx.memory.read('data', offset, POINTER_SIZE))[0]
+            val = self.ctx.memory.read('data', offset + (magic * POINTER_SIZE), POINTER_SIZE)
+            test_val = struct.unpack("<" + STRUCT, val)[0] & 0xFFFFFFFFFFFFF000
+            offsetstr = ("{0:#0" + str((POINTER_SIZE * 2) + 2) + "x}").format(offset)
+            testvalstr = ("{0:#0" + str((POINTER_SIZE * 2) + 2) + "x}").format(test_val)
+            if offset == test_val and offset != 0:
+                self.store_page_mappings(offset)
+                print("MATCH at", offsetstr, "with magic", magic, "null", null)
+                # print("Offset", offsetstr, "Value", testvalstr)
+
+        # print(repr(self.page_map))
+        self.process_page_map()
+
+    def process_page_map(self):
+        for offset in self.page_map:
+
+            # Read through each of the entries to see how close it is to the actual DTB
+            bitmap = ""
+            for index in range(0, PAGE_SIZE, POINTER_SIZE):
+                val = self.ctx.memory.read('data', offset + index, POINTER_SIZE)
+                correct_val = self.ctx.memory.read('data', 0x0000000000124000 + index, POINTER_SIZE)
+                if val == 0:
+                    bitmap += "."
+                else:
+                    bitmap += ("1" if val == correct_val else "0")
+            print("{0:#018x}".format(offset), bitmap, "\n")
+
+            # if offset == 0x00000000003c3000:
+            # if offset == 0x0000000000124000:
+            #                print(sorted("{0:#018x}".format(x) for x in self.page_map[offset] if x != 0))
+            #                print(sorted("{0:#018x}".format(x) for x in self.page_map.keys() if x != 0))
+            #                break
+            # for value in self.page_map[index]:
+            # if value in self.page_map.keys():
+            #        counts["{0:#018x}".format(value)] = counts.get("{0:#018x}".format(value), 0) + 1
+
+
+def display_dtb(ctx, dtb_offset):
+    data = ctx.memory['data'].read(dtb_offset, PAGE_SIZE)
+    for index in range(int(PAGE_SIZE / POINTER_SIZE)):
+        value = data[index * POINTER_SIZE:(index + 1) * POINTER_SIZE]
+        if binascii.hexlify(value) != b"0000000000000000":
+            print("Index", index, "Value", binascii.hexlify(value))
+
+
+if __name__ == '__main__':
+
+    if BIT == 32:
+        POINTER_SIZE = 4
+        STRUCT = "I"
+
+    ctx = utils_load_as()
+    data = layers.physical.FileLayer(ctx, 'name', 'data', filename = sys.argv[1])
+    ctx.memory.add_layer(data)
+    # display_dtb(ctx, int(sys.argv[2], 16))
+    DTBFinderX64(ctx).scan()