Merge branch 'indextbl'

This branch is a major semantic redesign of Symtbl and Payload.  These
two classes are now implemented as derivitives of the newly refactored
IndexTbl mechanism.

Necessary cascading changes have been made to keep these tools in
working order.

* indextbl:
  payload: rop: Update for new Payload class
  Update ROP gadget types to extend IndexEntry
  payload: Refactor as a concrete IndexTbl
  lict: Add new list-dictionary hybrid type
  symtbl: Refactor abstract IndexTbl interface

1 files changed, 99 insertions, 0 deletions

diff --git a/sploit/payload/payload_entry.py b/sploit/payload/payload_entry.py
new file mode 100644
index 0000000..7088f83
--- /dev/null
+++ b/sploit/payload/payload_entry.py
@@ -0,0 +1,99 @@
+from sploit.arch import arch, itob
+from sploit.types.index_entry import IndexEntry
+
+_PLACEHOLDER_MAGIC = b"\xef"
+
+class PayloadEntry(IndexEntry):
+    """Base class for dynamic Payload entries"""
+
+    def __repr__(self):
+        """Return human-readable entry description."""
+        return f"{self.__class__.__name__}{self.__dict__}"
+
+    def payload_insert(self, payload):
+        """
+        Called on insert into a payload object.
+
+        Override this method to perform any initialization which requires a
+        reference to the payload object.  self.base is set to the insertion
+        location.
+        """
+        pass
+
+    def payload_bytes(self, payload):
+        """
+        Called to generate bytes for this entry.
+
+        Override this method to generate and return the binary output for this
+        dynamic payload entry.  self.base is set to the current entry address
+        or offset.
+        """
+        return b""
+
+# Concrete payload entry definitions
+
+class pointer(PayloadEntry):
+    """Generate an integer which is always a fixed offset from self.base."""
+
+    def __init__(self, target=None):
+        self.target = target
+
+    def payload_insert(self, payload):
+        if self.target is None:
+            self.target = self.base
+        self.target -= self.base
+
+    def payload_bytes(self, payload):
+        return itob(self.target + self.base)
+
+class padlen(PayloadEntry):
+    """Generate padding to reach a target payload length."""
+
+    def __init__(self, size, data=None):
+        self.size = size
+        self.data = data
+
+    def _gen_padding(self, size):
+        data = self.data or arch.nopcode
+        if size < 0:
+            raise ValueError("padding: Available space is negative")
+        if (size := size / len(data)) != int(size):
+            raise ValueError("padding: Element does not divide the space evenly")
+        return data * int(size)
+
+    def payload_bytes(self, payload):
+        return self._gen_padding(self.size - (self.base - payload.base))
+
+class padabs(padlen):
+    """Generate padding to reach a target absolute address."""
+
+    def payload_bytes(self, payload):
+        return self._gen_padding(self.size - self.base)
+
+class padrel(padlen):
+    """Generate a fixed length of padding (aka: length relative to self)."""
+
+    def payload_bytes(self, payload):
+        return self._gen_padding(self.size)
+
+class padalign(padlen):
+    """Generate padding to reach next aligned address."""
+
+    def __init__(self, size=None, data=None):
+        self.size = size
+        self.data = data
+
+    def payload_bytes(self, payload):
+        size = self.size or arch.alignment
+        return self._gen_padding(-self.base % size)
+
+class placeholder(padlen):
+    """Generate fixed length of magic bytes, one word length by default."""
+
+    def __init__(self, size=None):
+        self.size = size
+        self.data = _PLACEHOLDER_MAGIC
+
+    def payload_bytes(self, payload):
+        size = self.size or arch.wordsize
+        return self._gen_padding(size)