1 files changed, 91 insertions, 0 deletions
diff --git a/sploit/builder/payload.py b/sploit/builder/payload.py
new file mode 100644
index 0000000..cef17e0
--- /dev/null
+++ b/sploit/builder/payload.py
@@ -0,0 +1,91 @@
+from sploit.arch import arch, itob
+from sploit.symtbl import Symtbl
+
+class Payload:
+    MAGIC = b'\xef'
+
+    def __init__(self, **kwargs):
+        self.payload = b''
+        self.sym = Symtbl(**kwargs)
+        self.ctrs = {}
+
+    def __len__(self):
+        return len(self.payload)
+
+    def __call__(self, badbytes=b''):
+        found = [ hex(x) for x in set(self.payload).intersection(badbytes) ]
+        if len(found) > 0:
+            raise Exception(f'Payload: bad bytes in content: {found}')
+        return self.payload
+
+    def _name(self, kind, sym):
+        if sym is not None: return sym
+        try: ctr = self.ctrs[kind]
+        except: ctr = 0
+        self.ctrs[kind] = ctr + 1
+        return f'{kind}_{ctr}'
+
+    def _append(self, value, sym):
+        (self.sym @ 0)[sym] = len(self)
+        self.payload += value
+        return self
+
+    def _prepend(self, value, sym):
+        self.sym >>= len(value)
+        (self.sym @ 0)[sym] = 0
+        self.payload = value + self.payload
+        return self
+
+    def bin(self, *values, sym=None):
+        return self._append(b''.join(values), sym=self._name('bin', sym))
+
+    def str(self, *values, sym=None):
+        values = [ v.encode() + b'\x00' for v in values ]
+        return self.bin(*values, sym=self._name('str', sym))
+
+    def int(self, *values, sym=None):
+        values = [ itob(v) for v in values ]
+        return self.bin(*values, sym=self._name('int', sym))
+
+    def int8(self, *values, sym=None):
+        values = [ itob(v, 1) for v in values ]
+        return self.bin(*values, sym=self._name('int', sym))
+
+    def int16(self, *values, sym=None):
+        values = [ itob(v, 2) for v in values ]
+        return self.bin(*values, sym=self._name('int', sym))
+
+    def int32(self, *values, sym=None):
+        values = [ itob(v, 4) for v in values ]
+        return self.bin(*values, sym=self._name('int', sym))
+
+    def int64(self, *values, sym=None):
+        values = [ itob(v, 8) for v in values ]
+        return self.bin(*values, sym=self._name('int', sym))
+
+    def ret(self, *values, sym=None):
+        return self.int(*values, sym=self._name('ret', sym))
+
+    def sbp(self, *values, sym=None):
+        if len(values) == 0:
+            return self.rep(self.MAGIC, arch.wordsize, sym=self._name('sbp', sym))
+        return self.int(*values, sym=self._name('sbp', sym))
+
+    def rep(self, value, size, sym=None):
+        return self.bin(self._rep_helper(value, size), sym=self._name('rep', sym))
+
+    def pad(self, size, value=None, sym=None):
+        return self.bin(self._pad_helper(size, value), sym=self._name('pad', sym))
+
+    def pad_front(self, size, value=None, sym=None):
+        return self._prepend(self._pad_helper(size, value), sym=self._name('pad', sym))
+
+    def _rep_helper(self, value, size, *, explain=''):
+        if size < 0:
+            raise Exception(f'Payload: {explain}rep: available space is negative')
+        if (size := size / len(value)) != int(size):
+            raise Exception(f'Payload: {explain}rep: element does not divide the space evenly')
+        return value * int(size)
+
+    def _pad_helper(self, size, value):
+        return self._rep_helper(value or arch.nopcode, size - len(self), explain='pad: ')