1 files changed, 86 insertions, 0 deletions
diff --git a/python/examples/jump_table.py b/python/examples/jump_table.py
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+++ b/python/examples/jump_table.py
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+# Copyright (c) 2015-2017 Vector 35 LLC
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to
+# deal in the Software without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+# sell copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+
+# This plugin will attempt to resolve simple jump tables (an array of code pointers) and add the destinations
+# as indirect branch targets so that the flow graph reflects the jump table's control flow.
+from binaryninja.plugin import PluginCommand
+from binaryninja.enums import InstructionTextTokenType
+import struct
+
+
+def find_jump_table(bv, addr):
+	for block in bv.get_basic_blocks_at(addr):
+		func = block.function
+		arch = func.arch
+		addrsize = arch.address_size
+
+		# Grab the instruction tokens so that we can look for the table's starting address
+		tokens, length = arch.get_instruction_text(bv.read(addr, 16), addr)
+
+		# Look for the next jump instruction, which may be the current instruction. Some jump tables will
+		# compute the address first then jump to the computed address as a separate instruction.
+		jump_addr = addr
+		while jump_addr < block.end:
+			info = arch.get_instruction_info(bv.read(jump_addr, 16), jump_addr)
+			if len(info.branches) != 0:
+				break
+			jump_addr += info.length
+		if jump_addr >= block.end:
+			print("Unable to find jump after instruction 0x%x" % addr)
+			continue
+		print("Jump at 0x%x" % jump_addr)
+
+		# Collect the branch targets for any tables referenced by the clicked instruction
+		branches = []
+		for token in tokens:
+			if InstructionTextTokenType(token.type) == InstructionTextTokenType.PossibleAddressToken:  # Table addresses will be a "possible address" token
+				tbl = token.value
+				print("Found possible table at 0x%x" % tbl)
+				i = 0
+				while True:
+					# Read the next pointer from the table
+					data = bv.read(tbl + (i * addrsize), addrsize)
+					if len(data) == addrsize:
+						if addrsize == 4:
+							ptr = struct.unpack("<I", data)[0]
+						else:
+							ptr = struct.unpack("<Q", data)[0]
+
+						# If the pointer is within the binary, add it as a destination and continue
+						# to the next entry
+						if (ptr >= bv.start) and (ptr < bv.end):
+							print("Found destination 0x%x" % ptr)
+							branches.append((arch, ptr))
+						else:
+							# Once a value that is not a pointer is encountered, the jump table is ended
+							break
+					else:
+						# Reading invalid memory
+						break
+
+					i += 1
+
+		# Set the indirect branch targets on the jump instruction to be the list of targets discovered
+		func.set_user_indirect_branches(jump_addr, branches)
+
+
+# Create a plugin command so that the user can right click on an instruction referencing a jump table and
+# invoke the command
+PluginCommand.register_for_address("Process jump table", "Look for jump table destinations", find_jump_table)