1 files changed, 63 insertions, 0 deletions
diff --git a/python/examples/jump-table.py b/python/examples/jump-table.py
new file mode 100644
index 00000000..f057f52c
--- /dev/null
+++ b/python/examples/jump-table.py
@@ -0,0 +1,63 @@
+# This plugin will attempt to resolve simple jump tables (an array of code pointers) and add the desintations
+# as indirect branch targets so that the flow graph reflects the jump table's control flow.
+from binaryninja import *
+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 token.type == "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(arch, 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)