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authorKyleMiles <krm504@nyu.edu>2018-07-05 18:28:59 -0400
committerRyan Snyder <ryan@vector35.com>2018-07-10 18:11:10 -0400
commit975249d22e10360ed2c4c0bcea151c39d9446b0a (patch)
tree93c2abb7b184bd64565ae1f116728141bfa051c2 /python/examples/jump_table.py
parentfd42578dce78f4c5a530177426e6a2ea11fc95ed (diff)
Rebased so commit history is correct now
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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)