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