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authorJordan Wiens <jordan@psifertex.com>2016-09-13 18:24:02 -0400
committerJordan Wiens <jordan@psifertex.com>2016-09-13 18:25:04 -0400
commit11d6f78e43e0f305be43aeb8fc75d9d6733e508a (patch)
treeab47f3aefcbc295971adef788e27fe50ce466cb9 /python/examples/jump_table.py
parentb398b6a0a8683ae844e6b61389d02317f53a252e (diff)
rename files to allow them to be imported
Diffstat (limited to 'python/examples/jump_table.py')
-rw-r--r--python/examples/jump_table.py63
1 files changed, 63 insertions, 0 deletions
diff --git a/python/examples/jump_table.py b/python/examples/jump_table.py
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+# 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 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)