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duckyscript parser: robustify
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Big fat warning: the firmware does not yet support the following newly
added features:

 - raw characters
 - repeat

This was tested against a corpus of sample files from Hak5's main repo.
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@mikeryan
mikeryan committed Dec 5, 2018
1 parent da6a715 commit 3417947
Showing 1 changed file with 124 additions and 40 deletions.
164 changes: 124 additions & 40 deletions script_gen.py
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Original file line number Diff line number Diff line change
Expand Up @@ -15,47 +15,93 @@
keywords = set((
'rem', 'gui', 'string', 'enter',
'default_delay', 'defaultdelay',
'delay', 'windows', 'menu', 'app',
'delay', 'windows', 'command', 'menu', 'app',
'shift', 'alt', 'control', 'ctrl',
'leftarrow', 'left', 'rightarrow', 'right',
'uparrow', 'up', 'downarrow', 'down',
'tab', 'esc', 'escape', 'backspace', 'back',
'space', 'repeat', 'printscreen',
'f1', 'f2', 'f3', 'f4', 'f5', 'f6',
'f7', 'f8', 'f9', 'f10', 'f11', 'f12',
))

canonical = {
'gui': 'windows',
'command': 'windows',
'defaultdelay': 'default_delay',
'app': 'menu',
'ctrl': 'control',
'leftarrow': 'left',
'rightarrow': 'right',
'uparrow': 'up',
'downarrow': 'down',
}

mods = {
'ctrl': 1,
'control': 1,
'shift': 2,
'alt': 4,
'windows': 8,
}

special = {
'enter': 1,
'tab': 2,
'esc': 3,
'back': 4,
}

raw = {
None: 0x00,
'menu': 0x76,
'printscreen': 0x46,
}

# convert arguments into canonical form
# returns None if there is a problem with the arg
# raises Exception if there is a problem with the arg
def clean_arg(arg):
if arg is None or len(arg) == 0:
return None
raise Exception('Empty argument')
if len(arg) == 1:
return arg
return { 'type': 'chr', 'value': arg }

arg = arg.lower()
if arg == 'enter':
return arg
arg = canonical.get(arg, arg)
if arg == 'space':
return ' '
return { 'type': 'chr', 'value': ' ' }
if arg == 'enter':
return { 'type': 'special', 'value': 'enter' };
if arg == 'tab':
return { 'type': 'special', 'value': 'tab' }
if arg == 'esc' or arg == 'escape':
return { 'type': 'special', 'value': 'esc' }
if arg == 'backspace' or arg == 'back':
return { 'type': 'special', 'value': 'back' }
if arg == 'menu':
return { 'type': 'raw', 'value': 'menu' }
if arg == 'printscreen':
return { 'type': 'raw', 'value': 'printscreen' }
if arg == 'right':
return { 'type': 'arrow', 'value': 0 }
if arg == 'left':
return { 'type': 'arrow', 'value': 1 }
if arg == 'down':
return { 'type': 'arrow', 'value': 2 }
if arg == 'up':
return { 'type': 'arrow', 'value': 3 }
if len(arg) > 1:
# f keys
if arg[0] == 'f':
try:
num = int(arg[1:])
if num >= 1 and num <= 12:
return arg
if num < 1 or num > 12:
raise Exception()
except:
pass
raise Exception('Invalid f-key "%s"' % arg)

return { 'type': 'fkey', 'value': num }

return None
raise Exception('Invalid argument "%s"' % arg)

# loads a script from a file and returns a list of tuples of (cmd, arg)
def load_script(file):
Expand All @@ -77,31 +123,45 @@ def load_script(file):
for cmd, arg in parsed_script:
if cmd == '':
continue

# multiple modifiers
if '-' in cmd:
rawparts = cmd.split('-')
parts = []
for p in rawparts:
if p in keywords:
m = canonical.get(p, p)
if m not in mods:
raise Exception("Invalid mod '%s'" % p)
parts.append(m)
arg = clean_arg(arg)
arg['mods'] = parts
script.append(arg)
continue

cmd = canonical.get(cmd, cmd)
if cmd not in keywords:
print "Error: unknown command '%s', ignoring" % cmd
raise Exception("Unknown command '%s'" % cmd)

# modifier key with a normal key argument
if cmd in mods:
try:
arg = clean_arg(arg)
except:
# special case: modifier with no argument
arg = { 'type': 'raw', 'value': None }
arg['mods'] = [cmd]
script.append(arg)
continue
canon = canonical.get(cmd)
if canon is not None:
cmd = canon

# comments
if cmd == 'rem':
pass

# command followed by argument
elif cmd in ('windows', 'menu', 'alt', 'control', 'shift'):
arg = clean_arg(arg)
if arg is not None:
script.append((cmd, arg))

# string of characters
elif cmd == 'string':
if len(arg) > 0:
script.append((cmd, arg))

# enter key
elif cmd == 'enter':
script.append((cmd, None))
script.append({ 'type': 'string', 'value': arg })

# default delay
elif cmd == 'default_delay':
Expand All @@ -115,26 +175,50 @@ def load_script(file):
arg = default_delay
else:
arg = int(arg)
script.append((cmd, arg))
script.append({ 'type': 'delay', 'value': arg })

elif cmd == 'repeat':
count = 1
if arg is not None:
count = int(arg)
script.append({ 'type': 'repeat', 'value': count })

else:
script.append(clean_arg(cmd))

return script

def ducky_to_bin(parsed):
script = []
for cmd, arg in s:
if cmd == 'delay':
script.append(struct.pack('<BH', 2, arg))
elif cmd in mods:
mod = mods[cmd]
script.append(struct.pack('BBBc', 1, 0, mod, arg))
elif cmd == 'enter':
script.append(struct.pack('BBBB', 1, 1, 0, 0))
elif cmd == 'string':
l = len(arg)
for cmd in s:
type, value = cmd['type'], cmd['value']

mod = 0
for m in cmd.get('mods', []):
mod |= mods[m]

if type == 'delay':
script.append(struct.pack('<BH', 2, value))
elif type == 'chr':
script.append(struct.pack('BBBc', 1, 0, mod, value))
elif type == 'special':
script.append(struct.pack('BBBB', 1, special[value], mod, 0))
elif type == 'fkey':
script.append(struct.pack('BBBB', 1, 5, mod, 0x3a + value-1))
elif type == 'arrow':
script.append(struct.pack('BBBB', 1, 5, mod, 0x4f + value))
elif type == 'printscreen':
script.append(struct.pack('BBBB', 1, 5, mod, 0x46))
elif type == 'raw':
script.append(struct.pack('BBBB', 1, 5, mod, raw[value]))
elif type == 'string':
l = len(value)
script.append(struct.pack('<BH', 3, l))
script.append(arg)
script.append(value)
elif type == 'repeat':
script.append(struct.pack('<BH', 4, value))
else:
print "not handled %s" % type
raise Exception("Unhandled command '%s'" % cmd[0])

binary_script = ''.join(script)
l = struct.pack('<H', len(binary_script))
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