def _alter_arg(number, arg, saved_arg, pid=pid):
if not saved_arg:
saved_arg = ptrace.peekuser(pid, 4 * number)
if arg != saved_arg:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, 4 * number, arg)
ptrace.pokeuser(pid, 4 * number, arg)
return (number, saved_arg)
def _alter_arg(number, arg, saved_arg, pid=pid):
if not saved_arg:
saved_arg = ptrace.peekuser(pid, 4 * number)
if arg != saved_arg:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, 4 * number, arg)
ptrace.pokeuser(pid, 4 * number, arg)
return (number, saved_arg)
def force_syscall(pid, scno, p1=0, p2=0, p3=0, p4=0, p5=0, p6=0):
registers = peek_args(pid, 6)
eip = ptrace.peekuser(pid, EIP)
eax = ptrace.peekuser(pid, EAX)
ptrace.pokeuser(pid, EIP, eip - 2)
ptrace.pokeuser(pid, EAX, scno) # Select new scno and point eip to syscall
poke_args(pid, 6, [p1, p2, p3, p4, p5, p6])
ptrace.syscall(pid, 0) # We make it return to userland and do syscal
wpid, status = os.waitpid(pid, wait_flags)
assert pid == wpid
ptrace.syscall(pid, 0) # Kernel stops us before syscall is done
wpid, status = os.waitpid(pid, wait_flags)
if wpid != pid:
print "problem: other syscall stopped woke up /2: ", pid, " != ", wpid
assert pid == wpid # Kernel stops us when syscall is done
res = ptrace.peekuser(pid, EAX) # We get the syscall result
ptrace.pokeuser(pid, EAX, eax) # and then mimic like nothing happened
poke_args(pid, 6, registers)
return res
def force_syscall(pid, scno, p1=0, p2=0, p3=0, p4=0, p5=0, p6=0):
registers = peek_args(pid, 6)
eip = ptrace.peekuser(pid, EIP)
eax = ptrace.peekuser(pid, EAX)
ptrace.pokeuser(pid, EIP, eip - 2)
ptrace.pokeuser(pid, EAX, scno) # Select new scno and point eip to syscall
poke_args(pid, 6, [p1, p2, p3, p4, p5, p6])
ptrace.syscall(pid, 0) # We make it return to userland and do syscal
wpid, status = os.waitpid(pid, wait_flags)
assert pid == wpid
ptrace.syscall(pid, 0) # Kernel stops us before syscall is done
wpid, status = os.waitpid(pid, wait_flags)
if wpid != pid:
print "problem: other syscall stopped woke up /2: ", pid, " != ", wpid
assert pid == wpid # Kernel stops us when syscall is done
res = ptrace.peekuser(pid, EAX) # We get the syscall result
ptrace.pokeuser(pid, EAX, eax) # and then mimic like nothing happened
poke_args(pid, 6, registers)
return res
def trace_syscall_after(pid, flags, tricklist, call, eax):
result = eax
state = flags["state"]
call_changes = flags["call_changes"]
# del flags['call_changes'] # ?
# FIX: copy/reverse slow?
tricklist = tricklist[:]
# do callafters for tricks we did callbefores on, in reverse order,
# minus the annulled trick (if any)
if flags.has_key("annul"):
result, annultrick = flags["annul"]
assert isinstance(result, types.IntType), "oops: waitsuspend not cleared?"
del flags["annul"]
call = call_changes[annultrick]
while tricklist and tricklist.pop()[0] != annultrick:
pass
elif flags.has_key("sigreturn"):
# we have to do this because ORIG_EAX somehow gets stomped by the
# sigreturn calls. maybe this is a kernel bug?
call = flags["sigreturn"]
del flags["sigreturn"]
tricklist.reverse()
memory = getMemory(pid)
for trick, callmask, signalmask in tricklist:
call = call_changes.get(trick, call)
if (not callmask or callmask.has_key(call)) and trick.is_enabled(pid):
r = trick.callafter(pid, call, result, state.get(trick))
if r != None:
result = r
memory.pop(trick)
assert memory.empty() # all momentary changes got popped
if result != eax:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, EAX, result)
ptrace.pokeuser(pid, EAX, result)
# undo any changes to child's args made on entry
# XXX: does this go here?
for n, arg in flags.get("args_delta", []):
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, 4 * n, arg)
ptrace.pokeuser(pid, 4 * n, arg)
call_save = flags.get("call_delta", -1)
if call_save >= 0:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, ORIG_EAX, call_save)
ptrace.pokeuser(pid, ORIG_EAX, call_save)
# could continue child hereabouts
ptrace.syscall(pid, 0)
if flags.has_key("call_delta"):
del flags["call_delta"]
if flags.has_key("args_delta"):
del flags["args_delta"]
del flags["insyscall"]
def trace_syscall_before(pid, flags, tricklist, call, scno, sysent):
nargs = sysent[syscallmap.NARGS]
args = peek_args(pid, nargs)
call_save = call
args_save = args[:]
call_changes = {}
state = {}
for trick, callmask, signalmask in tricklist:
if (not callmask or callmask.has_key(call)) and trick.is_enabled(pid):
r = trick.callbefore(pid, call, args)
# r is None or (state, result, call, args)
if r:
assert len(r) == 4, "callbefore must return None or a 4-tuple"
if r[1] != None:
# annul the call
call_changes[trick] = call
call = _badcall
args = []
flags["annul"] = (r[1], trick)
break
if r[0] != None:
state[trick] = r[0]
if r[2] != None:
call_changes[trick] = call
call = r[2]
assert isinstance(call, types.StringType)
if r[3] != None:
args = r[3]
assert len(args) <= 6, "kernel doesn't support 7+ args?"
# STATE at this point ?
# call_changes, args, args_save, scno, call, call_save, state, ???
flags["call_changes"] = call_changes
# XXX: maybe faster to just brute force args rather than this careful
# delta stuff?
# make any necessary changes to child's args, saving undo info
# (XXX: hmm, is this actually better than the iterative version?)
def _alter_arg(number, arg, saved_arg, pid=pid):
if not saved_arg:
saved_arg = ptrace.peekuser(pid, 4 * number)
if arg != saved_arg:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, 4 * number, arg)
ptrace.pokeuser(pid, 4 * number, arg)
return (number, saved_arg)
n = len(args)
args_delta = filter(None, map(_alter_arg, range(n), args, args_save[:n]))
if args_delta:
flags["args_delta"] = args_delta
if call == "sigreturn" or call == "rt_sigreturn":
flags["sigreturn"] = call
if call != call_save:
if isinstance(call, types.StringType):
callno = syscallmap.lookup_number(call)
else:
callno = call
try:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, ORIG_EAX, callno)
ptrace.pokeuser(pid, ORIG_EAX, callno)
flags["call_delta"] = scno
except OSError, e:
# FIX: do something better here
sys.exit("panic: call alter failed in trick %s (%s)" % (trick, e))
def poke_args(pid, nargs, args):
assert nargs <= 6, "kernel doesn't support 7+ args?"
for i in range(nargs):
ptrace.pokeuser(pid, 4 * i, args[i])
_skipcallafter = {}
def set_skipcallafter(pid):
global _skipcallafter
_skipcallafter[pid] = 1
def hard_kill(pid):
# FIX: isn't this a race? don't we need to wait on the child?
try:
poke_args(pid, 6, [0, 0, 0, 0, 0, 0])
except OSError, e:
print "warning: attempt to annul last syscall by zapping args failed" " (pid=%s, error=%s)" % (pid, e)
try:
ptrace.pokeuser(pid, ORIG_EAX, _badcall)
except OSError, e:
print "warning: attempt to annul last syscall" " (pid=%s, error=%s)" % (pid, e)
try:
ptrace.kill(pid)
except OSError, e:
print "warning: attempt to ptrace.kill process failed" " (pid=%s, error=%s)" % (pid, e)
except:
# XXX: should we really catch this? we shouldn't be absorbing
# arbitrary exceptions; this will cause trouble
print "warning: attempt to ptrace.kill process failed strangely" " (pid=%s, error=%s)" % (pid, e)
raise
try:
# SIGKILL isn't delivered until completion of the current syscall; this
# function tries to abort the current syscall before killing the child.
def callafter(self, pid, call, result, state):
v = ptrace.peekuser(pid, self.options['offset'])
print '[%s] found %s at offset %s' % (pid, v, self.options['offset'])
print '[%s] restoring %s at offset %s' % (pid, state,
self.options['offset'])
ptrace.pokeuser(pid, self.options['offset'], state)
def callbefore(self, pid, call, args):
v = ptrace.peekuser(pid, self.options['offset'])
print '[%s] poking %s at offset %s' % (pid, self.options['data'],
self.options['offset'])
ptrace.pokeuser(pid, self.options['offset'], self.options['data'])
return (v, None, None, None)
def callafter(self, pid, call, result, state):
v = ptrace.peekuser(pid, self.options['offset'])
print '[%s] found %s at offset %s' % (pid, v, self.options['offset'])
print '[%s] restoring %s at offset %s' % (pid, state, self.options['offset'])
ptrace.pokeuser(pid, self.options['offset'], state)
def callbefore(self, pid, call, args):
v = ptrace.peekuser(pid, self.options['offset'])
print '[%s] poking %s at offset %s' % (pid, self.options['data'], self.options['offset'])
ptrace.pokeuser(pid, self.options['offset'], self.options['data'])
return (v, None, None, None)
def trace_syscall_after(pid, flags, tricklist, call, eax):
result = eax
state = flags['state']
call_changes = flags['call_changes']
#del flags['call_changes'] # ?
# FIX: copy/reverse slow?
tricklist = tricklist[:]
# do callafters for tricks we did callbefores on, in reverse order,
# minus the annulled trick (if any)
if flags.has_key('annul'):
result, annultrick = flags['annul']
assert isinstance(result,
types.IntType), "oops: waitsuspend not cleared?"
del flags['annul']
call = call_changes[annultrick]
while tricklist and tricklist.pop()[0] != annultrick:
pass
elif flags.has_key('sigreturn'):
# we have to do this because ORIG_EAX somehow gets stomped by the
# sigreturn calls. maybe this is a kernel bug?
call = flags['sigreturn']
del flags['sigreturn']
tricklist.reverse()
memory = getMemory(pid)
for trick, callmask, signalmask in tricklist:
call = call_changes.get(trick, call)
if (not callmask or callmask.has_key(call)) \
and trick.is_enabled(pid):
r = trick.callafter(pid, call, result, state.get(trick))
if r != None:
result = r
memory.pop(trick)
assert memory.empty() # all momentary changes got popped
if result != eax:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, EAX, result)
ptrace.pokeuser(pid, EAX, result)
# undo any changes to child's args made on entry
# XXX: does this go here?
for n, arg in flags.get('args_delta', []):
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, 4 * n, arg)
ptrace.pokeuser(pid, 4 * n, arg)
call_save = flags.get('call_delta', -1)
if call_save >= 0:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, ORIG_EAX, call_save)
ptrace.pokeuser(pid, ORIG_EAX, call_save)
# could continue child hereabouts
ptrace.syscall(pid, 0)
if flags.has_key('call_delta'):
del flags['call_delta']
if flags.has_key('args_delta'):
del flags['args_delta']
del flags['insyscall']
def trace_syscall_before(pid, flags, tricklist, call, scno, sysent):
nargs = sysent[syscallmap.NARGS]
args = peek_args(pid, nargs)
call_save = call
args_save = args[:]
call_changes = {}
state = {}
for trick, callmask, signalmask in tricklist:
if (not callmask or callmask.has_key(call)) \
and trick.is_enabled(pid):
r = trick.callbefore(pid, call, args)
# r is None or (state, result, call, args)
if r:
assert len(r) == 4, "callbefore must return None or a 4-tuple"
if r[1] != None:
# annul the call
call_changes[trick] = call
call = _badcall
args = []
flags['annul'] = (r[1], trick)
break
if r[0] != None:
state[trick] = r[0]
if r[2] != None:
call_changes[trick] = call
call = r[2]
assert isinstance(call, types.StringType)
if r[3] != None:
args = r[3]
assert len(args) <= 6, "kernel doesn't support 7+ args?"
# STATE at this point ?
# call_changes, args, args_save, scno, call, call_save, state, ???
flags['call_changes'] = call_changes
# XXX: maybe faster to just brute force args rather than this careful
# delta stuff?
# make any necessary changes to child's args, saving undo info
# (XXX: hmm, is this actually better than the iterative version?)
def _alter_arg(number, arg, saved_arg, pid=pid):
if not saved_arg:
saved_arg = ptrace.peekuser(pid, 4 * number)
if arg != saved_arg:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, 4 * number, arg)
ptrace.pokeuser(pid, 4 * number, arg)
return (number, saved_arg)
n = len(args)
args_delta = filter(None, map(_alter_arg, range(n), args, args_save[:n]))
if args_delta:
flags['args_delta'] = args_delta
if call == 'sigreturn' or call == 'rt_sigreturn':
flags['sigreturn'] = call
if call != call_save:
if isinstance(call, types.StringType):
callno = syscallmap.lookup_number(call)
else:
callno = call
try:
if debug():
print "ptrace.pokeuser(%s, %s, %s)" % (pid, ORIG_EAX, callno)
ptrace.pokeuser(pid, ORIG_EAX, callno)
flags['call_delta'] = scno
except OSError, e:
# FIX: do something better here
sys.exit('panic: call alter failed in trick %s (%s)' % (trick, e))
def poke_args(pid, nargs, args):
assert nargs <= 6, "kernel doesn't support 7+ args?"
for i in range(nargs):
ptrace.pokeuser(pid, 4 * i, args[i])
def set_skipcallafter(pid):
global _skipcallafter
_skipcallafter[pid] = 1
def hard_kill(pid):
# FIX: isn't this a race? don't we need to wait on the child?
try:
poke_args(pid, 6, [0, 0, 0, 0, 0, 0])
except OSError, e:
print "warning: attempt to annul last syscall by zapping args failed" \
" (pid=%s, error=%s)" % (pid, e)
try:
ptrace.pokeuser(pid, ORIG_EAX, _badcall)
except OSError, e:
print "warning: attempt to annul last syscall" \
" (pid=%s, error=%s)" % (pid, e)
try:
ptrace.kill(pid)
except OSError, e:
print "warning: attempt to ptrace.kill process failed" \
" (pid=%s, error=%s)" % (pid, e)
except:
# XXX: should we really catch this? we shouldn't be absorbing
# arbitrary exceptions; this will cause trouble
print "warning: attempt to ptrace.kill process failed strangely" \
" (pid=%s, error=%s)" % (pid, e)
raise
