diff --git a/volatility3/framework/constants/linux/__init__.py b/volatility3/framework/constants/linux/__init__.py index 3eabc2341..a481e1ba9 100644 --- a/volatility3/framework/constants/linux/__init__.py +++ b/volatility3/framework/constants/linux/__init__.py @@ -302,3 +302,6 @@ class ELF_CLASS(IntEnum): ELFCLASSNONE = 0 ELFCLASS32 = 1 ELFCLASS64 = 2 + + +NSEC_PER_SEC = 1e9 diff --git a/volatility3/framework/symbols/linux/__init__.py b/volatility3/framework/symbols/linux/__init__.py index 219f120ee..95b476263 100644 --- a/volatility3/framework/symbols/linux/__init__.py +++ b/volatility3/framework/symbols/linux/__init__.py @@ -3,11 +3,15 @@ # import math import contextlib +import datetime +import dataclasses from abc import ABC, abstractmethod from typing import Iterator, List, Tuple, Optional, Union from volatility3 import framework from volatility3.framework import constants, exceptions, interfaces, objects +from volatility3.framework.renderers import conversion +from volatility3.framework.constants.linux import NSEC_PER_SEC from volatility3.framework.objects import utility from volatility3.framework.symbols import intermed from volatility3.framework.symbols.linux import extensions @@ -830,3 +834,97 @@ class PageCache(object): page = self.vmlinux.object("page", offset=page_addr, absolute=True) if page: yield page + + +@dataclasses.dataclass +class TimespecVol3(object): + """Internal helper class to handle all required timespec operations, convertions and + adjustments. + + NOTE: This is intended for exclusive use with get_boottime() and its related functions. + """ + + tv_sec: int = 0 + tv_nsec: int = 0 + + @classmethod + def new_from_timespec(cls, timespec) -> "TimespecVol3": + """Creates a new instance from a TimespecVol3 or timespec64 object""" + if not isinstance(timespec, (TimespecVol3, extensions.timespec64)): + raise TypeError("It requires either a TimespecVol3 or timespec64 type") + + tv_sec = int(timespec.tv_sec) + tv_nsec = int(timespec.tv_nsec) + return cls(tv_sec=tv_sec, tv_nsec=tv_nsec) + + @classmethod + def new_from_nsec(cls, nsec) -> "TimespecVol3": + """Creates a new instance from an integer in nanoseconds""" + + # Based on ns_to_timespec64() + if nsec > 0: + tv_sec = nsec // NSEC_PER_SEC + tv_nsec = nsec % NSEC_PER_SEC + elif nsec < 0: + tv_sec = -((-nsec - 1) // NSEC_PER_SEC) - 1 + rem = (-nsec - 1) % NSEC_PER_SEC + tv_nsec = NSEC_PER_SEC - rem - 1 + else: + tv_sec = tv_nsec = 0 + + return cls(tv_sec=tv_sec, tv_nsec=tv_nsec) + + def to_datetime(self) -> datetime.datetime: + """Converts this TimespecVol3 to a UTC aware datetime""" + return conversion.unixtime_to_datetime( + self.tv_sec + self.tv_nsec / NSEC_PER_SEC + ) + + def to_timedelta(self) -> datetime.timedelta: + """Converts this TimespecVol3 to timedelta""" + return datetime.timedelta(seconds=self.tv_sec + self.tv_nsec / NSEC_PER_SEC) + + def __add__(self, timespec) -> "TimespecVol3": + """Returns a new TimespecVol3 object that sums the current values with those + in the timespec argument""" + if not isinstance(timespec, (TimespecVol3, extensions.timespec64)): + raise TypeError("Cannot add a TimespecVol3 to this object") + + result = TimespecVol3( + tv_sec=self.tv_sec + timespec.tv_sec, + tv_nsec=self.tv_nsec + timespec.tv_nsec, + ) + + result.normalize() + + return result + + def __sub__(self, timespec) -> "TimespecVol3": + """Returns a new TimespecVol3 object that subtracts the values in the timespec + argument from the current object's values""" + if not isinstance(timespec, (TimespecVol3, extensions.timespec64)): + raise TypeError("Cannot add a TimespecVol3 to this object") + + result = TimespecVol3( + tv_sec=self.tv_sec - timespec.tv_sec, + tv_nsec=self.tv_nsec - timespec.tv_nsec, + ) + result.normalize() + + return result + + def normalize(self): + """Normalize any overflow in tv_sec and tv_nsec after previous addition or subtractions""" + # Based on kernel's set_normalized_timespec64() + while self.tv_nsec >= NSEC_PER_SEC: + self.tv_nsec -= NSEC_PER_SEC + self.tv_sec += 1 + + while self.tv_nsec < 0: + self.tv_nsec += NSEC_PER_SEC + self.tv_sec -= 1 + + def negate(self): + """Negates the sign of both tv_sec and tv_nsec""" + self.tv_sec = -self.tv_sec + self.tv_nsec = -self.tv_nsec diff --git a/volatility3/framework/symbols/linux/extensions/__init__.py b/volatility3/framework/symbols/linux/extensions/__init__.py index d9392b9ba..b3e836102 100644 --- a/volatility3/framework/symbols/linux/extensions/__init__.py +++ b/volatility3/framework/symbols/linux/extensions/__init__.py @@ -382,6 +382,203 @@ class task_struct(generic.GenericIntelProcess): threads_seen.add(task.vol.offset) yield task + def _get_task_start_time(self) -> datetime.timedelta: + """Returns the task's monotonic start_time as a timedelta. + + Returns: + The task's start time as a timedelta object. + """ + for member_name in ("start_boottime", "real_start_time", "start_time"): + if self.has_member(member_name): + start_time_obj = self.member(member_name) + start_time_obj_type = start_time_obj.vol.type_name + start_time_obj_type_name = start_time_obj_type.split(constants.BANG)[1] + if start_time_obj_type_name != "timespec": + # kernels >= 3.17 real_start_time and start_time are u64 + # kernels >= 5.5 uses start_boottime which is also a u64 + start_time = linux.TimespecVol3.new_from_nsec(start_time_obj) + else: + # kernels < 3.17 real_start_time and start_time are timespec + start_time = linux.TimespecVol3.new_from_timespec(start_time_obj) + + # This is relative to the boot time so it makes sense to be a timedelta. + return start_time.to_timedelta() + + raise AttributeError("Unsupported task_struct start_time member") + + def get_time_namespace(self) -> Optional[interfaces.objects.ObjectInterface]: + """Returns the task's time namespace""" + vmlinux = linux.LinuxUtilities.get_module_from_volobj_type(self._context, self) + if not self.has_member("nsproxy"): + # kernels < 2.6.19: ab516013ad9ca47f1d3a936fa81303bfbf734d52 + return None + + if not vmlinux.get_type("nsproxy").has_member("time_ns"): + # kernels < 5.6 769071ac9f20b6a447410c7eaa55d1a5233ef40c + return None + + return self.nsproxy.time_ns + + def get_time_namespace_id(self) -> int: + """Returns the task's time namespace ID.""" + time_ns = self.get_time_namespace() + if not time_ns: + # kernels < 5.6 + return + + # We are good. ns_common (ns) was introduced in kernels 3.19. So by the time the + # time namespace was added in kernels 5.6, it already included the ns member. + return time_ns.ns.inum + + def _get_time_namespace_offsets( + self, + ) -> Optional[interfaces.objects.ObjectInterface]: + """Returns the time offsets from the task's time namespace.""" + time_ns = self.get_time_namespace() + if not time_ns: + # kernels < 5.6 + return + + if not time_ns.has_member("offsets"): + # kernels < 5.6 af993f58d69ee9c1f421dfc87c3ed231c113989c + return None + + return time_ns.offsets + + def get_time_namespace_monotonic_offset( + self, + ) -> Optional[interfaces.objects.ObjectInterface]: + """Gets task's time namespace monotonic offset + + Returns: + a kernel's timespec64 object with the monotonic offset + """ + time_namespace_offsets = self._get_time_namespace_offsets() + if not time_namespace_offsets: + return None + + return time_namespace_offsets.monotonic + + def _get_time_namespace_boottime_offset( + self, + ) -> Optional[interfaces.objects.ObjectInterface]: + """Gets task's time namespace boottime offset + + Returns: + a kernel's timespec64 object with the boottime offset + """ + time_namespace_offsets = self._get_time_namespace_offsets() + if not time_namespace_offsets: + return None + + return time_namespace_offsets.boottime + + def _get_boottime_raw(self) -> "linux.TimespecVol3": + """Returns the boot time in a TimespecVol3.""" + + vmlinux = linux.LinuxUtilities.get_module_from_volobj_type(self._context, self) + if vmlinux.has_symbol("tk_core"): + # kernels >= 3.17 | tk_core | 3fdb14fd1df70325e1e91e1203a699a4803ed741 + tk_core = vmlinux.object_from_symbol("tk_core") + timekeeper = tk_core.timekeeper + if not timekeeper.offs_real.has_member("tv64"): + # kernels >= 4.10 - Tested on Ubuntu 6.8.0-41 + boottime_nsec = timekeeper.offs_real - timekeeper.offs_boot + else: + # 3.17 <= kernels < 4.10 - Tested on Ubuntu 4.4.0-142 + boottime_nsec = timekeeper.offs_real.tv64 - timekeeper.offs_boot.tv64 + return linux.TimespecVol3.new_from_nsec(boottime_nsec) + + elif vmlinux.has_symbol("timekeeper") and vmlinux.get_type( + "timekeeper" + ).has_member("wall_to_monotonic"): + # 3.4 <= kernels < 3.17 - Tested on Ubuntu 3.13.0-185 + timekeeper = vmlinux.object_from_symbol("timekeeper") + + # timekeeper.wall_to_monotonic is timespec + boottime = linux.TimespecVol3.new_from_timespec( + timekeeper.wall_to_monotonic + ) + + boottime += timekeeper.total_sleep_time + + boottime.negate() + boottime.normalize() + + return boottime + + elif vmlinux.has_symbol("wall_to_monotonic"): + # kernels < 3.4 - Tested on Debian7 3.2.0-4 (3.2.57-3+deb7u2) + wall_to_monotonic = vmlinux.object_from_symbol("wall_to_monotonic") + boottime = linux.TimespecVol3.new_from_timespec(wall_to_monotonic) + if vmlinux.has_symbol("total_sleep_time"): + # 2.6.23 <= kernels < 3.4 7c3f1a573237b90ef331267260358a0ec4ac9079 + total_sleep_time = vmlinux.object_from_symbol("total_sleep_time") + full_type_name = total_sleep_time.vol.type_name + type_name = full_type_name.split(constants.BANG)[1] + if type_name == "timespec": + # kernels >= 2.6.32 total_sleep_time is a timespec + boottime += total_sleep_time + else: + # kernels < 2.6.32 total_sleep_time is an unsigned long as seconds + boottime.tv_sec += total_sleep_time + + boottime.negate() + boottime.normalize() + + return boottime + + raise exceptions.VolatilityException("Unsupported") + + def get_boottime(self, root_time_namespace: bool = True) -> datetime.datetime: + """Returns the boot time in UTC as a datetime. + + Args: + root_time_namespace: If True, it returns the boot time as seen from the root + time namespace. Otherwise, it returns the boot time relative to the + task's time namespace. + + Returns: + A datetime with the UTC boot time. + """ + boottime = self._get_boottime_raw() + if not boottime: + return None + + if not root_time_namespace: + # Shift boot timestamp according to the task's time namespace offset + boottime_offset_timespec = self._get_time_namespace_boottime_offset() + if boottime_offset_timespec: + # Time namespace support is from kernels 5.6 + boottime -= boottime_offset_timespec + + return boottime.to_datetime() + + def get_create_time(self) -> datetime.datetime: + """Retrieves the task's start time from its time namespace. + Args: + context: The context to retrieve required elements (layers, symbol tables) from + vmlinux_module_name: The name of the kernel module on which to operate + task: A reference task + + Returns: + A datetime with task's start time + """ + # Typically, we want to see the creation time seen from the root time namespace + boottime = self.get_boottime(root_time_namespace=True) + + # The kernel exports only tv_sec to procfs, see kernel's show_stat(). + # This means user-space tools, like those in the procps package (e.g., ps, top, etc.), + # only use the boot time seconds to compute dates relatives to this. + boottime = boottime.replace(microsecond=0) + + task_start_time_timedelta = self._get_task_start_time() + + # NOTE: Do NOT apply the task's time namespace offsets here. While the kernel uses + # timens_add_boottime_ns(), it's not needed here since we're seeing it from the + # root time namespace, not within the task's own time namespace + return boottime + task_start_time_timedelta + class fs_struct(objects.StructType): def get_root_dentry(self):