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Merge 4.4.70 into android-4.4
Changes in 4.4.70
usb: misc: legousbtower: Fix buffers on stack
usb: misc: legousbtower: Fix memory leak
USB: ene_usb6250: fix DMA to the stack
watchdog: pcwd_usb: fix NULL-deref at probe
char: lp: fix possible integer overflow in lp_setup()
USB: core: replace %p with %pK
ARM: tegra: paz00: Mark panel regulator as enabled on boot
tpm_crb: check for bad response size
infiniband: call ipv6 route lookup via the stub interface
dm btree: fix for dm_btree_find_lowest_key()
dm raid: select the Kconfig option CONFIG_MD_RAID0
dm bufio: avoid a possible ABBA deadlock
dm bufio: check new buffer allocation watermark every 30 seconds
dm cache metadata: fail operations if fail_io mode has been established
dm bufio: make the parameter "retain_bytes" unsigned long
dm thin metadata: call precommit before saving the roots
dm space map disk: fix some book keeping in the disk space map
md: update slab_cache before releasing new stripes when stripes resizing
rtlwifi: rtl8821ae: setup 8812ae RFE according to device type
mwifiex: pcie: fix cmd_buf use-after-free in remove/reset
ima: accept previously set IMA_NEW_FILE
KVM: x86: Fix load damaged SSEx MXCSR register
KVM: X86: Fix read out-of-bounds vulnerability in kvm pio emulation
regulator: tps65023: Fix inverted core enable logic.
s390/kdump: Add final note
s390/cputime: fix incorrect system time
ath9k_htc: Add support of AirTies 1eda:2315 AR9271 device
ath9k_htc: fix NULL-deref at probe
drm/amdgpu: Avoid overflows/divide-by-zero in latency_watermark calculations.
drm/amdgpu: Make display watermark calculations more accurate
drm/nouveau/therm: remove ineffective workarounds for alarm bugs
drm/nouveau/tmr: ack interrupt before processing alarms
drm/nouveau/tmr: fix corruption of the pending list when rescheduling an alarm
drm/nouveau/tmr: avoid processing completed alarms when adding a new one
drm/nouveau/tmr: handle races with hw when updating the next alarm time
cdc-acm: fix possible invalid access when processing notification
proc: Fix unbalanced hard link numbers
of: fix sparse warning in of_pci_range_parser_one
iio: dac: ad7303: fix channel description
pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes
pid_ns: Fix race between setns'ed fork() and zap_pid_ns_processes()
USB: serial: ftdi_sio: fix setting latency for unprivileged users
USB: serial: ftdi_sio: add Olimex ARM-USB-TINY(H) PIDs
ext4 crypto: don't let data integrity writebacks fail with ENOMEM
ext4 crypto: fix some error handling
net: qmi_wwan: Add SIMCom 7230E
fscrypt: fix context consistency check when key(s) unavailable
f2fs: check entire encrypted bigname when finding a dentry
fscrypt: avoid collisions when presenting long encrypted filenames
sched/fair: Do not announce throttled next buddy in dequeue_task_fair()
sched/fair: Initialize throttle_count for new task-groups lazily
usb: host: xhci-plat: propagate return value of platform_get_irq()
xhci: apply PME_STUCK_QUIRK and MISSING_CAS quirk for Denverton
usb: host: xhci-mem: allocate zeroed Scratchpad Buffer
net: irda: irda-usb: fix firmware name on big-endian hosts
usbvision: fix NULL-deref at probe
mceusb: fix NULL-deref at probe
ttusb2: limit messages to buffer size
usb: musb: tusb6010_omap: Do not reset the other direction's packet size
USB: iowarrior: fix info ioctl on big-endian hosts
usb: serial: option: add Telit ME910 support
USB: serial: qcserial: add more Lenovo EM74xx device IDs
USB: serial: mct_u232: fix big-endian baud-rate handling
USB: serial: io_ti: fix div-by-zero in set_termios
USB: hub: fix SS hub-descriptor handling
USB: hub: fix non-SS hub-descriptor handling
ipx: call ipxitf_put() in ioctl error path
iio: proximity: as3935: fix as3935_write
ceph: fix recursion between ceph_set_acl() and __ceph_setattr()
gspca: konica: add missing endpoint sanity check
s5p-mfc: Fix unbalanced call to clock management
dib0700: fix NULL-deref at probe
zr364xx: enforce minimum size when reading header
dvb-frontends/cxd2841er: define symbol_rate_min/max in T/C fe-ops
cx231xx-audio: fix init error path
cx231xx-audio: fix NULL-deref at probe
cx231xx-cards: fix NULL-deref at probe
powerpc/book3s/mce: Move add_taint() later in virtual mode
powerpc/pseries: Fix of_node_put() underflow during DLPAR remove
powerpc/64e: Fix hang when debugging programs with relocated kernel
ARM: dts: at91: sama5d3_xplained: fix ADC vref
ARM: dts: at91: sama5d3_xplained: not all ADC channels are available
arm64: xchg: hazard against entire exchange variable
arm64: uaccess: ensure extension of access_ok() addr
arm64: documentation: document tagged pointer stack constraints
xc2028: Fix use-after-free bug properly
mm/huge_memory.c: respect FOLL_FORCE/FOLL_COW for thp
staging: rtl8192e: fix 2 byte alignment of register BSSIDR.
staging: rtl8192e: rtl92e_get_eeprom_size Fix read size of EPROM_CMD.
iommu/vt-d: Flush the IOTLB to get rid of the initial kdump mappings
metag/uaccess: Fix access_ok()
metag/uaccess: Check access_ok in strncpy_from_user
uwb: fix device quirk on big-endian hosts
genirq: Fix chained interrupt data ordering
osf_wait4(): fix infoleak
tracing/kprobes: Enforce kprobes teardown after testing
PCI: Fix pci_mmap_fits() for HAVE_PCI_RESOURCE_TO_USER platforms
PCI: Freeze PME scan before suspending devices
drm/edid: Add 10 bpc quirk for LGD 764 panel in HP zBook 17 G2
nfsd: encoders mustn't use unitialized values in error cases
drivers: char: mem: Check for address space wraparound with mmap()
Linux 4.4.70
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit d66bb1607e2d8d384e53f3d93db5c18483c8c4f7 upstream.
proc_create_mount_point() forgot to increase the parent's nlink, and
it resulted in unbalanced hard link numbers, e.g. /proc/fs shows one
less than expected.
Fixes: eb6d38d542 ("proc: Allow creating permanently empty directories...")
Reported-by: Tristan Ye <tristan.ye@suse.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge 4.4.63 into android-4.4
Changes in 4.4.63:
cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups
thp: fix MADV_DONTNEED vs clear soft dirty race
drm/nouveau/mpeg: mthd returns true on success now
drm/nouveau/mmu/nv4a: use nv04 mmu rather than the nv44 one
CIFS: store results of cifs_reopen_file to avoid infinite wait
Input: xpad - add support for Razer Wildcat gamepad
perf/x86: Avoid exposing wrong/stale data in intel_pmu_lbr_read_32()
x86/vdso: Ensure vdso32_enabled gets set to valid values only
x86/vdso: Plug race between mapping and ELF header setup
acpi, nfit, libnvdimm: fix interleave set cookie calculation (64-bit comparison)
iscsi-target: Fix TMR reference leak during session shutdown
iscsi-target: Drop work-around for legacy GlobalSAN initiator
scsi: sr: Sanity check returned mode data
scsi: sd: Consider max_xfer_blocks if opt_xfer_blocks is unusable
scsi: sd: Fix capacity calculation with 32-bit sector_t
xen, fbfront: fix connecting to backend
libnvdimm: fix reconfig_mutex, mmap_sem, and jbd2_handle lockdep splat
irqchip/irq-imx-gpcv2: Fix spinlock initialization
ftrace: Fix removing of second function probe
char: Drop bogus dependency of DEVPORT on !M68K
char: lack of bool string made CONFIG_DEVPORT always on
Revert "MIPS: Lantiq: Fix cascaded IRQ setup"
kvm: fix page struct leak in handle_vmon
zram: do not use copy_page with non-page aligned address
powerpc: Disable HFSCR[TM] if TM is not supported
crypto: ahash - Fix EINPROGRESS notification callback
ath9k: fix NULL pointer dereference
dvb-usb-v2: avoid use-after-free
ext4: fix inode checksum calculation problem if i_extra_size is small
platform/x86: acer-wmi: setup accelerometer when machine has appropriate notify event
rtc: tegra: Implement clock handling
mm: Tighten x86 /dev/mem with zeroing reads
dvb-usb: don't use stack for firmware load
dvb-usb-firmware: don't do DMA on stack
virtio-console: avoid DMA from stack
pegasus: Use heap buffers for all register access
rtl8150: Use heap buffers for all register access
catc: Combine failure cleanup code in catc_probe()
catc: Use heap buffer for memory size test
ibmveth: calculate gso_segs for large packets
SUNRPC: fix refcounting problems with auth_gss messages.
tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done
net: ipv6: check route protocol when deleting routes
sctp: deny peeloff operation on asocs with threads sleeping on it
MIPS: fix Select HAVE_IRQ_EXIT_ON_IRQ_STACK patch.
Linux 4.4.63
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit 5b7abeae3af8c08c577e599dd0578b9e3ee6687b upstream.
Yet another instance of the same race.
Fix is identical to change_huge_pmd().
See "thp: fix MADV_DONTNEED vs. numa balancing race" for more details.
Link: http://lkml.kernel.org/r/20170302151034.27829-5-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We hit hardened usercopy feature check for kernel text access by reading
kcore file:
usercopy: kernel memory exposure attempt detected from ffffffff8179a01f (<kernel text>) (4065 bytes)
kernel BUG at mm/usercopy.c:75!
Bypassing this check for kcore by adding bounce buffer for ktext data.
Reported-by: Steve Best <sbest@redhat.com>
Fixes: f5509cc18daa ("mm: Hardened usercopy")
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 31374226
Change-Id: Ic93e6041b67d804a994518bf4950811f828b406e
(cherry picked from commit df04abfd181acc276ba6762c8206891ae10ae00d)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Next patch adds bounce buffer for ktext area, so it's
convenient to have single bounce buffer for both
vmalloc/module and ktext cases.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: 31374226
Change-Id: I8f517354e6d12aed75ed4ae6c0a6adef0a1e61da
(cherry picked from commit f5beeb1851ea6f8cfcf2657f26cb24c0582b4945)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
commit cd81a9170e69e018bbaba547c1fd85a585f5697a upstream.
For more convenient access if one has a pointer to the task.
As a minor nit take advantage of the fact that only task lock + rcu are
needed to safely grab ->exe_file. This saves mm refcount dance.
Use the helper in proc_exe_link.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 65376df582174ffcec9e6471bf5b0dd79ba05e4a ]
Commit b76437579d ("procfs: mark thread stack correctly in
proc/<pid>/maps") added [stack:TID] annotation to /proc/<pid>/maps.
Finding the task of a stack VMA requires walking the entire thread list,
turning this into quadratic behavior: a thousand threads means a
thousand stacks, so the rendering of /proc/<pid>/maps needs to look at a
million combinations.
The cost is not in proportion to the usefulness as described in the
patch.
Drop the [stack:TID] annotation to make /proc/<pid>/maps (and
/proc/<pid>/numa_maps) usable again for higher thread counts.
The [stack] annotation inside /proc/<pid>/task/<tid>/maps is retained, as
identifying the stack VMA there is an O(1) operation.
Siddesh said:
"The end users needed a way to identify thread stacks programmatically and
there wasn't a way to do that. I'm afraid I no longer remember (or have
access to the resources that would aid my memory since I changed
employers) the details of their requirement. However, I did do this on my
own time because I thought it was an interesting project for me and nobody
really gave any feedback then as to its utility, so as far as I am
concerned you could roll back the main thread maps information since the
information is available in the thread-specific files"
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 8148a73c9901a8794a50f950083c00ccf97d43b3)
If /proc/<PID>/environ gets read before the envp[] array is fully set up
in create_{aout,elf,elf_fdpic,flat}_tables(), we might end up trying to
read more bytes than are actually written, as env_start will already be
set but env_end will still be zero, making the range calculation
underflow, allowing to read beyond the end of what has been written.
Fix this as it is done for /proc/<PID>/cmdline by testing env_end for
zero. It is, apparently, intentionally set last in create_*_tables().
This bug was found by the PaX size_overflow plugin that detected the
arithmetic underflow of 'this_len = env_end - (env_start + src)' when
env_end is still zero.
The expected consequence is that userland trying to access
/proc/<PID>/environ of a not yet fully set up process may get
inconsistent data as we're in the middle of copying in the environment
variables.
Fixes: https://forums.grsecurity.net/viewtopic.php?f=3&t=4363
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=116461
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Pax Team <pageexec@freemail.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: Ia2f58d48c15478ed4b6e237b63e704c70ff21e96
Bug: 30951939
In changing from checking ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)
to capable(CAP_SYS_NICE), I missed that ptrace_my_access succeeds
when p == current, but the CAP_SYS_NICE doesn't.
Thus while the previous commit was intended to loosen the needed
privledges to modify a processes timerslack, it needlessly restricted
a task modifying its own timerslack via the proc/<tid>/timerslack_ns
(which is permitted also via the PR_SET_TIMERSLACK method).
This patch corrects this by checking if p == current before checking
the CAP_SYS_NICE value.
Cc: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
CC: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Mailing-list-url: http://www.spinics.net/lists/kernel/msg2317488.html
Change-Id: Ia3e8aff07c2d41f55b6617502d33c39b7d781aac
Signed-off-by: John Stultz <john.stultz@linaro.org>
As requested, this patch checks the existing LSM hooks
task_getscheduler/task_setscheduler when reading or modifying
the task's timerslack value.
Previous versions added new get/settimerslack LSM hooks, but
since they checked the same PROCESS__SET/GETSCHED values as
existing hooks, it was suggested we just use the existing ones.
Cc: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
CC: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: James Morris <jmorris@namei.org>
Cc: Android Kernel Team <kernel-team@android.com>
Cc: linux-security-module@vger.kernel.org
Cc: selinux@tycho.nsa.gov
Signed-off-by: John Stultz <john.stultz@linaro.org>
FROMLIST URL: https://lkml.org/lkml/2016/7/21/523
Change-Id: Id157d10e2fe0b85f1be45035a6117358a42af028
(Cherry picked back to common/android-4.4)
Signed-off-by: John Stultz <john.stultz@linaro.org>
When an interface to allow a task to change another tasks
timerslack was first proposed, it was suggested that something
greater then CAP_SYS_NICE would be needed, as a task could be
delayed further then what normally could be done with nice
adjustments.
So CAP_SYS_PTRACE was adopted instead for what became the
/proc/<tid>/timerslack_ns interface. However, for Android (where
this feature originates), giving the system_server
CAP_SYS_PTRACE would allow it to observe and modify all tasks
memory. This is considered too high a privilege level for only
needing to change the timerslack.
After some discussion, it was realized that a CAP_SYS_NICE
process can set a task as SCHED_FIFO, so they could fork some
spinning processes and set them all SCHED_FIFO 99, in effect
delaying all other tasks for an infinite amount of time.
So as a CAP_SYS_NICE task can already cause trouble for other
tasks, using it as a required capability for accessing and
modifying /proc/<tid>/timerslack_ns seems sufficient.
Thus, this patch loosens the capability requirements to
CAP_SYS_NICE and removes CAP_SYS_PTRACE, simplifying some
of the code flow as well.
This is technically an ABI change, but as the feature just
landed in 4.6, I suspect no one is yet using it.
Cc: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
CC: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Reviewed-by: Nick Kralevich <nnk@google.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
FROMLIST URL: https://lkml.org/lkml/2016/7/21/522
Change-Id: Ia75481402e3948165a1b7c1551c539530cb25509
(Cherry picked against common/android-4.4)
Signed-off-by: John Stultz <john.stultz@linaro.org>
(cherry picked from commit e54ad7f1ee263ffa5a2de9c609d58dfa27b21cd9)
This prevents stacking filesystems (ecryptfs and overlayfs) from using
procfs as lower filesystem. There is too much magic going on inside
procfs, and there is no good reason to stack stuff on top of procfs.
(For example, procfs does access checks in VFS open handlers, and
ecryptfs by design calls open handlers from a kernel thread that doesn't
drop privileges or so.)
Signed-off-by: Jann Horn <jannh@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: Ib050ef9dc10e623589d22e3a9e6aee9ee4f0cd5d
Bug: 29444228
This patch backports 969624b (which backports caaee6234d0 upstream),
from the v4.4-stable branch to the common/android-4.4 branch.
This patch is needed to provide the PTRACE_MODE_ATTACH_FSCREDS definition
which was used by the backported version of proc/<tid>/timerslack_ns
in change-id: Ie5799b9a3402a31f88cd46437dcda4a0e46415a7
commit caaee6234d05a58c5b4d05e7bf766131b810a657 upstream.
By checking the effective credentials instead of the real UID / permitted
capabilities, ensure that the calling process actually intended to use its
credentials.
To ensure that all ptrace checks use the correct caller credentials (e.g.
in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS
flag), use two new flags and require one of them to be set.
The problem was that when a privileged task had temporarily dropped its
privileges, e.g. by calling setreuid(0, user_uid), with the intent to
perform following syscalls with the credentials of a user, it still passed
ptrace access checks that the user would not be able to pass.
While an attacker should not be able to convince the privileged task to
perform a ptrace() syscall, this is a problem because the ptrace access
check is reused for things in procfs.
In particular, the following somewhat interesting procfs entries only rely
on ptrace access checks:
/proc/$pid/stat - uses the check for determining whether pointers
should be visible, useful for bypassing ASLR
/proc/$pid/maps - also useful for bypassing ASLR
/proc/$pid/cwd - useful for gaining access to restricted
directories that contain files with lax permissions, e.g. in
this scenario:
lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar
drwx------ root root /root
drwxr-xr-x root root /root/foobar
-rw-r--r-- root root /root/foobar/secret
Therefore, on a system where a root-owned mode 6755 binary changes its
effective credentials as described and then dumps a user-specified file,
this could be used by an attacker to reveal the memory layout of root's
processes or reveal the contents of files he is not allowed to access
(through /proc/$pid/cwd).
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[jstultz: Cherry-picked for common/android-4.4]
Signed-off-by: John Stultz <john.stultz@linaro.org>
This backports 5de23d435e88996b1efe0e2cebe242074ce67c9e
This patch provides a proc/PID/timerslack_ns interface which exposes a
task's timerslack value in nanoseconds and allows it to be changed.
This allows power/performance management software to set timer slack for
other threads according to its policy for the thread (such as when the
thread is designated foreground vs. background activity)
If the value written is non-zero, slack is set to that value. Otherwise
sets it to the default for the thread.
This interface checks that the calling task has permissions to to use
PTRACE_MODE_ATTACH_FSCREDS on the target task, so that we can ensure
arbitrary apps do not change the timer slack for other apps.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit e54ad7f1ee263ffa5a2de9c609d58dfa27b21cd9 upstream.
This prevents stacking filesystems (ecryptfs and overlayfs) from using
procfs as lower filesystem. There is too much magic going on inside
procfs, and there is no good reason to stack stuff on top of procfs.
(For example, procfs does access checks in VFS open handlers, and
ecryptfs by design calls open handlers from a kernel thread that doesn't
drop privileges or so.)
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8148a73c9901a8794a50f950083c00ccf97d43b3 upstream.
If /proc/<PID>/environ gets read before the envp[] array is fully set up
in create_{aout,elf,elf_fdpic,flat}_tables(), we might end up trying to
read more bytes than are actually written, as env_start will already be
set but env_end will still be zero, making the range calculation
underflow, allowing to read beyond the end of what has been written.
Fix this as it is done for /proc/<PID>/cmdline by testing env_end for
zero. It is, apparently, intentionally set last in create_*_tables().
This bug was found by the PaX size_overflow plugin that detected the
arithmetic underflow of 'this_len = env_end - (env_start + src)' when
env_end is still zero.
The expected consequence is that userland trying to access
/proc/<PID>/environ of a not yet fully set up process may get
inconsistent data as we're in the middle of copying in the environment
variables.
Fixes: https://forums.grsecurity.net/viewtopic.php?f=3&t=4363
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=116461
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Pax Team <pageexec@freemail.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The PR_DUMPABLE flag causes the pid related paths of the
proc file system to be owned by ROOT. The implementation
of pthread_set/getname_np however needs access to
/proc/<pid>/task/<tid>/comm.
If PR_DUMPABLE is false this implementation is locked out.
This patch installs a special permission function for
the file "comm" that grants read and write access to
all threads of the same group regardless of the ownership
of the inode. For all other threads the function falls back
to the generic inode permission check.
Signed-off-by: Janis Danisevskis <jdanis@google.com>
commit 28093f9f34cedeaea0f481c58446d9dac6dd620f upstream.
In gather_pte_stats() a THP pmd is cast into a pte, which is wrong
because the layouts may differ depending on the architecture. On s390
this will lead to inaccurate numa_maps accounting in /proc because of
misguided pte_present() and pte_dirty() checks on the fake pte.
On other architectures pte_present() and pte_dirty() may work by chance,
but there may be an issue with direct-access (dax) mappings w/o
underlying struct pages when HAVE_PTE_SPECIAL is set and THP is
available. In vm_normal_page() the fake pte will be checked with
pte_special() and because there is no "special" bit in a pmd, this will
always return false and the VM_PFNMAP | VM_MIXEDMAP checking will be
skipped. On dax mappings w/o struct pages, an invalid struct page
pointer would then be returned that can crash the kernel.
This patch fixes the numa_maps THP handling by introducing new "_pmd"
variants of the can_gather_numa_stats() and vm_normal_page() functions.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5c2ff95e41c9290d16556cd02e35b25d81be8fe0 upstream.
When working with hugetlbfs ptes (which are actually pmds) is not valid to
directly use pte functions like pte_present() because the hardware bit
layout of pmds and ptes can be different. This is the case on s390.
Therefore we have to convert the hugetlbfs ptes first into a valid pte
encoding with huge_ptep_get().
Currently the /proc/<pid>/numa_maps code uses hugetlbfs ptes without
huge_ptep_get(). On s390 this leads to the following two problems:
1) The pte_present() function returns false (instead of true) for
PROT_NONE hugetlb ptes. Therefore PROT_NONE vmas are missing
completely in the "numa_maps" output.
2) The pte_dirty() function always returns false for all hugetlb ptes.
Therefore these pages are reported as "mapped=xxx" instead of
"dirty=xxx".
Therefore use huge_ptep_get() to correctly convert the hugetlb ptes.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit caaee6234d05a58c5b4d05e7bf766131b810a657 upstream.
By checking the effective credentials instead of the real UID / permitted
capabilities, ensure that the calling process actually intended to use its
credentials.
To ensure that all ptrace checks use the correct caller credentials (e.g.
in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS
flag), use two new flags and require one of them to be set.
The problem was that when a privileged task had temporarily dropped its
privileges, e.g. by calling setreuid(0, user_uid), with the intent to
perform following syscalls with the credentials of a user, it still passed
ptrace access checks that the user would not be able to pass.
While an attacker should not be able to convince the privileged task to
perform a ptrace() syscall, this is a problem because the ptrace access
check is reused for things in procfs.
In particular, the following somewhat interesting procfs entries only rely
on ptrace access checks:
/proc/$pid/stat - uses the check for determining whether pointers
should be visible, useful for bypassing ASLR
/proc/$pid/maps - also useful for bypassing ASLR
/proc/$pid/cwd - useful for gaining access to restricted
directories that contain files with lax permissions, e.g. in
this scenario:
lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar
drwx------ root root /root
drwxr-xr-x root root /root/foobar
-rw-r--r-- root root /root/foobar/secret
Therefore, on a system where a root-owned mode 6755 binary changes its
effective credentials as described and then dumps a user-specified file,
this could be used by an attacker to reveal the memory layout of root's
processes or reveal the contents of files he is not allowed to access
(through /proc/$pid/cwd).
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Userspace processes often have multiple allocators that each do
anonymous mmaps to get memory. When examining memory usage of
individual processes or systems as a whole, it is useful to be
able to break down the various heaps that were allocated by
each layer and examine their size, RSS, and physical memory
usage.
This patch adds a user pointer to the shared union in
vm_area_struct that points to a null terminated string inside
the user process containing a name for the vma. vmas that
point to the same address will be merged, but vmas that
point to equivalent strings at different addresses will
not be merged.
Userspace can set the name for a region of memory by calling
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name);
Setting the name to NULL clears it.
The names of named anonymous vmas are shown in /proc/pid/maps
as [anon:<name>] and in /proc/pid/smaps in a new "Name" field
that is only present for named vmas. If the userspace pointer
is no longer valid all or part of the name will be replaced
with "<fault>".
The idea to store a userspace pointer to reduce the complexity
within mm (at the expense of the complexity of reading
/proc/pid/mem) came from Dave Hansen. This results in no
runtime overhead in the mm subsystem other than comparing
the anon_name pointers when considering vma merging. The pointer
is stored in a union with fieds that are only used on file-backed
mappings, so it does not increase memory usage.
Includes fix from Jed Davis <jld@mozilla.com> for typo in
prctl_set_vma_anon_name, which could attempt to set the name
across two vmas at the same time due to a typo, which might
corrupt the vma list. Fix it to use tmp instead of end to limit
the name setting to a single vma at a time.
Change-Id: I9aa7b6b5ef536cd780599ba4e2fba8ceebe8b59f
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
Make oom_adj and oom_score_adj user read-only.
Bug: 19636629
Change-Id: I055bb172d5b4d3d856e25918f3c5de8edf31e4a3
Signed-off-by: Rom Lemarchand <romlem@google.com>
Writing to /proc/$pid/coredump_filter always returns -ESRCH because commit
774636e19e ("proc: convert to kstrto*()/kstrto*_from_user()") removed
the setting of ret after the get_proc_task call and incorrectly left it as
-ESRCH. Instead, return 0 when successful.
Example breakage:
echo 0 > /proc/self/coredump_filter
bash: echo: write error: No such process
Fixes: 774636e19e ("proc: convert to kstrto*()/kstrto*_from_user()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org> [4.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge second patch-bomb from Andrew Morton:
- most of the rest of MM
- procfs
- lib/ updates
- printk updates
- bitops infrastructure tweaks
- checkpatch updates
- nilfs2 update
- signals
- various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
dma-debug, dma-mapping, ...
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (102 commits)
ipc,msg: drop dst nil validation in copy_msg
include/linux/zutil.h: fix usage example of zlib_adler32()
panic: release stale console lock to always get the logbuf printed out
dma-debug: check nents in dma_sync_sg*
dma-mapping: tidy up dma_parms default handling
pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
kexec: use file name as the output message prefix
fs, seqfile: always allow oom killer
seq_file: reuse string_escape_str()
fs/seq_file: use seq_* helpers in seq_hex_dump()
coredump: change zap_threads() and zap_process() to use for_each_thread()
coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
signal: remove jffs2_garbage_collect_thread()->allow_signal(SIGCONT)
signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
signals: kill block_all_signals() and unblock_all_signals()
nilfs2: fix gcc uninitialized-variable warnings in powerpc build
nilfs2: fix gcc unused-but-set-variable warnings
MAINTAINERS: nilfs2: add header file for tracing
nilfs2: add tracepoints for analyzing reading and writing metadata files
...
Pull trivial updates from Jiri Kosina:
"Trivial stuff from trivial tree that can be trivially summed up as:
- treewide drop of spurious unlikely() before IS_ERR() from Viresh
Kumar
- cosmetic fixes (that don't really affect basic functionality of the
driver) for pktcdvd and bcache, from Julia Lawall and Petr Mladek
- various comment / printk fixes and updates all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
bcache: Really show state of work pending bit
hwmon: applesmc: fix comment typos
Kconfig: remove comment about scsi_wait_scan module
class_find_device: fix reference to argument "match"
debugfs: document that debugfs_remove*() accepts NULL and error values
net: Drop unlikely before IS_ERR(_OR_NULL)
mm: Drop unlikely before IS_ERR(_OR_NULL)
fs: Drop unlikely before IS_ERR(_OR_NULL)
drivers: net: Drop unlikely before IS_ERR(_OR_NULL)
drivers: misc: Drop unlikely before IS_ERR(_OR_NULL)
UBI: Update comments to reflect UBI_METAONLY flag
pktcdvd: drop null test before destroy functions
The commit 96d0df79f2 ("proc: make proc_fd_permission() thread-friendly")
fixed the access to /proc/self/fd from sub-threads, but introduced another
problem: a sub-thread can't access /proc/<tid>/fd/ or /proc/thread-self/fd
if generic_permission() fails.
Change proc_fd_permission() to check same_thread_group(pid_task(), current).
Fixes: 96d0df79f2 ("proc: make proc_fd_permission() thread-friendly")
Reported-by: "Jin, Yihua" <yihua.jin@intel.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For now in task_name() we ignore the return code of string_escape_str()
call. This is not good if buffer suddenly becomes not big enough. Do the
proper error handling there.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
/proc/pid/oom_adj exists solely to avoid breaking existing userspace
binaries that write to the tunable.
Add a comment in the only possible location within the kernel tree to
describe the situation and motivation for keeping it around.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As mentioned in the commit 56eecdb912 ("mm: Use ptep/pmdp_set_numa()
for updating _PAGE_NUMA bit"), architectures like ppc64 don't do tlb
flush in set_pte/pmd functions.
So when dealing with existing pte in clear_soft_dirty, the pte must be
cleared before being modified.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently there's no easy way to get per-process usage of hugetlb pages,
which is inconvenient because userspace applications which use hugetlb
typically want to control their processes on the basis of how much memory
(including hugetlb) they use. So this patch simply provides easy access
to the info via /proc/PID/status.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Joern Engel <joern@logfs.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull s390 updates from Martin Schwidefsky:
"There is only one new feature in this pull for the 4.4 merge window,
most of it is small enhancements, cleanup and bug fixes:
- Add the s390 backend for the software dirty bit tracking. This
adds two new pgtable functions pte_clear_soft_dirty and
pmd_clear_soft_dirty which is why there is a hit to
arch/x86/include/asm/pgtable.h in this pull request.
- A series of cleanup patches for the AP bus, this includes the
removal of the support for two outdated crypto cards (PCICC and
PCICA).
- The irq handling / signaling on buffer full in the runtime
instrumentation code is dropped.
- Some micro optimizations: remove unnecessary memory barriers for a
couple of functions: [smb_]rmb, [smb_]wmb, atomics, bitops, and for
spin_unlock. Use the builtin bswap if available and make
test_and_set_bit_lock more cache friendly.
- Statistics and a tracepoint for the diagnose calls to the
hypervisor.
- The CPU measurement facility support to sample KVM guests is
improved.
- The vector instructions are now always enabled for user space
processes if the hardware has the vector facility. This simplifies
the FPU handling code. The fpu-internal.h header is split into fpu
internals, api and types just like x86.
- Cleanup and improvements for the common I/O layer.
- Rework udelay to solve a problem with kprobe. udelay has busy loop
semantics but still uses an idle processor state for the wait"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (66 commits)
s390: remove runtime instrumentation interrupts
s390/cio: de-duplicate subchannel validation
s390/css: unneeded initialization in for_each_subchannel
s390/Kconfig: use builtin bswap
s390/dasd: fix disconnected device with valid path mask
s390/dasd: fix invalid PAV assignment after suspend/resume
s390/dasd: fix double free in dasd_eckd_read_conf
s390/kernel: fix ptrace peek/poke for floating point registers
s390/cio: move ccw_device_stlck functions
s390/cio: move ccw_device_call_handler
s390/topology: reduce per_cpu() invocations
s390/nmi: reduce size of percpu variable
s390/nmi: fix terminology
s390/nmi: remove casts
s390/nmi: remove pointless error strings
s390: don't store registers on disabled wait anymore
s390: get rid of __set_psw_mask()
s390/fpu: split fpu-internal.h into fpu internals, api, and type headers
s390/dasd: fix list_del corruption after lcu changes
s390/spinlock: remove unneeded serializations at unlock
...
Pull wchan kernel address hiding from Ingo Molnar:
"This fixes a wchan related information leak in /proc/PID/stat.
There's a bit of an ABI twist to it: instead of setting the wchan
field to 0 (which is our usual technique) we set it conditionally to a
0/1 flag to keep ABI compatibility with older procps versions that
only fetches /proc/PID/wchan (symbolic names) if the absolute wchan
address is nonzero"
* 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
fs/proc, core/debug: Don't expose absolute kernel addresses via wchan
It turns out that at least some versions of glibc end up reading
/proc/meminfo at every single startup, because glibc wants to know the
amount of memory the machine has. And while that's arguably insane,
it's just how things are.
And it turns out that it's not all that expensive most of the time, but
the vmalloc information statistics (amount of virtual memory used in the
vmalloc space, and the biggest remaining chunk) can be rather expensive
to compute.
The 'get_vmalloc_info()' function actually showed up on my profiles as
4% of the CPU usage of "make test" in the git source repository, because
the git tests are lots of very short-lived shell-scripts etc.
It turns out that apparently this same silly vmalloc info gathering
shows up on the facebook servers too, according to Dave Jones. So it's
not just "make test" for git.
We had two patches to just cache the information (one by me, one by
Ingo) to mitigate this issue, but the whole vmalloc information of of
rather dubious value to begin with, and people who *actually* want to
know what the situation is wrt the vmalloc area should just look at the
much more complete /proc/vmallocinfo instead.
In fact, according to my testing - and perhaps more importantly,
according to that big search engine in the sky: Google - there is
nothing out there that actually cares about those two expensive fields:
VmallocUsed and VmallocChunk.
So let's try to just remove them entirely. Actually, this just removes
the computation and reports the numbers as zero for now, just to try to
be minimally intrusive.
If this breaks anything, we'll obviously have to re-introduce the code
to compute this all and add the caching patches on top. But if given
the option, I'd really prefer to just remove this bad idea entirely
rather than add even more code to work around our historical mistake
that likely nobody really cares about.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are primitives to create and query the software dirty bits
in a pte or pmd. But the clearing of the software dirty bits is done
in common code with x86 specific page table functions.
Add the missing architecture primitives to clear the software dirty
bits to allow the feature to be used on non-x86 systems, e.g. the
s390 architecture.
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
So the /proc/PID/stat 'wchan' field (the 30th field, which contains
the absolute kernel address of the kernel function a task is blocked in)
leaks absolute kernel addresses to unprivileged user-space:
seq_put_decimal_ull(m, ' ', wchan);
The absolute address might also leak via /proc/PID/wchan as well, if
KALLSYMS is turned off or if the symbol lookup fails for some reason:
static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
unsigned long wchan;
char symname[KSYM_NAME_LEN];
wchan = get_wchan(task);
if (lookup_symbol_name(wchan, symname) < 0) {
if (!ptrace_may_access(task, PTRACE_MODE_READ))
return 0;
seq_printf(m, "%lu", wchan);
} else {
seq_printf(m, "%s", symname);
}
return 0;
}
This isn't ideal, because for example it trivially leaks the KASLR offset
to any local attacker:
fomalhaut:~> printf "%016lx\n" $(cat /proc/$$/stat | cut -d' ' -f35)
ffffffff8123b380
Most real-life uses of wchan are symbolic:
ps -eo pid:10,tid:10,wchan:30,comm
and procps uses /proc/PID/wchan, not the absolute address in /proc/PID/stat:
triton:~/tip> strace -f ps -eo pid:10,tid:10,wchan:30,comm 2>&1 | grep wchan | tail -1
open("/proc/30833/wchan", O_RDONLY) = 6
There's one compatibility quirk here: procps relies on whether the
absolute value is non-zero - and we can provide that functionality
by outputing "0" or "1" depending on whether the task is blocked
(whether there's a wchan address).
These days there appears to be very little legitimate reason
user-space would be interested in the absolute address. The
absolute address is mostly historic: from the days when we
didn't have kallsyms and user-space procps had to do the
decoding itself via the System.map.
So this patch sets all numeric output to "0" or "1" and keeps only
symbolic output, in /proc/PID/wchan.
( The absolute sleep address can generally still be profiled via
perf, by tasks with sufficient privileges. )
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: kasan-dev <kasan-dev@googlegroups.com>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150930135917.GA3285@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there
is no need to do that again from its callers. Drop it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Steve French <smfrench@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Convert from manual allocation/copy_from_user/... to kstrto*() family
which were designed for exactly that.
One case can not be converted to kstrto*_from_user() to make code even
more simpler because of whitespace stripping, oh well...
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The proc_subdir_lock spinlock is used to allow only one task to make
change to the proc directory structure as well as looking up information
in it. However, the information lookup part can actually be entered by
more than one task as the pde_get() and pde_put() reference count update
calls in the critical sections are atomic increment and decrement
respectively and so are safe with concurrent updates.
The x86 architecture has already used qrwlock which is fair and other
architectures like ARM are in the process of switching to qrwlock. So
unfairness shouldn't be a concern in that conversion.
This patch changed the proc_subdir_lock to a rwlock in order to enable
concurrent lookup. The following functions were modified to take a
write lock:
- proc_register()
- remove_proc_entry()
- remove_proc_subtree()
The following functions were modified to take a read lock:
- xlate_proc_name()
- proc_lookup_de()
- proc_readdir_de()
A parallel /proc filesystem search with the "find" command (1000 threads)
was run on a 4-socket Haswell-EX box (144 threads). Before the patch, the
parallel search took about 39s. After the patch, the parallel find took
only 25s, a saving of about 14s.
The micro-benchmark that I used was artificial, but it was used to
reproduce an exit hanging problem that I saw in real application. In
fact, only allow one task to do a lookup seems too limiting to me.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, /proc/<pid>/map_files/ is restricted to CAP_SYS_ADMIN, and is
only exposed if CONFIG_CHECKPOINT_RESTORE is set.
Each mapped file region gets a symlink in /proc/<pid>/map_files/
corresponding to the virtual address range at which it is mapped. The
symlinks work like the symlinks in /proc/<pid>/fd/, so you can follow them
to the backing file even if that backing file has been unlinked.
Currently, files which are mapped, unlinked, and closed are impossible to
stat() from userspace. Exposing /proc/<pid>/map_files/ closes this
functionality "hole".
Not being able to stat() such files makes noticing and explicitly
accounting for the space they use on the filesystem impossible. You can
work around this by summing up the space used by every file in the
filesystem and subtracting that total from what statfs() tells you, but
that obviously isn't great, and it becomes unworkable once your filesystem
becomes large enough.
This patch moves map_files/ out from behind CONFIG_CHECKPOINT_RESTORE, and
adjusts the permissions enforced on it as follows:
* proc_map_files_lookup()
* proc_map_files_readdir()
* map_files_d_revalidate()
Remove the CAP_SYS_ADMIN restriction, leaving only the current
restriction requiring PTRACE_MODE_READ. The information made
available to userspace by these three functions is already
available in /proc/PID/maps with MODE_READ, so I don't see any
reason to limit them any further (see below for more detail).
* proc_map_files_follow_link()
This stub has been added, and requires that the user have
CAP_SYS_ADMIN in order to follow the links in map_files/,
since there was concern on LKML both about the potential for
bypassing permissions on ancestor directories in the path to
files pointed to, and about what happens with more exotic
memory mappings created by some drivers (ie dma-buf).
In older versions of this patch, I changed every permission check in
the four functions above to enforce MODE_ATTACH instead of MODE_READ.
This was an oversight on my part, and after revisiting the discussion
it seems that nobody was concerned about anything outside of what is
made possible by ->follow_link(). So in this version, I've left the
checks for PTRACE_MODE_READ as-is.
[akpm@linux-foundation.org: catch up with concurrent proc_pid_follow_link() changes]
Signed-off-by: Calvin Owens <calvinowens@fb.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
