commit af2e8c68b9 upstream.
On some systems that are vulnerable to Spectre v2, it is up to
software to flush the link stack (return address stack), in order to
protect against Spectre-RSB.
When exiting from a guest we do some house keeping and then
potentially exit to C code which is several stack frames deep in the
host kernel. We will then execute a series of returns without
preceeding calls, opening up the possiblity that the guest could have
poisoned the link stack, and direct speculative execution of the host
to a gadget of some sort.
To prevent this we add a flush of the link stack on exit from a guest.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 39e72bf96f upstream.
In commit ee13cb249f ("powerpc/64s: Add support for software count
cache flush"), I added support for software to flush the count
cache (indirect branch cache) on context switch if firmware told us
that was the required mitigation for Spectre v2.
As part of that code we also added a software flush of the link
stack (return address stack), which protects against Spectre-RSB
between user processes.
That is all correct for CPUs that activate that mitigation, which is
currently Power9 Nimbus DD2.3.
What I got wrong is that on older CPUs, where firmware has disabled
the count cache, we also need to flush the link stack on context
switch.
To fix it we create a new feature bit which is not set by firmware,
which tells us we need to flush the link stack. We set that when
firmware tells us that either of the existing Spectre v2 mitigations
are enabled.
Then we adjust the patching code so that if we see that feature bit we
enable the link stack flush. If we're also told to flush the count
cache in software then we fall through and do that also.
On the older CPUs we don't need to do do the software count cache
flush, firmware has disabled it, so in that case we patch in an early
return after the link stack flush.
The naming of some of the functions is awkward after this patch,
because they're called "count cache" but they also do link stack. But
we'll fix that up in a later commit to ease backporting.
This is the fix for CVE-2019-18660.
Reported-by: Anthony Steinhauser <asteinhauser@google.com>
Fixes: ee13cb249f ("powerpc/64s: Add support for software count cache flush")
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5618332e5b upstream.
The userspace comedilib function 'get_cmd_generic_timed' fills
the cmd structure with an informed guess and then calls the
function 'usbduxfast_ai_cmdtest' in this driver repeatedly while
'usbduxfast_ai_cmdtest' is modifying the cmd struct until it
no longer changes. However, because of rounding errors this never
converged because 'steps = (cmd->convert_arg * 30) / 1000' and then
back to 'cmd->convert_arg = (steps * 1000) / 30' won't be the same
because of rounding errors. 'Steps' should only be converted back to
the 'convert_arg' if 'steps' has actually been modified. In addition
the case of steps being 0 wasn't checked which is also now done.
Signed-off-by: Bernd Porr <mail@berndporr.me.uk>
Cc: <stable@vger.kernel.org> # 4.4+
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20191118230759.1727-1-mail@berndporr.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 92fe35fb9c upstream.
The driver was setting the device remote-wakeup feature during probe in
violation of the USB specification (which says it should only be set
just prior to suspending the device). This could potentially waste
power during suspend as well as lead to spurious wakeups.
Note that USB core would clear the remote-wakeup feature at first
resume.
Fixes: 3f5429746d ("USB: Moschip 7840 USB-Serial Driver")
Cc: stable <stable@vger.kernel.org> # 2.6.19
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ea422312a4 upstream.
The driver was setting the device remote-wakeup feature during probe in
violation of the USB specification (which says it should only be set
just prior to suspending the device). This could potentially waste
power during suspend as well as lead to spurious wakeups.
Note that USB core would clear the remote-wakeup feature at first
resume.
Fixes: 0f64478cbc ("USB: add USB serial mos7720 driver")
Cc: stable <stable@vger.kernel.org> # 2.6.19
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e696d00e65 upstream.
Add USB ID for MOXA UPort 2210. This device contains mos7820 but
it passes GPIO0 check implemented by driver and it's detected as
mos7840. Hence product id check is added to force mos7820 mode.
Signed-off-by: Pavel Löbl <pavel@loebl.cz>
Cc: stable <stable@vger.kernel.org>
[ johan: rename id defines and add vendor-id check ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 91feb01596 upstream.
The work item can operate on
1. stale memory left over from the last transfer
the actual length of the data transfered needs to be checked
2. memory already freed
the error handling in appledisplay_probe() needs
to cancel the work in that case
Reported-and-tested-by: syzbot+495dab1f175edc9c2f13@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191106124902.7765-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 92aa5986f4 upstream.
In case of a timeout or if a signal aborts a read
communication with the device needs to be ended
lest we overwrite an active URB the next time we
do IO to the device, as the URB may still be active.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191107142856.16774-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 347bc8cb26 upstream.
Add support for the Mark-10 digital force gauge device to the cp201x
driver.
Based on a report and a larger patch from Joel Jennings
Reported-by: Joel Jennings <joel.jennings@makeitlabs.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191118092119.GA153852@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2a9125317b upstream.
Smatch reported that nents is not initialized and used in
stub_recv_cmd_submit(). nents is currently initialized by sgl_alloc()
and used to allocate multiple URBs when host controller doesn't
support scatter-gather DMA. The use of uninitialized nents means that
buf_len is zero and use_sg is true. But buffer length should not be
zero when an URB uses scatter-gather DMA.
To prevent this situation, add the conditional that checks buf_len
and use_sg. And move the use of nents right after the sgl_alloc() to
avoid the use of uninitialized nents.
If the error occurs, it adds SDEV_EVENT_ERROR_MALLOC and stub_priv
will be released by stub event handler and connection will be shut
down.
Fixes: ea44d19076 ("usbip: Implement SG support to vhci-hcd and stub driver")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Suwan Kim <suwan.kim027@gmail.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191111141035.27788-1-suwan.kim027@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 26a4d4c00f upstream.
We should close the fd before the return of read_attr_usbip_status.
Fixes: 3391ba0e27 ("usbip: tools: Extract generic code to be shared with vudc backend")
Signed-off-by: Hewenliang <hewenliang4@huawei.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191025043515.20053-1-hewenliang4@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5a858e79c9 upstream.
The old Nvidia chips have multiple HD-audio codecs on the same
HD-audio controller, and this doesn't work as expected with the current
audio component binding that is implemented under the one-codec-per-
controller assumption; at the probe time, the driver leads to several
kernel WARNING messages.
For the proper support, we may change the pin2port and port2pin to
traverse the codec list per the given pin number, but this needs more
development and testing.
As a quick workaround, instead, this patch drops the binding in the
audio side for these legacy chips since the audio component support in
nouveau graphics driver is still not merged (hence it's basically
unused).
[ Unlike the original commit, this patch actually disables the audio
component binding for all Nvidia chips, not only for legacy chips.
It doesn't matter much, though: nouveau gfx driver still doesn't
provide the audio component binding on 5.4.y, so it's only a
placeholder for now. Also, another difference from the original
commit is that this removes the nvhdmi_audio_ops and other
definitions completely in order to avoid a compile warning due to
unused stuff. -- tiwai ]
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=205625
Fixes: ade49db337 ("ALSA: hda/hdmi - Allow audio component for AMD/ATI and Nvidia HDMI")
Link: https://lore.kernel.org/r/20191122132000.4460-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e43148645d upstream.
Fix multiple cases of out of bounds (OOB) read associated with
MCE device receive/input data handling.
In reference for the OOB cases below, the incoming/read (byte) data
format when the MCE device responds to a command is:
{ cmd_prefix, subcmd, data0, data1, ... }
where cmd_prefix are:
MCE_CMD_PORT_SYS
MCE_CMD_PORT_IR
and subcmd examples are:
MCE_RSP_GETPORTSTATUS
MCE_RSP_EQIRNUMPORTS
...
Response size dynamically depends on cmd_prefix and subcmd.
So data0, data1, ... may or may not be present on input.
Multiple responses may return in a single receiver buffer.
The trigger condition for OOB read is typically random or
corrupt input data that fills the mceusb receiver buffer.
Case 1:
mceusb_handle_command() reads data0 (var hi) and data1 (var lo)
regardless of whether the response includes such data.
If { cmd_prefix, subcmd } is at the end of the receiver buffer,
read past end of buffer occurs.
This case was reported by
KASAN: slab-out-of-bounds Read in mceusb_dev_recv
https://syzkaller.appspot.com/bug?extid=c7fdb6cb36e65f2fe8c9
Fix: In mceusb_handle_command(), change variable hi and lo to
pointers, and dereference only when required.
Case 2:
If response with data is truncated at end of buffer after
{ cmd_prefix, subcmd }, mceusb_handle_command() reads past
end of buffer for data0, data1, ...
Fix: In mceusb_process_ir_data(), check response size with
remaining buffer size before invoking mceusb_handle_command().
+ if (i + ir->rem < buf_len)
mceusb_handle_command(ir, &ir->buf_in[i - 1]);
Case 3:
mceusb_handle_command() handles invalid/bad response such as
{ 0x??, MCE_RSP_GETPORTSTATUS } of length 2 as a response
{ MCE_CMD_PORT_SYS, MCE_RSP_GETPORTSTATUS, data0, ... }
of length 7. Read OOB occurs for non-existent data0, data1, ...
Cause is mceusb_handle_command() does not check cmd_prefix value.
Fix: mceusb_handle_command() must test both cmd_prefix and subcmd.
Case 4:
mceusb_process_ir_data() receiver parser state SUBCMD is
possible at start (i=0) of receiver buffer resulting in buffer
offset=-1 passed to mceusb_dev_printdata().
Bad offset results in OOB read before start of buffer.
[1214218.580308] mceusb 1-1.3:1.0: rx data[0]: 00 80 (length=2)
[1214218.580323] mceusb 1-1.3:1.0: Unknown command 0x00 0x80
...
[1214218.580406] mceusb 1-1.3:1.0: rx data[14]: 7f 7f (length=2)
[1214218.679311] mceusb 1-1.3:1.0: rx data[-1]: 80 90 (length=2)
[1214218.679325] mceusb 1-1.3:1.0: End of raw IR data
[1214218.679340] mceusb 1-1.3:1.0: rx data[1]: 7f 7f (length=2)
Fix: If parser_state is SUBCMD after processing receiver buffer,
reset parser_state to CMD_HEADER.
In effect, discard cmd_prefix at end of receiver buffer.
In mceusb_dev_printdata(), abort if buffer offset is out of bounds.
Case 5:
If response with data is truncated at end of buffer after
{ cmd_prefix, subcmd }, mceusb_dev_printdata() reads past
end of buffer for data0, data1, ...
while decoding the response to print out.
Fix: In mceusb_dev_printdata(), remove unneeded buffer offset
adjustments (var start and var skip) associated with MCE gen1 header.
Test for truncated MCE cmd response (compare offset+len with buf_len)
and skip decoding of incomplete response.
Move IR data tracing to execute before the truncation test.
Signed-off-by: A Sun <as1033x@comcast.net>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1b976fc6d6 upstream.
The driver needs an isochronous endpoint to be present. It will
oops in its absence. Add checking for it.
Reported-by: syzbot+d93dff37e6a89431c158@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8c279e9394 upstream.
When parsing the UVC control descriptors fails, the error path tries to
cleanup a media device that hasn't been initialised, potentially
resulting in a crash. Fix this by initialising the media device before
the error handling path can be reached.
Fixes: 5a254d751e ("[media] uvcvideo: Register a v4l2_device")
Reported-by: syzbot+c86454eb3af9e8a4da20@syzkaller.appspotmail.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3ef240eaff upstream.
Oleg provided the following test case:
int main(void)
{
struct sched_param sp = {};
sp.sched_priority = 2;
assert(sched_setscheduler(0, SCHED_FIFO, &sp) == 0);
int lock = vfork();
if (!lock) {
sp.sched_priority = 1;
assert(sched_setscheduler(0, SCHED_FIFO, &sp) == 0);
_exit(0);
}
syscall(__NR_futex, &lock, FUTEX_LOCK_PI, 0,0,0);
return 0;
}
This creates an unkillable RT process spinning in futex_lock_pi() on a UP
machine or if the process is affine to a single CPU. The reason is:
parent child
set FIFO prio 2
vfork() -> set FIFO prio 1
implies wait_for_child() sched_setscheduler(...)
exit()
do_exit()
....
mm_release()
tsk->futex_state = FUTEX_STATE_EXITING;
exit_futex(); (NOOP in this case)
complete() --> wakes parent
sys_futex()
loop infinite because
tsk->futex_state == FUTEX_STATE_EXITING
The same problem can happen just by regular preemption as well:
task holds futex
...
do_exit()
tsk->futex_state = FUTEX_STATE_EXITING;
--> preemption (unrelated wakeup of some other higher prio task, e.g. timer)
switch_to(other_task)
return to user
sys_futex()
loop infinite as above
Just for the fun of it the futex exit cleanup could trigger the wakeup
itself before the task sets its futex state to DEAD.
To cure this, the handling of the exiting owner is changed so:
- A refcount is held on the task
- The task pointer is stored in a caller visible location
- The caller drops all locks (hash bucket, mmap_sem) and blocks
on task::futex_exit_mutex. When the mutex is acquired then
the exiting task has completed the cleanup and the state
is consistent and can be reevaluated.
This is not a pretty solution, but there is no choice other than returning
an error code to user space, which would break the state consistency
guarantee and open another can of problems including regressions.
For stable backports the preparatory commits ac31c7ff86 .. ba31c1a485
are required as well, but for anything older than 5.3.y the backports are
going to be provided when this hits mainline as the other dependencies for
those kernels are definitely not stable material.
Fixes: 778e9a9c3e ("pi-futex: fix exit races and locking problems")
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stable Team <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20191106224557.041676471@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ac31c7ff86 upstream.
attach_to_pi_owner() returns -EAGAIN for various cases:
- Owner task is exiting
- Futex value has changed
The caller drops the held locks (hash bucket, mmap_sem) and retries the
operation. In case of the owner task exiting this can result in a live
lock.
As a preparatory step for seperating those cases, provide a distinct return
value (EBUSY) for the owner exiting case.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.935606117@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3f186d9748 upstream.
The mutex will be used in subsequent changes to replace the busy looping of
a waiter when the futex owner is currently executing the exit cleanup to
prevent a potential live lock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.845798895@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit af8cbda2cf upstream.
exec() attempts to handle potentially held futexes gracefully by running
the futex exit handling code like exit() does.
The current implementation has no protection against concurrent incoming
waiters. The reason is that the futex state cannot be set to
FUTEX_STATE_DEAD after the cleanup because the task struct is still active
and just about to execute the new binary.
While its arguably buggy when a task holds a futex over exec(), for
consistency sake the state handling can at least cover the actual futex
exit cleanup section. This provides state consistency protection accross
the cleanup. As the futex state of the task becomes FUTEX_STATE_OK after the
cleanup has been finished, this cannot prevent subsequent attempts to
attach to the task in case that the cleanup was not successfull in mopping
up all leftovers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.753355618@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4a8e991b91 upstream.
Instead of having a smp_mb() and an empty lock/unlock of task::pi_lock move
the state setting into to the lock section.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.645603214@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 18f694385c upstream.
Instead of relying on PF_EXITING use an explicit state for the futex exit
and set it in the futex exit function. This moves the smp barrier and the
lock/unlock serialization into the futex code.
As with the DEAD state this is restricted to the exit path as exec
continues to use the same task struct.
This allows to simplify that logic in a next step.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.539409004@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f24f22435d upstream.
Setting task::futex_state in do_exit() is rather arbitrarily placed for no
reason. Move it into the futex code.
Note, this is only done for the exit cleanup as the exec cleanup cannot set
the state to FUTEX_STATE_DEAD because the task struct is still in active
use.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.439511191@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 150d71584b upstream.
To allow separate handling of the futex exit state in the futex exit code
for exit and exec, split futex_mm_release() into two functions and invoke
them from the corresponding exit/exec_mm_release() callsites.
Preparatory only, no functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.332094221@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4610ba7ad8 upstream.
mm_release() contains the futex exit handling. mm_release() is called from
do_exit()->exit_mm() and from exec()->exec_mm().
In the exit_mm() case PF_EXITING and the futex state is updated. In the
exec_mm() case these states are not touched.
As the futex exit code needs further protections against exit races, this
needs to be split into two functions.
Preparatory only, no functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.240518241@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3d4775df0a upstream.
The futex exit handling relies on PF_ flags. That's suboptimal as it
requires a smp_mb() and an ugly lock/unlock of the exiting tasks pi_lock in
the middle of do_exit() to enforce the observability of PF_EXITING in the
futex code.
Add a futex_state member to task_struct and convert the PF_EXITPIDONE logic
over to the new state. The PF_EXITING dependency will be cleaned up in a
later step.
This prepares for handling various futex exit issues later.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.149449274@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ba31c1a485 upstream.
The futex exit handling is #ifdeffed into mm_release() which is not pretty
to begin with. But upcoming changes to address futex exit races need to add
more functionality to this exit code.
Split it out into a function, move it into futex code and make the various
futex exit functions static.
Preparatory only and no functional change.
Folded build fix from Borislav.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.049705556@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e6e8df0726 upstream.
Add NULL checks to show() and store() in cpufreq.c to avoid attempts
to invoke a NULL callback.
Though some interfaces of cpufreq are set as read-only, users can
still get write permission using chmod which can lead to a kernel
crash, as follows:
chmod +w /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
echo 1 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
This bug was found in linux 4.19.
Signed-off-by: Kai Shen <shenkai8@huawei.com>
Reported-by: Feilong Lin <linfeilong@huawei.com>
Reviewed-by: Feilong Lin <linfeilong@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9e08117c9d upstream.
Visual inspection of the usbvision driver shows that it suffers from
three races between its open, close, and disconnect handlers. In
particular, the driver is careful to update its usbvision->user and
usbvision->remove_pending flags while holding the private mutex, but:
usbvision_v4l2_close() and usbvision_radio_close() don't hold
the mutex while they check the value of
usbvision->remove_pending;
usbvision_disconnect() doesn't hold the mutex while checking
the value of usbvision->user; and
also, usbvision_v4l2_open() and usbvision_radio_open() don't
check whether the device has been unplugged before allowing
the user to open the device files.
Each of these can potentially lead to usbvision_release() being called
twice and use-after-free errors.
This patch fixes the races by reading the flags while the mutex is
still held and checking for pending removes before allowing an open to
succeed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c7a1914640 upstream.
The syzbot fuzzer found two invalid-access bugs in the usbvision
driver. These bugs occur when userspace keeps the device file open
after the device has been disconnected and usbvision_disconnect() has
set usbvision->dev to NULL:
When the device file is closed, usbvision_radio_close() tries
to issue a usb_set_interface() call, passing the NULL pointer
as its first argument.
If userspace performs a querycap ioctl call, vidioc_querycap()
calls usb_make_path() with the same NULL pointer.
This patch fixes the problems by making the appropriate tests
beforehand. Note that vidioc_querycap() is protected by
usbvision->v4l2_lock, acquired in a higher layer of the V4L2
subsystem.
Reported-and-tested-by: syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6dcd5d7a7a upstream.
There is the same incorrect approach to locking implemented in
vivid_stop_generating_vid_cap(), vivid_stop_generating_vid_out() and
sdr_cap_stop_streaming().
These functions are called during streaming stopping with vivid_dev.mutex
locked. And they all do the same mistake while stopping their kthreads,
which need to lock this mutex as well. See the example from
vivid_stop_generating_vid_cap():
/* shutdown control thread */
vivid_grab_controls(dev, false);
mutex_unlock(&dev->mutex);
kthread_stop(dev->kthread_vid_cap);
dev->kthread_vid_cap = NULL;
mutex_lock(&dev->mutex);
But when this mutex is unlocked, another vb2_fop_read() can lock it
instead of vivid_thread_vid_cap() and manipulate the buffer queue.
That causes a use-after-free access later.
To fix those issues let's:
1. avoid unlocking the mutex in vivid_stop_generating_vid_cap(),
vivid_stop_generating_vid_out() and sdr_cap_stop_streaming();
2. use mutex_trylock() with schedule_timeout_uninterruptible() in
the loops of the vivid kthread handlers.
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org> # for v3.18 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b4add02d22 upstream.
When vbi stream is started, followed by video streaming,
the vid_cap_streaming and vid_out_streaming were not being set to true,
which would cause the video stream to stop when vbi stream is stopped.
This patch allows to set vid_cap_streaming and vid_out_streaming to true.
According to Hans Verkuil it appears that these 'if (dev->kthread_vid_cap)'
checks are a left-over from the original vivid development and should never
have been there.
Signed-off-by: Vandana BN <bnvandana@gmail.com>
Cc: <stable@vger.kernel.org> # for v3.18 and up
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ce3cba788a upstream.
The s6i6_gen2_info.ports[] array had the Mixer and PCM port type
entries in the wrong place. Use designators to explicitly specify the
array elements being set.
Fixes: 9e4d5c1be2 ("ALSA: usb-audio: Scarlett Gen 2 mixer interface")
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Tested-by: Alex Fellows <alex.fellows@gmail.com>
Tested-by: Markus Schroetter <project.m.schroetter@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191110134356.GA31589@b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9435f2bb66 upstream.
snd_usb_mixer_controls_badd() that parses UAC3 BADD profiles misses a
NULL check for the given interfaces. When a malformed USB descriptor
is passed, this may lead to an Oops, as spotted by syzkaller.
Skip the iteration if the interface doesn't exist for avoiding the
crash.
Fixes: 17156f23e9 ("ALSA: usb: add UAC3 BADD profiles support")
Reported-by: syzbot+a36ab65c6653d7ccdd62@syzkaller.appspotmail.com
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191122112840.24797-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ca16d5bee5 upstream.
Robust futexes utilize the robust_list mechanism to allow the kernel to
release futexes which are held when a task exits. The exit can be voluntary
or caused by a signal or fault. This prevents that waiters block forever.
The futex operations in user space store a pointer to the futex they are
either locking or unlocking in the op_pending member of the per task robust
list.
After a lock operation has succeeded the futex is queued in the robust list
linked list and the op_pending pointer is cleared.
After an unlock operation has succeeded the futex is removed from the
robust list linked list and the op_pending pointer is cleared.
The robust list exit code checks for the pending operation and any futex
which is queued in the linked list. It carefully checks whether the futex
value is the TID of the exiting task. If so, it sets the OWNER_DIED bit and
tries to wake up a potential waiter.
This is race free for the lock operation but unlock has two race scenarios
where waiters might not be woken up. These issues can be observed with
regular robust pthread mutexes. PI aware pthread mutexes are not affected.
(1) Unlocking task is killed after unlocking the futex value in user space
before being able to wake a waiter.
pthread_mutex_unlock()
|
V
atomic_exchange_rel (&mutex->__data.__lock, 0)
<------------------------killed
lll_futex_wake () |
|
|(__lock = 0)
|(enter kernel)
|
V
do_exit()
exit_mm()
mm_release()
exit_robust_list()
handle_futex_death()
|
|(__lock = 0)
|(uval = 0)
|
V
if ((uval & FUTEX_TID_MASK) != task_pid_vnr(curr))
return 0;
The sanity check which ensures that the user space futex is owned by
the exiting task prevents the wakeup of waiters which in consequence
block infinitely.
(2) Waiting task is killed after a wakeup and before it can acquire the
futex in user space.
OWNER WAITER
futex_wait()
pthread_mutex_unlock() |
| |
|(__lock = 0) |
| |
V |
futex_wake() ------------> wakeup()
|
|(return to userspace)
|(__lock = 0)
|
V
oldval = mutex->__data.__lock
<-----------------killed
atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, |
id | assume_other_futex_waiters, 0) |
|
|
(enter kernel)|
|
V
do_exit()
|
|
V
handle_futex_death()
|
|(__lock = 0)
|(uval = 0)
|
V
if ((uval & FUTEX_TID_MASK) != task_pid_vnr(curr))
return 0;
The sanity check which ensures that the user space futex is owned
by the exiting task prevents the wakeup of waiters, which seems to
be correct as the exiting task does not own the futex value, but
the consequence is that other waiters wont be woken up and block
infinitely.
In both scenarios the following conditions are true:
- task->robust_list->list_op_pending != NULL
- user space futex value == 0
- Regular futex (not PI)
If these conditions are met then it is reasonably safe to wake up a
potential waiter in order to prevent the above problems.
As this might be a false positive it can cause spurious wakeups, but the
waiter side has to handle other types of unrelated wakeups, e.g. signals
gracefully anyway. So such a spurious wakeup will not affect the
correctness of these operations.
This workaround must not touch the user space futex value and cannot set
the OWNER_DIED bit because the lock value is 0, i.e. uncontended. Setting
OWNER_DIED in this case would result in inconsistent state and subsequently
in malfunction of the owner died handling in user space.
The rest of the user space state is still consistent as no other task can
observe the list_op_pending entry in the exiting tasks robust list.
The eventually woken up waiter will observe the uncontended lock value and
take it over.
[ tglx: Massaged changelog and comment. Made the return explicit and not
depend on the subsequent check and added constants to hand into
handle_futex_death() instead of plain numbers. Fixed a few coding
style issues. ]
Fixes: 0771dfefc9 ("[PATCH] lightweight robust futexes: core")
Signed-off-by: Yang Tao <yang.tao172@zte.com.cn>
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1573010582-35297-1-git-send-email-wang.yi59@zte.com.cn
Link: https://lkml.kernel.org/r/20191106224555.943191378@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4a13b0e3e1 upstream.
UNWIND_ESPFIX_STACK needs to read the GDT, and the GDT mapping that
can be accessed via %fs is not mapped in the user pagetables. Use
SGDT to find the cpu_entry_area mapping and read the espfix offset
from that instead.
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 05b042a194 upstream.
When two recent commits that increased the size of the 'struct cpu_entry_area'
were merged in -tip, the 32-bit defconfig build started failing on the following
build time assert:
./include/linux/compiler.h:391:38: error: call to ‘__compiletime_assert_189’ declared with attribute error: BUILD_BUG_ON failed: CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE
arch/x86/mm/cpu_entry_area.c:189:2: note: in expansion of macro ‘BUILD_BUG_ON’
In function ‘setup_cpu_entry_area_ptes’,
Which corresponds to the following build time assert:
BUILD_BUG_ON(CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE);
The purpose of this assert is to sanity check the fixed-value definition of
CPU_ENTRY_AREA_PAGES arch/x86/include/asm/pgtable_32_types.h:
#define CPU_ENTRY_AREA_PAGES (NR_CPUS * 41)
The '41' is supposed to match sizeof(struct cpu_entry_area)/PAGE_SIZE, which value
we didn't want to define in such a low level header, because it would cause
dependency hell.
Every time the size of cpu_entry_area is changed, we have to adjust CPU_ENTRY_AREA_PAGES
accordingly - and this assert is checking that constraint.
But the assert is both imprecise and buggy, primarily because it doesn't
include the single readonly IDT page that is mapped at CPU_ENTRY_AREA_BASE
(which begins at a PMD boundary).
This bug was hidden by the fact that by accident CPU_ENTRY_AREA_PAGES is defined
too large upstream (v5.4-rc8):
#define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40)
While 'struct cpu_entry_area' is 155648 bytes, or 38 pages. So we had two extra
pages, which hid the bug.
The following commit (not yet upstream) increased the size to 40 pages:
x86/iopl: ("Restrict iopl() permission scope")
... but increased CPU_ENTRY_AREA_PAGES only 41 - i.e. shortening the gap
to just 1 extra page.
Then another not-yet-upstream commit changed the size again:
880a98c33996: ("x86/cpu_entry_area: Add guard page for entry stack on 32bit")
Which increased the cpu_entry_area size from 38 to 39 pages, but
didn't change CPU_ENTRY_AREA_PAGES (kept it at 40). This worked
fine, because we still had a page left from the accidental 'reserve'.
But when these two commits were merged into the same tree, the
combined size of cpu_entry_area grew from 38 to 40 pages, while
CPU_ENTRY_AREA_PAGES finally caught up to 40 as well.
Which is fine in terms of functionality, but the assert broke:
BUILD_BUG_ON(CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE);
because CPU_ENTRY_AREA_MAP_SIZE is the total size of the area,
which is 1 page larger due to the IDT page.
To fix all this, change the assert to two precise asserts:
BUILD_BUG_ON((CPU_ENTRY_AREA_PAGES+1)*PAGE_SIZE != CPU_ENTRY_AREA_MAP_SIZE);
BUILD_BUG_ON(CPU_ENTRY_AREA_TOTAL_SIZE != CPU_ENTRY_AREA_MAP_SIZE);
This takes the IDT page into account, and also connects the size-based
define of CPU_ENTRY_AREA_TOTAL_SIZE with the address-subtraction based
define of CPU_ENTRY_AREA_MAP_SIZE.
Also clean up some of the names which made it rather confusing:
- 'CPU_ENTRY_AREA_TOT_SIZE' wasn't actually the 'total' size of
the cpu-entry-area, but the per-cpu array size, so rename this
to CPU_ENTRY_AREA_ARRAY_SIZE.
- Introduce CPU_ENTRY_AREA_TOTAL_SIZE that _is_ the total mapping
size, with the IDT included.
- Add comments where '+1' denotes the IDT mapping - it wasn't
obvious and took me about 3 hours to decode...
Finally, because this particular commit is actually applied after
this patch:
880a98c33996: ("x86/cpu_entry_area: Add guard page for entry stack on 32bit")
Fix the CPU_ENTRY_AREA_PAGES value from 40 pages to the correct 39 pages.
All future commits that change cpu_entry_area will have to adjust
this value precisely.
As a side note, we should probably attempt to remove CPU_ENTRY_AREA_PAGES
and derive its value directly from the structure, without causing
header hell - but that is an adventure for another day! :-)
Fixes: 880a98c33996: ("x86/cpu_entry_area: Add guard page for entry stack on 32bit")
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4d2fa82d98 upstream.
If the kernel accidentally uses DS or ES while the user values are
loaded, it will work fine for sane userspace. In the interest of
simulating maximally insane userspace, make sigreturn_32 zero out DS
and ES for the nasty parts so that inadvertent use of these segments
will crash.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8caa016bfc upstream.
For reasons that I haven't quite fully diagnosed, running
mov_ss_trap_32 on a 32-bit kernel results in an infinite loop in
userspace. This appears to be because the hacky SYSENTER test
doesn't segfault as desired; instead it corrupts the program state
such that it infinite loops.
Fix it by explicitly clearing EBP before doing SYSENTER. This will
give a more reliable segfault.
Fixes: 59c2a7226f ("x86/selftests: Add mov_to_ss test")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8954290765 upstream.
When the NMI lands on an ESPFIX_SS, we are on the entry stack and must
swizzle, otherwise we'll run do_nmi() on the entry stack, which is
BAD.
Also, similar to the normal exception path, we need to correct the
ESPFIX magic before leaving the entry stack, otherwise pt_regs will
present a non-flat stack pointer.
Tested by running sigreturn_32 concurrent with perf-record.
Fixes: e5862d0515 ("x86/entry/32: Leave the kernel via trampoline stack")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a1a338e5b6 upstream.
Right now, we do some fancy parts of the exception entry path while SS
might have a nonzero base: we fill in regs->ss and regs->sp, and we
consider switching to the kernel stack. This results in regs->ss and
regs->sp referring to a non-flat stack and it may result in
overflowing the entry stack. The former issue means that we can try to
call iret_exc on a non-flat stack, which doesn't work.
Tested with selftests/x86/sigreturn_32.
Fixes: 45d7b25574 ("x86/entry/32: Enter the kernel via trampoline stack")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 82cb8a0b1d upstream.
This will allow us to get percpu access working before FIXUP_FRAME,
which will allow us to unwind ESPFIX earlier.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4c4fd55d3d upstream.
When re-building the IRET frame we use %eax as an destination %esp,
make sure to then also match the segment for when there is a nonzero
SS base (ESPFIX).
[peterz: Changelog and minor edits]
Fixes: 3c88c692c2 ("x86/stackframe/32: Provide consistent pt_regs")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 40ad219958 upstream.
As reported by Lai, the commit 3c88c692c2 ("x86/stackframe/32:
Provide consistent pt_regs") wrecked the IRET EXTABLE entry by making
.Lirq_return not point at IRET.
Fix this by placing IRET_FRAME in RESTORE_REGS, to mirror how
FIXUP_FRAME is part of SAVE_ALL.
Fixes: 3c88c692c2 ("x86/stackframe/32: Provide consistent pt_regs")
Reported-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 880a98c339 upstream.
The entry stack in the cpu entry area is protected against overflow by the
readonly GDT on 64-bit, but on 32-bit the GDT needs to be writeable and
therefore does not trigger a fault on stack overflow.
Add a guard page.
Fixes: c482feefe1 ("x86/entry/64: Make cpu_entry_area.tss read-only")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f490e07c53 upstream.
Commit 945fd17ab6 ("x86/cpu_entry_area: Sync cpu_entry_area to
initial_page_table") introduced the sync for the initial page table for
32bit.
sync_initial_page_table() uses clone_pgd_range() which does the update for
the kernel page table. If PTI is enabled it also updates the user space
page table counterpart, which is assumed to be in the next page after the
target PGD.
At this point in time 32-bit did not have PTI support, so the user space
page table update was not taking place.
The support for PTI on 32-bit which was introduced later on, did not take
that into account and missed to add the user space counter part for the
initial page table.
As a consequence sync_initial_page_table() overwrites any data which is
located in the page behing initial_page_table causing random failures,
e.g. by corrupting doublefault_tss and wreckaging the doublefault handler
on 32bit.
Fix it by adding a "user" page table right after initial_page_table.
Fixes: 7757d607c6 ("x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Michael Ellerman