roccat_report_event() is responsible for registering
roccat-related reports in struct roccat_device.

int roccat_report_event(int minor, u8 const *data)
{
	struct roccat_device *device;
	struct roccat_reader *reader;
	struct roccat_report *report;
	uint8_t *new_value;

	device = devices[minor];

	new_value = kmemdup(data, device->report_size, GFP_ATOMIC);
	if (!new_value)
		return -ENOMEM;

	report = &device->cbuf[device->cbuf_end];

	/* passing NULL is safe */
	kfree(report->value);
	...

The registered report is stored in the struct roccat_device member
"struct roccat_report cbuf[ROCCAT_CBUF_SIZE];".
If more reports are received than the "ROCCAT_CBUF_SIZE" value,
kfree() the saved report from cbuf[0] and allocates a new reprot.
Since there is no lock when this kfree() is performed,
kfree() can be performed even while reading the saved report.

static ssize_t roccat_read(struct file *file, char __user *buffer,
		size_t count, loff_t *ppos)
{
	struct roccat_reader *reader = file->private_data;
	struct roccat_device *device = reader->device;
	struct roccat_report *report;
	ssize_t retval = 0, len;
	DECLARE_WAITQUEUE(wait, current);

	mutex_lock(&device->cbuf_lock);

	...

	report = &device->cbuf[reader->cbuf_start];
	/*
	 * If report is larger than requested amount of data, rest of report
	 * is lost!
	 */
	len = device->report_size > count ? count : device->report_size;

	if (copy_to_user(buffer, report->value, len)) {
		retval = -EFAULT;
		goto exit_unlock;
	}
	...

The roccat_read() function receives the device->cbuf report and
delivers it to the user through copy_to_user().
If the N+ROCCAT_CBUF_SIZE th report is received while copying of
the Nth report->value is in progress, the pointer that copy_to_user()
is working on is kfree()ed and UAF read may occur. (race condition)

Since the device node of this driver does not set separate permissions,
this is not a security vulnerability, but because it is used for
requesting screen display of profile or dpi settings,
a user using the roccat device can apply udev to this device node or
There is a possibility to use it by giving.

Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

My static checker complains because we use "dev_id" before we check for
errors so it could be uninitialized.  Fix this by moving the error
handling forward a couple lines.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Return value of cdev_add in hid_roccat.c init was not checked.

Signed-off-by: Michael Rissi <michael.rissi@dectris.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Fixed parameter documentation.

Signed-off-by: Stefan Achatz <erazor_de@users.sourceforge.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h