media: pvrusb2: fix uaf in pvr2_context_set_notify

[Syzbot reported]
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
Read of size 4 at addr ffff888113aeb0d8 by task kworker/1:1/26

CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.8.0-rc1-syzkaller-00046-gf1a27f081c1f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:488
kasan_report+0xda/0x110 mm/kasan/report.c:601
pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
pvr2_context_notify drivers/media/usb/pvrusb2/pvrusb2-context.c:95 [inline]
pvr2_context_disconnect+0x94/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:272

Freed by task 906:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
poison_slab_object mm/kasan/common.c:241 [inline]
__kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kfree+0x105/0x340 mm/slub.c:4409
pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158

[Analyze]
Task A set disconnect_flag = !0, which resulted in Task B's condition being met
and releasing mp, leading to this issue.

[Fix]
Place the disconnect_flag assignment operation after all code in pvr2_context_disconnect()
to avoid this issue.

Reported-and-tested-by: syzbot+ce750e124675d4599449@syzkaller.appspotmail.com
Fixes: e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload")
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: pvrusb2: fix pvr2_stream_callback casts

clang-16 complains about a control flow integrity (KCFI) issue in pvrusb2,
which casts three different prototypes into pvr2_stream_callback:

drivers/media/usb/pvrusb2/pvrusb2-v4l2.c:1070:30: error: cast from 'void (*)(struct pvr2_v4l2_fh *)' to 'pvr2_stream_callback' (aka 'void (*)(void *)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
1070 | pvr2_stream_set_callback(sp,(pvr2_stream_callback)pvr2_v4l2_notify,fh);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/usb/pvrusb2/pvrusb2-context.c:110:6: error: cast from 'void (*)(struct pvr2_context *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
110 | (void (*)(void *))pvr2_context_notify,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/usb/pvrusb2/pvrusb2-dvb.c:152:6: error: cast from 'void (*)(struct pvr2_dvb_adapter *)' to 'pvr2_stream_callback' (aka 'void (*)(void *)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
152 | (pvr2_stream_callback) pvr2_dvb_notify, adap);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change the functions to actually take a void* argument so the cast is no longer
needed.

Fixes: bb8ce9d9143c ("V4L/DVB (7682): pvrusb2-dvb: finish up stream & buffer handling")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: pvrusb2: fix use after free on context disconnection

Upon module load, a kthread is created targeting the
pvr2_context_thread_func function, which may call pvr2_context_destroy
and thus call kfree() on the context object. However, that might happen
before the usb hub_event handler is able to notify the driver. This
patch adds a sanity check before the invalid read reported by syzbot,
within the context disconnection call stack.

Reported-and-tested-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000a02a4205fff8eb92@google.com/

Fixes: e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload")
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Acked-by: Mike Isely <isely@pobox.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 235

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 this
program is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 53 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.904365654@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[media] media: Drop FSF's postal address from the source code files

Drop the FSF's postal address from the source code files that typically
contain mostly the license text. Of the 628 removed instances, 578 are
outdated.

The patch has been created with the following command without manual edits:

git grep -l "675 Mass Ave\|59 Temple Place\|51 Franklin St" -- \
drivers/media/ include/media|while read i; do i=$i perl -e '
open(F,"< $ENV{i}");
$a=join("", <F>);
$a =~ s/[ \t]*\*\n.*You should.*\n.*along with.*\n.*(\n.*USA.*$)?\n//m
&& $a =~ s/(^.*)Or, (point your browser to) /$1To obtain the license, $2\n$1/m;
close(F);
open(F, "> $ENV{i}");
print F $a;
close(F);'; done

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

[media] pvrusb2: correctly handling failed thread run

Since kthread_run returns -ENOMEM if failed,
it needs to be checked whether it is error, not whether it is null.

Signed-off-by: Insu Yun <wuninsu@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

[media] pvrusb2: fix inconsistent indenting

smatch complains about multiple issues here:
drivers/media/usb/pvrusb2/pvrusb2-context.c:402 pvr2_channel_claim_stream() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-ioread.c:240 pvr2_ioread_setup() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-ioread.c:255 pvr2_ioread_set_enabled() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-ioread.c:485 pvr2_ioread_read() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-io.c:522 pvr2_stream_set_callback() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-io.c:561 pvr2_stream_set_buffer_count() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-io.c:640 pvr2_buffer_queue() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-io.c:667 pvr2_buffer_set_buffer() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-io.c:668 pvr2_buffer_set_buffer() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2614 pvr2_hdw_create() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2740 pvr2_hdw_destroy() warn: inconsistent indenting
drivers/media/usb/pvrusb2/pvrusb2-hdw.c:3353 pvr2_hdw_trigger_module_log() warn: inconsistent indenting

Let's get rid of those, in order to cleanup as much as possible the smatch error log.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

[media] media: remove emacs editor variables

1) This is not allowed by the kernel coding style
2) Just configure your editor correctly
3) It's really ugly

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

[media] USB: Deletion of unnecessary checks before three function calls

GIT_AUTHOR_DATE=1416486805
The functions pvr2_hdw_destroy(), rc_unregister_device() and vfree() perform
also input parameter validation. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

[media] rename most media/video usb drivers to media/usb

Rename all USB drivers with their own directory under
drivers/media/video into drivers/media/usb and update the
building system.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>