<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/gpu/drm/drm_auth.c, branch linux-5.4.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drm: Lock pointer access in drm_master_release()</title>
<updated>2021-06-16T09:59:39+00:00</updated>
<author>
<name>Desmond Cheong Zhi Xi</name>
<email>desmondcheongzx@gmail.com</email>
</author>
<published>2021-06-09T09:21:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=977d11df793280fe592a68896a8e00b9f813e75c'/>
<id>977d11df793280fe592a68896a8e00b9f813e75c</id>
<content type='text'>
commit c336a5ee984708db4826ef9e47d184e638e29717 upstream.

This patch eliminates the following smatch warning:
drivers/gpu/drm/drm_auth.c:320 drm_master_release() warn: unlocked access 'master' (line 318) expected lock '&amp;dev-&gt;master_mutex'

The 'file_priv-&gt;master' field should be protected by the mutex lock to
'&amp;dev-&gt;master_mutex'. This is because other processes can concurrently
modify this field and free the current 'file_priv-&gt;master'
pointer. This could result in a use-after-free error when 'master' is
dereferenced in subsequent function calls to
'drm_legacy_lock_master_cleanup()' or to 'drm_lease_revoke()'.

An example of a scenario that would produce this error can be seen
from a similar bug in 'drm_getunique()' that was reported by Syzbot:
https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803

In the Syzbot report, another process concurrently acquired the
device's master mutex in 'drm_setmaster_ioctl()', then overwrote
'fpriv-&gt;master' in 'drm_new_set_master()'. The old value of
'fpriv-&gt;master' was subsequently freed before the mutex was unlocked.

Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Desmond Cheong Zhi Xi &lt;desmondcheongzx@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20210609092119.173590-1-desmondcheongzx@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c336a5ee984708db4826ef9e47d184e638e29717 upstream.

This patch eliminates the following smatch warning:
drivers/gpu/drm/drm_auth.c:320 drm_master_release() warn: unlocked access 'master' (line 318) expected lock '&amp;dev-&gt;master_mutex'

The 'file_priv-&gt;master' field should be protected by the mutex lock to
'&amp;dev-&gt;master_mutex'. This is because other processes can concurrently
modify this field and free the current 'file_priv-&gt;master'
pointer. This could result in a use-after-free error when 'master' is
dereferenced in subsequent function calls to
'drm_legacy_lock_master_cleanup()' or to 'drm_lease_revoke()'.

An example of a scenario that would produce this error can be seen
from a similar bug in 'drm_getunique()' that was reported by Syzbot:
https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803

In the Syzbot report, another process concurrently acquired the
device's master mutex in 'drm_setmaster_ioctl()', then overwrote
'fpriv-&gt;master' in 'drm_new_set_master()'. The old value of
'fpriv-&gt;master' was subsequently freed before the mutex was unlocked.

Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Desmond Cheong Zhi Xi &lt;desmondcheongzx@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20210609092119.173590-1-desmondcheongzx@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm: drop use of drmP.h in drm/*</title>
<updated>2019-05-27T16:07:03+00:00</updated>
<author>
<name>Sam Ravnborg</name>
<email>sam@ravnborg.org</email>
</author>
<published>2019-05-26T17:35:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0500c04ea14a4143edf902d087079c4e7b2f0229'/>
<id>0500c04ea14a4143edf902d087079c4e7b2f0229</id>
<content type='text'>
The use of the drmP.h header file is deprecated.
Remove use from all files in drm/*
so people do not look there and follow a bad example.

Build tested allyesconfig,allmodconfig on x86, arm etc.
Including alpha that is as always more challenging than
the rest.

Signed-off-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Acked-by: Daniel Vetter &lt;daniel@ffwll.ch&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Cc: Sean Paul &lt;sean@poorly.run&gt;
Cc: David Airlie &lt;airlied@linux.ie&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190526173535.32701-8-sam@ravnborg.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The use of the drmP.h header file is deprecated.
Remove use from all files in drm/*
so people do not look there and follow a bad example.

Build tested allyesconfig,allmodconfig on x86, arm etc.
Including alpha that is as always more challenging than
the rest.

Signed-off-by: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Acked-by: Daniel Vetter &lt;daniel@ffwll.ch&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Maxime Ripard &lt;maxime.ripard@bootlin.com&gt;
Cc: Sean Paul &lt;sean@poorly.run&gt;
Cc: David Airlie &lt;airlied@linux.ie&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190526173535.32701-8-sam@ravnborg.org
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/fb-helper: Avoid race with DRM userspace</title>
<updated>2019-05-14T14:11:28+00:00</updated>
<author>
<name>Noralf Trønnes</name>
<email>noralf@tronnes.org</email>
</author>
<published>2019-05-06T18:01:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=03a9606e7feef902979bbc0601d6d93e764f251d'/>
<id>03a9606e7feef902979bbc0601d6d93e764f251d</id>
<content type='text'>
drm_fb_helper_is_bound() is used to check if DRM userspace is in control.
This is done by looking at the fb on the primary plane. By the time
fb-helper gets around to committing, it's possible that the facts have
changed.

Avoid this race by holding the drm_device-&gt;master_mutex lock while
committing. When DRM userspace does its first open, it will now wait
until fb-helper is done. The helper will stay away if there's a master.

Two igt tests fail with the new 'bail out if master' rule. Work around
this by relaxing this rule for drm_fb_helper_restore_fbdev_mode_unlocked()
until the tests have been fixed. Add todo entry for this.

Locking rule: Always take the fb-helper lock first.

v5: drm_fb_helper_restore_fbdev_mode_unlocked(): Use
    restore_fbdev_mode_force()

v2:
- Remove drm_fb_helper_is_bound() (Daniel Vetter)
- No need to check fb_helper-&gt;dev-&gt;master in
  drm_fb_helper_single_fb_probe(), restore_fbdev_mode() has the check.

Suggested-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Noralf Trønnes &lt;noralf@tronnes.org&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190506180139.6913-3-noralf@tronnes.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
drm_fb_helper_is_bound() is used to check if DRM userspace is in control.
This is done by looking at the fb on the primary plane. By the time
fb-helper gets around to committing, it's possible that the facts have
changed.

Avoid this race by holding the drm_device-&gt;master_mutex lock while
committing. When DRM userspace does its first open, it will now wait
until fb-helper is done. The helper will stay away if there's a master.

Two igt tests fail with the new 'bail out if master' rule. Work around
this by relaxing this rule for drm_fb_helper_restore_fbdev_mode_unlocked()
until the tests have been fixed. Add todo entry for this.

Locking rule: Always take the fb-helper lock first.

v5: drm_fb_helper_restore_fbdev_mode_unlocked(): Use
    restore_fbdev_mode_force()

v2:
- Remove drm_fb_helper_is_bound() (Daniel Vetter)
- No need to check fb_helper-&gt;dev-&gt;master in
  drm_fb_helper_single_fb_probe(), restore_fbdev_mode() has the check.

Suggested-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Noralf Trønnes &lt;noralf@tronnes.org&gt;
Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190506180139.6913-3-noralf@tronnes.org
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'drm-misc-next-fixes-2019-04-24' of git://anongit.freedesktop.org/drm/drm-misc into drm-next</title>
<updated>2019-04-26T01:35:44+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2019-04-26T01:35:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5a67928651640233a44106c8a1a83a441a9e5648'/>
<id>5a67928651640233a44106c8a1a83a441a9e5648</id>
<content type='text'>
- fb_helper: Fix NULL deref in legacy drivers (Noralf)
- leases: Ensure lessees can't connect to objects outside their perview (Daniel)
- leases: Enforce that lessees hold the lease for implicitly set planes (Daniel)
- leases: A few non-functional cleanups (Daniel)

Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Noralf Trønnes &lt;noralf@tronnes.org&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;

From: Sean Paul &lt;sean@poorly.run&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190424210604.GA32581@art_vandelay
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
- fb_helper: Fix NULL deref in legacy drivers (Noralf)
- leases: Ensure lessees can't connect to objects outside their perview (Daniel)
- leases: Enforce that lessees hold the lease for implicitly set planes (Daniel)
- leases: A few non-functional cleanups (Daniel)

Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Noralf Trønnes &lt;noralf@tronnes.org&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;

From: Sean Paul &lt;sean@poorly.run&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190424210604.GA32581@art_vandelay
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/leases: Don't init to 0 in drm_master_create</title>
<updated>2019-04-24T09:29:06+00:00</updated>
<author>
<name>Daniel Vetter</name>
<email>daniel.vetter@ffwll.ch</email>
</author>
<published>2019-02-28T14:49:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4285c7e1aaad6ffe5520b36047a28fc960e32482'/>
<id>4285c7e1aaad6ffe5520b36047a28fc960e32482</id>
<content type='text'>
We kzalloc.

Cc: Keith Packard &lt;keithp@keithp.com&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@collabora.com&gt;
Reviewed-by: Dave Airlie &lt;airlied@redhat.com&gt;
Reviewed-by: Mika Kuoppala &lt;mika.kuoppala@linux.intel.com&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190228144910.26488-4-daniel.vetter@ffwll.ch
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We kzalloc.

Cc: Keith Packard &lt;keithp@keithp.com&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@collabora.com&gt;
Reviewed-by: Dave Airlie &lt;airlied@redhat.com&gt;
Reviewed-by: Mika Kuoppala &lt;mika.kuoppala@linux.intel.com&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20190228144910.26488-4-daniel.vetter@ffwll.ch
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/legacy: remove some legacy lock struct members</title>
<updated>2019-04-24T02:36:32+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2019-04-23T00:01:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ee22f76306a68359c33809f8895eff603e71584b'/>
<id>ee22f76306a68359c33809f8895eff603e71584b</id>
<content type='text'>
This removes these unless legacy is enabled.

The lock count init is unneeded anyways since it's kzalloc.

Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This removes these unless legacy is enabled.

The lock count init is unneeded anyways since it's kzalloc.

Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/legacy: move lock cleanup for master into lock file (v2)</title>
<updated>2019-04-24T02:32:15+00:00</updated>
<author>
<name>Dave Airlie</name>
<email>airlied@redhat.com</email>
</author>
<published>2019-04-22T23:36:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=058ca50ce3f1d40dac4d918a91684b0af4a0c468'/>
<id>058ca50ce3f1d40dac4d918a91684b0af4a0c468</id>
<content type='text'>
This makes it easier to remove legacy code later.

v2: move check into lock file as well.

Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This makes it easier to remove legacy code later.

v2: move check into lock file as well.

Reviewed-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm: set is_master to 0 upon drm_new_set_master() failure</title>
<updated>2018-11-26T21:14:27+00:00</updated>
<author>
<name>Sergio Correia</name>
<email>sergio@correia.cc</email>
</author>
<published>2018-11-22T05:33:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=23a336b34258aba3b50ea6863cca4e81b5ef6384'/>
<id>23a336b34258aba3b50ea6863cca4e81b5ef6384</id>
<content type='text'>
When drm_new_set_master() fails, set is_master to 0, to prevent a
possible NULL pointer deref.

Here is a problematic flow: we check is_master in drm_is_current_master(),
then proceed to call drm_lease_owner() passing master. If we do not restore
is_master status when drm_new_set_master() fails, we may have a situation
in which is_master will be 1 and master itself, NULL, leading to the deref
of a NULL pointer in drm_lease_owner().

This fixes the following OOPS, observed on an ArchLinux running a 4.19.2
kernel:

[   97.804282] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
[   97.807224] PGD 0 P4D 0
[   97.807224] Oops: 0000 [#1] PREEMPT SMP NOPTI
[   97.807224] CPU: 0 PID: 1348 Comm: xfwm4 Tainted: P           OE     4.19.2-arch1-1-ARCH #1
[   97.807224] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./AB350 Pro4, BIOS P5.10 10/16/2018
[   97.807224] RIP: 0010:drm_lease_owner+0xd/0x20 [drm]
[   97.807224] Code: 83 c4 18 5b 5d c3 b8 ea ff ff ff eb e2 b8 ed ff ff ff eb db e8 b4 ca 68 fb 0f 1f 40 00 0f 1f 44 00 00 48 89 f8 eb 03 48 89 d0 &lt;48&gt; 8b 90 80 00 00 00 48 85 d2 75 f1 c3 66 0f 1f 44 00 00 0f 1f 44
[   97.807224] RSP: 0018:ffffb8cf08e07bb0 EFLAGS: 00010202
[   97.807224] RAX: 0000000000000000 RBX: ffff9cf0f2586c00 RCX: ffff9cf0f2586c88
[   97.807224] RDX: ffff9cf0ddbd8000 RSI: 0000000000000000 RDI: 0000000000000000
[   97.807224] RBP: ffff9cf1040e9800 R08: 0000000000000000 R09: 0000000000000000
[   97.807224] R10: ffffdeb30fd5d680 R11: ffffdeb30f5d6808 R12: ffff9cf1040e9888
[   97.807224] R13: 0000000000000000 R14: dead000000000200 R15: ffff9cf0f2586cc8
[   97.807224] FS:  00007f4145513180(0000) GS:ffff9cf10ea00000(0000) knlGS:0000000000000000
[   97.807224] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   97.807224] CR2: 0000000000000080 CR3: 00000003d7548000 CR4: 00000000003406f0
[   97.807224] Call Trace:
[   97.807224]  drm_is_current_master+0x1a/0x30 [drm]
[   97.807224]  drm_master_release+0x3e/0x130 [drm]
[   97.807224]  drm_file_free.part.0+0x2be/0x2d0 [drm]
[   97.807224]  drm_open+0x1ba/0x1e0 [drm]
[   97.807224]  drm_stub_open+0xaf/0xe0 [drm]
[   97.807224]  chrdev_open+0xa3/0x1b0
[   97.807224]  ? cdev_put.part.0+0x20/0x20
[   97.807224]  do_dentry_open+0x132/0x340
[   97.807224]  path_openat+0x2d1/0x14e0
[   97.807224]  ? mem_cgroup_commit_charge+0x7a/0x520
[   97.807224]  do_filp_open+0x93/0x100
[   97.807224]  ? __check_object_size+0x102/0x189
[   97.807224]  ? _raw_spin_unlock+0x16/0x30
[   97.807224]  do_sys_open+0x186/0x210
[   97.807224]  do_syscall_64+0x5b/0x170
[   97.807224]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   97.807224] RIP: 0033:0x7f4147b07976
[   97.807224] Code: 89 54 24 08 e8 7b f4 ff ff 8b 74 24 0c 48 8b 3c 24 41 89 c0 44 8b 54 24 08 b8 01 01 00 00 89 f2 48 89 fe bf 9c ff ff ff 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 30 44 89 c7 89 44 24 08 e8 a6 f4 ff ff 8b 44
[   97.807224] RSP: 002b:00007ffcced96ca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
[   97.807224] RAX: ffffffffffffffda RBX: 00005619d5037f80 RCX: 00007f4147b07976
[   97.807224] RDX: 0000000000000002 RSI: 00005619d46b969c RDI: 00000000ffffff9c
[   98.040039] RBP: 0000000000000024 R08: 0000000000000000 R09: 0000000000000000
[   98.040039] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000024
[   98.040039] R13: 0000000000000012 R14: 00005619d5035950 R15: 0000000000000012
[   98.040039] Modules linked in: nct6775 hwmon_vid algif_skcipher af_alg nls_iso8859_1 nls_cp437 vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common arc4 videodev media snd_usb_audio snd_hda_codec_hdmi snd_usbmidi_lib snd_rawmidi snd_seq_device mousedev input_leds iwlmvm mac80211 snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec edac_mce_amd kvm_amd snd_hda_core kvm iwlwifi snd_hwdep r8169 wmi_bmof cfg80211 snd_pcm irqbypass snd_timer snd libphy soundcore pinctrl_amd rfkill pcspkr sp5100_tco evdev gpio_amdpt k10temp mac_hid i2c_piix4 wmi pcc_cpufreq acpi_cpufreq vboxnetflt(OE) vboxnetadp(OE) vboxpci(OE) vboxdrv(OE) msr sg crypto_user ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 fscrypto uas usb_storage dm_crypt hid_generic usbhid hid
[   98.040039]  dm_mod raid1 md_mod sd_mod crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pcbc ahci libahci aesni_intel aes_x86_64 libata crypto_simd cryptd glue_helper ccp xhci_pci rng_core scsi_mod xhci_hcd nvidia_drm(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm agpgart nvidia_uvm(POE) nvidia_modeset(POE) nvidia(POE) ipmi_devintf ipmi_msghandler
[   98.040039] CR2: 0000000000000080
[   98.040039] ---[ end trace 3b65093b6fe62b2f ]---
[   98.040039] RIP: 0010:drm_lease_owner+0xd/0x20 [drm]
[   98.040039] Code: 83 c4 18 5b 5d c3 b8 ea ff ff ff eb e2 b8 ed ff ff ff eb db e8 b4 ca 68 fb 0f 1f 40 00 0f 1f 44 00 00 48 89 f8 eb 03 48 89 d0 &lt;48&gt; 8b 90 80 00 00 00 48 85 d2 75 f1 c3 66 0f 1f 44 00 00 0f 1f 44
[   98.040039] RSP: 0018:ffffb8cf08e07bb0 EFLAGS: 00010202
[   98.040039] RAX: 0000000000000000 RBX: ffff9cf0f2586c00 RCX: ffff9cf0f2586c88
[   98.040039] RDX: ffff9cf0ddbd8000 RSI: 0000000000000000 RDI: 0000000000000000
[   98.040039] RBP: ffff9cf1040e9800 R08: 0000000000000000 R09: 0000000000000000
[   98.040039] R10: ffffdeb30fd5d680 R11: ffffdeb30f5d6808 R12: ffff9cf1040e9888
[   98.040039] R13: 0000000000000000 R14: dead000000000200 R15: ffff9cf0f2586cc8
[   98.040039] FS:  00007f4145513180(0000) GS:ffff9cf10ea00000(0000) knlGS:0000000000000000
[   98.040039] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   98.040039] CR2: 0000000000000080 CR3: 00000003d7548000 CR4: 00000000003406f0

Signed-off-by: Sergio Correia &lt;sergio@correia.cc&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20181122053329.2692-1-sergio@correia.cc
Signed-off-by: Sean Paul &lt;seanpaul@chromium.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When drm_new_set_master() fails, set is_master to 0, to prevent a
possible NULL pointer deref.

Here is a problematic flow: we check is_master in drm_is_current_master(),
then proceed to call drm_lease_owner() passing master. If we do not restore
is_master status when drm_new_set_master() fails, we may have a situation
in which is_master will be 1 and master itself, NULL, leading to the deref
of a NULL pointer in drm_lease_owner().

This fixes the following OOPS, observed on an ArchLinux running a 4.19.2
kernel:

[   97.804282] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
[   97.807224] PGD 0 P4D 0
[   97.807224] Oops: 0000 [#1] PREEMPT SMP NOPTI
[   97.807224] CPU: 0 PID: 1348 Comm: xfwm4 Tainted: P           OE     4.19.2-arch1-1-ARCH #1
[   97.807224] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./AB350 Pro4, BIOS P5.10 10/16/2018
[   97.807224] RIP: 0010:drm_lease_owner+0xd/0x20 [drm]
[   97.807224] Code: 83 c4 18 5b 5d c3 b8 ea ff ff ff eb e2 b8 ed ff ff ff eb db e8 b4 ca 68 fb 0f 1f 40 00 0f 1f 44 00 00 48 89 f8 eb 03 48 89 d0 &lt;48&gt; 8b 90 80 00 00 00 48 85 d2 75 f1 c3 66 0f 1f 44 00 00 0f 1f 44
[   97.807224] RSP: 0018:ffffb8cf08e07bb0 EFLAGS: 00010202
[   97.807224] RAX: 0000000000000000 RBX: ffff9cf0f2586c00 RCX: ffff9cf0f2586c88
[   97.807224] RDX: ffff9cf0ddbd8000 RSI: 0000000000000000 RDI: 0000000000000000
[   97.807224] RBP: ffff9cf1040e9800 R08: 0000000000000000 R09: 0000000000000000
[   97.807224] R10: ffffdeb30fd5d680 R11: ffffdeb30f5d6808 R12: ffff9cf1040e9888
[   97.807224] R13: 0000000000000000 R14: dead000000000200 R15: ffff9cf0f2586cc8
[   97.807224] FS:  00007f4145513180(0000) GS:ffff9cf10ea00000(0000) knlGS:0000000000000000
[   97.807224] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   97.807224] CR2: 0000000000000080 CR3: 00000003d7548000 CR4: 00000000003406f0
[   97.807224] Call Trace:
[   97.807224]  drm_is_current_master+0x1a/0x30 [drm]
[   97.807224]  drm_master_release+0x3e/0x130 [drm]
[   97.807224]  drm_file_free.part.0+0x2be/0x2d0 [drm]
[   97.807224]  drm_open+0x1ba/0x1e0 [drm]
[   97.807224]  drm_stub_open+0xaf/0xe0 [drm]
[   97.807224]  chrdev_open+0xa3/0x1b0
[   97.807224]  ? cdev_put.part.0+0x20/0x20
[   97.807224]  do_dentry_open+0x132/0x340
[   97.807224]  path_openat+0x2d1/0x14e0
[   97.807224]  ? mem_cgroup_commit_charge+0x7a/0x520
[   97.807224]  do_filp_open+0x93/0x100
[   97.807224]  ? __check_object_size+0x102/0x189
[   97.807224]  ? _raw_spin_unlock+0x16/0x30
[   97.807224]  do_sys_open+0x186/0x210
[   97.807224]  do_syscall_64+0x5b/0x170
[   97.807224]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   97.807224] RIP: 0033:0x7f4147b07976
[   97.807224] Code: 89 54 24 08 e8 7b f4 ff ff 8b 74 24 0c 48 8b 3c 24 41 89 c0 44 8b 54 24 08 b8 01 01 00 00 89 f2 48 89 fe bf 9c ff ff ff 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 30 44 89 c7 89 44 24 08 e8 a6 f4 ff ff 8b 44
[   97.807224] RSP: 002b:00007ffcced96ca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
[   97.807224] RAX: ffffffffffffffda RBX: 00005619d5037f80 RCX: 00007f4147b07976
[   97.807224] RDX: 0000000000000002 RSI: 00005619d46b969c RDI: 00000000ffffff9c
[   98.040039] RBP: 0000000000000024 R08: 0000000000000000 R09: 0000000000000000
[   98.040039] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000024
[   98.040039] R13: 0000000000000012 R14: 00005619d5035950 R15: 0000000000000012
[   98.040039] Modules linked in: nct6775 hwmon_vid algif_skcipher af_alg nls_iso8859_1 nls_cp437 vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common arc4 videodev media snd_usb_audio snd_hda_codec_hdmi snd_usbmidi_lib snd_rawmidi snd_seq_device mousedev input_leds iwlmvm mac80211 snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec edac_mce_amd kvm_amd snd_hda_core kvm iwlwifi snd_hwdep r8169 wmi_bmof cfg80211 snd_pcm irqbypass snd_timer snd libphy soundcore pinctrl_amd rfkill pcspkr sp5100_tco evdev gpio_amdpt k10temp mac_hid i2c_piix4 wmi pcc_cpufreq acpi_cpufreq vboxnetflt(OE) vboxnetadp(OE) vboxpci(OE) vboxdrv(OE) msr sg crypto_user ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 fscrypto uas usb_storage dm_crypt hid_generic usbhid hid
[   98.040039]  dm_mod raid1 md_mod sd_mod crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pcbc ahci libahci aesni_intel aes_x86_64 libata crypto_simd cryptd glue_helper ccp xhci_pci rng_core scsi_mod xhci_hcd nvidia_drm(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm agpgart nvidia_uvm(POE) nvidia_modeset(POE) nvidia(POE) ipmi_devintf ipmi_msghandler
[   98.040039] CR2: 0000000000000080
[   98.040039] ---[ end trace 3b65093b6fe62b2f ]---
[   98.040039] RIP: 0010:drm_lease_owner+0xd/0x20 [drm]
[   98.040039] Code: 83 c4 18 5b 5d c3 b8 ea ff ff ff eb e2 b8 ed ff ff ff eb db e8 b4 ca 68 fb 0f 1f 40 00 0f 1f 44 00 00 48 89 f8 eb 03 48 89 d0 &lt;48&gt; 8b 90 80 00 00 00 48 85 d2 75 f1 c3 66 0f 1f 44 00 00 0f 1f 44
[   98.040039] RSP: 0018:ffffb8cf08e07bb0 EFLAGS: 00010202
[   98.040039] RAX: 0000000000000000 RBX: ffff9cf0f2586c00 RCX: ffff9cf0f2586c88
[   98.040039] RDX: ffff9cf0ddbd8000 RSI: 0000000000000000 RDI: 0000000000000000
[   98.040039] RBP: ffff9cf1040e9800 R08: 0000000000000000 R09: 0000000000000000
[   98.040039] R10: ffffdeb30fd5d680 R11: ffffdeb30f5d6808 R12: ffff9cf1040e9888
[   98.040039] R13: 0000000000000000 R14: dead000000000200 R15: ffff9cf0f2586cc8
[   98.040039] FS:  00007f4145513180(0000) GS:ffff9cf10ea00000(0000) knlGS:0000000000000000
[   98.040039] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   98.040039] CR2: 0000000000000080 CR3: 00000003d7548000 CR4: 00000000003406f0

Signed-off-by: Sergio Correia &lt;sergio@correia.cc&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20181122053329.2692-1-sergio@correia.cc
Signed-off-by: Sean Paul &lt;seanpaul@chromium.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm: Check for lessee in DROP_MASTER ioctl</title>
<updated>2018-01-31T08:27:51+00:00</updated>
<author>
<name>Keith Packard</name>
<email>keithp@keithp.com</email>
</author>
<published>2018-01-19T01:51:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=761e05a702f5d537ffcca1ba933f9f0a968aa022'/>
<id>761e05a702f5d537ffcca1ba933f9f0a968aa022</id>
<content type='text'>
Don't let a lessee control what the current DRM master is set to;
that's the job of the "real" master. Otherwise, the lessee would
disable all access to master operations for the owner and all lessees
under it.

This matches the same check made in the SET_MASTER ioctl.

Signed-off-by: Keith Packard &lt;keithp@keithp.com&gt;
Fixes: 2ed077e467ee ("drm: Add drm_object lease infrastructure [v5]")
Cc: &lt;stable@vger.kernel.org&gt; # v4.15+
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20180119015159.1606-1-keithp@keithp.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Don't let a lessee control what the current DRM master is set to;
that's the job of the "real" master. Otherwise, the lessee would
disable all access to master operations for the owner and all lessees
under it.

This matches the same check made in the SET_MASTER ioctl.

Signed-off-by: Keith Packard &lt;keithp@keithp.com&gt;
Fixes: 2ed077e467ee ("drm: Add drm_object lease infrastructure [v5]")
Cc: &lt;stable@vger.kernel.org&gt; # v4.15+
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Link: https://patchwork.freedesktop.org/patch/msgid/20180119015159.1606-1-keithp@keithp.com
</pre>
</div>
</content>
</entry>
<entry>
<title>drm: Check mode object lease status in all master ioctl paths [v4]</title>
<updated>2017-10-25T06:31:30+00:00</updated>
<author>
<name>Keith Packard</name>
<email>keithp@keithp.com</email>
</author>
<published>2017-04-10T04:35:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7de440db20d4531e4b740bf17b56afc426c54377'/>
<id>7de440db20d4531e4b740bf17b56afc426c54377</id>
<content type='text'>
Attempts to modify un-leased objects are rejected with an error.
Information returned about unleased objects is modified to make them
appear unusable and/or disconnected.

Changes for v2 as suggested by Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;:

 * With the change in the __drm_mode_object_find API to pass the
   file_priv along, we can now centralize most of the lease-based
   access checks in that function.

 * A few places skip that API and require in-line checks.

Changes for v3 provided by Dave Airlie &lt;airlied@redhat.com&gt;

 * remove support for leasing encoders.
 * add support for leasing planes.

Changes for v4

 * Only call drm_lease_held if DRIVER_MODESET.

Signed-off-by: Keith Packard &lt;keithp@keithp.com&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Attempts to modify un-leased objects are rejected with an error.
Information returned about unleased objects is modified to make them
appear unusable and/or disconnected.

Changes for v2 as suggested by Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;:

 * With the change in the __drm_mode_object_find API to pass the
   file_priv along, we can now centralize most of the lease-based
   access checks in that function.

 * A few places skip that API and require in-line checks.

Changes for v3 provided by Dave Airlie &lt;airlied@redhat.com&gt;

 * remove support for leasing encoders.
 * add support for leasing planes.

Changes for v4

 * Only call drm_lease_held if DRIVER_MODESET.

Signed-off-by: Keith Packard &lt;keithp@keithp.com&gt;
Signed-off-by: Dave Airlie &lt;airlied@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
