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Filename Latest commit message Latest commit date
Desmond Cheong Zhi Xi 977d11df79 drm: Lock pointer access in drm_master_release()
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 '&dev->master_mutex'

The 'file_priv->master' field should be protected by the mutex lock to
'&dev->master_mutex'. This is because other processes can concurrently
modify this field and free the current 'file_priv->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->master' in 'drm_new_set_master()'. The old value of
'fpriv->master' was subsequently freed before the mutex was unlocked.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210609092119.173590-1-desmondcheongzx@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16 11:59:39 +02:00
arch x86/boot: Add .text.* to setup.ld 2021-06-16 11:59:38 +02:00
block
certs
crypto
Documentation XArray: add xas_split 2021-06-10 13:37:14 +02:00
drivers drm: Lock pointer access in drm_master_release() 2021-06-16 11:59:39 +02:00
fs proc: Track /proc/$pid/attr/ opener mm_struct 2021-06-16 11:59:32 +02:00
include XArray: add xas_split 2021-06-10 13:37:14 +02:00
init pid: take a reference when initializing cad_pid 2021-06-10 13:37:11 +02:00
ipc
kernel wq: handle VM suspension in stall detection 2021-06-16 11:59:35 +02:00
lib lib/lz4: explicitly support in-place decompression 2021-06-10 13:37:16 +02:00
LICENSES
mm mm/filemap: fix storing to a THP shadow entry 2021-06-10 13:37:15 +02:00
net RDS tcp loopback connection can hang 2021-06-16 11:59:35 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts
security
sound ASoC: sti-sas: add missing MODULE_DEVICE_TABLE 2021-06-16 11:59:33 +02:00
tools perf jevents: Fix getting maximum number of fds 2021-06-03 08:59:08 +02:00
usr
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Makefile Linux 5.4.125 2021-06-10 13:37:17 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.