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Desmond Cheong Zhi Xi 34609faad0 drm: protect drm_master pointers in drm_lease.c
[ Upstream commit 56f0729a51 ]

drm_file->master pointers should be protected by
drm_device.master_mutex or drm_file.master_lookup_lock when being
dereferenced.

However, in drm_lease.c, there are multiple instances where
drm_file->master is accessed and dereferenced while neither lock is
held. This makes drm_lease.c vulnerable to use-after-free bugs.

We address this issue in 2 ways:

1. Add a new drm_file_get_master() function that calls drm_master_get
on drm_file->master while holding on to
drm_file.master_lookup_lock. Since drm_master_get increments the
reference count of master, this prevents master from being freed until
we unreference it with drm_master_put.

2. In each case where drm_file->master is directly accessed and
eventually dereferenced in drm_lease.c, we wrap the access in a call
to the new drm_file_get_master function, then unreference the master
pointer once we are done using it.

Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210712043508.11584-6-desmondcheongzx@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-18 13:40:19 +02:00
Documentation docs: Fix infiniband uverbs minor number 2021-09-18 13:40:11 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
arch ARM: dts: qcom: apq8064: correct clock names 2021-09-18 13:40:18 +02:00
block scsi: bsg: Remove support for SCSI_IOCTL_SEND_COMMAND 2021-09-18 13:40:11 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:50:29 +02:00
crypto crypto: sm2 - fix a memory leak in sm2 2021-07-14 16:56:06 +02:00
drivers drm: protect drm_master pointers in drm_lease.c 2021-09-18 13:40:19 +02:00
fs userfaultfd: prevent concurrent API initialization 2021-09-18 13:40:17 +02:00
include drm: protect drm_master pointers in drm_lease.c 2021-09-18 13:40:19 +02:00
init sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel dma-debug: fix debugfs initialization order 2021-09-18 13:40:13 +02:00
lib lib/mpi: use kcalloc in mpi_resize 2021-09-15 09:50:29 +02:00
mm mm/page_alloc: speed up the iteration of max_order 2021-09-12 08:58:26 +02:00
net netlink: Deal with ESRCH error in nlmsg_notify() 2021-09-18 13:40:18 +02:00
samples samples: pktgen: add missing IPv6 option to pktgen scripts 2021-09-15 09:50:40 +02:00
scripts kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y 2021-09-18 13:40:16 +02:00
security Smack: Fix wrong semantics in smk_access_entry() 2021-09-18 13:40:18 +02:00
sound ASoC: atmel: ATMEL drivers don't need HAS_DMA 2021-09-18 13:40:17 +02:00
tools libbpf: Fix reuse of pinned map on older kernel 2021-09-18 13:40:17 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: Do not leak memory for duplicate debugfs directories 2021-08-12 13:22:17 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
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.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
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COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS f2fs: move ioctl interface definitions to separated file 2021-05-19 10:13:00 +02:00
Makefile Linux 5.10.66 2021-09-16 12:51:23 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.