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Linux kernel source tree for SHARP Brain series (PW-SH1 or later)
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Yang Yingliang 7f0365b4da workqueue: fix UAF in pwq_unbound_release_workfn() 
commit b42b0bddcbc87b4c66f6497f66fc72d52b712aa7 upstream.

I got a UAF report when doing fuzz test:

[  152.880091][ T8030] ==================================================================
[  152.881240][ T8030] BUG: KASAN: use-after-free in pwq_unbound_release_workfn+0x50/0x190
[  152.882442][ T8030] Read of size 4 at addr ffff88810d31bd00 by task kworker/3:2/8030
[  152.883578][ T8030]
[  152.883932][ T8030] CPU: 3 PID: 8030 Comm: kworker/3:2 Not tainted 5.13.0+ #249
[  152.885014][ T8030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[  152.886442][ T8030] Workqueue: events pwq_unbound_release_workfn
[  152.887358][ T8030] Call Trace:
[  152.887837][ T8030]  dump_stack_lvl+0x75/0x9b
[  152.888525][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.889371][ T8030]  print_address_description.constprop.10+0x48/0x70
[  152.890326][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.891163][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.891999][ T8030]  kasan_report.cold.15+0x82/0xdb
[  152.892740][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.893594][ T8030]  __asan_load4+0x69/0x90
[  152.894243][ T8030]  pwq_unbound_release_workfn+0x50/0x190
[  152.895057][ T8030]  process_one_work+0x47b/0x890
[  152.895778][ T8030]  worker_thread+0x5c/0x790
[  152.896439][ T8030]  ? process_one_work+0x890/0x890
[  152.897163][ T8030]  kthread+0x223/0x250
[  152.897747][ T8030]  ? set_kthread_struct+0xb0/0xb0
[  152.898471][ T8030]  ret_from_fork+0x1f/0x30
[  152.899114][ T8030]
[  152.899446][ T8030] Allocated by task 8884:
[  152.900084][ T8030]  kasan_save_stack+0x21/0x50
[  152.900769][ T8030]  __kasan_kmalloc+0x88/0xb0
[  152.901416][ T8030]  __kmalloc+0x29c/0x460
[  152.902014][ T8030]  alloc_workqueue+0x111/0x8e0
[  152.902690][ T8030]  __btrfs_alloc_workqueue+0x11e/0x2a0
[  152.903459][ T8030]  btrfs_alloc_workqueue+0x6d/0x1d0
[  152.904198][ T8030]  scrub_workers_get+0x1e8/0x490
[  152.904929][ T8030]  btrfs_scrub_dev+0x1b9/0x9c0
[  152.905599][ T8030]  btrfs_ioctl+0x122c/0x4e50
[  152.906247][ T8030]  __x64_sys_ioctl+0x137/0x190
[  152.906916][ T8030]  do_syscall_64+0x34/0xb0
[  152.907535][ T8030]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  152.908365][ T8030]
[  152.908688][ T8030] Freed by task 8884:
[  152.909243][ T8030]  kasan_save_stack+0x21/0x50
[  152.909893][ T8030]  kasan_set_track+0x20/0x30
[  152.910541][ T8030]  kasan_set_free_info+0x24/0x40
[  152.911265][ T8030]  __kasan_slab_free+0xf7/0x140
[  152.911964][ T8030]  kfree+0x9e/0x3d0
[  152.912501][ T8030]  alloc_workqueue+0x7d7/0x8e0
[  152.913182][ T8030]  __btrfs_alloc_workqueue+0x11e/0x2a0
[  152.913949][ T8030]  btrfs_alloc_workqueue+0x6d/0x1d0
[  152.914703][ T8030]  scrub_workers_get+0x1e8/0x490
[  152.915402][ T8030]  btrfs_scrub_dev+0x1b9/0x9c0
[  152.916077][ T8030]  btrfs_ioctl+0x122c/0x4e50
[  152.916729][ T8030]  __x64_sys_ioctl+0x137/0x190
[  152.917414][ T8030]  do_syscall_64+0x34/0xb0
[  152.918034][ T8030]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  152.918872][ T8030]
[  152.919203][ T8030] The buggy address belongs to the object at ffff88810d31bc00
[  152.919203][ T8030]  which belongs to the cache kmalloc-512 of size 512
[  152.921155][ T8030] The buggy address is located 256 bytes inside of
[  152.921155][ T8030]  512-byte region [ffff88810d31bc00, ffff88810d31be00)
[  152.922993][ T8030] The buggy address belongs to the page:
[  152.923800][ T8030] page:ffffea000434c600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d318
[  152.925249][ T8030] head:ffffea000434c600 order:2 compound_mapcount:0 compound_pincount:0
[  152.926399][ T8030] flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
[  152.927515][ T8030] raw: 057ff00000010200 dead000000000100 dead000000000122 ffff888009c42c80
[  152.928716][ T8030] raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
[  152.929890][ T8030] page dumped because: kasan: bad access detected
[  152.930759][ T8030]
[  152.931076][ T8030] Memory state around the buggy address:
[  152.931851][ T8030]  ffff88810d31bc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.932967][ T8030]  ffff88810d31bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.934068][ T8030] >ffff88810d31bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.935189][ T8030]                    ^
[  152.935763][ T8030]  ffff88810d31bd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.936847][ T8030]  ffff88810d31be00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  152.937940][ T8030] ==================================================================

If apply_wqattrs_prepare() fails in alloc_workqueue(), it will call put_pwq()
which invoke a work queue to call pwq_unbound_release_workfn() and use the 'wq'.
The 'wq' allocated in alloc_workqueue() will be freed in error path when
apply_wqattrs_prepare() fails. So it will lead a UAF.

CPU0                                          CPU1
alloc_workqueue()
alloc_and_link_pwqs()
apply_wqattrs_prepare() fails
apply_wqattrs_cleanup()
schedule_work(&pwq->unbound_release_work)
kfree(wq)
                                              worker_thread()
                                              pwq_unbound_release_workfn() <- trigger uaf here

If apply_wqattrs_prepare() fails, the new pwq are not linked, it doesn't
hold any reference to the 'wq', 'wq' is invalid to access in the worker,
so add check pwq if linked to fix this.

Fixes: 2d5f0764b5 ("workqueue: split apply_workqueue_attrs() into 3 stages")
Cc: stable@vger.kernel.org # v4.2+
Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Tested-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2021-07-31 08:19:37 +02:00
Documentation userfaultfd: do not untag user pointers 2021-07-28 13:31:01 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch KVM: x86: determine if an exception has an error code only when injecting it. 2021-07-31 08:19:37 +02:00
block rq-qos: fix missed wake-ups in rq_qos_throttle try two 2021-07-19 08:53:16 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
drivers xhci: add xhci_get_virt_ep() helper 2021-07-28 13:31:02 +02:00
fs btrfs: compression: don't try to compress if we don't have enough pages 2021-07-28 13:31:02 +02:00
include drm: Return -ENOTTY for non-drm ioctls 2021-07-28 13:31:01 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel workqueue: fix UAF in pwq_unbound_release_workfn() 2021-07-31 08:19:37 +02:00
lib lib/decompress_unlz4.c: correctly handle zero-padding around initrds. 2021-07-20 16:10:46 +02:00
mm mm: slab: fix kmem_cache_create failed when sysfs node not destroyed 2021-07-25 14:35:14 +02:00
net af_unix: fix garbage collect vs MSG_PEEK 2021-07-31 08:19:37 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:53:30 +02:00
scripts kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set 2021-07-25 14:35:12 +02:00
security smackfs: restrict bytes count in smk_set_cipso() 2021-07-19 08:53:18 +02:00
sound ALSA: hdmi: Expose all pins on MSI MS-7C94 board 2021-07-28 13:30:59 +02:00
tools tools: Allow proper CC/CXX/... override with LLVM=1 in Makefile.include 2021-07-31 08:19:37 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio 2021-07-20 16:10:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.136 2021-07-28 13:31:02 +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.