No description
Find a file
Li Jinlin d12ddd843f blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd
[ Upstream commit 858560b276 ]

KASAN reports a use-after-free report when doing fuzz test:

[693354.104835] ==================================================================
[693354.105094] BUG: KASAN: use-after-free in bfq_io_set_weight_legacy+0xd3/0x160
[693354.105336] Read of size 4 at addr ffff888be0a35664 by task sh/1453338

[693354.105607] CPU: 41 PID: 1453338 Comm: sh Kdump: loaded Not tainted 4.18.0-147
[693354.105610] Hardware name: Huawei 2288H V5/BC11SPSCB0, BIOS 0.81 07/02/2018
[693354.105612] Call Trace:
[693354.105621]  dump_stack+0xf1/0x19b
[693354.105626]  ? show_regs_print_info+0x5/0x5
[693354.105634]  ? printk+0x9c/0xc3
[693354.105638]  ? cpumask_weight+0x1f/0x1f
[693354.105648]  print_address_description+0x70/0x360
[693354.105654]  kasan_report+0x1b2/0x330
[693354.105659]  ? bfq_io_set_weight_legacy+0xd3/0x160
[693354.105665]  ? bfq_io_set_weight_legacy+0xd3/0x160
[693354.105670]  bfq_io_set_weight_legacy+0xd3/0x160
[693354.105675]  ? bfq_cpd_init+0x20/0x20
[693354.105683]  cgroup_file_write+0x3aa/0x510
[693354.105693]  ? ___slab_alloc+0x507/0x540
[693354.105698]  ? cgroup_file_poll+0x60/0x60
[693354.105702]  ? 0xffffffff89600000
[693354.105708]  ? usercopy_abort+0x90/0x90
[693354.105716]  ? mutex_lock+0xef/0x180
[693354.105726]  kernfs_fop_write+0x1ab/0x280
[693354.105732]  ? cgroup_file_poll+0x60/0x60
[693354.105738]  vfs_write+0xe7/0x230
[693354.105744]  ksys_write+0xb0/0x140
[693354.105749]  ? __ia32_sys_read+0x50/0x50
[693354.105760]  do_syscall_64+0x112/0x370
[693354.105766]  ? syscall_return_slowpath+0x260/0x260
[693354.105772]  ? do_page_fault+0x9b/0x270
[693354.105779]  ? prepare_exit_to_usermode+0xf9/0x1a0
[693354.105784]  ? enter_from_user_mode+0x30/0x30
[693354.105793]  entry_SYSCALL_64_after_hwframe+0x65/0xca

[693354.105875] Allocated by task 1453337:
[693354.106001]  kasan_kmalloc+0xa0/0xd0
[693354.106006]  kmem_cache_alloc_node_trace+0x108/0x220
[693354.106010]  bfq_pd_alloc+0x96/0x120
[693354.106015]  blkcg_activate_policy+0x1b7/0x2b0
[693354.106020]  bfq_create_group_hierarchy+0x1e/0x80
[693354.106026]  bfq_init_queue+0x678/0x8c0
[693354.106031]  blk_mq_init_sched+0x1f8/0x460
[693354.106037]  elevator_switch_mq+0xe1/0x240
[693354.106041]  elevator_switch+0x25/0x40
[693354.106045]  elv_iosched_store+0x1a1/0x230
[693354.106049]  queue_attr_store+0x78/0xb0
[693354.106053]  kernfs_fop_write+0x1ab/0x280
[693354.106056]  vfs_write+0xe7/0x230
[693354.106060]  ksys_write+0xb0/0x140
[693354.106064]  do_syscall_64+0x112/0x370
[693354.106069]  entry_SYSCALL_64_after_hwframe+0x65/0xca

[693354.106114] Freed by task 1453336:
[693354.106225]  __kasan_slab_free+0x130/0x180
[693354.106229]  kfree+0x90/0x1b0
[693354.106233]  blkcg_deactivate_policy+0x12c/0x220
[693354.106238]  bfq_exit_queue+0xf5/0x110
[693354.106241]  blk_mq_exit_sched+0x104/0x130
[693354.106245]  __elevator_exit+0x45/0x60
[693354.106249]  elevator_switch_mq+0xd6/0x240
[693354.106253]  elevator_switch+0x25/0x40
[693354.106257]  elv_iosched_store+0x1a1/0x230
[693354.106261]  queue_attr_store+0x78/0xb0
[693354.106264]  kernfs_fop_write+0x1ab/0x280
[693354.106268]  vfs_write+0xe7/0x230
[693354.106271]  ksys_write+0xb0/0x140
[693354.106275]  do_syscall_64+0x112/0x370
[693354.106280]  entry_SYSCALL_64_after_hwframe+0x65/0xca

[693354.106329] The buggy address belongs to the object at ffff888be0a35580
                 which belongs to the cache kmalloc-1k of size 1024
[693354.106736] The buggy address is located 228 bytes inside of
                 1024-byte region [ffff888be0a35580, ffff888be0a35980)
[693354.107114] The buggy address belongs to the page:
[693354.107273] page:ffffea002f828c00 count:1 mapcount:0 mapping:ffff888107c17080 index:0x0 compound_mapcount: 0
[693354.107606] flags: 0x17ffffc0008100(slab|head)
[693354.107760] raw: 0017ffffc0008100 ffffea002fcbc808 ffffea0030bd3a08 ffff888107c17080
[693354.108020] raw: 0000000000000000 00000000001c001c 00000001ffffffff 0000000000000000
[693354.108278] page dumped because: kasan: bad access detected

[693354.108511] Memory state around the buggy address:
[693354.108671]  ffff888be0a35500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[693354.116396]  ffff888be0a35580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.124473] >ffff888be0a35600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.132421]                                                        ^
[693354.140284]  ffff888be0a35680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.147912]  ffff888be0a35700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.155281] ==================================================================

blkgs are protected by both queue and blkcg locks and holding
either should stabilize them. However, the path of destroying
blkg policy data is only protected by queue lock in
blkcg_activate_policy()/blkcg_deactivate_policy(). Other tasks
can get the blkg policy data before the blkg policy data is
destroyed, and use it after destroyed, which will result in a
use-after-free.

CPU0                             CPU1
blkcg_deactivate_policy
  spin_lock_irq(&q->queue_lock)
                                 bfq_io_set_weight_legacy
                                   spin_lock_irq(&blkcg->lock)
                                   blkg_to_bfqg(blkg)
                                     pd_to_bfqg(blkg->pd[pol->plid])
                                     ^^^^^^blkg->pd[pol->plid] != NULL
                                           bfqg != NULL
  pol->pd_free_fn(blkg->pd[pol->plid])
    pd_to_bfqg(blkg->pd[pol->plid])
    bfqg_put(bfqg)
      kfree(bfqg)
  blkg->pd[pol->plid] = NULL
  spin_unlock_irq(q->queue_lock);
                                   bfq_group_set_weight(bfqg, val, 0)
                                     bfqg->entity.new_weight
                                     ^^^^^^trigger uaf here
                                   spin_unlock_irq(&blkcg->lock);

Fix by grabbing the matching blkcg lock before trying to
destroy blkg policy data.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Li Jinlin <lijinlin3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210914042605.3260596-1-lijinlin3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-30 10:09:25 +02:00
arch sparc32: page align size in arch_dma_alloc 2021-09-30 10:09:25 +02:00
block blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd 2021-09-30 10:09:25 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation 2021-09-22 12:26:43 +02:00
drivers nvme-multipath: fix ANA state updates when a namespace is not present 2021-09-30 10:09:25 +02:00
fs cifs: fix a sign extension bug 2021-09-30 10:09:24 +02:00
include erofs: fix up erofs_lookup tracepoint 2021-09-30 10:09:22 +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 bpf: Add oversize check before call kvcalloc() 2021-09-30 10:09:25 +02:00
lib Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH 2021-09-26 14:07:10 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range() 2021-09-22 12:26:43 +02:00
net ipv6: delay fib6_sernum increase in fib6_add 2021-09-30 10:09:24 +02:00
samples samples: bpf: Fix tracex7 error raised on the missing argument 2021-09-22 12:26:30 +02:00
scripts kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y 2021-09-22 12:26:26 +02:00
security apparmor: remove duplicate macro list_entry_is_head() 2021-09-26 14:07:06 +02:00
sound ASoC: rockchip: i2s: Fixup config for DAIFMT_DSP_A/B 2021-09-22 12:26:35 +02:00
tools perf unwind: Do not overwrite FEATURE_CHECK_LDFLAGS-libunwind-{x86,aarch64} 2021-09-22 12:26:45 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: remember position in kvm->vcpus array 2021-09-26 14:07:05 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.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 5.4.149 2021-09-26 14:07:14 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.