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Fedor Pchelkin bdb3c41b35 wifi: rtw89: fix use-after-free in rtw89_core_tx_kick_off_and_wait() 
commit 3e31a6bc07 upstream.

There is a bug observed when rtw89_core_tx_kick_off_and_wait() tries to
access already freed skb_data:

 BUG: KFENCE: use-after-free write in rtw89_core_tx_kick_off_and_wait drivers/net/wireless/realtek/rtw89/core.c:1110

 CPU: 6 UID: 0 PID: 41377 Comm: kworker/u64:24 Not tainted  6.17.0-rc1+ #1 PREEMPT(lazy)
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS edk2-20250523-14.fc42 05/23/2025
 Workqueue: events_unbound cfg80211_wiphy_work [cfg80211]

 Use-after-free write at 0x0000000020309d9d (in kfence-#251):
 rtw89_core_tx_kick_off_and_wait drivers/net/wireless/realtek/rtw89/core.c:1110
 rtw89_core_scan_complete drivers/net/wireless/realtek/rtw89/core.c:5338
 rtw89_hw_scan_complete_cb drivers/net/wireless/realtek/rtw89/fw.c:7979
 rtw89_chanctx_proceed_cb drivers/net/wireless/realtek/rtw89/chan.c:3165
 rtw89_chanctx_proceed drivers/net/wireless/realtek/rtw89/chan.h:141
 rtw89_hw_scan_complete drivers/net/wireless/realtek/rtw89/fw.c:8012
 rtw89_mac_c2h_scanofld_rsp drivers/net/wireless/realtek/rtw89/mac.c:5059
 rtw89_fw_c2h_work drivers/net/wireless/realtek/rtw89/fw.c:6758
 process_one_work kernel/workqueue.c:3241
 worker_thread kernel/workqueue.c:3400
 kthread kernel/kthread.c:463
 ret_from_fork arch/x86/kernel/process.c:154
 ret_from_fork_asm arch/x86/entry/entry_64.S:258

 kfence-#251: 0x0000000056e2393d-0x000000009943cb62, size=232, cache=skbuff_head_cache

 allocated by task 41377 on cpu 6 at 77869.159548s (0.009551s ago):
 __alloc_skb net/core/skbuff.c:659
 __netdev_alloc_skb net/core/skbuff.c:734
 ieee80211_nullfunc_get net/mac80211/tx.c:5844
 rtw89_core_send_nullfunc drivers/net/wireless/realtek/rtw89/core.c:3431
 rtw89_core_scan_complete drivers/net/wireless/realtek/rtw89/core.c:5338
 rtw89_hw_scan_complete_cb drivers/net/wireless/realtek/rtw89/fw.c:7979
 rtw89_chanctx_proceed_cb drivers/net/wireless/realtek/rtw89/chan.c:3165
 rtw89_chanctx_proceed drivers/net/wireless/realtek/rtw89/chan.c:3194
 rtw89_hw_scan_complete drivers/net/wireless/realtek/rtw89/fw.c:8012
 rtw89_mac_c2h_scanofld_rsp drivers/net/wireless/realtek/rtw89/mac.c:5059
 rtw89_fw_c2h_work drivers/net/wireless/realtek/rtw89/fw.c:6758
 process_one_work kernel/workqueue.c:3241
 worker_thread kernel/workqueue.c:3400
 kthread kernel/kthread.c:463
 ret_from_fork arch/x86/kernel/process.c:154
 ret_from_fork_asm arch/x86/entry/entry_64.S:258

 freed by task 1045 on cpu 9 at 77869.168393s (0.001557s ago):
 ieee80211_tx_status_skb net/mac80211/status.c:1117
 rtw89_pci_release_txwd_skb drivers/net/wireless/realtek/rtw89/pci.c:564
 rtw89_pci_release_tx_skbs.isra.0 drivers/net/wireless/realtek/rtw89/pci.c:651
 rtw89_pci_release_tx drivers/net/wireless/realtek/rtw89/pci.c:676
 rtw89_pci_napi_poll drivers/net/wireless/realtek/rtw89/pci.c:4238
 __napi_poll net/core/dev.c:7495
 net_rx_action net/core/dev.c:7557 net/core/dev.c:7684
 handle_softirqs kernel/softirq.c:580
 do_softirq.part.0 kernel/softirq.c:480
 __local_bh_enable_ip kernel/softirq.c:407
 rtw89_pci_interrupt_threadfn drivers/net/wireless/realtek/rtw89/pci.c:927
 irq_thread_fn kernel/irq/manage.c:1133
 irq_thread kernel/irq/manage.c:1257
 kthread kernel/kthread.c:463
 ret_from_fork arch/x86/kernel/process.c:154
 ret_from_fork_asm arch/x86/entry/entry_64.S:258

It is a consequence of a race between the waiting and the signaling side
of the completion:

            Waiting thread                            Completing thread

rtw89_core_tx_kick_off_and_wait()
  rcu_assign_pointer(skb_data->wait, wait)
  /* start waiting */
  wait_for_completion_timeout()
                                                rtw89_pci_tx_status()
                                                  rtw89_core_tx_wait_complete()
                                                    rcu_read_lock()
                                                    /* signals completion and
                                                     * proceeds further
                                                     */
                                                    complete(&wait->completion)
                                                    rcu_read_unlock()
                                                  ...
                                                  /* frees skb_data */
                                                  ieee80211_tx_status_ni()
  /* returns (exit status doesn't matter) */
  wait_for_completion_timeout()
  ...
  /* accesses the already freed skb_data */
  rcu_assign_pointer(skb_data->wait, NULL)

The completing side might proceed and free the underlying skb even before
the waiting side is fully awoken and run to execution.  Actually the race
happens regardless of wait_for_completion_timeout() exit status, e.g.
the waiting side may hit a timeout and the concurrent completing side is
still able to free the skb.

Skbs which are sent by rtw89_core_tx_kick_off_and_wait() are owned by the
driver.  They don't come from core ieee80211 stack so no need to pass them
to ieee80211_tx_status_ni() on completing side.

Introduce a work function which will act as a garbage collector for
rtw89_tx_wait_info objects and the associated skbs.  Thus no potentially
heavy locks are required on the completing side.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 1ae5ca6152 ("wifi: rtw89: add function to wait for completion of TX skbs")
Cc: stable@vger.kernel.org
Suggested-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250919210852.823912-2-pchelkin@ispras.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-10-06 11:20:05 +02:00
arch ARM fixes for 6.17 2025-09-28 13:24:43 -07:00
block blk-mq: fix blk_mq_tags double free while nr_requests grown 2025-10-06 11:20:04 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push fixes a NULL pointer dereference in ccp and a couple of 2025-09-19 09:58:21 -07:00
Documentation i2c-for-6.17-rc8 2025-09-28 13:19:23 -07:00
drivers wifi: rtw89: fix use-after-free in rtw89_core_tx_kick_off_and_wait() 2025-10-06 11:20:05 +02:00
fs 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
include 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
init kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on clang < 17 2025-09-24 09:29:15 +02:00
io_uring io_uring-6.17-20250919 2025-09-19 12:10:49 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel tracing fixes for v6.17 2025-09-28 10:26:35 -07:00
lib hardening fixes for v6.17-rc4 2025-08-31 08:56:45 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
net nexthop: Forbid FDB status change while nexthop is in a group 2025-09-23 17:01:05 -07:00
rust Driver core fixes for 6.17-rc6 2025-09-13 10:36:06 -07:00
samples 15 hotfixes. 11 are cc:stable and the remainder address post-6.16 issues 2025-09-17 21:34:26 -07:00
scripts gcc-plugins: Remove TODO_verify_il for GCC >= 16 2025-10-06 11:20:04 +02:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free 2025-10-06 11:20:05 +02:00
tools Two fixes for rtla in v6.17: 2025-09-27 09:50:46 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap 7 hotfixes. 4 are cc:stable and the remainder address post-6.16 issues or 2025-09-28 09:32:00 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: retire Boris from TLS maintainers 2025-08-26 17:36:01 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS i2c-for-6.17-rc8 2025-09-28 13:19:23 -07:00
Makefile Linux 6.17 2025-09-28 14:39:22 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.