From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 123541DB127; Tue, 8 Jul 2025 16:54:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751993688; cv=none; b=J7Dy0zK6/NeOY7q/4NzxdoK2GcdxfAkLl1t2AqkjmHa/FqDW35UqowkbFgmOdVy4z5pjhAKCVkqDwhzhky4xkKUH4tmbX5P37z/Hi+hfF04tqq97OFbU9YmiM0gfRrbKmKYz207YDt5fVrg4gqpy/CtwZpoDMqa8s5LlO78Z/w4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751993688; c=relaxed/simple; bh=jMrVoTsG4e38dY/z2J9dSxlVIolTAcH2gWENm6POU8c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P5neusQabqXZjcUDGjee/wv8H8QmLZX9lZ9GWS6oVuhHL7BpNbBvlc0zM7/3u4BBbQZBo8lwYRjlGyQPpG5txPqcbIPtqoPoJd6wS9jpguouNGeOirspvyzbrkqWVaJNa26FOkFUR0VP/KvEgchTDRqqqcpK4UjH3OV9rDAcZq4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ys5nnzg3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ys5nnzg3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86914C4CEED; Tue, 8 Jul 2025 16:54:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751993687; bh=jMrVoTsG4e38dY/z2J9dSxlVIolTAcH2gWENm6POU8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ys5nnzg3zcW59bGI11Dvx3bdgFhT9PEgPLXD8PQYwkVNf/YCh75WxUta3EYtsIOnW N0dhXKARo5wCDsdxeHhe7iz3qpPtizEWsXd/OOShbalp6bsCnjkS0DqTIj0wtHKGDu MN3gx1ELq3cAmGDrRZ++B83OMBUBbVf22C54fEis= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qasim Ijaz , Aditya Garg , Jiri Kosina Subject: [PATCH 6.15 159/178] HID: appletb-kbd: fix slab use-after-free bug in appletb_kbd_probe Date: Tue, 8 Jul 2025 18:23:16 +0200 Message-ID: <20250708162240.640999934@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250708162236.549307806@linuxfoundation.org> References: <20250708162236.549307806@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qasim Ijaz commit 38224c472a038fa9ccd4085511dd9f3d6119dbf9 upstream. In probe appletb_kbd_probe() a "struct appletb_kbd *kbd" is allocated via devm_kzalloc() to store touch bar keyboard related data. Later on if backlight_device_get_by_name() finds a backlight device with name "appletb_backlight" a timer (kbd->inactivity_timer) is setup with appletb_inactivity_timer() and the timer is armed to run after appletb_tb_dim_timeout (60) seconds. A use-after-free is triggered when failure occurs after the timer is armed. This ultimately means probe failure occurs and as a result the "struct appletb_kbd *kbd" which is device managed memory is freed. After 60 seconds the timer will have expired and __run_timers will attempt to access the timer (kbd->inactivity_timer) however the kdb structure has been freed causing a use-after free. [ 71.636938] ================================================================== [ 71.637915] BUG: KASAN: slab-use-after-free in __run_timers+0x7ad/0x890 [ 71.637915] Write of size 8 at addr ffff8881178c5958 by task swapper/1/0 [ 71.637915] [ 71.637915] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.16.0-rc2-00318-g739a6c93cc75-dirty #12 PREEMPT(voluntary) [ 71.637915] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 [ 71.637915] Call Trace: [ 71.637915] [ 71.637915] dump_stack_lvl+0x53/0x70 [ 71.637915] print_report+0xce/0x670 [ 71.637915] ? __run_timers+0x7ad/0x890 [ 71.637915] kasan_report+0xce/0x100 [ 71.637915] ? __run_timers+0x7ad/0x890 [ 71.637915] __run_timers+0x7ad/0x890 [ 71.637915] ? __pfx___run_timers+0x10/0x10 [ 71.637915] ? update_process_times+0xfc/0x190 [ 71.637915] ? __pfx_update_process_times+0x10/0x10 [ 71.637915] ? _raw_spin_lock_irq+0x80/0xe0 [ 71.637915] ? _raw_spin_lock_irq+0x80/0xe0 [ 71.637915] ? __pfx__raw_spin_lock_irq+0x10/0x10 [ 71.637915] run_timer_softirq+0x141/0x240 [ 71.637915] ? __pfx_run_timer_softirq+0x10/0x10 [ 71.637915] ? __pfx___hrtimer_run_queues+0x10/0x10 [ 71.637915] ? kvm_clock_get_cycles+0x18/0x30 [ 71.637915] ? ktime_get+0x60/0x140 [ 71.637915] handle_softirqs+0x1b8/0x5c0 [ 71.637915] ? __pfx_handle_softirqs+0x10/0x10 [ 71.637915] irq_exit_rcu+0xaf/0xe0 [ 71.637915] sysvec_apic_timer_interrupt+0x6c/0x80 [ 71.637915] [ 71.637915] [ 71.637915] Allocated by task 39: [ 71.637915] kasan_save_stack+0x33/0x60 [ 71.637915] kasan_save_track+0x14/0x30 [ 71.637915] __kasan_kmalloc+0x8f/0xa0 [ 71.637915] __kmalloc_node_track_caller_noprof+0x195/0x420 [ 71.637915] devm_kmalloc+0x74/0x1e0 [ 71.637915] appletb_kbd_probe+0x37/0x3c0 [ 71.637915] hid_device_probe+0x2d1/0x680 [ 71.637915] really_probe+0x1c3/0x690 [ 71.637915] __driver_probe_device+0x247/0x300 [ 71.637915] driver_probe_device+0x49/0x210 [...] [ 71.637915] [ 71.637915] Freed by task 39: [ 71.637915] kasan_save_stack+0x33/0x60 [ 71.637915] kasan_save_track+0x14/0x30 [ 71.637915] kasan_save_free_info+0x3b/0x60 [ 71.637915] __kasan_slab_free+0x37/0x50 [ 71.637915] kfree+0xcf/0x360 [ 71.637915] devres_release_group+0x1f8/0x3c0 [ 71.637915] hid_device_probe+0x315/0x680 [ 71.637915] really_probe+0x1c3/0x690 [ 71.637915] __driver_probe_device+0x247/0x300 [ 71.637915] driver_probe_device+0x49/0x210 [...] The root cause of the issue is that the timer is not disarmed on failure paths leading to it remaining active and accessing freed memory. To fix this call timer_delete_sync() to deactivate the timer. Another small issue is that timer_delete_sync is called unconditionally in appletb_kbd_remove(), fix this by checking for a valid kbd->backlight_dev before calling timer_delete_sync. Fixes: 93a0fc489481 ("HID: hid-appletb-kbd: add support for automatic brightness control while using the touchbar") Cc: stable@vger.kernel.org Signed-off-by: Qasim Ijaz Reviewed-by: Aditya Garg Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-appletb-kbd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/hid/hid-appletb-kbd.c +++ b/drivers/hid/hid-appletb-kbd.c @@ -437,8 +437,10 @@ static int appletb_kbd_probe(struct hid_ unregister_handler: input_unregister_handler(&kbd->inp_handler); close_hw: - if (kbd->backlight_dev) + if (kbd->backlight_dev) { put_device(&kbd->backlight_dev->dev); + timer_delete_sync(&kbd->inactivity_timer); + } hid_hw_close(hdev); stop_hw: hid_hw_stop(hdev); @@ -452,10 +454,10 @@ static void appletb_kbd_remove(struct hi appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF); input_unregister_handler(&kbd->inp_handler); - timer_delete_sync(&kbd->inactivity_timer); - - if (kbd->backlight_dev) + if (kbd->backlight_dev) { put_device(&kbd->backlight_dev->dev); + timer_delete_sync(&kbd->inactivity_timer); + } hid_hw_close(hdev); hid_hw_stop(hdev);