From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CB8D349363D; Mon, 31 Aug 2026 14:05:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788185149; cv=none; b=WJZXyDgLcfk90l2+ZT+2i2GhBtz6YQ404yckCcnD1kQWZ62k7L0Wi7SpMqOM/2JWNaL2hFWehWv96F6KKjtxHjuJxDLbPlgFyp/3uT9UJ9i10Np0+Vr2H4hci8TRZLkXqWZJK6ivkvUWCHJPPr1Lb9GbmGZZmsOVyscIx+IPchw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788185149; c=relaxed/simple; bh=VjLJdTGGv67VxzJItH3g2UUoBTfEZ0fwXYyGpDAXKgc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cjXYSI/2FAeX4K0A02PcJz5zOkqvkB/pSXlEEpwygqottX4llugUYln8lqXnHKd1x0k6XuRGrpEbmr7nseR8gOju67NsGqW4Yi1oE2edp7hrDi90kpFnu756BfEXEjuVlTzbwAVEse8G1uOjjooSQb6wxy32gH/nZ6Ghlkv+Vcg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jh8T6vV9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jh8T6vV9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DABCC1F000E9; Mon, 31 Aug 2026 14:05:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788185147; bh=Q2XCsJW0xVX3fN5HKY56276uNMHQZaKkpgFvA2q1F2A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jh8T6vV99/HaC+JXAymxO8t2tmoQ/rrd2MR1LXM1iYLhV/tWMby4Nshor2E9t+z25 r3Rm6Xl3j6H6KArLB3WV3EXTNChO3Y4eSpuCXZbYovDRIme/No/dZmqE2PZY5W+jzi Xq2aGOBcg4539zN23jnCc07Yd5ix5QCH8OMhKwhQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ibrahim Hashimov , Jiri Kosina , Sasha Levin Subject: [PATCH 5.15 32/69] HID: uclogic: fix use-after-free of inrange_timer on remove Date: Mon, 31 Aug 2026 15:35:05 +0200 Message-ID: <20260831133400.097841064@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831133358.601894154@linuxfoundation.org> References: <20260831133358.601894154@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ibrahim Hashimov [ Upstream commit 506fd50a9027340f0e9dcc587d10ccb03312dba6 ] uclogic_remove() cancels the pen in-range timer and then stops the device: timer_delete_sync(&drvdata->inrange_timer); hid_hw_stop(hdev); timer_delete_sync() only guarantees the timer is idle at that instant. uclogic_raw_event_pen() keeps delivering pen reports until hid_hw_stop() stops the transport several lines later, and every report with pen->inrange == UCLOGIC_PARAMS_PEN_INRANGE_NONE re-arms the timer: mod_timer(&drvdata->inrange_timer, jiffies + msecs_to_jiffies(100)); A report landing between the timer_delete_sync() call and the transport teardown in hid_hw_stop() re-arms inrange_timer after it was cancelled. uclogic_remove() then returns and the devm drvdata is freed, while hid_hw_stop() has already freed the input device drvdata->pen_input points at, so when the timer fires ~100 ms later uclogic_inrange_timeout() dereferences freed memory -- a use-after-free in timer-softirq context. Swapping the two calls is not a fix: stopping the device first frees drvdata->pen_input via hidinput_disconnect() while the timer may still be pending, so a timer already armed before removal fires on the freed input device in the window before timer_delete_sync() runs. Use timer_shutdown_sync() before hid_hw_stop() instead. It cancels the timer, waits for a running callback while pen_input is still valid, and prevents any further re-arming -- a later mod_timer() from an in-flight report is silently ignored -- so the timer is provably dead before hid_hw_stop() frees the inputs. This is the ordering the timer core documents for this "timer re-armed from another path" teardown case. Fixes: 01309e29eb95 ("HID: uclogic: Support in-range reporting emulation") Cc: stable@vger.kernel.org Signed-off-by: Ibrahim Hashimov Assisted-by: AuditCode-AI:2026.07 Signed-off-by: Jiri Kosina [ changed timer_delete_sync() to del_timer_sync() in the removed line to match the pre-rename API on this branch ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-uclogic-core.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/drivers/hid/hid-uclogic-core.c +++ b/drivers/hid/hid-uclogic-core.c @@ -346,7 +346,17 @@ static void uclogic_remove(struct hid_de { struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev); - del_timer_sync(&drvdata->inrange_timer); + /* + * Shut the in-range timer down before stopping the device. + * uclogic_raw_event_pen() re-arms inrange_timer on every pen report + * and keeps running until hid_hw_stop() stops the transport, so a + * plain timer_delete_sync() here can be undone by a report landing in + * the window before hid_hw_stop(). timer_shutdown_sync() cancels the + * timer and makes any later re-arm a no-op, so it is provably dead + * before hid_hw_stop() frees the input device drvdata->pen_input + * points at. + */ + timer_shutdown_sync(&drvdata->inrange_timer); hid_hw_stop(hdev); kfree(drvdata->desc_ptr); uclogic_params_cleanup(&drvdata->params);