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 4762248095A; Tue, 25 Aug 2026 13:38:05 +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=1787665086; cv=none; b=RuYEqVQkoAphVWgsJZX+FUal+vy8GCFCU3kcfzweJXnp/e787z51T9i6FliFgL5vpfd5KzuVL88dWMp9VL5pZeJJPsu/dK/CJzC2iffJzBnxLR7v651LcWf3bk2reoD2/hinwDqO9pBHgQGfSPndpVgLQo6MMD/eaKaAwEDnNK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787665086; c=relaxed/simple; bh=F4F5+pJwaRlZvGCEzx0xHN1LAFTaOU1LFzI+bauOUS0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=plsQi1TC5X5ppCbjRxPqAepzId8VXYVvYHPaKI21PXgaxNmCa6qcgavqEYMQFP6mue2MFmpAnbiXz7bJyMSXG4vRlgrz/SguD4u4Tk9Z6DYSMPpaS0LjsvHNvpacjWo9+MfQvH7JTlYVuD2Oou6aoIXBVpx8edEjKT7rj8tDN+0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=plUEeJDe; 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="plUEeJDe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91A691F000E9; Tue, 25 Aug 2026 13:38:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787665085; bh=M4TlgoXvhS+pPpewdsINTldvfj51Tn4N2y0wQwSzxTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=plUEeJDeRn+F+CGdvxswQttU5faENT376sid/cdiF7zBo8KpMux1IQGfNvitcAGEh OHCvKoTADTCJNV0nD/AqayMKh3vB0hE2x7iy2ut5QcAOxUJyu60VC5dnF8/ECOOmgf vzLly1+mBvqjINWMcxNOhlrBjiLLp06V39LUhyIQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ibrahim Hashimov , Jiri Kosina Subject: [PATCH 7.1 091/101] HID: uclogic: fix use-after-free of inrange_timer on remove Date: Tue, 25 Aug 2026 15:26:09 +0200 Message-ID: <20260825132545.405778714@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260825132541.986300899@linuxfoundation.org> References: <20260825132541.986300899@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 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ibrahim Hashimov commit 506fd50a9027340f0e9dcc587d10ccb03312dba6 upstream. 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 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 @@ -548,7 +548,17 @@ static void uclogic_remove(struct hid_de { struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev); - timer_delete_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);