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 4433D436361 for ; Wed, 26 Aug 2026 13:47:05 +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=1787752028; cv=none; b=HDafVYghEbQoTOYcY13gbWvGgRHGP1KVxipZdgZuNeSPvrCjJKfwXG1FhY0KjqeSprYrEGBVWHtMuzR85ywRCLukgmmAy0MCpK+CPqjLR26wx0mZ39FfRHnBr811HoxLmC2L+7+tzI6xAqpjxRy85W2seX9l7Hks8EOuyapthbk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787752028; c=relaxed/simple; bh=ztCja3qIh9gKMcH01OXsYgLG6gJ68vFAxym/SX4wQQU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fZE9ttbZUwM2fluojxdcX6p/MZfGFDnUuKqf9pX+x+krZ7tNIDHr9chQlI+34oIUD0bs3zH+IoGlsQZ4rmzJwYthTVR3lc3uAOXb1cvEzbqL5vxlIpRcQpOCkF4641J1msMM5BID8X1dufhRtZoSfwadUAwcRTcvT7YoGd/Gg9k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ELrTD+FX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ELrTD+FX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B85311F00A3A; Wed, 26 Aug 2026 13:47:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787752025; bh=knV9yxTvgn6N+elzgJGaqlj5AWID1SzRI3X6DG0C190=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ELrTD+FXIvKtdDluVa+BmUz6GN0chdw6wdocZIaWPI8Pm29DGCHlA+J0cL//jNeQj Zep/MeSetiUsvtPSXZ/vVsaBVDe66sCCi/qvkzxdDAsTWwSqwON/mdFNOgBbOpIUlT QZ7UM3dRjVnrSGxZiPTpwDZZvz6hhIJThWAE82ERw0TDMkt+BQl5W7pR70PcEt0eSt yuDAIfc9REiJeiX/zZgLYX3+sQ0LuK2Dn6NAb4mgiV0S7HHaUv5xwX1VInBXT9KC/M CUf/t6cGRRCKTOxMq1BaQHI9BqBPvt0V0PGFKjdOOtd3YyD2eD5bN636gihwOlUS4g F/WiOM6Bgwu6g== From: Sasha Levin To: stable@vger.kernel.org Cc: =?UTF-8?q?Jose=20Villase=C3=B1or=20Montfort?= , Alec Hall , Jiri Kosina , Sasha Levin Subject: [PATCH 5.10.y] HID: magicmouse: do not keep a stale msc->input if no input is claimed Date: Wed, 26 Aug 2026 09:47:02 -0400 Message-ID: <20260826134702.3959044-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026082503-contort-glorified-efe1@gregkh> References: <2026082503-contort-glorified-efe1@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jose Villaseñor Montfort [ Upstream commit 0af3b89705688af01aa06025b84fa7a1e06ba6cc ] magicmouse_input_mapping() caches the first hid_input's input_dev in msc->input while the report descriptor is parsed, and the rest of the driver treats a non-NULL msc->input as proof that an input device was registered. That does not hold on the hid-input error path. If hidinput_connect() fails -- for instance because input_register_device() returns an error -- it unwinds through hidinput_disconnect(), which frees every input_dev it created, including the one cached in msc->input. The failure does not abort the probe. hid_connect() only skips the claim: if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev, connect_mask & HID_CONNECT_HIDINPUT_FORCE)) hdev->claimed |= HID_CLAIMED_INPUT; and the "device has no listeners" bailout below it does not fire for this driver, which sets ->raw_event; on the USB Magic Mouse 2 / Magic Trackpad 2 paths hidraw and hiddev are claimed as well. hid_hw_start() therefore returns 0 and magicmouse_probe() continues with msc->input pointing at freed memory. Being non-NULL, it passes the "input not registered" check in probe and the NULL checks in ->raw_event and ->event, so the next input report dereferences freed memory. Clear msc->input when the HID core did not claim an input device, so the existing NULL checks cover this case as well. Fixes: f1a9a149abc8 ("HID: magicmouse: fix race between input_register() and probe()") Link: https://lore.kernel.org/linux-input/20260728185542.65F091F000E9@smtp.kernel.org/ Cc: stable@vger.kernel.org Signed-off-by: Jose Villaseñor Montfort Reviewed-by: Alec Hall Tested-by: Alec Hall Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin --- drivers/hid/hid-magicmouse.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c index afde78319b996..e39e32680feee 100644 --- a/drivers/hid/hid-magicmouse.c +++ b/drivers/hid/hid-magicmouse.c @@ -627,6 +627,16 @@ static int magicmouse_probe(struct hid_device *hdev, return ret; } + /* + * When hidinput_connect() fails it frees every input device it + * created, but that does not fail hid_hw_start(): the core simply + * does not claim an input. msc->input, cached in ->input_mapping + * while the report descriptor was parsed, would then be a dangling + * pointer that passes every NULL check. Trust the core's claim. + */ + if (!(hdev->claimed & HID_CLAIMED_INPUT)) + msc->input = NULL; + if (!msc->input) { hid_err(hdev, "magicmouse input not registered\n"); ret = -ENOMEM; -- 2.53.0