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 D6C85358378; Fri, 4 Sep 2026 06:10:19 +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=1788502221; cv=none; b=K1rVI1cTw+U8W4MG1X7PrN7zlxl7BouhiK9xbhLyrZpxPTSjzkoKkC47WOk7deaJFNAucs4MzKxGkXk70cXepelJTn+3/UqL2SZbbP41oZJ5HJF0idgX4+sXY5psedWTmis8n/m7+5pw3gGiM5Y0L0ltJY11ytFHCSEbAHHH/LQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788502221; c=relaxed/simple; bh=a4AKjsWjy9E2Y7KhxJw/xzU6gCddnJ+3FZq+foyfNWM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uqW0OLTJyQW8vJfimQtDmNvol13OCIAySg2mhgNglNXFGZFQOsoH8CElEWB4YQidaP5Ax4F4VUuFn0tx4OUO5v/I7cP+ryYyQyfY5WKSt2+SzWxktKyq0zB+CzGh9omnpFb8MxoDnxNoORGcsWLCV4DopTZM0/kOMbGZ1hr2W9g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vzAwSoEt; 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="vzAwSoEt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C1DF1F00A3D; Fri, 4 Sep 2026 06:10:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788502219; bh=rYYdafv5/7oVhPcWCmm0gIZH99EOiQ4BhwSbESoynFM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vzAwSoEtvS/lCh+wLcH8A6H28WuRP5NccTnZdrOD96kn/7JfC24eeqX2U/eWcKK96 TuD1Ek5quMPzXz/vmYj8nX7/QSum92L/1i8AKNOoh8o6mNc6KetZ1DaDYbDiLpz6eL VvoKKYf1rcjGrrjWcHctJ95xEfi5c2NGWmWcJGGg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiangshan Yi , Jiri Kosina Subject: [PATCH 6.12 129/403] HID: mcp2221: validate report size in mcp2221_raw_event() Date: Fri, 4 Sep 2026 06:58:52 +0200 Message-ID: <20260904045737.771444725@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045734.806166532@linuxfoundation.org> References: <20260904045734.806166532@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiangshan Yi commit 2c9a6998c19503626c57a2267bf279e204113079 upstream. mcp2221_raw_event() never validates the size of incoming HID reports. In the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3] as the copy length without checking that 4 + data[3] bytes actually exist in the received report. A malicious or misbehaving USB device can send a short report with a large data[3], causing the memcpy to read past the valid report data in the HID transfer buffer and leak uninitialized kernel memory back to userspace through the I2C/SMBus read path. Add a minimum size check at entry and validate that the source range fits within the received report before the copy. Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Cc: stable@vger.kernel.org Signed-off-by: Jiangshan Yi Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-mcp2221.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -759,6 +759,9 @@ static int mcp2221_raw_event(struct hid_ u8 *buf; struct mcp2221 *mcp = hid_get_drvdata(hdev); + if (size < 4) + return 0; + switch (data[0]) { case MCP2221_I2C_WR_DATA: @@ -820,6 +823,10 @@ static int mcp2221_raw_event(struct hid_ mcp->status = -EINVAL; break; } + if (4 + data[3] > size) { + mcp->status = -EINVAL; + break; + } buf = mcp->rxbuf; memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]); mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];