From patchwork Thu Aug 4 16:03:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bastien Nocera X-Patchwork-Id: 12936511 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2F20C19F2D for ; Thu, 4 Aug 2022 16:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232125AbiHDQDP (ORCPT ); Thu, 4 Aug 2022 12:03:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231602AbiHDQDN (ORCPT ); Thu, 4 Aug 2022 12:03:13 -0400 Received: from relay12.mail.gandi.net (relay12.mail.gandi.net [217.70.178.232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71BB05F138 for ; Thu, 4 Aug 2022 09:03:12 -0700 (PDT) Received: (Authenticated sender: hadess@hadess.net) by mail.gandi.net (Postfix) with ESMTPSA id 4104A200002; Thu, 4 Aug 2022 16:03:10 +0000 (UTC) From: Bastien Nocera To: linux-usb@vger.kernel.org Cc: Greg Kroah-Hartman , Alan Stern , Benjamin Tissoires , Peter Hutterer , Bastien Nocera Subject: [RFC v2 2/2] usb: Implement usb_revoke() BPF function Date: Thu, 4 Aug 2022 18:03:06 +0200 Message-Id: <20220804160306.134014-3-hadess@hadess.net> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220804160306.134014-1-hadess@hadess.net> References: <20220804160306.134014-1-hadess@hadess.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org This functionality allows a sufficiently privileged user-space process to upload a script that will call to usb_revoke_device() as if it were a kernel API. This functionality will be used by logind to revoke access to devices on fast user-switching to start with. Signed-off-by: Bastien Nocera --- drivers/usb/core/usb.c | 51 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index 2f71636af6e1..8cac72271a8a 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -38,6 +38,8 @@ #include #include #include +#include +#include #include #include @@ -438,6 +440,41 @@ static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env) return 0; } +struct revoke_data { + struct usb_revoke_match match; + int ret; +}; + +static int +__usb_revoke(struct usb_device *udev, void *data) +{ + struct revoke_data *revoke_data = data; + struct usb_revoke_match match = revoke_data->match; + int ret; + + ret = usb_revoke(udev, &match); + if (ret == 0) + revoke_data->ret = 0; + else if (revoke_data->ret == 1) + revoke_data->ret = ret; + return 0; +} + +noinline int +usb_revoke_device(int busnum, int devnum, unsigned int euid) +{ + struct revoke_data revoke_data; + + revoke_data.match.busnum = busnum; + revoke_data.match.devnum = devnum; + revoke_data.match.euid = euid; + revoke_data.ret = 1; + + usb_for_each_dev(&revoke_data, __usb_revoke); + + return revoke_data.ret; +} + #ifdef CONFIG_PM /* USB device Power-Management thunks. @@ -1004,6 +1041,15 @@ static void usb_debugfs_cleanup(void) /* * Init */ +BTF_SET_START(usbdev_kfunc_ids) +BTF_ID(func, usb_revoke_device) +BTF_SET_END(usbdev_kfunc_ids) + +static const struct btf_kfunc_id_set usbdev_kfunc_set = { + .owner = THIS_MODULE, + .check_set = &usbdev_kfunc_ids, +}; + static int __init usb_init(void) { int retval; @@ -1035,9 +1081,14 @@ static int __init usb_init(void) if (retval) goto hub_init_failed; retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE); + if (retval) + goto register_failed; + retval = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &usbdev_kfunc_set); if (!retval) goto out; + usb_deregister_device_driver(&usb_generic_driver); +register_failed: usb_hub_cleanup(); hub_init_failed: usb_devio_cleanup();