From mboxrd@z Thu Jan 1 00:00:00 1970 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 7E048C433FE for ; Fri, 18 Mar 2022 21:02:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241006AbiCRVDx (ORCPT ); Fri, 18 Mar 2022 17:03:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233725AbiCRVDq (ORCPT ); Fri, 18 Mar 2022 17:03:46 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BDA02DF3CE; Fri, 18 Mar 2022 14:02:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 188C5B825A1; Fri, 18 Mar 2022 21:02:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB1B7C340F0; Fri, 18 Mar 2022 21:02:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647637343; bh=fS4BOjVzyvppTrYK3z2dZ89hlOvrjRZPlby5Ug9xKl4=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=GAxtZ/K/N3qJKE1Zn61u2HMgZLGxJotxT/hbdsXKLBvh+5trwG+FLNYbX1zyeWkAg FRBkGoFSikcuJ5Whhp94HSQ+M7Vn58gmMNR0Twe9gfgmD1InmAjqViDMapTiPBusdj zCRh3GyYeighr9Xsh/cBbN2XwKbQIBniUu/mz3exNdRr6pmpGm59pCNo5ZcUfeBbDR G8jpiJBzl1MneE1HVpeeKZVk5zMeV6Yw4bjuWnt6Tg6Ttp4uRJzeP+EY3nvVDY/Mja /Ub7bAqnsJdH8RnguZiI7pIO9Kh/rlnUXU+xxEazulP6YC7kihSrGjiaee2LEDgh8u gZLK2juPjUMRg== Received: by mail-yw1-f172.google.com with SMTP id 00721157ae682-2e5e31c34bfso24434317b3.10; Fri, 18 Mar 2022 14:02:23 -0700 (PDT) X-Gm-Message-State: AOAM533y5DvLwvb47go+Y7rd3CIuK7cfPAjfumA4O8V3KXUCjKYgMjMb drsNK5PIWGQut5PGcQZ43K43lWnVd9p72pAoJtg= X-Google-Smtp-Source: ABdhPJx3jkCbHbr6rgCRI1G9liFl3sZGGO4Sefl0ajvshE1KR7J20nmtMuEtiMTGTVGlaJq+g0+7ACPLFUfwE8uv+Cg= X-Received: by 2002:a81:951:0:b0:2e5:9e38:147c with SMTP id 78-20020a810951000000b002e59e38147cmr13265656ywj.211.1647637342737; Fri, 18 Mar 2022 14:02:22 -0700 (PDT) MIME-Version: 1.0 References: <20220318161528.1531164-1-benjamin.tissoires@redhat.com> <20220318161528.1531164-6-benjamin.tissoires@redhat.com> In-Reply-To: <20220318161528.1531164-6-benjamin.tissoires@redhat.com> From: Song Liu Date: Fri, 18 Mar 2022 14:02:11 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH bpf-next v3 05/17] HID: hook up with bpf To: Benjamin Tissoires Cc: Greg KH , Jiri Kosina , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Shuah Khan , Dave Marchevsky , Joe Stringer , Jonathan Corbet , Tero Kristo , open list , "open list:HID CORE LAYER" , Networking , bpf , linux-kselftest@vger.kernel.org, Linux Doc Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 18, 2022 at 9:17 AM Benjamin Tissoires wrote: > > Now that BPF can be compatible with HID, add the capability into HID. > drivers/hid/hid-bpf.c takes care of the glue between bpf and HID, and > hid-core can then inject any incoming event from the device into a BPF > program to filter/analyze it. So we only need this part for DEVICE EVENT? > > Signed-off-by: Benjamin Tissoires > > --- > > changes in v3: > - squashed "only call hid_bpf_raw_event() if a ctx is available" > and "bpf: compute only the required buffer size for the device" > into this one > - ensure the ctx.size is properly bounded by allocated size > - s/link_attach/pre_link_attach/ > - s/array_detached/array_detach/ > - fix default switch case when doing nothing > - reworked hid_bpf_pre_link_attach() to avoid the switch > > changes in v2: > - split the series by bpf/libbpf/hid/selftests and samples > - addressed review comments from v1 > --- > drivers/hid/Makefile | 1 + > drivers/hid/hid-bpf.c | 174 +++++++++++++++++++++++++++++++++++++++++ > drivers/hid/hid-core.c | 24 +++++- > include/linux/hid.h | 11 +++ > 4 files changed, 207 insertions(+), 3 deletions(-) > create mode 100644 drivers/hid/hid-bpf.c > > diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile > index 6d3e630e81af..08d2d7619937 100644 > --- a/drivers/hid/Makefile > +++ b/drivers/hid/Makefile > @@ -4,6 +4,7 @@ > # > hid-y := hid-core.o hid-input.o hid-quirks.o > hid-$(CONFIG_DEBUG_FS) += hid-debug.o > +hid-$(CONFIG_BPF) += hid-bpf.o > > obj-$(CONFIG_HID) += hid.o > obj-$(CONFIG_UHID) += uhid.o > diff --git a/drivers/hid/hid-bpf.c b/drivers/hid/hid-bpf.c > new file mode 100644 > index 000000000000..5060ebcb9979 > --- /dev/null > +++ b/drivers/hid/hid-bpf.c > @@ -0,0 +1,174 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * BPF in HID support for Linux > + * > + * Copyright (c) 2022 Benjamin Tissoires > + */ > + > +#include > +#include > +#include > + > +#include > +#include > + > +static int __hid_bpf_match_sysfs(struct device *dev, const void *data) > +{ > + struct kernfs_node *kn = dev->kobj.sd; > + struct kernfs_node *uevent_kn; > + > + uevent_kn = kernfs_find_and_get_ns(kn, "uevent", NULL); > + > + return uevent_kn == data; > +} > + > +static struct hid_device *hid_bpf_fd_to_hdev(int fd) > +{ > + struct device *dev; > + struct hid_device *hdev; > + struct fd f = fdget(fd); > + struct inode *inode; > + struct kernfs_node *node; > + > + if (!f.file) { > + hdev = ERR_PTR(-EBADF); > + goto out; > + } > + > + inode = file_inode(f.file); > + node = inode->i_private; > + > + dev = bus_find_device(&hid_bus_type, NULL, node, __hid_bpf_match_sysfs); > + > + if (dev) > + hdev = to_hid_device(dev); > + else > + hdev = ERR_PTR(-EINVAL); > + > + out: > + fdput(f); > + return hdev; > +} > + > +static int hid_bpf_pre_link_attach(struct hid_device *hdev, enum bpf_hid_attach_type type) > +{ > + int err = 0; > + unsigned int i, j, max_report_len = 0; > + unsigned int alloc_size = 0; > + > + if (type != BPF_HID_ATTACH_DEVICE_EVENT) > + return 0; > + > + /* hdev->bpf.device_data is already allocated, abort */ > + if (hdev->bpf.device_data) > + return 0; > + > + /* compute the maximum report length for this device */ > + for (i = 0; i < HID_REPORT_TYPES; i++) { > + struct hid_report_enum *report_enum = hdev->report_enum + i; > + > + for (j = 0; j < HID_MAX_IDS; j++) { > + struct hid_report *report = report_enum->report_id_hash[j]; > + > + if (report) > + max_report_len = max(max_report_len, hid_report_len(report)); > + } > + } > + > + /* > + * Give us a little bit of extra space and some predictability in the > + * buffer length we create. This way, we can tell users that they can > + * work on chunks of 64 bytes of memory without having the bpf verifier > + * scream at them. > + */ > + alloc_size = DIV_ROUND_UP(max_report_len, 64) * 64; > + > + hdev->bpf.device_data = kzalloc(alloc_size, GFP_KERNEL); > + if (!hdev->bpf.device_data) > + err = -ENOMEM; > + else > + hdev->bpf.allocated_data = alloc_size; > + > + return err; > +} > + > +static void hid_bpf_array_detach(struct hid_device *hdev, enum bpf_hid_attach_type type) > +{ > + switch (type) { > + case BPF_HID_ATTACH_DEVICE_EVENT: > + kfree(hdev->bpf.device_data); > + hdev->bpf.device_data = NULL; > + break; > + default: > + /* do nothing */ > + break; > + } > +} > + > +static int hid_bpf_run_progs(struct hid_device *hdev, struct hid_bpf_ctx_kern *ctx) > +{ > + enum bpf_hid_attach_type type; > + > + if (!ctx) > + return -EINVAL; > + > + switch (ctx->type) { > + case HID_BPF_DEVICE_EVENT: > + type = BPF_HID_ATTACH_DEVICE_EVENT; > + break; > + default: > + return -EINVAL; > + } > + > + if (!hdev->bpf.run_array[type]) > + return 0; > + > + return BPF_PROG_RUN_ARRAY(hdev->bpf.run_array[type], ctx, bpf_prog_run); > +} > + > +u8 *hid_bpf_raw_event(struct hid_device *hdev, u8 *data, int *size) > +{ > + int ret; > + struct hid_bpf_ctx_kern ctx = { > + .type = HID_BPF_DEVICE_EVENT, > + .hdev = hdev, > + .size = *size, > + .data = hdev->bpf.device_data, > + .allocated_size = hdev->bpf.allocated_data, > + }; > + > + if (bpf_hid_link_empty(&hdev->bpf, BPF_HID_ATTACH_DEVICE_EVENT)) > + return data; > + > + memset(ctx.data, 0, hdev->bpf.allocated_data); > + memcpy(ctx.data, data, *size); > + > + ret = hid_bpf_run_progs(hdev, &ctx); > + if (ret) > + return ERR_PTR(-EIO); > + > + if (!ctx.size || ctx.size > ctx.allocated_size) > + return ERR_PTR(-EINVAL); > + > + *size = ctx.size; > + > + return ctx.data; > +} > + > +int __init hid_bpf_module_init(void) > +{ > + struct bpf_hid_hooks hooks = { > + .hdev_from_fd = hid_bpf_fd_to_hdev, > + .pre_link_attach = hid_bpf_pre_link_attach, > + .array_detach = hid_bpf_array_detach, > + }; > + > + bpf_hid_set_hooks(&hooks); > + > + return 0; > +} > + > +void __exit hid_bpf_module_exit(void) > +{ > + bpf_hid_set_hooks(NULL); > +} > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c > index f1aed5bbd000..937fab7eb9c6 100644 > --- a/drivers/hid/hid-core.c > +++ b/drivers/hid/hid-core.c > @@ -1748,13 +1748,24 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, > struct hid_driver *hdrv; > unsigned int a; > u32 rsize, csize = size; > - u8 *cdata = data; > + u8 *cdata; > int ret = 0; > > + /* we pre-test if device_data is available here to cut the calls at the earliest */ > + if (hid->bpf.device_data) { > + data = hid_bpf_raw_event(hid, data, &size); > + if (IS_ERR(data)) { > + ret = PTR_ERR(data); > + goto out; > + } > + } > + > report = hid_get_report(report_enum, data); > if (!report) > goto out; > > + cdata = data; > + > if (report_enum->numbered) { > cdata++; > csize--; > @@ -2528,10 +2539,12 @@ int hid_add_device(struct hid_device *hdev) > > hid_debug_register(hdev, dev_name(&hdev->dev)); > ret = device_add(&hdev->dev); > - if (!ret) > + if (!ret) { > hdev->status |= HID_STAT_ADDED; > - else > + } else { > hid_debug_unregister(hdev); > + bpf_hid_exit(hdev); > + } > > return ret; > } > @@ -2567,6 +2580,7 @@ struct hid_device *hid_allocate_device(void) > spin_lock_init(&hdev->debug_list_lock); > sema_init(&hdev->driver_input_lock, 1); > mutex_init(&hdev->ll_open_lock); > + bpf_hid_init(hdev); > > return hdev; > } > @@ -2574,6 +2588,7 @@ EXPORT_SYMBOL_GPL(hid_allocate_device); > > static void hid_remove_device(struct hid_device *hdev) > { > + bpf_hid_exit(hdev); > if (hdev->status & HID_STAT_ADDED) { > device_del(&hdev->dev); > hid_debug_unregister(hdev); > @@ -2700,6 +2715,8 @@ static int __init hid_init(void) > > hid_debug_init(); > > + hid_bpf_module_init(); > + > return 0; > err_bus: > bus_unregister(&hid_bus_type); > @@ -2709,6 +2726,7 @@ static int __init hid_init(void) > > static void __exit hid_exit(void) > { > + hid_bpf_module_exit(); > hid_debug_exit(); > hidraw_exit(); > bus_unregister(&hid_bus_type); > diff --git a/include/linux/hid.h b/include/linux/hid.h > index 56f6f4ad45a7..8fd79011f461 100644 > --- a/include/linux/hid.h > +++ b/include/linux/hid.h > @@ -27,6 +27,7 @@ > #include > #include > #include > +#include > > /* > * We parse each description item into this structure. Short items data > @@ -1210,4 +1211,14 @@ do { \ > #define hid_dbg_once(hid, fmt, ...) \ > dev_dbg_once(&(hid)->dev, fmt, ##__VA_ARGS__) > > +#ifdef CONFIG_BPF > +u8 *hid_bpf_raw_event(struct hid_device *hdev, u8 *rd, int *size); > +int hid_bpf_module_init(void); > +void hid_bpf_module_exit(void); > +#else > +static inline u8 *hid_bpf_raw_event(struct hid_device *hdev, u8 *rd, int *size) { return rd; } > +static inline int hid_bpf_module_init(void) { return 0; } > +static inline void hid_bpf_module_exit(void) {} > +#endif > + > #endif > -- > 2.35.1 >