From patchwork Fri Mar 18 16:15:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 552894 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 C6E6EC43219 for ; Fri, 18 Mar 2022 16:18:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238879AbiCRQTv (ORCPT ); Fri, 18 Mar 2022 12:19:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238820AbiCRQSK (ORCPT ); Fri, 18 Mar 2022 12:18:10 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CB22F2EAF54 for ; Fri, 18 Mar 2022 09:16:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647620196; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eXuLy5g/OhC5EeUy3VzZbdQz9XUs2ZGjc4bL864jlXU=; b=AfM3t1AbuaZLiEh9GTEk0Gl5JOa4nl1OoNMmW+99iPU/ei3KG7LaUTiL90N1JmfZ3ux8SY R45qJPYB+gh1oYrvLNU56eJoSlHqmwacl17EcpuqR7vGVqeK+Is+YGdLoBIRMej9/S1IbQ 0trVXp96xDiKXmMYBeSKr5t5Ypq4zss= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-327-uMjUVThaOgikLjtTgGLUNw-1; Fri, 18 Mar 2022 12:16:33 -0400 X-MC-Unique: uMjUVThaOgikLjtTgGLUNw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 472A03804092; Fri, 18 Mar 2022 16:16:32 +0000 (UTC) Received: from plouf.redhat.com (unknown [10.39.192.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id 22E4233250; Fri, 18 Mar 2022 16:16:29 +0000 (UTC) From: Benjamin Tissoires To: 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 Cc: Tero Kristo , linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, Benjamin Tissoires Subject: [PATCH bpf-next v3 05/17] HID: hook up with bpf Date: Fri, 18 Mar 2022 17:15:16 +0100 Message-Id: <20220318161528.1531164-6-benjamin.tissoires@redhat.com> In-Reply-To: <20220318161528.1531164-1-benjamin.tissoires@redhat.com> References: <20220318161528.1531164-1-benjamin.tissoires@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org 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. 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