From patchwork Fri Mar 18 16:15:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 552895 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 5C062C352B6 for ; Fri, 18 Mar 2022 16:18:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238869AbiCRQTO (ORCPT ); Fri, 18 Mar 2022 12:19:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238853AbiCRQSM (ORCPT ); Fri, 18 Mar 2022 12:18:12 -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 A95B62EF0D6 for ; Fri, 18 Mar 2022 09:16:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647620205; 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=g5tRmrZUKM3tsTBn6dkiecWK2nGanjyI5ExDEzCAG/c=; b=eqcPX29FiZO8y/dVbhMJMuS/OsvhPEQa8bMIXFTP7ArdFtuYFnoJ4UnCavnBmFIs2R20YZ fmU0I2hvym94vquwxI2TUULrQyLirnEUuKUcvj0zPIBhNFxScYzp++TpHdndZ3QoZI8P0G FAvnNaZTfhcCHWxvc7tk3c4JiSq0hLM= 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-623-ejlFZfI0P8WeJMJ7D26siA-1; Fri, 18 Mar 2022 12:16:41 -0400 X-MC-Unique: ejlFZfI0P8WeJMJ7D26siA-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 6C180380407F; Fri, 18 Mar 2022 16:16:39 +0000 (UTC) Received: from plouf.redhat.com (unknown [10.39.192.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id 83F933543C; Fri, 18 Mar 2022 16:16:32 +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 06/17] HID: allow to change the report descriptor from an eBPF program Date: Fri, 18 Mar 2022 17:15:17 +0100 Message-Id: <20220318161528.1531164-7-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 Make use of BPF_HID_ATTACH_RDESC_FIXUP so we can trigger an rdesc fixup in the bpf world. Whenever the program gets attached/detached, the device is reconnected meaning that userspace will see it disappearing and reappearing with the new report descriptor. Signed-off-by: Benjamin Tissoires --- changes in v3: - ensure the ctx.size is properly bounded by allocated size - s/link_attached/post_link_attach/ - removed the switch statement with only one case changes in v2: - split the series by bpf/libbpf/hid/selftests and samples --- drivers/hid/hid-bpf.c | 62 ++++++++++++++++++++++++++++++++++++++++++ drivers/hid/hid-core.c | 3 +- include/linux/hid.h | 6 ++++ 3 files changed, 70 insertions(+), 1 deletion(-) diff --git a/drivers/hid/hid-bpf.c b/drivers/hid/hid-bpf.c index 5060ebcb9979..45c87ff47324 100644 --- a/drivers/hid/hid-bpf.c +++ b/drivers/hid/hid-bpf.c @@ -50,6 +50,14 @@ static struct hid_device *hid_bpf_fd_to_hdev(int fd) return hdev; } +static int hid_reconnect(struct hid_device *hdev) +{ + if (!test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status)) + return device_reprobe(&hdev->dev); + + return 0; +} + static int hid_bpf_pre_link_attach(struct hid_device *hdev, enum bpf_hid_attach_type type) { int err = 0; @@ -92,6 +100,12 @@ static int hid_bpf_pre_link_attach(struct hid_device *hdev, enum bpf_hid_attach_ return err; } +static void hid_bpf_post_link_attach(struct hid_device *hdev, enum bpf_hid_attach_type type) +{ + if (type == BPF_HID_ATTACH_RDESC_FIXUP) + hid_reconnect(hdev); +} + static void hid_bpf_array_detach(struct hid_device *hdev, enum bpf_hid_attach_type type) { switch (type) { @@ -99,6 +113,9 @@ static void hid_bpf_array_detach(struct hid_device *hdev, enum bpf_hid_attach_ty kfree(hdev->bpf.device_data); hdev->bpf.device_data = NULL; break; + case BPF_HID_ATTACH_RDESC_FIXUP: + hid_reconnect(hdev); + break; default: /* do nothing */ break; @@ -116,6 +133,9 @@ static int hid_bpf_run_progs(struct hid_device *hdev, struct hid_bpf_ctx_kern *c case HID_BPF_DEVICE_EVENT: type = BPF_HID_ATTACH_DEVICE_EVENT; break; + case HID_BPF_RDESC_FIXUP: + type = BPF_HID_ATTACH_RDESC_FIXUP; + break; default: return -EINVAL; } @@ -155,11 +175,53 @@ u8 *hid_bpf_raw_event(struct hid_device *hdev, u8 *data, int *size) return ctx.data; } +u8 *hid_bpf_report_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) +{ + int ret; + struct hid_bpf_ctx_kern ctx = { + .type = HID_BPF_RDESC_FIXUP, + .hdev = hdev, + .size = *size, + }; + + if (bpf_hid_link_empty(&hdev->bpf, BPF_HID_ATTACH_RDESC_FIXUP)) + goto ignore_bpf; + + ctx.data = kmemdup(rdesc, HID_MAX_DESCRIPTOR_SIZE, GFP_KERNEL); + if (!ctx.data) + goto ignore_bpf; + + ctx.allocated_size = HID_MAX_DESCRIPTOR_SIZE; + + ret = hid_bpf_run_progs(hdev, &ctx); + if (ret) + goto ignore_bpf; + + if (ctx.size > ctx.allocated_size) + goto ignore_bpf; + + *size = ctx.size; + + if (*size) { + rdesc = krealloc(ctx.data, *size, GFP_KERNEL); + } else { + rdesc = NULL; + kfree(ctx.data); + } + + return rdesc; + + ignore_bpf: + kfree(ctx.data); + return kmemdup(rdesc, *size, GFP_KERNEL); +} + 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, + .post_link_attach = hid_bpf_post_link_attach, .array_detach = hid_bpf_array_detach, }; diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 937fab7eb9c6..3182c39db006 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1213,7 +1213,8 @@ int hid_open_report(struct hid_device *device) return -ENODEV; size = device->dev_rsize; - buf = kmemdup(start, size, GFP_KERNEL); + /* hid_bpf_report_fixup() ensures we work on a copy of rdesc */ + buf = hid_bpf_report_fixup(device, start, &size); if (buf == NULL) return -ENOMEM; diff --git a/include/linux/hid.h b/include/linux/hid.h index 8fd79011f461..66d949d10b78 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -1213,10 +1213,16 @@ do { \ #ifdef CONFIG_BPF u8 *hid_bpf_raw_event(struct hid_device *hdev, u8 *rd, int *size); +u8 *hid_bpf_report_fixup(struct hid_device *hdev, u8 *rdesc, unsigned 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 u8 *hid_bpf_report_fixup(struct hid_device *hdev, u8 *rdesc, + unsigned int *size) +{ + return kmemdup(rdesc, *size, GFP_KERNEL); +} static inline int hid_bpf_module_init(void) { return 0; } static inline void hid_bpf_module_exit(void) {} #endif