From patchwork Fri Mar 4 17:28:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 548643 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 E2836C433F5 for ; Fri, 4 Mar 2022 17:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241159AbiCDRcp (ORCPT ); Fri, 4 Mar 2022 12:32:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233859AbiCDRcl (ORCPT ); Fri, 4 Mar 2022 12:32:41 -0500 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 9454E1D084D for ; Fri, 4 Mar 2022 09:31:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646415108; 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=63XOkucXPoA9BHtkIxmyyJJF1thlmZZsP4rRoHSnHtU=; b=YAUWPZQ/5TceItxSJPloCNljtvMwFRwvQeJLIxrdc1N/U6vUIQwZqcE156EVXKaVMkxFoS ABqL6XNmibqEqlrJRVnBboS4bsJ87STUabtFcyQtQ6oqeMV3U+MGYL6rucWokDfKkAvh0r jomePCRjC8w4LQVnpNnIVkjLPvAUs98= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-665-kbUcF6rtML6PKyFbOs9qiw-1; Fri, 04 Mar 2022 12:31:43 -0500 X-MC-Unique: kbUcF6rtML6PKyFbOs9qiw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 25CE618766D2; Fri, 4 Mar 2022 17:31:40 +0000 (UTC) Received: from plouf.redhat.com (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2F6C286595; Fri, 4 Mar 2022 17:31:15 +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 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, Benjamin Tissoires Subject: [PATCH bpf-next v2 07/28] bpf/hid: add a new attach type to change the report descriptor Date: Fri, 4 Mar 2022 18:28:31 +0100 Message-Id: <20220304172852.274126-8-benjamin.tissoires@redhat.com> In-Reply-To: <20220304172852.274126-1-benjamin.tissoires@redhat.com> References: <20220304172852.274126-1-benjamin.tissoires@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org The report descriptor is the dictionary of the HID protocol specific to the given device. Changing it is a common habit in the HID world, and making that feature accessible from eBPF allows to fix devices without having to install a new kernel. However, the report descriptor is supposed to be static on a device. To be able to change it, we need to reconnect the device at the HID level. So whenever the report descriptor program type is attached or detached, we call on a hook on HID to notify it that there is something to be done. Signed-off-by: Benjamin Tissoires Reviewed-by: Greg Kroah-Hartman --- changes in v2: - split the series by bpf/libbpf/hid/selftests and samples - unsigned long -> __u16 in uapi/linux/bpf_hid.h --- include/linux/bpf-hid.h | 4 ++++ include/uapi/linux/bpf.h | 1 + include/uapi/linux/bpf_hid.h | 1 + kernel/bpf/hid.c | 5 +++++ kernel/bpf/syscall.c | 2 ++ tools/include/uapi/linux/bpf.h | 1 + 6 files changed, 14 insertions(+) diff --git a/include/linux/bpf-hid.h b/include/linux/bpf-hid.h index 3cda78051b5f..0c5000b28b20 100644 --- a/include/linux/bpf-hid.h +++ b/include/linux/bpf-hid.h @@ -15,6 +15,7 @@ struct hid_device; enum bpf_hid_attach_type { BPF_HID_ATTACH_INVALID = -1, BPF_HID_ATTACH_DEVICE_EVENT = 0, + BPF_HID_ATTACH_RDESC_FIXUP, MAX_BPF_HID_ATTACH_TYPE }; @@ -32,6 +33,8 @@ to_bpf_hid_attach_type(enum bpf_attach_type attach_type) switch (attach_type) { case BPF_HID_DEVICE_EVENT: return BPF_HID_ATTACH_DEVICE_EVENT; + case BPF_HID_RDESC_FIXUP: + return BPF_HID_ATTACH_RDESC_FIXUP; default: return BPF_HID_ATTACH_INVALID; } @@ -88,6 +91,7 @@ static inline bool bpf_hid_link_empty(struct bpf_hid *bpf, struct bpf_hid_hooks { struct hid_device *(*hdev_from_fd)(int fd); int (*link_attach)(struct hid_device *hdev, enum bpf_hid_attach_type type); + void (*link_attached)(struct hid_device *hdev, enum bpf_hid_attach_type type); void (*array_detached)(struct hid_device *hdev, enum bpf_hid_attach_type type); }; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 5978b92cacd3..a7a8d9cfcf24 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -999,6 +999,7 @@ enum bpf_attach_type { BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, BPF_PERF_EVENT, BPF_HID_DEVICE_EVENT, + BPF_HID_RDESC_FIXUP, __MAX_BPF_ATTACH_TYPE }; diff --git a/include/uapi/linux/bpf_hid.h b/include/uapi/linux/bpf_hid.h index 975ca5bd526f..634f17c0b1cb 100644 --- a/include/uapi/linux/bpf_hid.h +++ b/include/uapi/linux/bpf_hid.h @@ -24,6 +24,7 @@ struct hid_device; enum hid_bpf_event { HID_BPF_UNDEF = 0, HID_BPF_DEVICE_EVENT, /* when attach type is BPF_HID_DEVICE_EVENT */ + HID_BPF_RDESC_FIXUP, /* ................... BPF_HID_RDESC_FIXUP */ }; struct hid_bpf_ctx { diff --git a/kernel/bpf/hid.c b/kernel/bpf/hid.c index db7f75a0a812..37500313e270 100644 --- a/kernel/bpf/hid.c +++ b/kernel/bpf/hid.c @@ -315,6 +315,8 @@ static int bpf_hid_max_progs(enum bpf_hid_attach_type type) switch (type) { case BPF_HID_ATTACH_DEVICE_EVENT: return 64; + case BPF_HID_ATTACH_RDESC_FIXUP: + return 1; default: return 0; } @@ -355,6 +357,9 @@ static int bpf_hid_link_attach(struct hid_device *hdev, struct bpf_link *link, lockdep_is_held(&bpf_hid_mutex)); bpf_prog_array_free(run_array); + if (hid_hooks.link_attached) + hid_hooks.link_attached(hdev, type); + out_unlock: mutex_unlock(&bpf_hid_mutex); return err; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a94e78ec3211..7428a1a512c6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3203,6 +3203,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) case BPF_XDP: return BPF_PROG_TYPE_XDP; case BPF_HID_DEVICE_EVENT: + case BPF_HID_RDESC_FIXUP: return BPF_PROG_TYPE_HID; default: return BPF_PROG_TYPE_UNSPEC; @@ -3348,6 +3349,7 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_SK_SKB_VERDICT: return sock_map_bpf_prog_query(attr, uattr); case BPF_HID_DEVICE_EVENT: + case BPF_HID_RDESC_FIXUP: return bpf_hid_prog_query(attr, uattr); default: return -EINVAL; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 5978b92cacd3..a7a8d9cfcf24 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -999,6 +999,7 @@ enum bpf_attach_type { BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, BPF_PERF_EVENT, BPF_HID_DEVICE_EVENT, + BPF_HID_RDESC_FIXUP, __MAX_BPF_ATTACH_TYPE };