From patchwork Tue Jul 12 14:58:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 589915 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 1A1BEC433EF for ; Tue, 12 Jul 2022 15:06:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233973AbiGLPGi (ORCPT ); Tue, 12 Jul 2022 11:06:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233853AbiGLPGF (ORCPT ); Tue, 12 Jul 2022 11:06:05 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0F0A260681 for ; Tue, 12 Jul 2022 08:00:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657638022; 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=yZy/kU520bjEz6wDtwvraJBCu2Or6TJf8DYrrvVCTDk=; b=L3f2CBTh3fLGe/XPTa/bu1DIkCyuLoWRPusbWSO1PXcycULEwQxmJ72A/o2501U1Mv6IRE RAtlhRj2Or7H/BLqrx8k+StZeLFYiLgQs5+kpbMQxB1Yl1XJzDugk2Szpv71m0Yllsdjoq UMSs5o9qHSBAYjN1s3+wLXdERFcmzfo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-604-htrWjFIJNIO5wdNKO8appg-1; Tue, 12 Jul 2022 11:00:18 -0400 X-MC-Unique: htrWjFIJNIO5wdNKO8appg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 83EAB802D2C; Tue, 12 Jul 2022 15:00:16 +0000 (UTC) Received: from plouf.redhat.com (unknown [10.39.195.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id 35E142166B26; Tue, 12 Jul 2022 15:00:12 +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 v6 18/23] HID: bpf: allow to change the report descriptor Date: Tue, 12 Jul 2022 16:58:45 +0200 Message-Id: <20220712145850.599666-19-benjamin.tissoires@redhat.com> In-Reply-To: <20220712145850.599666-1-benjamin.tissoires@redhat.com> References: <20220712145850.599666-1-benjamin.tissoires@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Add a new tracepoint hid_bpf_rdesc_fixup() so we can trigger a report descriptor 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 v6: - use BTF_ID to get the btf_id of hid_bpf_rdesc_fixup changes in v5: - adapted for new API not in v4 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/bpf/hid_bpf_dispatch.c | 77 ++++++++++++++++++++++++++++- drivers/hid/bpf/hid_bpf_dispatch.h | 1 + drivers/hid/bpf/hid_bpf_jmp_table.c | 7 +++ drivers/hid/hid-core.c | 3 +- include/linux/hid_bpf.h | 8 +++ 5 files changed, 94 insertions(+), 2 deletions(-) diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 8348f5ae17f8..bcaeb65ed2a8 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -85,6 +85,63 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } EXPORT_SYMBOL_GPL(dispatch_hid_bpf_device_event); +/** + * hid_bpf_rdesc_fixup - Called when the probe function parses the report + * descriptor of the HID device + * + * @ctx: The HID-BPF context + * + * @return 0 on success and keep processing; a positive value to change the + * incoming size buffer; a negative error code to interrupt the processing + * of this event + * + * Declare an %fmod_ret tracing bpf program to this function and attach this + * program through hid_bpf_attach_prog() to have this helper called before any + * parsing of the report descriptor by HID. + */ +/* never used by the kernel but declared so we can load and attach a tracepoint */ +__weak noinline int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) +{ + return 0; +} +ALLOW_ERROR_INJECTION(hid_bpf_rdesc_fixup, ERRNO); + +u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) +{ + int ret; + struct hid_bpf_ctx_kern ctx_kern = { + .ctx = { + .hid = hdev, + .size = *size, + .allocated_size = HID_MAX_DESCRIPTOR_SIZE, + }, + }; + + ctx_kern.data = kmemdup(rdesc, ctx_kern.ctx.allocated_size, GFP_KERNEL); + if (!ctx_kern.data) + goto ignore_bpf; + + ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern); + if (ret < 0) + goto ignore_bpf; + + if (ret) { + if (ret > ctx_kern.ctx.allocated_size) + goto ignore_bpf; + + *size = ret; + } + + rdesc = krealloc(ctx_kern.data, *size, GFP_KERNEL); + + return rdesc; + + ignore_bpf: + kfree(ctx_kern.data); + return kmemdup(rdesc, *size, GFP_KERNEL); +} +EXPORT_SYMBOL_GPL(call_hid_bpf_rdesc_fixup); + /** * hid_bpf_get_data - Get the kernel memory pointer associated with the context @ctx * @@ -188,6 +245,14 @@ static int hid_bpf_allocate_event_data(struct hid_device *hdev) return __hid_bpf_allocate_data(hdev, &hdev->bpf.device_data, &hdev->bpf.allocated_data); } +int hid_bpf_reconnect(struct hid_device *hdev) +{ + if (!test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status)) + return device_reprobe(&hdev->dev); + + return 0; +} + /** * hid_bpf_attach_prog - Attach the given @prog_fd to the given HID device * @@ -229,7 +294,17 @@ hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) return err; } - return __hid_bpf_attach_prog(hdev, prog_type, prog_fd, flags); + err = __hid_bpf_attach_prog(hdev, prog_type, prog_fd, flags); + if (err) + return err; + + if (prog_type == HID_BPF_PROG_TYPE_RDESC_FIXUP) { + err = hid_bpf_reconnect(hdev); + if (err) + return err; + } + + return 0; } /** diff --git a/drivers/hid/bpf/hid_bpf_dispatch.h b/drivers/hid/bpf/hid_bpf_dispatch.h index 98c378e18b2b..1d1d5bcccbd7 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.h +++ b/drivers/hid/bpf/hid_bpf_dispatch.h @@ -18,6 +18,7 @@ int __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_t void __hid_bpf_destroy_device(struct hid_device *hdev); int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, struct hid_bpf_ctx_kern *ctx_kern); +int hid_bpf_reconnect(struct hid_device *hdev); struct bpf_prog; diff --git a/drivers/hid/bpf/hid_bpf_jmp_table.c b/drivers/hid/bpf/hid_bpf_jmp_table.c index 0f20deab81ff..3a5ab70d1a95 100644 --- a/drivers/hid/bpf/hid_bpf_jmp_table.c +++ b/drivers/hid/bpf/hid_bpf_jmp_table.c @@ -59,12 +59,15 @@ static DECLARE_WORK(release_work, hid_bpf_release_progs); BTF_ID_LIST(hid_bpf_btf_ids) BTF_ID(func, hid_bpf_device_event) /* HID_BPF_PROG_TYPE_DEVICE_EVENT */ +BTF_ID(func, hid_bpf_rdesc_fixup) /* HID_BPF_PROG_TYPE_RDESC_FIXUP */ static int hid_bpf_max_programs(enum hid_bpf_prog_type type) { switch (type) { case HID_BPF_PROG_TYPE_DEVICE_EVENT: return HID_BPF_MAX_PROGS_PER_DEV; + case HID_BPF_PROG_TYPE_RDESC_FIXUP: + return 1; default: return -EINVAL; } @@ -234,6 +237,10 @@ static void hid_bpf_release_progs(struct work_struct *work) if (next->hdev == hdev && next->type == type) next->hdev = NULL; } + + /* if type was rdesc fixup, reconnect device */ + if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP) + hid_bpf_reconnect(hdev); } } diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 356d3822f17d..42aed754123c 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1218,7 +1218,8 @@ int hid_open_report(struct hid_device *device) return -ENODEV; size = device->dev_rsize; - buf = kmemdup(start, size, GFP_KERNEL); + /* call_hid_bpf_rdesc_fixup() ensures we work on a copy of rdesc */ + buf = call_hid_bpf_rdesc_fixup(device, start, &size); if (buf == NULL) return -ENOMEM; diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index ade0def154b6..4f5eb27a188b 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -59,6 +59,7 @@ struct hid_bpf_ctx { /* Following functions are tracepoints that BPF programs can attach to */ int hid_bpf_device_event(struct hid_bpf_ctx *ctx); +int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx); /* Following functions are kfunc that we export to BPF programs */ /* available everywhere in HID-BPF */ @@ -82,6 +83,7 @@ void hid_bpf_release_context(struct hid_bpf_ctx *ctx); enum hid_bpf_prog_type { HID_BPF_PROG_TYPE_UNDEF = -1, HID_BPF_PROG_TYPE_DEVICE_EVENT, /* an event is emitted from the device */ + HID_BPF_PROG_TYPE_RDESC_FIXUP, HID_BPF_PROG_TYPE_MAX, }; @@ -125,6 +127,7 @@ int hid_bpf_connect_device(struct hid_device *hdev); void hid_bpf_disconnect_device(struct hid_device *hdev); void hid_bpf_destroy_device(struct hid_device *hid); void hid_bpf_device_init(struct hid_device *hid); +u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size); #else /* CONFIG_BPF */ static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, int type, u8 *data, u32 *size, int interrupt) { return 0; } @@ -132,6 +135,11 @@ static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; } static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {} static inline void hid_bpf_destroy_device(struct hid_device *hid) {} static inline void hid_bpf_device_init(struct hid_device *hid) {} +static inline u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) +{ + return kmemdup(rdesc, *size, GFP_KERNEL); +} + #endif /* CONFIG_BPF */ #endif /* __HID_BPF_H */