From patchwork Wed Jun 26 13:46:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 807614 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 89D67186E39; Wed, 26 Jun 2024 13:46:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719409614; cv=none; b=qSbQHyPwqtGELt7ZR5eD2p9Z9YD64X5vpCDiDveXVwa5C/Tih4itFO0wo90E9LF0PNVE5Vl2YPm7PBMD0j3O+fSztxGsKFaf+bCDnqfT5gr72VD3Z/KE8rJ5pdDW1wkxyx5f3yqA+z0kDhwVI0DchIU0tvAfY7ougNtVAcb11uo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719409614; c=relaxed/simple; bh=B5RcoIbutWmEtYXbPfsY1oRwm9bGSb4lgVEA9mGXIHs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=O7a5z7ZhqNLFmSW9PvCHpZcPPy59J8RLDvyEHjdLvoNV0RoTJgAvXhBhNMalUCoMGW1dqBcjHwg9CKW/ZI1RmW4z0FTYWkL9HTNNbQ8a9+lzk4Jj5eb+A0kj4U116YB1X+zXPCXu4jYAFd6HPXuSpbRAcW33MO35fEOTGAO+5FQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YupSo94w; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YupSo94w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FFB4C4AF0A; Wed, 26 Jun 2024 13:46:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719409614; bh=B5RcoIbutWmEtYXbPfsY1oRwm9bGSb4lgVEA9mGXIHs=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=YupSo94w9dMTCVttRtG+nZkRrPO6C77Je1EZLD6PByg7H6+YP0oEpSwmVeAclvrdh OECU3Ow2vCqk6l/QGrd7NUWA035AvzSzPfiJrpk2r2Ghx6OJAgznJLiYXxSwazNrQm bqfmVeGOxa5jrclVd90ZflMNNMhJAdw49hUZMcuHND1OsSognN+/KeptcccbWN38AU OT8+Zuv4Awtlvnlck/6W3kjCAcrMPHqATOh4upQwSjh+0ytgenQJB2fpMHwZPLsJLa zOpEKi4ROg5fds9u3/1w0SfpCis935WxTEeIWh6VQkQpL0TIJHH9Cymbk0L5L6VC63 DRkL9cLdoaURA== From: Benjamin Tissoires Date: Wed, 26 Jun 2024 15:46:25 +0200 Subject: [PATCH HID v2 04/13] HID: bpf: add HID-BPF hooks for hid_hw_raw_requests Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240626-hid_hw_req_bpf-v2-4-cfd60fb6c79f@kernel.org> References: <20240626-hid_hw_req_bpf-v2-0-cfd60fb6c79f@kernel.org> In-Reply-To: <20240626-hid_hw_req_bpf-v2-0-cfd60fb6c79f@kernel.org> To: Jiri Kosina , Alexei Starovoitov , Shuah Khan , Jonathan Corbet Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, Benjamin Tissoires X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1719409602; l=6531; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=B5RcoIbutWmEtYXbPfsY1oRwm9bGSb4lgVEA9mGXIHs=; b=ap86IjvdzdO19bJIsBM5btV8JBPEV8eM2lIZmsCe0aR9wqgGDLxjjZ9MI5CLwBFW4XQ8M8Um2 hEpPQo2xrkoAG/eWRRopfr01NCYxNjH1D7t3WiMrM+Nm3QB4TIJsohZ X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= This allows to intercept and prevent or change the behavior of hid_hw_raw_request() from a bpf program. The intent is to solve a couple of use case: - firewalling a HID device: a firewall can monitor who opens the hidraw nodes and then prevent or allow access to write operations on that hidraw node. - change the behavior of a device and emulate a new HID feature request The hook is allowed to be run as sleepable so it can itself call hid_bpf_hw_request(), which allows to "convert" one feature request into another or even call the feature request on a different HID device on the same physical device. Signed-off-by: Benjamin Tissoires --- changes in v2: - make use of SRCU --- drivers/hid/bpf/hid_bpf_dispatch.c | 37 ++++++++++++++++++++++++++++++++++++ drivers/hid/bpf/hid_bpf_struct_ops.c | 1 + drivers/hid/hid-core.c | 6 ++++++ include/linux/hid_bpf.h | 35 ++++++++++++++++++++++++++++++++++ 4 files changed, 79 insertions(+) diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index c026248e3d73..ac98bab4c96d 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -74,6 +74,43 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } EXPORT_SYMBOL_GPL(dispatch_hid_bpf_device_event); +int dispatch_hid_bpf_raw_requests(struct hid_device *hdev, + unsigned char reportnum, u8 *buf, + u32 size, enum hid_report_type rtype, + enum hid_class_request reqtype, + u64 source) +{ + struct hid_bpf_ctx_kern ctx_kern = { + .ctx = { + .hid = hdev, + .allocated_size = size, + .size = size, + }, + .data = buf, + }; + struct hid_bpf_ops *e; + int ret, idx; + + if (rtype >= HID_REPORT_TYPES) + return -EINVAL; + + idx = srcu_read_lock(&hdev->bpf.srcu); + list_for_each_entry_srcu(e, &hdev->bpf.prog_list, list, + srcu_read_lock_held(&hdev->bpf.srcu)) { + if (e->hid_hw_request) { + ret = e->hid_hw_request(&ctx_kern.ctx, reportnum, rtype, reqtype, source); + if (ret) + goto out; + } + } + ret = 0; + +out: + srcu_read_unlock(&hdev->bpf.srcu, idx); + return ret; +} +EXPORT_SYMBOL_GPL(dispatch_hid_bpf_raw_requests); + u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) { int ret; diff --git a/drivers/hid/bpf/hid_bpf_struct_ops.c b/drivers/hid/bpf/hid_bpf_struct_ops.c index d34731a1b457..a540a4417174 100644 --- a/drivers/hid/bpf/hid_bpf_struct_ops.c +++ b/drivers/hid/bpf/hid_bpf_struct_ops.c @@ -44,6 +44,7 @@ static int hid_bpf_ops_check_member(const struct btf_type *t, switch (moff) { case offsetof(struct hid_bpf_ops, hid_rdesc_fixup): + case offsetof(struct hid_bpf_ops, hid_hw_request): break; default: if (prog->sleepable) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index ad08289752da..16731804c6bd 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2406,6 +2406,7 @@ int __hid_hw_raw_request(struct hid_device *hdev, __u64 source) { unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE; + int ret; if (hdev->ll_driver->max_buffer_size) max_buffer_size = hdev->ll_driver->max_buffer_size; @@ -2413,6 +2414,11 @@ int __hid_hw_raw_request(struct hid_device *hdev, if (len < 1 || len > max_buffer_size || !buf) return -EINVAL; + ret = dispatch_hid_bpf_raw_requests(hdev, reportnum, buf, len, rtype, + reqtype, source); + if (ret) + return ret; + return hdev->ll_driver->raw_request(hdev, reportnum, buf, len, rtype, reqtype); } diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index f93845de5cac..3c01f7f8b6fc 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -130,6 +130,31 @@ struct hid_bpf_ops { */ int (*hid_rdesc_fixup)(struct hid_bpf_ctx *ctx); + /** + * @hid_hw_request: called whenever a hid_hw_raw_request() call is emitted + * on the HID device + * + * It has the following arguments: + * + * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx + * ``reportnum``: the report number, as in hid_hw_raw_request() + * ``rtype``: the report type (``HID_INPUT_REPORT``, ``HID_FEATURE_REPORT``, + * ``HID_OUTPUT_REPORT``) + * ``reqtype``: the request + * ``source``: a u64 referring to a uniq but identifiable source. If %0, the + * kernel itself emitted that call. For hidraw, ``source`` is set + * to the associated ``struct file *``. + * + * Return: %0 to keep processing the request by hid-core; any other value + * stops hid-core from processing that event. A positive value should be + * returned with the number of bytes returned in the incoming buffer; a + * negative error code interrupts the processing of this call. + */ + int (*hid_hw_request)(struct hid_bpf_ctx *ctx, unsigned char reportnum, + enum hid_report_type rtype, enum hid_class_request reqtype, + __u64 source); + + /* private: do not show up in the docs */ struct hid_device *hdev; }; @@ -152,6 +177,11 @@ struct hid_bpf { #ifdef CONFIG_HID_BPF u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data, u32 *size, int interrupt, u64 source); +int dispatch_hid_bpf_raw_requests(struct hid_device *hdev, + unsigned char reportnum, __u8 *buf, + u32 size, enum hid_report_type rtype, + enum hid_class_request reqtype, + __u64 source); 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); @@ -161,6 +191,11 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data, u32 *size, int interrupt, u64 source) { return data; } +static inline int dispatch_hid_bpf_raw_requests(struct hid_device *hdev, + unsigned char reportnum, u8 *buf, + u32 size, enum hid_report_type rtype, + enum hid_class_request reqtype, + u64 source) { return 0; } 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) {}