From patchwork Fri Aug 9 10:03:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Hutterer X-Patchwork-Id: 13758659 Received: from fhigh1-smtp.messagingengine.com (fhigh1-smtp.messagingengine.com [103.168.172.152]) (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 CA78B1922D7; Fri, 9 Aug 2024 10:03:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=103.168.172.152 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723197832; cv=none; b=UcwWlwOReGnVpLvFw+1RNwG3iLV8tfK07b8fWcBEzEBQxg3zqLyA2NkPdzcA4QAZ8HZG2QaMDRluaM83DRfweo+RFd5VuXohSe9tcqgdpc+gn1E7YTuPVtS67/57P3jOBg+8r+0Pl62JkhxtGH7W2nt6uX1YoVjBlJx9bRkOBeM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723197832; c=relaxed/simple; bh=9GQcy1qd9NWVxlLrLF3rWsQ8GGkY667hqZKg2cR9b9c=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=NZPp5GD8W3JthRhp7x1d3fgNujinrpxK5oKhApQQUpUqJ3TGZV/154rvVWwQ1dZbY6vWsGoVDqCqX99EZYjxGAoklrjqSIROFpO0j25jfViTpVs8isczvGWRrTVS8PGRnekWNxDRVWkKfq1ymhjQEXRS2zbCnVAghxdLo/tQkfg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=who-t.net; spf=pass smtp.mailfrom=who-t.net; dkim=pass (2048-bit key) header.d=who-t.net header.i=@who-t.net header.b=anFpHUMJ; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=F2cDuWdh; arc=none smtp.client-ip=103.168.172.152 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=who-t.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=who-t.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=who-t.net header.i=@who-t.net header.b="anFpHUMJ"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="F2cDuWdh" Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailfhigh.nyi.internal (Postfix) with ESMTP id BD4781151B1D; Fri, 9 Aug 2024 06:03:48 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Fri, 09 Aug 2024 06:03:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=who-t.net; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :message-id:mime-version:reply-to:subject:subject:to:to; s=fm2; t=1723197828; x=1723284228; bh=rN+bQCwzpuaxy9DuH7JMnY29r/U8Bdci iIULDINT+i0=; b=anFpHUMJoQRuiQ6DV8yOya2H/QeNct6j3vYfqVX4GUa7B1rY sC7Q4caUE5vsF04Uc6IHgnKFmdgHKp5o44XUwOTghkP79h/I5xLv3qB0MrYYGZGa rBlIhqaOZq0povLDKsC4M8vFE/XIWA82CK8Yw0fXtExfqAM0Q7sfJmfRikYp63dE r11LA79K4OpHcpJuLqCpCrcBg/zRqw8HzxclQpwKu1Ht0RwwQtSQbQ+JhNWoemVQ rAs2De4kjsojFKefNCZfv2bkinJh6kSQwEjdXCmY50aoMmr1WSCs871hzNccd0Wy QMtFxw481D3GgyGx4Cnaq49uvdsXb93UQhtR3A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:message-id :mime-version:reply-to:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t= 1723197828; x=1723284228; bh=rN+bQCwzpuaxy9DuH7JMnY29r/U8BdciiIU LDINT+i0=; b=F2cDuWdhEVTLurg3lorG/No788xqn56kC6WLeH12vp+St0WW7cj WGU3e9GSsyfmfsl+2WHOFmGzkH2aqSR2qm145/qXOXv9lgY3gulCAzK16O5iwe0Z pKB4f97+le6QjNBL0GSSurMfxqO5xZpNluAc/DguqoRpG8PSPlqsvB9QtaXC4mtS RRhNbCHwimr5lnuISt/XVT3RqpEEReh4Ez/rKgaFo2CDvYOAzgm0bs99fTGhXV6y BTt7+2U7iEQ6ADfVlaFX6gO8haF214OL/sthyjF+7KttrhSw/5PKD+bTfozP9cXT rmuC3hhPX6LQ8DC/YrQn4ZTb4wVhlmK1NNA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeftddrleeggddvvdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdpuffr tefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnth hsucdlqddutddtmdenucfjughrpeffhffvvefukfggtggusehttdertddttddvnecuhfhr ohhmpefrvghtvghrucfjuhhtthgvrhgvrhcuoehpvghtvghrrdhhuhhtthgvrhgvrhesfi hhohdqthdrnhgvtheqnecuggftrfgrthhtvghrnhepkeejueffveetgeffieegudeitddu fefhhffgjeefueeuheelhfevhffghedutdefnecuffhomhgrihhnpehgihhthhhusgdrtg homhdpkhgvrhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghm pehmrghilhhfrhhomhepphgvthgvrhdrhhhuthhtvghrvghrseifhhhoqdhtrdhnvghtpd hnsggprhgtphhtthhopeegpdhmohguvgepshhmthhpohhuthdprhgtphhtthhopehjihhk ohhssehkvghrnhgvlhdrohhrghdprhgtphhtthhopegsvghnjhgrmhhinhdrthhishhsoh hirhgvshesrhgvughhrghtrdgtohhmpdhrtghpthhtoheplhhinhhugidqihhnphhuthes vhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlh esvhhgvghrrdhkvghrnhgvlhdrohhrgh X-ME-Proxy: Feedback-ID: i7ce144cd:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 9 Aug 2024 06:03:46 -0400 (EDT) Date: Fri, 9 Aug 2024 20:03:42 +1000 From: Peter Hutterer To: Jiri Kosina , Benjamin Tissoires Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] HID: hidraw - add HIDIOCREVOKE ioctl Message-ID: <20240809100342.GA52163@quokka> Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline There is a need for userspace applications to open HID devices directly. Use-cases include configuration of gaming mice or direct access to joystick devices. The latter is currently handled by the uaccess tag in systemd, other devices include more custom/local configurations or just sudo. A better approach is what we already have for evdev devices: give the application a file descriptor and revoke it when it may no longer access that device. This patch is the hidraw equivalent to the EVIOCREVOKE ioctl, see commit c7dc65737c9a607d3e6f8478659876074ad129b8 for full details. An MR for systemd-logind has been filed here: https://github.com/systemd/systemd/pull/33970 hidraw_is_revoked() and hidraw_open_errno() are both defined as weak functions to allow for a BPF program to deny access to a /dev/hidraw device. The functions return 0 on success or a negative errno otherwise that is returned to the caller. As a use-case example, a gamepad-managing process could attach a BPF program that defaults to -EACCESS for all hidraw devices except those with ID_INPUT_JOYSTICK set by udev. Signed-off-by: Peter Hutterer --- First version of the patch: https://patchwork.kernel.org/project/linux-input/patch/YmEAPZKDisM2HAsG@quokka/ Changes to v1: - add the hidraw_is_revoked and hidraw_open_errno weak functions as suggested by Benjamin drivers/hid/hidraw.c | 52 +++++++++++++++++++++++++++++++++---- include/linux/hidraw.h | 1 + include/uapi/linux/hidraw.h | 1 + 3 files changed, 49 insertions(+), 5 deletions(-) diff --git ./drivers/hid/hidraw.c ../drivers/hid/hidraw.c index 2bc762d31ac7..a9c68448cb20 100644 --- ./drivers/hid/hidraw.c +++ ../drivers/hid/hidraw.c @@ -38,12 +38,27 @@ static const struct class hidraw_class = { static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; static DECLARE_RWSEM(minors_rwsem); +__weak noinline bool hidraw_is_revoked(struct hidraw_list *list) +{ + return list->revoked; +} +ALLOW_ERROR_INJECTION(hidraw_is_revoked, TRUE); + +__weak noinline int hidraw_open_errno(__u32 major, __u32 minor) +{ + return 0; +} +ALLOW_ERROR_INJECTION(hidraw_open_errno, ERRNO); + static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) { struct hidraw_list *list = file->private_data; int ret = 0, len; DECLARE_WAITQUEUE(wait, current); + if (hidraw_is_revoked(list)) + return -ENODEV; + mutex_lock(&list->read_mutex); while (ret == 0) { @@ -161,9 +176,13 @@ static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { + struct hidraw_list *list = file->private_data; ssize_t ret; down_read(&minors_rwsem); - ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT); + if (hidraw_is_revoked(list)) + ret = -ENODEV; + else + ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT); up_read(&minors_rwsem); return ret; } @@ -256,7 +275,7 @@ static __poll_t hidraw_poll(struct file *file, poll_table *wait) poll_wait(file, &list->hidraw->wait, wait); if (list->head != list->tail) mask |= EPOLLIN | EPOLLRDNORM; - if (!list->hidraw->exist) + if (!list->hidraw->exist || hidraw_is_revoked(list)) mask |= EPOLLERR | EPOLLHUP; return mask; } @@ -267,7 +286,11 @@ static int hidraw_open(struct inode *inode, struct file *file) struct hidraw *dev; struct hidraw_list *list; unsigned long flags; - int err = 0; + int err; + + err = hidraw_open_errno(hidraw_major, minor); + if (err < 0) + return err; if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { err = -ENOMEM; @@ -320,6 +343,9 @@ static int hidraw_fasync(int fd, struct file *file, int on) { struct hidraw_list *list = file->private_data; + if (hidraw_is_revoked(list)) + return -ENODEV; + return fasync_helper(fd, file, on, &list->fasync); } @@ -372,6 +398,13 @@ static int hidraw_release(struct inode * inode, struct file * file) return 0; } +static int hidraw_revoke(struct hidraw_list *list) +{ + list->revoked = true; + + return 0; +} + static long hidraw_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -379,11 +412,12 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd, unsigned int minor = iminor(inode); long ret = 0; struct hidraw *dev; + struct hidraw_list *list = file->private_data; void __user *user_arg = (void __user*) arg; down_read(&minors_rwsem); dev = hidraw_table[minor]; - if (!dev || !dev->exist) { + if (!dev || !dev->exist || hidraw_is_revoked(list)) { ret = -ENODEV; goto out; } @@ -421,6 +455,14 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd, ret = -EFAULT; break; } + case HIDIOCREVOKE: + { + if (user_arg) + ret = -EINVAL; + else + ret = hidraw_revoke(list); + break; + } default: { struct hid_device *hid = dev->hid; @@ -527,7 +569,7 @@ int hidraw_report_event(struct hid_device *hid, u8 *data, int len) list_for_each_entry(list, &dev->list, node) { int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); - if (new_head == list->tail) + if (hidraw_is_revoked(list) || new_head == list->tail) continue; if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) { diff --git ./include/linux/hidraw.h ../include/linux/hidraw.h index cd67f4ca5599..18fd30a288de 100644 --- ./include/linux/hidraw.h +++ ../include/linux/hidraw.h @@ -32,6 +32,7 @@ struct hidraw_list { struct hidraw *hidraw; struct list_head node; struct mutex read_mutex; + bool revoked; }; #ifdef CONFIG_HIDRAW diff --git ./include/uapi/linux/hidraw.h ../include/uapi/linux/hidraw.h index 33ebad81720a..d0563f251da5 100644 --- ./include/uapi/linux/hidraw.h +++ ../include/uapi/linux/hidraw.h @@ -46,6 +46,7 @@ struct hidraw_devinfo { /* The first byte of SOUTPUT and GOUTPUT is the report number */ #define HIDIOCSOUTPUT(len) _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x0B, len) #define HIDIOCGOUTPUT(len) _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x0C, len) +#define HIDIOCREVOKE _IOW('H', 0x0D, int) /* Revoke device access */ #define HIDRAW_FIRST_MINOR 0 #define HIDRAW_MAX_DEVICES 64