From patchwork Mon Aug 26 15:47:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 822533 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 92CB319413C; Mon, 26 Aug 2024 15:48:10 +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=1724687290; cv=none; b=uttdxsjQ6apWfn4xC2W8Q6RQ6TKBlJTcwKIi1ks5rC3awT1Ge0wX0pgKQxuwXi9oNjfi3ui9ybk6lja5435k8AsPp948WXmTHqyu/OlbOA3i1GUGR/79VkJvUqHmd+QWSMXpd7b399I2vymTJgpmkhAcL4Nx4siLPSxgePfucK4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724687290; c=relaxed/simple; bh=iZtHxr1WnOWyNhEFKU4cqBivzhqrUHFlW667gxNouVQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=LOpXrw7AnLy3oHqCGQWDkfxpZ5RMJ32PhmYs7mUHPX2fdVEB/vVD2S/yEEN1YdA0O+ksTs3EqEH9Z0m8HqGUryBdndfNGGlOIrzGqTAq/msbkFBgskuj4iFZNUY3lKUqHOhgu8TtQj86+uVuIGVr/Blyk47xMHSjN5HVySuG18w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fdKGW/17; 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="fdKGW/17" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6E5FC4DDFA; Mon, 26 Aug 2024 15:48:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724687290; bh=iZtHxr1WnOWyNhEFKU4cqBivzhqrUHFlW667gxNouVQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=fdKGW/17gRxd6YSwcwlYMifez7QDlpd932Zkq1oU2fEhRJvxonuLyl6hTbdQcQoxM tAy7M9GnIVie2W9m+A0HEGxpAA0bQT+mRWWbP9eiEAyuH5OhRCHQh5Z6OUbnM6GjzY svjdV1F+DIOzJ6e0pU6ChD1YbfKC6x9C5xwL6BXSrY98DjD40Y2oZLBbr/QxeJYQOP 0KK9MaTPnxlSzZMVw/iRUrT6kN2suOVU72p9o5fSk/XLTYEszWixdtMBvArtW4O3tU O6hu1kYZ2v+FOrBLNVOV56ho11sMojLisnn3GuKCoB6sN/FBzK1BP4X0BayCg+Ecq2 xNnJd3nUQi/6A== From: bentiss@kernel.org Date: Tue, 27 Aug 2024 00:47:51 +0900 Subject: [PATCH v4 1/3] HID: hidraw: add HIDIOCREVOKE ioctl Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240827-hidraw-revoke-v4-1-88c6795bf867@kernel.org> References: <20240827-hidraw-revoke-v4-0-88c6795bf867@kernel.org> In-Reply-To: <20240827-hidraw-revoke-v4-0-88c6795bf867@kernel.org> To: Jiri Kosina , Shuah Khan , Peter Hutterer Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Benjamin Tissoires X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=ed25519-sha256; t=1724687286; l=5969; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=RLM4AWuodTCoo87UHgn6rO5j8XYNQ3myQZuV/MXya34=; b=3qrw0P9PzCrBZwlnrph7NkvpfwYJBMDNR9reduDTIS7tPA2hAvcEbCpcJ90DEJW4xMB6ZlV5k KYQeFYz1n2+A8iBP9B3g9hc8yleb4xGyMDUKACvCIURDtRfdsVIbDRd X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= From: Peter Hutterer 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 c7dc65737c9a ("Input: evdev - add EVIOCREVOKE ioctl") for full details. An MR for systemd-logind has been filed here: https://github.com/systemd/systemd/pull/33970 Signed-off-by: Peter Hutterer Signed-off-by: Benjamin Tissoires --- 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 Changes to v2: - use __bpf_hook_start/end to silence compiler warnings (see kernel test bot) Changes to v3 (bentiss): - drop the BPF related changes, the API is not clear ATM, and it's wrong in v2, as ERROR_INJECTION should not be used for normal fmodret. - drop hidraw_open_errno() new function. The API seems interesting, but nothing is really ready, so let's not add a useless API for nothing. --- drivers/hid/hidraw.c | 39 +++++++++++++++++++++++++++++++++++---- include/linux/hidraw.h | 1 + include/uapi/linux/hidraw.h | 1 + 3 files changed, 37 insertions(+), 4 deletions(-) diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index 716294e40e8a..c887f48756f4 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -38,12 +38,20 @@ static const struct class hidraw_class = { static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; static DECLARE_RWSEM(minors_rwsem); +static inline bool hidraw_is_revoked(struct hidraw_list *list) +{ + return list->revoked; +} + 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 +169,13 @@ 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 +268,7 @@ 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; } @@ -320,6 +332,9 @@ 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 +387,13 @@ 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 +401,12 @@ 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 +444,14 @@ 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 +558,7 @@ 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 a/include/linux/hidraw.h b/include/linux/hidraw.h index cd67f4ca5599..18fd30a288de 100644 --- a/include/linux/hidraw.h +++ b/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 a/include/uapi/linux/hidraw.h b/include/uapi/linux/hidraw.h index 33ebad81720a..d5ee269864e0 100644 --- a/include/uapi/linux/hidraw.h +++ b/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