kernel.git/drivers/hid/uhid.c, branch linux-4.9.y

HID: uhid: Fix worker destroying device without any protection

2022-01-27T07:47:31Z

commit 4ea5763fb79ed89b3bdad455ebf3f33416a81624 upstream. uhid has to run hid_add_device() from workqueue context while allowing parallel use of the userspace API (which is protected with ->devlock). But hid_add_device() can fail. Currently, that is handled by immediately destroying the associated HID device, without using ->devlock - but if there are concurrent requests from userspace, that's wrong and leads to NULL dereferences and/or memory corruption (via use-after-free). Fix it by leaving the HID device as-is in the worker. We can clean it up later, either in the UHID_DESTROY command handler or in the ->release() handler. Cc: stable@vger.kernel.org Fixes: 67f8ecc550b5 ("HID: uhid: fix timeout when probe races with IO") Signed-off-by: Jann Horn Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman

HID: introduce hid_is_using_ll_driver

2021-12-14T09:04:46Z

commit fc2237a724a9e448599076d7d23497f51e2f7441 upstream. Although HID itself is transport-agnostic, occasionally a driver may want to interact with the low-level transport that a device is connected through. To do this, we need to know what kind of bus is in use. The first guess may be to look at the 'bus' field of the 'struct hid_device', but this field may be emulated in some cases (e.g. uhid). More ideally, we can check which ll_driver a device is using. This function introduces a 'hid_is_using_ll_driver' function and makes the 'struct hid_ll_driver' of the four most common transports accessible through hid.h. Signed-off-by: Jason Gerecke Acked-By: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman

HID: hidraw, uhid: Always report EPOLLOUT

2020-01-23T07:19:33Z

[ Upstream commit 9e635c2851df6caee651e589fbf937b637973c91 ] hidraw and uhid device nodes are always available for writing so we should always report EPOLLOUT and EPOLLWRNORM bits, not only in the cases when there is nothing to read. Reported-by: Linus Torvalds Fixes: be54e7461ffdc ("HID: uhid: Fix returning EPOLLOUT from uhid_char_poll") Fixes: 9f3b61dc1dd7b ("HID: hidraw: Fix returning EPOLLOUT from hidraw_poll") Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin

HID: uhid: Fix returning EPOLLOUT from uhid_char_poll

2020-01-14T19:04:27Z

commit be54e7461ffdc5809b67d2aeefc1ddc9a91470c7 upstream. Always return EPOLLOUT from uhid_char_poll to allow polling /dev/uhid for writable state. Fixes: 1f9dec1e0164 ("HID: uhid: allow poll()'ing on uhid devices") Signed-off-by: Marcel Holtmann Cc: stable@vger.kernel.org Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman

HID: uhid: forbid UHID_CREATE under KERNEL_DS or elevated privileges

2018-11-27T15:09:42Z

commit 8c01db7619f07c85c5cd81ec5eb83608b56c88f5 upstream. When a UHID_CREATE command is written to the uhid char device, a copy_from_user() is done from a user pointer embedded in the command. When the address limit is KERNEL_DS, e.g. as is the case during sys_sendfile(), this can read from kernel memory. Alternatively, information can be leaked from a setuid binary that is tricked to write to the file descriptor. Therefore, forbid UHID_CREATE in these cases. No other commands in uhid_char_write() are affected by this bug and UHID_CREATE is marked as "obsolete", so apply the restriction to UHID_CREATE only rather than to uhid_char_write() entirely. Thanks to Dmitry Vyukov for adding uhid definitions to syzkaller and to Jann Horn for commit 9da3f2b740544 ("x86/fault: BUG() when uaccess helpers fault on kernel addresses"), allowing this bug to be found. Reported-by: syzbot+72473edc9bf4eb1c6556@syzkaller.appspotmail.com Fixes: d365c6cfd337 ("HID: uhid: add UHID_CREATE and UHID_DESTROY events") Cc: # v3.6+ Cc: Jann Horn Cc: Andy Lutomirski Signed-off-by: Eric Biggers Reviewed-by: Jann Horn Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman

miscdevice: Add helper macro for misc device boilerplate

2016-08-31T12:12:35Z

Many modules call misc_register and misc_deregister in its module init and exit methods without any additional code. This ends up being boilerplate. This patch adds helper macro module_misc_device(), that replaces module_init()/ module_exit() with template functions. This patch also converts drivers to use new macro. Change since v1: Add device.h include in miscdevice.h as module_driver macro was not available from other include files in some architectures. Signed-off-by: PrasannaKumar Muralidharan Signed-off-by: Greg Kroah-Hartman

HID: uhid: fix timeout when probe races with IO

2016-06-01T14:24:54Z

Many devices use userspace bluetooth stacks like BlueZ or Bluedroid in combination with uhid. If any of these stacks is used with a HID device for which the driver performs a HID request as part .probe (or technically another HID operation), this results in a deadlock situation. The deadlock results in a 5 second timeout for I/O operations in HID drivers, so isn't fatal, but none of the I/O operations have a chance of succeeding. The root cause for the problem is that uhid only allows for one request to be processed at a time per uhid instance and locks out other operations. This means that if a user space is creating a new HID device through 'UHID_CREATE', which ultimately triggers '.probe' through the HID layer. Then any HID request e.g. a read for calibration data would trigger a HID operation on uhid again, but it won't go out to userspace, because it is still stuck in UHID_CREATE. In addition bluetooth stacks are typically single threaded, so they wouldn't be able to handle any requests while waiting on uhid. Lucikly the UHID spec is somewhat flexible and allows for fixing the issue, without breaking user space. The idea which the patch implements as discussed with David Herrmann is to decouple adding of a hid device (which triggers .probe) from UHID_CREATE. The work will kick off roughly once UHID_CREATE completed (or else will wait a tiny bit of time in .probe for a lock). A HID driver has to call HID to call 'hid_hw_start()' as part of .probe once it is ready for I/O, which triggers UHID_START to user space. Any HID operations should function now within .probe and won't deadlock because userspace is stuck on UHID_CREATE. We verified this patch on Bluedroid with Android 6.0 and on desktop Linux with BlueZ stacks. Prior to the patch they had the deadlock issue. [jkosina@suse.cz: reword subject] Signed-off-by: Roderick Colenbrander Cc: stable@vger.kernel.org Signed-off-by: Jiri Kosina

drivers/hid/uhid.c: check write() bitness using in_compat_syscall

2016-03-22T22:36:02Z

uhid changes the format expected in write() depending on bitness. It should check the syscall bitness directly. Signed-off-by: Andy Lutomirski Cc: David Herrmann Acked-by: Jiri Kosina Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

HID: uHID: fix excepted report type

2014-10-01T18:58:46Z

When uhid_get_report() or uhid_set_report() are called, they emit on the char device a UHID_GET_REPORT or UHID_SET_REPORT message. Then, the protocol says that the user space asnwers with UHID_GET_REPORT_REPLY or UHID_SET_REPORT_REPLY. Unfortunatelly, the current code waits for an event of type UHID_GET_REPORT or UHID_SET_REPORT instead of the reply one. Add 1 to UHID_GET_REPORT or UHID_SET_REPORT to actually wait for the reply, and validate the reply. Signed-off-by: Benjamin Tissoires Reviewed-by: David Herrmann Signed-off-by: Jiri Kosina

HID: uhid: report to user-space whether reports are numbered

2014-08-25T08:28:08Z

This makes UHID_START include a "dev_flags" field that describes details of the hid-device in the kernel. The first flags we introduce describe whether a given report-type uses numbered reports. This is useful for transport layers that force report-numbers and therefore might have to prefix kernel-provided HID-messages with the report-number. Currently, only HoG needs this and the spec only talks about "global report numbers". That is, it's a global boolean not a per-type boolean. However, given the quirks we already have in kernel-space, a per-type value seems much more appropriate. Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina