kernel/linux.git/drivers/usb/gadget/function/f_hid.c, branch v5.10.257

usb: gadget: f_hid: move list and spinlock inits from bind to alloc

2026-04-18T08:31:16+00:00

[ Upstream commit 4e0a88254ad59f6c53a34bf5fa241884ec09e8b2 ] There was an issue when you did the following: - setup and bind an hid gadget - open /dev/hidg0 - use the resulting fd in EPOLL_CTL_ADD - unbind the UDC - bind the UDC - use the fd in EPOLL_CTL_DEL When CONFIG_DEBUG_LIST was enabled, a list_del corruption was reported within remove_wait_queue (via ep_remove_wait_queue). After some debugging I found out that the queues, which f_hid registers via poll_wait were the problem. These were initialized using init_waitqueue_head inside hidg_bind. So effectively, the bind function re-initialized the queues while there were still items in them. The solution is to move the initialization from hidg_bind to hidg_alloc to extend their lifetimes to the lifetime of the function instance. Additionally, I found many other possibly problematic init calls in the bind function, which I moved as well. Signed-off-by: Michael Zimmermann Cc: stable Link: https://patch.msgid.link/20260331184844.2388761-1-sigmaepsilon92@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: Fix zero length packet transfer

2025-12-06T21:08:13+00:00

[ Upstream commit ed6f727c575b1eb8136e744acfd5e7306c9548f6 ] Set the hid req->zero flag of ep0/in_ep to true by default, then the UDC drivers can transfer a zero length packet at the end if the hid transfer with size divisible to EPs max packet size according to the USB 2.0 spec. Signed-off-by: William Wu Link: https://lore.kernel.org/r/1756204087-26111-1-git-send-email-william.wu@rock-chips.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

HID: usbhid: Eliminate recurrent out-of-bounds bug in usbhid_parse()

2025-06-27T10:04:20+00:00

commit fe7f7ac8e0c708446ff017453add769ffc15deed upstream. Update struct hid_descriptor to better reflect the mandatory and optional parts of the HID Descriptor as per USB HID 1.11 specification. Note: the kernel currently does not parse any optional HID class descriptors, only the mandatory report descriptor. Update all references to member element desc[0] to rpt_desc. Add test to verify bLength and bNumDescriptors values are valid. Replace the for loop with direct access to the mandatory HID class descriptor member for the report descriptor. This eliminates the possibility of getting an out-of-bounds fault. Add a warning message if the HID descriptor contains any unsupported optional HID class descriptors. Reported-by: syzbot+c52569baf0c843f35495@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c52569baf0c843f35495 Fixes: f043bfc98c19 ("HID: usbhid: fix out-of-bounds bug") Cc: stable@vger.kernel.org Signed-off-by: Terry Junge Reviewed-by: Michael Kelley Signed-off-by: Jiri Kosina Signed-off-by: Terry Junge Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: fix report descriptor allocation

2023-12-13T17:27:04+00:00

commit 61890dc28f7d9e9aac8a9471302613824c22fae4 upstream. The commit 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev") has introduced a bug that leads to hid device corruption after the replug operation. Reverse device managed memory allocation for the report descriptor to fix the issue. Tested: This change was tested on the AMD EthanolX CRB server with the BMC based on the OpenBMC distribution. The BMC provides KVM functionality via the USB gadget device: - before: KVM page refresh results in a broken USB device, - after: KVM page refresh works without any issues. Fixes: 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev") Cc: stable@vger.kernel.org Signed-off-by: Konstantin Aladyshev Link: https://lore.kernel.org/r/20231206080744.253-2-aladyshev22@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: fix refcount leak on error path

2023-01-14T09:15:59+00:00

[ Upstream commit 70a3288a7586526315105c699b687d78cd32559a ] When failing to allocate report_desc, opts->refcnt has already been incremented so it needs to be decremented to avoid leaving the options structure permanently locked. Fixes: 21a9476a7ba8 ("usb: gadget: hid: add configfs support") Tested-by: Lee Jones Reviewed-by: Andrzej Pietrasiewicz Reviewed-by: Lee Jones Signed-off-by: John Keeping Link: https://lore.kernel.org/r/20221122123523.3068034-3-john@metanate.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

usb: gadget: f_hid: fix f_hidg lifetime vs cdev

2023-01-14T09:15:59+00:00

[ Upstream commit 89ff3dfac604614287ad5aad9370c3f984ea3f4b ] The embedded struct cdev does not have its lifetime correctly tied to the enclosing struct f_hidg, so there is a use-after-free if /dev/hidgN is held open while the gadget is deleted. This can readily be replicated with libusbgx's example programs (for conciseness - operating directly via configfs is equivalent): gadget-hid exec 3<> /dev/hidg0 gadget-vid-pid-remove exec 3<&- Pull the existing device up in to struct f_hidg and make use of the cdev_device_{add,del}() helpers. This changes the lifetime of the device object to match struct f_hidg, but note that it is still added and deleted at the same time. Fixes: 71adf1189469 ("USB: gadget: add HID gadget driver") Tested-by: Lee Jones Reviewed-by: Andrzej Pietrasiewicz Reviewed-by: Lee Jones Signed-off-by: John Keeping Link: https://lore.kernel.org/r/20221122123523.3068034-2-john@metanate.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

usb: gadget: f_hid: optional SETUP/SET_REPORT mode

2023-01-14T09:15:59+00:00

[ Upstream commit d7428bc26fc767942c38d74b80299bcd4f01e7cb ] f_hid provides the OUT Endpoint as only way for receiving reports from the host. SETUP/SET_REPORT method is not supported, and this causes a number of compatibility problems with various host drivers, especially in the case of keyboard emulation using f_hid. - Some hosts do not support the OUT Endpoint and ignore it, so it becomes impossible for the gadget to receive a report from the host. In the case of a keyboard, the gadget loses the ability to receive the status of the LEDs. - Some BIOSes/UEFIs can't work with HID devices with the OUT Endpoint at all. This may be due to their bugs or incomplete implementation of the HID standard. For example, absolutely all Apple UEFIs can't handle the OUT Endpoint if it goes after IN Endpoint in the descriptor and require the reverse order (OUT, IN) which is a violation of the standard. Other hosts either do not initialize gadgets with a descriptor containing the OUT Endpoint completely (like some HP and DELL BIOSes and embedded firmwares like on KVM switches), or initialize them, but will not poll the IN Endpoint. This patch adds configfs option no_out_endpoint=1 to disable the OUT Endpoint and allows f_hid to receive reports from the host via SETUP/SET_REPORT. Previously, there was such a feature in f_hid, but it was replaced by the OUT Endpoint [1] in the commit 99c515005857 ("usb: gadget: hidg: register OUT INT endpoint for SET_REPORT"). So this patch actually returns the removed functionality while making it optional. For backward compatibility reasons, the OUT Endpoint mode remains the default behaviour. - The OUT Endpoint mode provides the report queue and reduces USB overhead (eliminating SETUP routine) on transmitting a report from the host. - If the SETUP/SET_REPORT mode is used, there is no report queue, so the userspace will only read last report. For classic HID devices like keyboards this is not a problem, since it's intended to transmit the status of the LEDs and only the last report is important. This mode provides better compatibility with strange and buggy host drivers. Both modes passed USBCV tests. Checking with the USB protocol analyzer also confirmed that everything is working as it should and the new mode ensures operability in all of the described cases. Link: https://www.spinics.net/lists/linux-usb/msg65494.html [1] Reviewed-by: Maciej Żenczykowski Acked-by: Felipe Balbi Signed-off-by: Maxim Devaev Link: https://lore.kernel.org/r/20210821134004.363217-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev") Signed-off-by: Sasha Levin

usb: gadget: f_hid: idle uses the highest byte for duration

2021-08-12T11:22:11+00:00

commit fa20bada3f934e3b3e4af4c77e5b518cd5a282e5 upstream. SET_IDLE value must be shifted 8 bits to the right to get duration. This confirmed by USBCV test. Fixes: afcff6dc690e ("usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers") Cc: stable Signed-off-by: Maxim Devaev Link: https://lore.kernel.org/r/20210727185800.43796-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: fixed NULL pointer dereference

2021-08-12T11:22:11+00:00

commit 2867652e4766360adf14dfda3832455e04964f2a upstream. Disconnecting and reconnecting the USB cable can lead to crashes and a variety of kernel log spam. The problem was found and reproduced on the Raspberry Pi [1] and the original fix was created in Raspberry's own fork [2]. Link: https://github.com/raspberrypi/linux/issues/3870 [1] Link: https://github.com/raspberrypi/linux/commit/a6e47d5f4efbd2ea6a0b6565cd2f9b7bb217ded5 [2] Signed-off-by: Maxim Devaev Signed-off-by: Phil Elwell Cc: stable Link: https://lore.kernel.org/r/20210723155928.210019-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers

2021-08-12T11:22:10+00:00

commit afcff6dc690e24d636a41fd4bee6057e7c70eebd upstream. The USB HID standard declares mandatory support for GET_IDLE and SET_IDLE requests for Boot Keyboard. Most hosts can handle their absence, but others like some old/strange UEFIs and BIOSes consider this a critical error and refuse to work with f_hid. This primitive implementation of saving and returning idle is sufficient to meet the requirements of the standard and these devices. Acked-by: Felipe Balbi Cc: stable Signed-off-by: Maxim Devaev Link: https://lore.kernel.org/r/20210721180351.129450-1-mdevaev@gmail.com Signed-off-by: Greg Kroah-Hartman