From: Alan Stern <stern@rowland.harvard.edu> mainline inclusion from mainline-v6.12-rc1 commit 2240fed37afbcdb5e8b627bc7ad986891100e05d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPC7J CVE: CVE-2025-21776 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Robert Morris created a test program which can cause usb_hub_to_struct_hub() to dereference a NULL or inappropriate pointer: Oops: general protection fault, probably for non-canonical address 0xcccccccccccccccc: 0000 [#1] SMP DEBUG_PAGEALLOC PTI CPU: 7 UID: 0 PID: 117 Comm: kworker/7:1 Not tainted 6.13.0-rc3-00017-gf44d154d6e3d #14 Hardware name: FreeBSD BHYVE/BHYVE, BIOS 14.0 10/17/2021 Workqueue: usb_hub_wq hub_event RIP: 0010:usb_hub_adjust_deviceremovable+0x78/0x110 ... Call Trace: <TASK> ? die_addr+0x31/0x80 ? exc_general_protection+0x1b4/0x3c0 ? asm_exc_general_protection+0x26/0x30 ? usb_hub_adjust_deviceremovable+0x78/0x110 hub_probe+0x7c7/0xab0 usb_probe_interface+0x14b/0x350 really_probe+0xd0/0x2d0 ? __pfx___device_attach_driver+0x10/0x10 __driver_probe_device+0x6e/0x110 driver_probe_device+0x1a/0x90 __device_attach_driver+0x7e/0xc0 bus_for_each_drv+0x7f/0xd0 __device_attach+0xaa/0x1a0 bus_probe_device+0x8b/0xa0 device_add+0x62e/0x810 usb_set_configuration+0x65d/0x990 usb_generic_driver_probe+0x4b/0x70 usb_probe_device+0x36/0xd0 The cause of this error is that the device has two interfaces, and the hub driver binds to interface 1 instead of interface 0, which is where usb_hub_to_struct_hub() looks. We can prevent the problem from occurring by refusing to accept hub devices that violate the USB spec by having more than one configuration or interface. Reported-and-tested-by: Robert Morris <rtm@csail.mit.edu> Cc: stable <stable@kernel.org> Closes: https://lore.kernel.org/linux-usb/95564.1737394039@localhost/ Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/c27f3bf4-63d8-4fb5-ac82-09e3cd19f61c@rowland.harva... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Bowen You <youbowen2@huawei.com> --- drivers/usb/core/hub.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 1ba3feb5e190..f295609649b1 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1818,6 +1818,17 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) desc = intf->cur_altsetting; hdev = interface_to_usbdev(intf); + /* + * The USB 2.0 spec prohibits hubs from having more than one + * configuration or interface, and we rely on this prohibition. + * Refuse to accept a device that violates it. + */ + if (hdev->descriptor.bNumConfigurations > 1 || + hdev->actconfig->desc.bNumInterfaces > 1) { + dev_err(&intf->dev, "Invalid hub with more than one config or interface\n"); + return -EINVAL; + } + /* * Set default autosuspend delay as 0 to speedup bus suspend, * based on the below considerations: -- 2.34.1