From c3720b04df84b5459050ae4e03ec7d545652f897 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Wed, 22 Jan 2025 14:26:17 -0500
Subject: [PATCH] USB: hub: Ignore non-compliant devices with too many configs
or interfaces
commit 2240fed37afbcdb5e8b627bc7ad986891100e05d upstream.
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.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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 e180841383b3c..ead112aeb3c3c 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:
--
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