| Message ID | 20250417195032.1811338-1-chenyuan0y@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | usb: acpi: Prevent null pointer dereference in usb_acpi_add_usb4_devlink() | expand |
On Thu, Apr 17, 2025 at 02:50:32PM -0500, Chenyuan Yang wrote: > As demonstrated by the fix for update_port_device_state, > commit 12783c0b9e2c ("usb: core: Prevent null pointer dereference in update_port_device_state"), > usb_hub_to_struct_hub() can return NULL in certain scenarios, > such as during hub driver unbind or teardown race conditions, > even if the underlying usb_device structure exists. Those are not the conditions addressed by that commit. The commit was specifically meant to handle a bizarre situation created by the lvstest driver (a child device added "by hand" after deconfiguring the parent hub). > Plus, all other places that call usb_hub_to_struct_hub() in the same file > do check for NULL return values. > > If usb_hub_to_struct_hub() returns NULL, the subsequent access to > hub->ports[udev->portnum - 1] will cause a null pointer dereference. > > Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com> > Fixes: f1bfb4a6fed6 ("usb: acpi: add device link between tunneled USB3 device and USB4 Host Interface") > > --- > drivers/usb/core/usb-acpi.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c > index 935c0efea0b6..ea1ce8beb0cb 100644 > --- a/drivers/usb/core/usb-acpi.c > +++ b/drivers/usb/core/usb-acpi.c > @@ -165,6 +165,8 @@ static int usb_acpi_add_usb4_devlink(struct usb_device *udev) > return 0; > > hub = usb_hub_to_struct_hub(udev->parent); > + if (!hub) > + return 0; > port_dev = hub->ports[udev->portnum - 1]; While this test may not be strictly necessary, it doesn't hurt since this isn't a hot path. Acked-by: Alan Stern <stern@rowland.harvard.edu> Alan Stern
diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c index 935c0efea0b6..ea1ce8beb0cb 100644 --- a/drivers/usb/core/usb-acpi.c +++ b/drivers/usb/core/usb-acpi.c @@ -165,6 +165,8 @@ static int usb_acpi_add_usb4_devlink(struct usb_device *udev) return 0; hub = usb_hub_to_struct_hub(udev->parent); + if (!hub) + return 0; port_dev = hub->ports[udev->portnum - 1]; struct fwnode_handle *nhi_fwnode __free(fwnode_handle) =
As demonstrated by the fix for update_port_device_state, commit 12783c0b9e2c ("usb: core: Prevent null pointer dereference in update_port_device_state"), usb_hub_to_struct_hub() can return NULL in certain scenarios, such as during hub driver unbind or teardown race conditions, even if the underlying usb_device structure exists. Plus, all other places that call usb_hub_to_struct_hub() in the same file do check for NULL return values. If usb_hub_to_struct_hub() returns NULL, the subsequent access to hub->ports[udev->portnum - 1] will cause a null pointer dereference. Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com> Fixes: f1bfb4a6fed6 ("usb: acpi: add device link between tunneled USB3 device and USB4 Host Interface") --- drivers/usb/core/usb-acpi.c | 2 ++ 1 file changed, 2 insertions(+)