Hi Greg,
On 1/4/2024 4:14 PM, Greg Kroah-Hartman wrote:
On Thu, Jan 04, 2024 at 03:56:16PM +0530, Udipto Goswami wrote:
Currently,the function update_port_device_state gets the usb_hub from
udev->parent by calling usb_hub_to_struct_hub.
However, in case the actconfig or the maxchild is 0, the usb_hub would
be NULL and upon further accessing to get port_dev would result in null
pointer dereference.
Is this true for any real (or fake) hardware?
We saw this in our QCOM hardwares where lvstest.c was calling
get_dev_desc_store:
usb_set_device_state+0x128/0x17c
create_lvs_device+0x60/0xf8 [lvstest]
get_dev_desc_store+0x94/0x18c [lvstest]
dev_attr_store+0x30/0x48
I think the part of the test procedure is to first unbind the hub driver
which calls hub_disconnect setting the maxchild = 0.
So if after this the dev_attr try to access, it throws the NULL pointer
de-reference.
Fix this by introducing an if check after the usb_hub is populated.
Fixes: 83cb2604f641 ("usb: core: add sysfs entry for usb device state")
Signed-off-by: Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>
Any specific reason you don't want this backported to the stable kernels
that include the commit you marked this as a fix for?
As my bot says:
- You have marked a patch with a "Fixes:" tag for a commit that is in an
older released kernel, yet you do not have a cc: stable line in the
signed-off-by area at all, which means that the patch will not be
applied to any older kernel releases. To properly fix this, please
follow the documented rules in the
Documentation/process/stable-kernel-rules.rst file for how to resolve
this.
Got it, I'll take care of it in next version.
Thanks,
-Udipto
