On 16/09/2020 17.39, Bastien Nocera wrote:
On Wed, 2020-09-16 at 16:15 +0200, Greg Kroah-Hartman wrote:
On Wed, Sep 16, 2020 at 03:33:25PM +0200, Andrey Konovalov wrote:
Hi Bastien, Greg, Alan,
Looks like commit adb6e6ac20ee ("USB: Also match device drivers
using
the ->match vfunc") broke the USB driver ID matching process. This,
in
turn, led to a complete breakage of the USB fuzzing instance.
This is how an attempt to connect a USB device looks now:
[ 39.781642][ T12] usb 1-1: new high-speed USB device number 2
using dummy_hcd
[ 40.299955][ T12] usb 1-1: New USB device found,
idVendor=0cf3,
idProduct=9271, bcdDevice= 1.08
[ 40.303072][ T12] usb 1-1: New USB device strings: Mfr=1,
Product=2, SerialNumber=3
[ 40.305678][ T12] usb 1-1: Product: syz
[ 40.307041][ T12] usb 1-1: Manufacturer: syz
[ 40.308556][ T12] usb 1-1: SerialNumber: syz
[ 40.314825][ T12] usbip-host 1-1: 1-1 is not in match_busid
table... skip!
[ 42.500114][ T51] usb 1-1: USB disconnect, device number 2
It seems that when going through the list of registered IDs the
code
tries to match against USB/IP and succeeds as usbip_match() always
returns true.
I'm not sure what's the best fix for this is.
I thought that is what the patch from Bastien was supposed to fix?
If it didn't, we can revert it.
It wasn't. Are you thinking of "usbip: Implement a match function to
fix usbip" by M. Vefa Bicakci (CC:ed)?
Seems to me that usbip wants to match *every* device. Wouldn't that be
a bug in usbip?
Hello all,
I agree with Bastien; it looks like the match function that I had prepared
for the "USB-IP no longer works starting with v5.7.y" bug at [1] is not
appropriate due to the fact that the match function always returns true.
My understanding of how USB-IP works is that the user-space provides the
USB bus identifier of the device to be published via USB-IP to the kernel
via /sys/bus/usb/drivers/usbip-host/match_busid. Given that the bus
identifiers written to match_busid are stored in a table, perhaps this
table can be queried in the usbip_match function to avoid the issue
reported by Andrey while preserving USB-IP's functionality?
If needed, I can prepare a patch implementing this proposal, perhaps after
commit 7a2f2974 ("usbip: Implement a match function to fix usbip") is
reverted. The only catch is that my bandwidth is a bit limited, hence it
may take some time for me to publish a patch.
Sorry for this unexpected bug,
Vefa
[1] https://bugzilla.kernel.org/show_bug.cgi?id=208267
