CVE-2023-54277

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> fbdev: udlfb: Fix endpoint check<br /> <br /> The syzbot fuzzer detected a problem in the udlfb driver, caused by an<br /> endpoint not having the expected type:<br /> <br /> usb 1-1: Read EDID byte 0 failed: -71<br /> usb 1-1: Unable to get valid EDID from device/display<br /> ------------[ cut here ]------------<br /> usb 1-1: BOGUS urb xfer, pipe 3 != type 1<br /> WARNING: CPU: 0 PID: 9 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880<br /> drivers/usb/core/urb.c:504<br /> Modules linked in:<br /> CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted<br /> 6.4.0-rc1-syzkaller-00016-ga4422ff22142 #0<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google<br /> 04/28/2023<br /> Workqueue: usb_hub_wq hub_event<br /> RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504<br /> ...<br /> Call Trace:<br /> <br /> dlfb_submit_urb+0x92/0x180 drivers/video/fbdev/udlfb.c:1980<br /> dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315<br /> dlfb_ops_set_par+0x2a7/0x8d0 drivers/video/fbdev/udlfb.c:1111<br /> dlfb_usb_probe+0x149a/0x2710 drivers/video/fbdev/udlfb.c:1743<br /> <br /> The current approach for this issue failed to catch the problem<br /> because it only checks for the existence of a bulk-OUT endpoint; it<br /> doesn&amp;#39;t check whether this endpoint is the one that the driver will<br /> actually use.<br /> <br /> We can fix the problem by instead checking that the endpoint used by<br /> the driver does exist and is bulk-OUT.