Bug 2426041 (CVE-2023-54277) - CVE-2023-54277 kernel: fbdev: udlfb: Fix endpoint check
Summary: CVE-2023-54277 kernel: fbdev: udlfb: Fix endpoint check
Keywords:
Status: NEW
Alias: CVE-2023-54277
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-12-30 13:04 UTC by OSIDB Bzimport
Modified: 2025-12-31 13:41 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2025-12-30 13:04:12 UTC
In the Linux kernel, the following vulnerability has been resolved:

fbdev: udlfb: Fix endpoint check

The syzbot fuzzer detected a problem in the udlfb driver, caused by an
endpoint not having the expected type:

usb 1-1: Read EDID byte 0 failed: -71
usb 1-1: Unable to get valid EDID from device/display
------------[ cut here ]------------
usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 9 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880
drivers/usb/core/urb.c:504
Modules linked in:
CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted
6.4.0-rc1-syzkaller-00016-ga4422ff22142 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
04/28/2023
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
...
Call Trace:
 <TASK>
 dlfb_submit_urb+0x92/0x180 drivers/video/fbdev/udlfb.c:1980
 dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315
 dlfb_ops_set_par+0x2a7/0x8d0 drivers/video/fbdev/udlfb.c:1111
 dlfb_usb_probe+0x149a/0x2710 drivers/video/fbdev/udlfb.c:1743

The current approach for this issue failed to catch the problem
because it only checks for the existence of a bulk-OUT endpoint; it
doesn't check whether this endpoint is the one that the driver will
actually use.

We can fix the problem by instead checking that the endpoint used by
the driver does exist and is bulk-OUT.


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