Bug 2373496 (CVE-2022-50221) - CVE-2022-50221 kernel: drm/fb-helper: Fix out-of-bounds access
Summary: CVE-2022-50221 kernel: drm/fb-helper: Fix out-of-bounds access
Keywords:
Status: NEW
Alias: CVE-2022-50221
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-06-18 12:05 UTC by OSIDB Bzimport
Modified: 2025-06-19 22:34 UTC (History)
4 users (show)

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


Attachments (Terms of Use)

Description OSIDB Bzimport 2025-06-18 12:05:35 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/fb-helper: Fix out-of-bounds access

Clip memory range to screen-buffer size to avoid out-of-bounds access
in fbdev deferred I/O's damage handling.

Fbdev's deferred I/O can only track pages. From the range of pages, the
damage handler computes the clipping rectangle for the display update.
If the fbdev screen buffer ends near the beginning of a page, that page
could contain more scanlines. The damage handler would then track these
non-existing scanlines as dirty and provoke an out-of-bounds access
during the screen update. Hence, clip the maximum memory range to the
size of the screen buffer.

While at it, rename the variables min/max to min_off/max_off in
drm_fb_helper_deferred_io(). This avoids confusion with the macros of
the same name.

Comment 1 Avinash Hanwate 2025-06-19 22:25:34 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061847-CVE-2022-50221-1b80@gregkh/T


Note You need to log in before you can comment on or make changes to this bug.