Bug 1221380 (CVE-2024-26630)

Summary:	VUL-0: CVE-2024-26630: kernel: mm: cachestat: fix folio read-after-free in cache walk
Product:	[Novell Products] SUSE Security Incidents	Reporter:	SMASH SMASH <smash_bz>
Component:	Incidents	Assignee:	Kernel Bugs <kernel-bugs>
Status:	RESOLVED FIXED	QA Contact:	Security Team bot <security-team>
Severity:	Normal
Priority:	P5 - None	CC:	rfrohl
Version:	unspecified
Target Milestone:	---
Hardware:	Other
OS:	Other
URL:	https://smash.suse.de/issue/397558/
Whiteboard:
Found By:	Security Response Team	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description SMASH SMASH 2024-03-14 08:23:46 UTC

In the Linux kernel, the following vulnerability has been resolved:

mm: cachestat: fix folio read-after-free in cache walk

In cachestat, we access the folio from the page cache's xarray to compute
its page offset, and check for its dirty and writeback flags.  However, we
do not hold a reference to the folio before performing these actions,
which means the folio can concurrently be released and reused as another
folio/page/slab.

Get around this altogether by just using xarray's existing machinery for
the folio page offsets and dirty/writeback states.

This changes behavior for tmpfs files to now always report zeroes in their
dirty and writeback counters.  This is okay as tmpfs doesn't follow
conventional writeback cache behavior: its pages get "cleaned" during
swapout, after which they're no longer resident etc.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-26630
https://www.cve.org/CVERecord?id=CVE-2024-26630
https://git.kernel.org/stable/c/3a75cb05d53f4a6823a32deb078de1366954a804
https://git.kernel.org/stable/c/ba60fdf75e89ea762bb617be578dc47f27655117
https://git.kernel.org/stable/c/fe7e008e0ce728252e4ec652cceebcc62211657c
https://bugzilla.redhat.com/show_bug.cgi?id=2269436

Comment 1 Robert Frohl 2024-03-14 08:34:55 UTC

not relevant for SLE and pending release to users from openSUSE Factory, closing