Bug 1217845

Summary: VUL-0: kernel: SLAM - Spectre based on Linear Address Masking
Product: [Novell Products] SUSE Security Incidents Reporter: Marcus Meissner <meissner>
Component: IncidentsAssignee: Nikolay Borisov <nik.borisov>
Status: NEW --- QA Contact: Security Team bot <security-team>
Severity: Normal    
Priority: P3 - Medium CC: andrea.porta, ivan.ivanov, mbenes, mhocko, nborisov, stanimir.varbanov
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/387195/
Whiteboard:
Found By: --- Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description Marcus Meissner 2023-12-06 09:52:52 UTC 
A vulnerability in closed source CPUs which open source OSes may need
to mitigate was disclosed today:

https://www.vusec.net/projects/slam/
https://github.com/vusec/slam
https://www.youtube.com/watch?v=y4wZ-tREaNk
https://x.com/vu5ec/status/1732099516621521003

The first page lists these processors as affected:

    - Existing AMD CPUs vulnerable to CVE-2020-12965;
    - Future Intel CPUs supporting LAM (both 4- and 5-level paging);
    - Future AMD CPUs supporting UAI and 5-level paging;
    - Future Arm CPUs supporting TBI and 5-level paging.

as it takes advantage of CPU features which allow masking off some bits of
pointer addresses to store additional data in, such as Intel’s Linear Address
Masking (LAM), AMD’s Upper Address Ignore (UAI), or ARM's Top-byte Ignore (TBI).
Comment 1 Marcus Meissner 2023-12-06 13:10:02 UTC 
We are a bit thin on mitigation possibilities.

Some will happen in the future CPUs hopefully.

Source level wise throwing in more lfences is not really feasible.