CVE-2022-49164 Affecting kernel-default-devel package, versions <5.14.21-150400.24.158.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-SLES154-KERNELDEFAULTDEVEL-9529377
- published27 Mar 2025
- disclosed26 Mar 2025
Introduced: 26 Mar 2025
NewCVE-2022-49164 (opens in a new tab)How to fix?
Upgrade SLES:15.4 kernel-default-devel to version 5.14.21-150400.24.158.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-default-devel package and not the kernel-default-devel package as distributed by SLES.
See How to fix? for SLES:15.4 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
powerpc/tm: Fix more userspace r13 corruption
Commit cf13435b730a ("powerpc/tm: Fix userspace r13 corruption") fixes a problem in treclaim where a SLB miss can occur on the thread_struct->ckpt_regs while SCRATCH0 is live with the saved user r13 value, clobbering it with the kernel r13 and ultimately resulting in kernel r13 being stored in ckpt_regs.
There is an equivalent problem in trechkpt where the user r13 value is loaded into r13 from chkpt_regs to be recheckpointed, but a SLB miss could occur on ckpt_regs accesses after that, which will result in r13 being clobbered with a kernel value and that will get recheckpointed and then restored to user registers.
The same memory page is accessed right before this critical window where a SLB miss could cause corruption, so hitting the bug requires the SLB entry be removed within a small window of instructions, which is possible if a SLB related MCE hits there. PAPR also permits the hypervisor to discard this SLB entry (because slb_shadow->persistent is only set to SLB_NUM_BOLTED) although it's not known whether any implementations would do this (KVM does not). So this is an extremely unlikely bug, only found by inspection.
Fix this by also storing user r13 in a temporary location on the kernel stack and don't change the r13 register from kernel r13 until the RI=0 critical section that does not fault.
The SCRATCH0 change is not strictly part of the fix, it's only used in the RI=0 section so it does not have the same problem as the previous SCRATCH0 bug.
References
- https://www.suse.com/security/cve/CVE-2022-49164.html
- https://bugzilla.suse.com/1238108
- https://git.kernel.org/stable/c/5dce84f475d13b773a1a4c823581cab25044d86a
- https://git.kernel.org/stable/c/73d8082c90f17dfba57cad4ca94db5cae323f1b1
- https://git.kernel.org/stable/c/9d71165d3934e607070c4e48458c0cf161b1baea