The current implementation of the prctl syscall does not issue an IBPB immediately during the syscall. The ib_prctl_set  function updates the Thread Information Flags (TIFs) for the task and updates the SPEC_CTRL MSR on the function __speculation_ctrl_update, but the IBPB is only issued on the next schedule, when the TIF bits are checked. This leaves the victim vulnerable to values already injected on the BTB, prior to the prctl syscall.  The patch that added the support for the conditional mitigation via prctl (ib_prctl_set) dates back to the kernel 4.9.176. We recommend upgrading past commit a664ec9158eeddd75121d39c9a0758016097fa96
History

No history.

cve-icon MITRE

Status: PUBLISHED

Assigner: Google

Published: 2023-04-25T22:44:57.262Z

Updated: 2024-08-02T04:54:32.575Z

Reserved: 2023-01-04T10:07:20.469Z

Link: CVE-2023-0045

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2023-04-25T23:15:09.013

Modified: 2024-11-21T07:36:27.150

Link: CVE-2023-0045

cve-icon Redhat

Severity : Low

Publid Date: 2023-02-03T00:00:00Z

Links: CVE-2023-0045 - Bugzilla