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

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cve-icon MITRE Information

Status: PUBLISHED

Assigner: Google

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

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

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


Link: CVE-2023-0045

JSON object: View

cve-icon NVD Information

Status : Analyzed

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

Modified: 2023-08-11T19:53:56.443


Link: CVE-2023-0045

JSON object: View

cve-icon Redhat Information

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CWE