A flaw was found in the way the Linux kernel's KVM hypervisor handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, processor does not deliver interrupts and exceptions, they are delivered once the first instruction after the stack switch is executed. An unprivileged KVM guest user could use this flaw to crash the guest and/or potentially escalate their privileges in the guest. Upstream patch: --------------- -> https://git.kernel.org/linus/32d43cd391bacb5f0814c2624399a5dad3501d09 Reference: ---------- -> http://www.openwall.com/lists/oss-security/2018/05/08/5
Acknowledgments: Name: Andy Lutomirski
This issue was fixed for Fedora with the 4.16 rebases.
Statement: This issue does not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 5, 6, and Red Hat Enterprise MRG 2. This issue affects the version of the kernel package as shipped with Red Hat Enterprise Linux 7. Future kernel updates for Red Hat Enterprise Linux 7 may address this issue.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:1318 https://access.redhat.com/errata/RHSA-2018:1318
External References: https://access.redhat.com/security/vulnerabilities/pop_ss
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.4 Extended Update Support Via RHSA-2018:1345 https://access.redhat.com/errata/RHSA-2018:1345
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.2 Advanced Update Support Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions Red Hat Enterprise Linux 7.2 Telco Extended Update Support Via RHSA-2018:1347 https://access.redhat.com/errata/RHSA-2018:1347
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.3 Extended Update Support Via RHSA-2018:1348 https://access.redhat.com/errata/RHSA-2018:1348
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:1355 https://access.redhat.com/errata/RHSA-2018:1355
This issue has been addressed in the following products: Red Hat Virtualization 4 for RHEL-7 Via RHSA-2018:1524 https://access.redhat.com/errata/RHSA-2018:1524