CVE-2018-12891

An issue was discovered in Xen through 4.10.x. Certain PV MMU operations may take a long time to process. For that reason Xen explicitly checks for the need to preempt the current vCPU at certain points. A few rarely taken code paths did bypass such checks. By suitably enforcing the conditions through its own page table contents, a malicious guest may cause such bypasses to be used for an unbounded number of iterations. A malicious or buggy PV guest may cause a Denial of Service (DoS) affecting the entire host. Specifically, it may prevent use of a physical CPU for an indeterminate period of time. All Xen versions from 3.4 onwards are vulnerable. Xen versions 3.3 and earlier are vulnerable to an even wider class of attacks, due to them lacking preemption checks altogether in the affected code paths. Only x86 systems are affected. ARM systems are not affected. Only multi-vCPU x86 PV guests can leverage the vulnerability. x86 HVM or PVH guests as well as x86 single-vCPU PV ones cannot leverage the vulnerability.

An issue was discovered in Xen through 4.10.x. Certain PV MMU operations may take a long time to process. For that reason Xen explicitly checks for the need to preempt the current vCPU at certain points. A few rarely taken code paths did bypass such checks. By suitably enforcing the conditions through its own page table contents, a malicious guest may cause such bypasses to be used for an unbounded number of iterations. A malicious or buggy PV guest may cause a Denial of Service (DoS) affecting the entire host. Specifically, it may prevent use of a physical CPU for an indeterminate period of time. All Xen versions from 3.4 onwards are vulnerable. Xen versions 3.3 and earlier are vulnerable to an even wider class of attacks, due to them lacking preemption checks altogether in the affected code paths. Only x86 systems are affected. ARM systems are not affected. Only multi-vCPU x86 PV guests can leverage the vulnerability. x86 HVM or PVH guests as well as x86 single-vCPU PV ones cannot leverage the vulnerability.

These are all security issues fixed in the xen-4.15.1_01-1.2 package on the GA media of openSUSE Tumbleweed.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-3665: Fix Lazy FP Save/Restore issue (XSA-267) (bsc#1095242).
• CVE-2018-12891: Fix possible Denial of Service (DoS) via certain PV MMU operations that affect the entire host (XSA-264) (bsc#1097521).
• CVE-2018-12892: Fix libxl to honour the readonly flag on HVM emulated SCSI disks (XSA-266) (bsc#1097523).
• CVE-2018-12893: Fix crash/Denial of Service (DoS) via safety check (XSA-265) (bsc#1097522).

Bug fixes:

• bsc#1027519: Add upstream patches from January.
• bsc#1098403: Fix regression introduced by changes for bsc#1079730. A PV domU without qcow2 and/or vfb has no qemu attached. Ignore QMP errors for PV domUs to handle PV domUs with and without an attached qemu-xen.
• bsc#1087289: Fix xen scheduler crash.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-12617: Fix integer overflow that causes segmentation fault in qmp_guest_file_read() with g_malloc() (bsc#1098744).
• CVE-2018-3665: Fix Lazy FP Save/Restore issue (XSA-267) (bsc#1095242).
• CVE-2018-11806: Fix heap buffer overflow while reassembling fragmented datagrams (bsc#1096224).
• CVE-2018-12891: Fix possible Denial of Service (DoS) via certain PV MMU operations that affect the entire host (XSA-264) (bsc#1097521).
• CVE-2018-12893: Fix crash/Denial of Service (DoS) via safety check (XSA-265) (bsc#1097522).

Bug fixes:

• bsc#1079730: Fix failed 'write' lock.
• bsc#1027519: Add upstream patches from January.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-12617: Fix integer overflow that causes segmentation fault in qmp_guest_file_read() with g_malloc() (bsc#1098744).
• CVE-2018-3665: Fix Lazy FP Save/Restore issue (XSA-267) (bsc#1095242).
• CVE-2018-11806: Fix heap buffer overflow while reassembling fragmented datagrams (bsc#1096224).
• CVE-2018-12891: Fix possible Denial of Service (DoS) via certain PV MMU operations that affect the entire host (XSA-264) (bsc#1097521).
• CVE-2018-12893: Fix crash/Denial of Service (DoS) via safety check (XSA-265) (bsc#1097522).

Bug fixes:

• bsc#1079730: Fix failed 'write' lock.
• bsc#1027519: Add upstream patches from January.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-3665: Fix Lazy FP Save/Restore issue (XSA-267) (bsc#1095242).
• CVE-2018-12891: Fix possible Denial of Service (DoS) via certain PV MMU operations that affect the entire host (XSA-264) (bsc#1097521).
• CVE-2018-12892: Fix libxl to honour the readonly flag on HVM emulated SCSI disks (XSA-266) (bsc#1097523).
• CVE-2018-12893: Fix crash/Denial of Service (DoS) via safety check (XSA-265) (bsc#1097522).
• CVE-2018-11806: Fix heap buffer overflow while reassembling fragmented datagrams (bsc#1096224).

Bug fixes:

• bsc#1027519: Add upstream patches from January.
• bsc#1087289: Fix xen scheduler crash.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-12617: Fix integer overflow that causes segmentation fault in qmp_guest_file_read() with g_malloc() (bsc#1098744).
• CVE-2018-3665: Fix Lazy FP Save/Restore issue (XSA-267) (bsc#1095242).
• CVE-2018-11806: Fix heap buffer overflow while reassembling fragmented datagrams (bsc#1096224).
• CVE-2018-12891: Fix possible Denial of Service (DoS) via certain PV MMU operations that affect the entire host (XSA-264) (bsc#1097521).
• CVE-2018-12893: Fix crash/Denial of Service (DoS) via safety check (XSA-265) (bsc#1097522).

Bug fixes:

• bsc#1079730: Fix failed 'write' lock.
• bsc#1027519: Add upstream patches from January.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-12891: Fix preemption checks bypass in x86 PV MM handling (XSA-264) (bsc#1097521).
• CVE-2018-12892: Fix libxl failure to honour readonly flag on HVM emulated SCSI disks (XSA-266) (bsc#1097523).
• CVE-2018-12893: Fix #DB exception safety check that could be triggered by a guest (XSA-265) (bsc#1097522).
• CVE-2018-11806: Fix heap buffer overflow while reassembling fragmented datagrams (bsc#1096224).
• CVE-2018-3665: Fix lazy FP Save/Restore (XSA-267) (bsc#1095242).

Bug fixes:

• bsc#1027519: Update to Xen 4.7.6 bug fix only release.
• bsc#1087289: Xen BUG at sched_credit.c:1663.
• bsc#1094725: virsh blockresize does not work with Xen qdisks.

This update for xen fixes the following issues:

Security issues fixed:

• CVE-2018-12891: Fix preemption checks bypass in x86 PV MM handling (XSA-264) (bsc#1097521).
• CVE-2018-12892: Fix libxl failure to honour readonly flag on HVM emulated SCSI disks (XSA-266) (bsc#1097523).
• CVE-2018-12893: Fix #DB exception safety check that could be triggered by a guest (XSA-265) (bsc#1097522).
• CVE-2018-11806: Fix heap buffer overflow while reassembling fragmented datagrams (bsc#1096224).
• CVE-2018-3665: Fix lazy FP Save/Restore (XSA-267) (bsc#1095242).

Bug fixes:

• bsc#1027519: Update to Xen 4.7.6 bug fix only release.
• bsc#1087289: Xen BUG at sched_credit.c:1663.
• bsc#1094725: virsh blockresize does not work with Xen qdisks.

This update for xen fixes the following issues:

These security issue were fixed:

• CVE-2018-3646: Systems with microprocessors utilizing speculative execution and address translations may have allowed unauthorized disclosure of information residing in the L1 data cache to an attacker with local user access with guest OS privilege via a terminal page fault and a side-channel analysis (bsc#1091107, bsc#1027519).
• CVE-2018-12617: An integer overflow that could cause a segmentation fault in qmp_guest_file_read() with g_malloc() in qemu-guest-agent was fixed (bsc#1098744)
• CVE-2018-3665: System software utilizing Lazy FP state restore technique on systems using Intel Core-based microprocessors may potentially allow a local process to infer data from another process through a speculative execution side channel. (bsc#1095242)
• CVE-2018-3639: Systems with microprocessors utilizing speculative execution and speculative execution of memory reads before the addresses of all prior memory writes are known may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis, aka Speculative Store Bypass (SSB), Variant 4. (bsc#1092631)
• CVE-2017-5715: Systems with microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis. (bsc#1074562)
• CVE-2017-5753: Systems with microprocessors utilizing speculative execution and branch prediction may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis. (bsc#1074562)
• CVE-2017-5754: Systems with microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis of the data cache. (bsc#1074562)
• CVE-2018-12891: Certain PV MMU operations may take a long time to process. For that reason Xen explicitly checks for the need to preempt the current vCPU at certain points. A few rarely taken code paths did bypass such checks. By suitably enforcing the conditions through its own page table contents, a malicious guest may cause such bypasses to be used for an unbounded number of iterations. A malicious or buggy PV guest may cause a Denial of Service (DoS) affecting the entire host. Specifically, it may prevent use of a physical CPU for an indeterminate period of time. (bsc#1097521)
• CVE-2018-12893: One of the fixes in XSA-260 added some safety checks to help prevent Xen livelocking with debug exceptions. Unfortunately, due to an oversight, at least one of these safety checks can be triggered by a guest. A malicious PV guest can crash Xen, leading to a Denial of Service. Only x86 PV guests can exploit the vulnerability. x86 HVM and PVH guests cannot exploit the vulnerability. An attacker needs to be able to control hardware debugging facilities to exploit the vulnerability, but such permissions are typically available to unprivileged users. (bsc#1097522)
• CVE-2018-11806: m_cat in slirp/mbuf.c in Qemu has a heap-based buffer overflow via incoming fragmented datagrams. (bsc#1096224)
• CVE-2018-10982: An issue was discovered in Xen allowed x86 HVM guest OS users to cause a denial of service (unexpectedly high interrupt number, array overrun, and hypervisor crash) or possibly gain hypervisor privileges by setting up an HPET timer to deliver interrupts in IO-APIC mode, aka vHPET interrupt injection. (bsc#1090822)
• CVE-2018-10981: An issue was discovered in Xen that allowed x86 HVM guest OS users to cause a denial of service (host OS infinite loop) in situations where a QEMU device model attempts to make invalid transitions between states of a request. (bsc#1090823)

Following bugs were fixed:

• After updating to kernel 3.0.101-0.47.106.32-xen system crashes in…