CVE-2019-18425

An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.

An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.

• Updated from 4.12.0 to 4.12.1
• Device quarantine for alternate pci assignment methods [XSA-306]
• x86: Machine Check Error on Page Size Change DoS [XSA-304, CVE-2018-12207]
• TSX Asynchronous Abort speculative side channel [XSA-305, CVE-2019-11135]
• VCPUOP_initialise DoS [XSA-296, CVE-2019-18420] (rhbz#1771368)
• missing descriptor table limit checking in x86 PV emulation [XSA-298, CVE-2019-18425] (rhbz#1771341)
• Issues with restartable PV type change operations [XSA-299, CVE-2019-18421] (rhbz#1767726)
• add-to-physmap can be abused to DoS Arm hosts [XSA-301, CVE-2019-18423] (rhbz#1771345)
• passed through PCI devices may corrupt host memory after deassignment [XSA-302, CVE-2019-18424] (rhbz#1767731)
• ARM: Interrupts are unconditionally unmasked in exception handlers [XSA-303, CVE-2019-18422] (rhbz#1771443)
• Unlimited Arm Atomics Operations [XSA-295, CVE-2019-17349, CVE-2019-17350] (rhbz#1720760)
• fix HVM DomU boot on some chipsets
• adjust grub2 workaround

This update for xen fixes the following issues:

• CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945)
• CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497).
• CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456).
• CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458).
• CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a Denial of Service (Dos). (bsc#1154448)

This update was imported from the SUSE:SLE-15:Update update project.

This update for xen fixes the following issues:

• CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945)
• CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497).
• CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456).
• CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458).
• CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a Denial of Service (Dos). (bsc#1154448)

This update for xen fixes the following issues:

• CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945)
• CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497).
• CVE-2019-18423: A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). (bsc#1154460).
• CVE-2019-18422: A malicious ARM guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified. (bsc#1154464)
• CVE-2019-18424: An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. (bsc#1154461).
• CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458).
• CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456).
• CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a Denial of Service (Dos). (bsc#1154448)
• Upstream bug fixes (bsc#1027519)

This update for xen fixes the following issues:

• CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945)
• CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497).
• CVE-2019-18424: An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. (bsc#1154461).
• CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458).
• CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456).
• CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a Denial of Service (Dos). (bsc#1154448)

This update for xen fixes the following issues:

• CVE-2019-19581: Fixed a potential out of bounds on 32-bit Arm (bsc#1158003 XSA-307).
• CVE-2019-19582: Fixed a potential infinite loop when x86 accesses to bitmaps with a compile time known size of 64 (bsc#1158003 XSA-307).
• CVE-2019-19583: Fixed improper checks which could have allowed HVM/PVH guest userspace code to crash the guest,leading to a guest denial of service (bsc#1158004 XSA-308).
• CVE-2019-19578: Fixed an issue where a malicious or buggy PV guest could have caused hypervisor crash resulting in denial of service affecting the entire host (bsc#1158005 XSA-309).
• CVE-2019-19580: Fixed a privilege escalation where a malicious PV guest administrator could have been able to escalate their privilege to that of the host (bsc#1158006 XSA-310).
• CVE-2019-19577: Fixed an issue where a malicious guest administrator could have caused Xen to access data structures while they are being modified leading to a crash (bsc#1158007 XSA-311).
• CVE-2019-19579: Fixed a privilege escaltion where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).
• CVE-2019-18420: Malicious x86 PV guests may have caused a hypervisor crash, resulting in a denial of service (bsc#1154448 XSA-296)
• CVE-2019-18425: 32-bit PV guest user mode could elevate its privileges to that of the guest kernel. (bsc#1154456 XSA-298).
• CVE-2019-18421: A malicious PV guest administrator may have been able to escalate their privilege to that of the host. (bsc#1154458 XSA-299).
• CVE-2019-18423: A malicious guest administrator may cause a hypervisor crash, resulting in a denial of service (bsc#1154460 XSA-301).
• CVE-2019-18422: A malicious ARM guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption, denial of service, or possibly even privilege escalation. However a precise attack technique has not been identified. (bsc#1154464 XSA-303)
• CVE-2019-18424: An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. (bsc#1154461 XSA-302).
• CVE-2018-12207: Untrusted virtual machines on Intel CPUs could exploit a race condition in the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional. (bsc#1155945 XSA-304)
• CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate sidechannel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497 XSA-305).

This update for xen fixes the following issues:

• CVE-2020-7211: potential directory traversal using relative paths via tftp server on Windows host (bsc#1161181).
• CVE-2019-19579: Device quarantine for alternate pci assignment methods (bsc#1157888).
• CVE-2019-19581: find_next_bit() issues (bsc#1158003).
• CVE-2019-19583: VMentry failure with debug exceptions and blocked states (bsc#1158004).
• CVE-2019-19578: Linear pagetable use / entry miscounts (bsc#1158005).
• CVE-2019-19580: Further issues with restartable PV type change operations (bsc#1158006).
• CVE-2019-19577: dynamic height for the IOMMU pagetables (bsc#1158007).
• CVE-2019-18420: VCPUOP_initialise DoS (bsc#1154448).
• CVE-2019-18425: missing descriptor table limit checking in x86 PV emulation (bsc#1154456).
• CVE-2019-18421: Issues with restartable PV type change operations (bsc#1154458).
• CVE-2019-18424: passed through PCI devices may corrupt host memory after deassignment (bsc#1154461).
• CVE-2018-12207: Machine Check Error Avoidance on Page Size Change (aka IFU issue) (bsc#1155945).
• CVE-2019-11135: TSX Asynchronous Abort (TAA) issue (bsc#1152497).

This update for xen fixes the following issues:

• CVE-2018-12207: Fixed a race condition where untrusted virtual machines could have been using the Instruction Fetch Unit of the Intel CPU to cause a Machine Exception during Page Size Change, causing the CPU core to be non-functional (bsc#1155945 XSA-304).
• CVE-2018-19965: Fixed a DoS from attempting to use INVPCID with a non-canonical addresses (bsc#1115045 XSA-279).
• CVE-2019-11135: Aborting an asynchronous TSX operation on Intel CPUs with Transactional Memory support could be used to facilitate side-channel information leaks out of microarchitectural buffers, similar to the previously described 'Microarchitectural Data Sampling' attack. (bsc#1152497 XSA-305).
• CVE-2019-12067: Fixed a null pointer dereference in QEMU AHCI (bsc#1145652).
• CVE-2019-12068: Fixed an infinite loop while executing script (bsc#1146874).
• CVE-2019-12155: Fixed a null pointer dereference while releasing spice resources (bsc#1135905).
• CVE-2019-14378: Fixed a heap buffer overflow during packet reassembly in slirp networking implementation (bsc#1143797).
• CVE-2019-15890: Fixed a use-after-free during packet reassembly (bsc#1149813).
• CVE-2019-17340: Fixed grant table transfer issues on large hosts (XSA-284 bsc#1126140).
• CVE-2019-17341: Fixed a race with pass-through device hotplug (XSA-285 bsc#1126141).
• CVE-2019-17342: Fixed steal_page violating page_struct access discipline (XSA-287 bsc#1126192).
• CVE-2019-17343: Fixed an inconsistent PV IOMMU discipline (XSA-288 bsc#1126195).
• CVE-2019-17344: Fixed a missing preemption in x86 PV page table unvalidation (XSA-290 bsc#1126196).
• CVE-2019-17347: Fixed a PV kernel context switch corruption (XSA-293 bsc#1126201).
• CVE-2019-18420: Fixed a hypervisor crash that could be caused by malicious x86 PV guests, resulting in a denial of service (bsc#1154448 XSA-296).
• CVE-2019-18421: Fixed a privilege escalation through malicious PV guest administrators (bsc#1154458 XSA-299).
• CVE-2019-18424: Fixed a privilege escalation through DMA to physical devices by untrusted domains (bsc#1154461 XSA-302).
• CVE-2019-18425: Fixed a privilege escalation from 32-bit PV guest used mode (bsc#1154456 XSA-298).
• CVE-2019-19577: Fixed an issue where a malicious guest administrator could have caused Xen to access data structures while they are being modified leading to a crash (bsc#1158007 XSA-311).
• CVE-2019-19578: Fixed an issue where a malicious or buggy PV guest could have caused hypervisor crash resulting in denial of service affecting the entire host (bsc#1158005 XSA-309).
• CVE-2019-19579: Fixed a privilege escalation where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).
• CVE-2019-19580: Fixed a privilege escalation where a malicious PV guest administrator could have been able to escalate their privilege to that of the host (bsc#1158006 XSA-310).
• CVE-2019-19581: Fixed a potential out of bounds on 32-bit Arm (bsc#1158003 XSA-307).
• CVE-2019-19583: Fixed improper checks which could have allowed HVM/PVH guest userspace code to crash the guest, leading to a guest denial of service (bsc#1158004 XSA-308).

This update for xen fixes the following issues:

• bsc#1174543 - secure boot related fixes
• bsc#1163019 - CVE-2020-8608: potential OOB access due to unsafe snprintf() usages
• bsc#1169392 - CVE-2020-11742: Bad continuation handling in GNTTABOP_copy
• bsc#1168140 - CVE-2020-11740, CVE-2020-11741: multiple xenoprof issues
• bsc#1161181 - CVE-2020-7211: potential directory traversal using relative paths via tftp server on Windows host
• bsc#1157888 - CVE-2019-19579: Device quarantine for alternate pci assignment methods
• bsc#1158004 - CVE-2019-19583: VMX: VMentry failure with debug exceptions and blocked states
• bsc#1158005 - CVE-2019-19578: Linear pagetable use / entry miscounts
• bsc#1158006 - CVE-2019-19580: Further issues with restartable PV type change operations
• bsc#1158007 - CVE-2019-19577: dynamic height for the IOMMU pagetables
• bsc#1154448 - CVE-2019-18420: VCPUOP_initialise DoS
• bsc#1154456 - CVE-2019-18425: missing descriptor table limit checking in x86 PV emulation
• bsc#1154458 - CVE-2019-18421: Issues with restartable PV type change operations
• bsc#1154461 - CVE-2019-18424: passed through PCI devices may corrupt host memory after deassignment
• bsc#1155945 - CVE-2018-12207: Machine Check Error Avoidance on Page Size Change (aka IFU issue)
• bsc#1152497 - CVE-2019-11135: TSX Asynchronous Abort (TAA) issue

This update for xen fixes the following issues:

• bsc#1174543 - secure boot related fixes
• bsc#1163019 - CVE-2020-8608: potential OOB access due to unsafe snprintf() usages
• bsc#1169392 - CVE-2020-11742: Bad continuation handling in GNTTABOP_copy
• bsc#1168140 - CVE-2020-11740, CVE-2020-11741: multiple xenoprof issues
• bsc#1161181 - CVE-2020-7211: potential directory traversal using relative paths via tftp server on Windows host
• bsc#1154456 - CVE-2019-18425: missing descriptor table limit checking in x86 PV emulation
• bsc#1154458 - CVE-2019-18421: Issues with restartable PV type change operations