Описание
Security update for xen
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).
Список пакетов
SUSE Linux Enterprise Server 12 SP2-BCL
SUSE Linux Enterprise Server 12 SP2-LTSS
SUSE Linux Enterprise Server for SAP Applications 12 SP2
SUSE OpenStack Cloud 7
Ссылки
- Link for SUSE-SU-2020:0334-1
- E-Mail link for SUSE-SU-2020:0334-1
- SUSE Security Ratings
- SUSE Bug 1152497
- SUSE Bug 1154448
- SUSE Bug 1154456
- SUSE Bug 1154458
- SUSE Bug 1154461
- SUSE Bug 1155945
- SUSE Bug 1157888
- SUSE Bug 1158003
- SUSE Bug 1158004
- SUSE Bug 1158005
- SUSE Bug 1158006
- SUSE Bug 1158007
- SUSE Bug 1161181
- SUSE CVE CVE-2018-12207 page
- SUSE CVE CVE-2019-11135 page
- SUSE CVE CVE-2019-18420 page
- SUSE CVE CVE-2019-18421 page
Описание
Improper invalidation for page table updates by a virtual guest operating system for multiple Intel(R) Processors may allow an authenticated user to potentially enable denial of service of the host system via local access.
Затронутые продукты
Ссылки
- CVE-2018-12207
- SUSE Bug 1117665
- SUSE Bug 1139073
- SUSE Bug 1152505
- SUSE Bug 1155812
- SUSE Bug 1155817
- SUSE Bug 1155945
- SUSE Bug 1178658
- SUSE Bug 1201877
Описание
TSX Asynchronous Abort condition on some CPUs utilizing speculative execution may allow an authenticated user to potentially enable information disclosure via a side channel with local access.
Затронутые продукты
Ссылки
- CVE-2019-11135
- SUSE Bug 1139073
- SUSE Bug 1152497
- SUSE Bug 1152505
- SUSE Bug 1152506
- SUSE Bug 1160120
- SUSE Bug 1201877
Описание
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via a VCPUOP_initialise hypercall. hypercall_create_continuation() is a variadic function which uses a printf-like format string to interpret its parameters. Error handling for a bad format character was done using BUG(), which crashes Xen. One path, via the VCPUOP_initialise hypercall, has a bad format character. The BUG() can be hit if VCPUOP_initialise executes for a sufficiently long period of time for a continuation to be created. Malicious guests may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen versions 4.6 and newer are vulnerable. Xen versions 4.5 and earlier are not vulnerable. Only x86 PV guests can exploit the vulnerability. HVM and PVH guests, and guests on ARM systems, cannot exploit the vulnerability.
Затронутые продукты
Ссылки
- CVE-2019-18420
- SUSE Bug 1154448
Описание
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations. There are issues with restartable PV type change operations. To avoid using shadow pagetables for PV guests, Xen exposes the actual hardware pagetables to the guest. In order to prevent the guest from modifying these page tables directly, Xen keeps track of how pages are used using a type system; pages must be "promoted" before being used as a pagetable, and "demoted" before being used for any other type. Xen also allows for "recursive" promotions: i.e., an operating system promoting a page to an L4 pagetable may end up causing pages to be promoted to L3s, which may in turn cause pages to be promoted to L2s, and so on. These operations may take an arbitrarily large amount of time, and so must be re-startable. Unfortunately, making recursive pagetable promotion and demotion operations restartable is incredibly complicated, and the code contains several races which, if triggered, can cause Xen to drop or retain extra type counts, potentially allowing guests to get write access to in-use pagetables. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All x86 systems with untrusted PV guests are vulnerable. HVM and PVH guests cannot exercise this vulnerability.
Затронутые продукты
Ссылки
- CVE-2019-18421
- SUSE Bug 1154458
- SUSE Bug 1178658
Описание
An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a situation where an untrusted domain has access to a physical device. This occurs because passed through PCI devices may corrupt host memory after deassignment. When a PCI device is assigned to an untrusted domain, it is possible for that domain to program the device to DMA to an arbitrary address. The IOMMU is used to protect the host from malicious DMA by making sure that the device addresses can only target memory assigned to the guest. However, when the guest domain is torn down, or the device is deassigned, the device is assigned back to dom0, thus allowing any in-flight DMA to potentially target critical host data. An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. Only systems where guests are given direct access to physical devices capable of DMA (PCI pass-through) are vulnerable. Systems which do not use PCI pass-through are not vulnerable.
Затронутые продукты
Ссылки
- CVE-2019-18424
- SUSE Bug 1154461
Описание
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.
Затронутые продукты
Ссылки
- CVE-2019-18425
- SUSE Bug 1154456
- SUSE Bug 1178658
Описание
An issue was discovered in Xen through 4.12.x allowing x86 AMD HVM guest OS users to cause a denial of service or possibly gain privileges by triggering data-structure access during pagetable-height updates. When running on AMD systems with an IOMMU, Xen attempted to dynamically adapt the number of levels of pagetables (the pagetable height) in the IOMMU according to the guest's address space size. The code to select and update the height had several bugs. Notably, the update was done without taking a lock which is necessary for safe operation. A malicious guest administrator can cause Xen to access data structures while they are being modified, causing Xen to crash. Privilege escalation is thought to be very difficult but cannot be ruled out. Additionally, there is a potential memory leak of 4kb per guest boot, under memory pressure. Only Xen on AMD CPUs is vulnerable. Xen running on Intel CPUs is not vulnerable. ARM systems are not vulnerable. Only systems where guests are given direct access to physical devices are vulnerable. Systems which do not use PCI pass-through are not vulnerable. Only HVM guests can exploit the vulnerability. PV and PVH guests cannot. All versions of Xen with IOMMU support are vulnerable.
Затронутые продукты
Ссылки
- CVE-2019-19577
- SUSE Bug 1158007
Описание
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via degenerate chains of linear pagetables, because of an incorrect fix for CVE-2017-15595. "Linear pagetables" is a technique which involves either pointing a pagetable at itself, or to another pagetable of the same or higher level. Xen has limited support for linear pagetables: A page may either point to itself, or point to another pagetable of the same level (i.e., L2 to L2, L3 to L3, and so on). XSA-240 introduced an additional restriction that limited the "depth" of such chains by allowing pages to either *point to* other pages of the same level, or *be pointed to* by other pages of the same level, but not both. To implement this, we keep track of the number of outstanding times a page points to or is pointed to another page table, to prevent both from happening at the same time. Unfortunately, the original commit introducing this reset this count when resuming validation of a partially-validated pagetable, incorrectly dropping some "linear_pt_entry" counts. If an attacker could engineer such a situation to occur, they might be able to make loops or other arbitrary chains of linear pagetables, as described in XSA-240. A malicious or buggy PV guest may cause the hypervisor to crash, resulting in Denial of Service (DoS) affecting the entire host. Privilege escalation and information leaks cannot be excluded. All versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Only systems which have enabled linear pagetables are vulnerable. Systems which have disabled linear pagetables, either by selecting CONFIG_PV_LINEAR_PT=n when building the hypervisor, or adding pv-linear-pt=false on the command-line, are not vulnerable.
Затронутые продукты
Ссылки
- CVE-2019-19578
- SUSE Bug 1158005
- SUSE Bug 1178658
Описание
An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a situation where an untrusted domain has access to a physical device (and assignable-add is not used), because of an incomplete fix for CVE-2019-18424. XSA-302 relies on the use of libxl's "assignable-add" feature to prepare devices to be assigned to untrusted guests. Unfortunately, this is not considered a strictly required step for device assignment. The PCI passthrough documentation on the wiki describes alternate ways of preparing devices for assignment, and libvirt uses its own ways as well. Hosts where these "alternate" methods are used will still leave the system in a vulnerable state after the device comes back from a guest. An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. Only systems where guests are given direct access to physical devices capable of DMA (PCI pass-through) are vulnerable. Systems which do not use PCI pass-through are not vulnerable.
Затронутые продукты
Ссылки
- CVE-2019-19579
- SUSE Bug 1157888
Описание
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations, because of an incomplete fix for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations. Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All security-supported versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Note that these attacks require very precise timing, which may be difficult to exploit in practice.
Затронутые продукты
Ссылки
- CVE-2019-19580
- SUSE Bug 1158006
- SUSE Bug 1178658
Описание
An issue was discovered in Xen through 4.12.x allowing 32-bit Arm guest OS users to cause a denial of service (out-of-bounds access) because certain bit iteration is mishandled. In a number of places bitmaps are being used by the hypervisor to track certain state. Iteration over all bits involves functions which may misbehave in certain corner cases: On 32-bit Arm accesses to bitmaps with bit a count which is a multiple of 32, an out of bounds access may occur. A malicious guest may cause a hypervisor crash or hang, resulting in a Denial of Service (DoS). All versions of Xen are vulnerable. 32-bit Arm systems are vulnerable. 64-bit Arm systems are not vulnerable.
Затронутые продукты
Ссылки
- CVE-2019-19581
- SUSE Bug 1158003
Описание
An issue was discovered in Xen through 4.12.x allowing x86 HVM/PVH guest OS users to cause a denial of service (guest OS crash) because VMX VMEntry checks mishandle a certain case. Please see XSA-260 for background on the MovSS shadow. Please see XSA-156 for background on the need for #DB interception. The VMX VMEntry checks do not like the exact combination of state which occurs when #DB in intercepted, Single Stepping is active, and blocked by STI/MovSS is active, despite this being a legitimate state to be in. The resulting VMEntry failure is fatal to the guest. HVM/PVH guest userspace code may be able to crash the guest, resulting in a guest Denial of Service. All versions of Xen are affected. Only systems supporting VMX hardware virtual extensions (Intel, Cyrix, or Zhaoxin CPUs) are affected. Arm and AMD systems are unaffected. Only HVM/PVH guests are affected. PV guests cannot leverage the vulnerability.
Затронутые продукты
Ссылки
- CVE-2019-19583
- SUSE Bug 1158004
- SUSE Bug 1178658
Описание
tftp.c in libslirp 4.1.0, as used in QEMU 4.2.0, does not prevent ..\ directory traversal on Windows.
Затронутые продукты
Ссылки
- CVE-2020-7211
- SUSE Bug 1161180
- SUSE Bug 1161181
- SUSE Bug 1178658