Описание
Security update for xen
This update for xen fixes the following issues:
- CVE-2020-0543: Fixed a side channel attack against special registers which could have resulted in leaking of read values to cores other than the one which called it. This attack is known as Special Register Buffer Data Sampling (SRBDS) or 'CrossTalk' (bsc#1172205).
- CVE-2020-11742: Bad continuation handling in GNTTABOP_copy (bsc#1169392).
- CVE-2020-11740, CVE-2020-11741: xen: XSA-313 multiple xenoprof issues (bsc#1168140).
- CVE-2020-11739: Missing memory barriers in read-write unlock paths (bsc#1168142).
- 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-2019-19581: Fixed a potential out of bounds on 32-bit Arm (bsc#1158003 XSA-307).
- 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-2019-19579: Fixed a privilege escalation where an untrusted domain with access to a physical device can DMA into host memory (bsc#1157888 XSA-306).
- CVE-2019-19578: 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-2019-19577: 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).
- Xenstored Crashed during VM install (bsc#1167152)
Список пакетов
HPE Helion OpenStack 8
SUSE Enterprise Storage 5
SUSE Linux Enterprise Server 12 SP3-BCL
SUSE Linux Enterprise Server 12 SP3-LTSS
SUSE Linux Enterprise Server for SAP Applications 12 SP3
SUSE OpenStack Cloud 8
SUSE OpenStack Cloud Crowbar 8
Ссылки
- Link for SUSE-SU-2020:1630-1
- E-Mail link for SUSE-SU-2020:1630-1
- SUSE Security Ratings
- SUSE Bug 1157888
- SUSE Bug 1158003
- SUSE Bug 1158004
- SUSE Bug 1158005
- SUSE Bug 1158006
- SUSE Bug 1158007
- SUSE Bug 1161181
- SUSE Bug 1167152
- SUSE Bug 1168140
- SUSE Bug 1168142
- SUSE Bug 1169392
- SUSE Bug 1172205
- SUSE CVE CVE-2019-19577 page
- SUSE CVE CVE-2019-19578 page
- SUSE CVE CVE-2019-19579 page
- SUSE CVE CVE-2019-19580 page
- SUSE CVE CVE-2019-19581 page
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
Incomplete cleanup from specific special register read operations in some Intel(R) Processors may allow an authenticated user to potentially enable information disclosure via local access.
Затронутые продукты
Ссылки
- CVE-2020-0543
- SUSE Bug 1154824
- SUSE Bug 1172205
- SUSE Bug 1172206
- SUSE Bug 1172207
- SUSE Bug 1172770
- SUSE Bug 1178658
- SUSE Bug 1201877
Описание
An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain privileges because of missing memory barriers in read-write unlock paths. The read-write unlock paths don't contain a memory barrier. On Arm, this means a processor is allowed to re-order the memory access with the preceding ones. In other words, the unlock may be seen by another processor before all the memory accesses within the "critical" section. As a consequence, it may be possible to have a writer executing a critical section at the same time as readers or another writer. In other words, many of the assumptions (e.g., a variable cannot be modified after a check) in the critical sections are not safe anymore. The read-write locks are used in hypercalls (such as grant-table ones), so a malicious guest could exploit the race. For instance, there is a small window where Xen can leak memory if XENMAPSPACE_grant_table is used concurrently. A malicious guest may be able to leak memory, or cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded.
Затронутые продукты
Ссылки
- CVE-2020-11739
- SUSE Bug 1168142
Описание
An issue was discovered in xenoprof in Xen through 4.13.x, allowing guest OS users (without active profiling) to obtain sensitive information about other guests. Unprivileged guests can request to map xenoprof buffers, even if profiling has not been enabled for those guests. These buffers were not scrubbed.
Затронутые продукты
Ссылки
- CVE-2020-11740
- SUSE Bug 1168140
- SUSE Bug 1178658
Описание
An issue was discovered in xenoprof in Xen through 4.13.x, allowing guest OS users (with active profiling) to obtain sensitive information about other guests, cause a denial of service, or possibly gain privileges. For guests for which "active" profiling was enabled by the administrator, the xenoprof code uses the standard Xen shared ring structure. Unfortunately, this code did not treat the guest as a potential adversary: it trusts the guest not to modify buffer size information or modify head / tail pointers in unexpected ways. This can crash the host (DoS). Privilege escalation cannot be ruled out.
Затронутые продукты
Ссылки
- CVE-2020-11741
- SUSE Bug 1168140
- SUSE Bug 1178658
Описание
An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of bad continuation handling in GNTTABOP_copy. Grant table operations are expected to return 0 for success, and a negative number for errors. The fix for CVE-2017-12135 introduced a path through grant copy handling where success may be returned to the caller without any action taken. In particular, the status fields of individual operations are left uninitialised, and may result in errant behaviour in the caller of GNTTABOP_copy. A buggy or malicious guest can construct its grant table in such a way that, when a backend domain tries to copy a grant, it hits the incorrect exit path. This returns success to the caller without doing anything, which may cause crashes or other incorrect behaviour.
Затронутые продукты
Ссылки
- CVE-2020-11742
- SUSE Bug 1169392
- 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