CVE-2020-15566

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a host OS crash because of incorrect error handling in event-channel port allocation. The allocation of an event-channel port may fail for multiple reasons: (1) port is already in use, (2) the memory allocation failed, or (3) the port we try to allocate is higher than what is supported by the ABI (e.g., 2L or FIFO) used by the guest or the limit set by an administrator (max_event_channels in xl cfg). Due to the missing error checks, only (1) will be considered an error. All the other cases will provide a valid port and will result in a crash when trying to access the event channel. When the administrator configured a guest to allow more than 1023 event channels, that guest may be able to crash the host. When Xen is out-of-memory, allocation of new event channels will result in crashing the host rather than reporting an error. Xen versions 4.10 and later are affected. All architectures are affected. The default configuration, when guests are created with xl/libxl, is not vulnerable, because of the default event-channel limit.

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a host OS crash because of incorrect error handling in event-channel port allocation. The allocation of an event-channel port may fail for multiple reasons: (1) port is already in use, (2) the memory allocation failed, or (3) the port we try to allocate is higher than what is supported by the ABI (e.g., 2L or FIFO) used by the guest or the limit set by an administrator (max_event_channels in xl cfg). Due to the missing error checks, only (1) will be considered an error. All the other cases will provide a valid port and will result in a crash when trying to access the event channel. When the administrator configured a guest to allow more than 1023 event channels, that guest may be able to crash the host. When Xen is out-of-memory, allocation of new event channels will result in crashing the host rather than reporting an error. Xen versions 4.10 and later are affected. All architectures are affected. The default configuration, when guests are created with xl/libxl, is not vulnerable, because of the default event-channel limit.

This update for xen fixes the following issues:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).
• CVE-2020-0543: Special Register Buffer Data Sampling (SRBDS) aka 'CrossTalk' (bsc#1172205).

Additional upstream bug fixes (bsc#1027519)

This update was imported from the SUSE:SLE-15-SP1:Update update project.

This update for xen fixes the following issues:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).
• CVE-2020-0543: Special Register Buffer Data Sampling (SRBDS) aka 'CrossTalk' (bsc#1172205).

Additional upstream bug fixes (bsc#1027519)

This update was imported from the SUSE:SLE-15-SP2:Update update project.

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:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).
• CVE-2020-0543: Special Register Buffer Data Sampling (SRBDS) aka 'CrossTalk' (bsc#1172205).

Additional upstream bug fixes (bsc#1027519)

This update for xen fixes the following issues:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).

This update for xen fixes the following issues:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).
• CVE-2020-0543: Special Register Buffer Data Sampling (SRBDS) aka 'CrossTalk' (bsc#1172205).

Additional upstream bug fixes (bsc#1027519)

This update for xen fixes the following issues:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).

This update for xen fixes the following issues:

• CVE-2020-15563: Fixed inverted code paths in x86 dirty VRAM tracking (bsc#1173377).
• CVE-2020-15565: Fixed insufficient cache write-back under VT-d (bsc#1173378).
• CVE-2020-15566: Fixed incorrect error handling in event channel port allocation (bsc#1173376).
• CVE-2020-15567: Fixed non-atomic modification of live EPT PTE (bsc#1173380).
• CVE-2020-0543: Special Register Buffer Data Sampling (SRBDS) aka 'CrossTalk' (bsc#1172205).

Additional upstream bug fixes (bsc#1027519)

It was discovered that memory contents previously stored in microarchitectural special registers after RDRAND, RDSEED, and SGX EGETKEY read operations on Intel client and Xeon E3 processors may be briefly exposed to processes on the same or different processor cores. A local attacker could use this to expose sensitive information. (CVE-2020-0543)

Julien Grall discovered that Xen incorrectly handled memory barriers on ARM-based systems. An attacker could possibly use this issue to cause a denial of service, obtain sensitive information or escalate privileges. (CVE-2020-11739)

Ilja Van Sprundel discovered that Xen incorrectly handled profiling of guests. An unprivileged attacker could use this issue to obtain sensitive information from other guests, cause a denial of service or possibly gain privileges. (CVE-2020-11740, CVE-2020-11741)

It was discovered that Xen incorrectly handled grant tables. A malicious guest could possibly use this issue to cause a denial of service. (CVE-2020-11742, CVE-2020-11743)

Jan Beulich discovered that Xen incorrectly handled certain code paths. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-15563)

Julien Grall discovered that Xen incorrectly verified memory addresses provided by the guest on ARM-based systems. A malicious guest administrator could possibly use this issue to cause a denial of service. (CVE-2020-15564)

Roger Pau Monné discovered that Xen incorrectly handled caching on x86 Intel systems. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-15565)

It was discovered that Xen incorrectly handled error in event-channel port allocation. A malicious guest could possibly use this issue to cause a denial of service. (CVE-2020-15566)

Jan Beulich discovered that Xen incorrectly handled certain EPT (Extended Page Tables). An attacker could possibly use this issue to cause a denial of service, data corruption or privilege escalation. (CVE-2020-15567)

Andrew Cooper discovered that Xen incorrectly handled PCI passthrough. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25595)

Andrew Cooper discovered that Xen incorrectly sanitized path injections. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25596)

Jan Beulich discovered that Xen incorrectly handled validation of event channels. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25597)

Julien Grall and Jan Beulich discovered that Xen incorrectly handled resetting event channels. An attacker could possibly use this issue to cause a denial of service or obtain sensitive information. (CVE-2020-25599)

Julien Grall discovered that Xen incorrectly handled event channels memory allocation on 32-bits domains. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25600)

Jan Beulich discovered that Xen incorrectly handled resetting or cleaning up event channels. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25601)

Andrew Cooper discovered that Xen incorrectly handled certain Intel specific MSR (Model Specific Registers). An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25602)

Julien Grall discovered that Xen incorrectly handled accessing/allocating event channels. An attacker could possibly use this issue to cause a denial of service, obtain sensitive information of privilege escalation. (CVE-2020-25603)

Igor Druzhinin discovered that Xen incorrectly handled locks. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-25604)