xen: Missing check for grant table (XSA-232)

An issue was discovered in Xen 4.5.x through 4.9.x. The function `__gnttab_cache_flush` handles GNTTABOP_cache_flush grant table operations. It checks to see if the calling domain is the owner of the page that is to be operated on. If it is not, the owner's grant table is checked to see if a grant mapping to the calling domain exists for the page in question. However, the function does not check to see if the owning domain actually has a grant table or not. Some special domains, such as `DOMID_XEN`, `DOMID_IO` and `DOMID_COW` are created without grant tables. Hence, if __gnttab_cache_flush operates on a page owned by these special domains, it will attempt to dereference a NULL pointer in the domain struct.

xen: ARM guests may induce host asynchronous abort (XSA-201)

Xen through 4.7.x allows local ARM guest OS users to cause a denial of service (host panic) by sending an asynchronous abort.

xen: x86: Mishandling of SYSCALL singlestep during emulation (XSA-204)

Xen through 4.8.x allows local 64-bit x86 HVM guest OS users to gain privileges by leveraging mishandling of SYSCALL singlestep during emulation.

xen: x86 PV guests may be able to mask interrupts (XSA-202)

Xen through 4.8.x allows local x86 PV guest OS kernel administrators to cause a denial of service (host hang or crash) by modifying the instruction stream asynchronously while performing certain kernel operations.

xen: delimiter injection vulnerabilities in pygrub (XSA-198)

The pygrub boot loader emulator in Xen, when nul-delimited output format is requested, allows local pygrub-using guest OS administrators to read or delete arbitrary files on the host via NUL bytes in the bootloader configuration file.

kernel: xen: Insufficient restrictions on certain MMU update hypercalls (xsa109)

The do_mmu_update function in arch/x86/mm.c in Xen 4.x through 4.4.x does not properly restrict updates to only PV page tables, which allows remote PV guests to cause a denial of service (NULL pointer dereference) by leveraging hardware emulation services for HVM guests using Hardware Assisted Paging (HAP).

kernel: xen: Improper MSR range used for x2APIC emulation (xsa108)

The hvm_msr_read_intercept function in arch/x86/hvm/hvm.c in Xen 4.1 through 4.4.x uses an improper MSR range for x2APIC emulation, which allows local HVM guests to cause a denial of service (host crash) or read data from the hypervisor or other guests via unspecified vectors.

kernel: xen: Missing privilege level checks in x86 emulation of software interrupts (XSA-106)

The x86_emulate function in arch/x86/x86_emulate/x86_emulate.c in Xen 3.3.x through 4.4.x does not check the supervisor mode permissions for instructions that generate software interrupts, which allows local HVM guest users to cause a denial of service (guest crash) via unspecified vectors.

kernel: xen: Missing privilege level checks in x86 HLT, LGDT, LIDT, and LMSW emulation (XSA-105)

The x86_emulate function in arch/x86/x86_emulate/x86_emulate.c in Xen 4.4.x and earlier does not properly check supervisor mode permissions, which allows local HVM users to cause a denial of service (guest crash) or gain guest kernel mode privileges via vectors involving an (1) HLT, (2) LGDT, (3) LIDT, or (4) LMSW instruction.

kernel: xen: Race condition in HVMOP_track_dirty_vram (XSA-104)

Race condition in HVMOP_track_dirty_vram in Xen 4.0.0 through 4.4.x does not ensure possession of the guarding lock for dirty video RAM tracking, which allows certain local guest domains to cause a denial of service via unspecified vectors.

kernel: xen: Mishandling of uninitialised FIFO-based event channel control blocks (xsa107)

The evtchn_fifo_set_pending function in Xen 4.4.x allows local guest users to cause a denial of service (host crash) via vectors involving an uninitialized FIFO-based event channel control block when (1) binding or (2) moving an event to a different VCPU.

xen: Long latency virtual-mmu operations are not preemptible (xsa-97)

Certain MMU virtualization operations in Xen 4.2.x through 4.4.x, when using shadow pagetables, are not preemptible, which allows local HVM guest to cause a denial of service (vcpu consumption) by invoking these operations, which process every page assigned to a guest, a different vulnerability than CVE-2014-5146.

Xen 4.4.x, when running on an ARM system and "handling an unknown system register access from 64-bit userspace," returns to an instruction of the trap handler for kernel space faults instead of an instruction that is associated with faults in 64-bit userspace, which allows local guest users to cause a denial of service (crash) and possibly gain privileges via a crafted process.

Xen 4.4.x, when running a 64-bit kernel on an ARM system, does not properly handle traps from the guest domain that use a different address width, which allows local guest users to cause a denial of service (host crash) via a crafted 32-bit process.

xen: Long latency virtual-mmu operations are not preemptible (xsa-97)

Certain MMU virtualization operations in Xen 4.2.x through 4.4.x before the xsa97-hap patch, when using Hardware Assisted Paging (HAP), are not preemptible, which allows local HVM guest to cause a denial of service (vcpu consumption) by invoking these operations, which process every page assigned to a guest, a different vulnerability than CVE-2014-5149.

The alloc_domain_struct function in arch/arm/domain.c in Xen 4.4.x, when running on an ARM platform, does not properly initialize the structure containing the grant table pages for a domain, which allows local guest administrators to obtain sensitive information via the GNTTABOP_setup_table subhypercall.

xen: Hypervisor heap contents leaked to guests (xsa-100)

Xen 3.2.x through 4.4.x does not properly clean memory pages recovered from guests, which allows local guest OS users to obtain sensitive information via unspecified vectors.

Xen 4.4.x, when running on an ARM system, does not properly check write permissions on virtual addresses, which allows local guest administrators to gain privileges via unspecified vectors.

xen: Vulnerabilities in HVM MSI injection (XSA-96)

The HVMOP_inject_msi function in Xen 4.2.x, 4.3.x, and 4.4.x allows local guest HVM administrators to cause a denial of service (host crash) via a large number of crafted requests, which trigger an error messages to be logged.

xen: Vulnerabilities in HVM MSI injection (XSA-96)

The HVMOP_inject_msi function in Xen 4.2.x, 4.3.x, and 4.4.x does not properly check the return value from the IRQ setup check, which allows local HVM guest administrators to cause a denial of service (NULL pointer dereference and crash) via unspecified vectors.