x86: incorrect error handling for guest p2m page removals

ISSUE DESCRIPTION The internal function querying a domain's p2m table grabs the p2m lock by default, so that the answer to the query remains true until the caller can act on that information; it is up to the caller then to release the lock. Unfortunately, certain failure paths don't release the...

Missing p2m error checking in PoD code

ISSUE DESCRIPTION Certain actions require modification of entries in a guest's P2M Physical-to-Machine table. When large pages are in use for this table, such an operation may incur a memory allocation to replace a large mapping with individual smaller ones. If this allocation fails, the...

kernel: xen: Memory mapping failure can crash Xen

Xen 3.4 through 4.2, and possibly earlier versions, does not properly synchronize the p2m and m2p tables when the setp2mentry function fails, which allows local HVM guest OS administrators to cause a denial of service memory consumption and assertion failure, aka "Memory mapping failure DoS...

Fedora 16 : xen-4.1.3-4.fc16 (2012-18249)

A guest can block a cpu by setting a bad VCPU deadline XSA 20, CVE-2012-4535 876198 HVM guest can use invalid pirq values to crash xen XSA 21, CVE-2012-4536 876200 HVM guest can exhaust p2m table crashing xen XSA 22, CVE-2012-4537 876203 PAE HVM guest can crash hypervisor XSA-23, CVE-2012-4538...

Fedora 17 : xen-4.1.3-6.fc17 (2012-18242)

A guest can block a cpu by setting a bad VCPU deadline XSA 20, CVE-2012-4535 876198 HVM guest can use invalid pirq values to crash xen XSA 21, CVE-2012-4536 876200 HVM guest can exhaust p2m table crashing xen XSA 22, CVE-2012-4537 876203 PAE HVM guest can crash hypervisor XSA-23, CVE-2012-4538...

Memory mapping failure DoS vulnerability

ISSUE DESCRIPTION When setp2mentry fails, Xen's internal data structures the p2m and m2p tables can get out of sync. This failure can be triggered by unusual guest behaviour exhausting the memory reserved for the p2m table. If it happens, subsequent guest-invoked memory operations can cause Xen t...