In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory
Ignore nCR3[4:0] when loading PDPTEs from memory for nested SVM, as bits 4:0 of CR3 are ignored when PAE paging is used, and thus VMRUN doesn't enforce 32-byte alignment of nCR3.
In the absolute worst case scenario, failure to ignore bits 4:0 can result in an out-of-bounds read, e.g. if the target page is at the end of a memslot, and the VMM isn't using guard pages.
Per the APM:
The CR3 register points to the base address of the page-directory-pointer table. The page-directory-pointer table is aligned on a 32-byte boundary, with the low 5 address bits 4:0 assumed to be 0.
And the SDM's much more explicit:
4:0 Ignored
Note, KVM gets this right when loading PDPTRs, it's only the nSVM flow that is broken.
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"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@58cb697d80e669c56197f703e188867c8c54c494", "id": "CVE-2024-50115-210ce79f" }, { "signature_type": "Function", "target": { "file": "arch/x86/kvm/svm/nested.c", "function": "nested_svm_get_tdp_pdptr" }, "signature_version": "v1", "digest": { "length": 287.0, "function_hash": "299529071607363560809733421298292969233" }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@426682afec71ea3f889b972d038238807b9443e4", "id": "CVE-2024-50115-2277780d" }, { "signature_type": "Line", "target": { "file": "arch/x86/kvm/svm/nested.c" }, "signature_version": "v1", "digest": { "threshold": 0.9, "line_hashes": [ "257726702429890352280785356537092435508", "266617827858878903260923036290000860998", "209484903039847682216310601915076824786", "266325309548746422232961149291378629429", "252684292326872723685814863949595052838" ] }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@6876793907cbe19d42e9edc8c3315a21e06c32ae", "id": "CVE-2024-50115-442c4c35" }, { "signature_type": "Line", "target": { "file": "arch/x86/kvm/svm/nested.c" }, "signature_version": "v1", "digest": { "threshold": 0.9, "line_hashes": [ "257726702429890352280785356537092435508", "266617827858878903260923036290000860998", "209484903039847682216310601915076824786", "266325309548746422232961149291378629429", "252684292326872723685814863949595052838" ] }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@76ce386feb14ec9a460784fcd495d8432acce7a5", "id": "CVE-2024-50115-511c87a0" }, { "signature_type": "Function", "target": { "file": "arch/x86/kvm/svm/nested.c", "function": "nested_svm_get_tdp_pdptr" }, "signature_version": "v1", "digest": { "length": 287.0, "function_hash": "299529071607363560809733421298292969233" }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@58cb697d80e669c56197f703e188867c8c54c494", "id": "CVE-2024-50115-72165890" }, { "signature_type": "Line", "target": { "file": "arch/x86/kvm/svm/nested.c" }, "signature_version": "v1", "digest": { "threshold": 0.9, "line_hashes": [ "257726702429890352280785356537092435508", "266617827858878903260923036290000860998", "209484903039847682216310601915076824786", "266325309548746422232961149291378629429", "252684292326872723685814863949595052838" ] }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@426682afec71ea3f889b972d038238807b9443e4", "id": "CVE-2024-50115-75f7f68a" }, { "signature_type": "Line", "target": { "file": "arch/x86/kvm/svm/nested.c" }, "signature_version": "v1", "digest": { "threshold": 0.9, "line_hashes": [ "257726702429890352280785356537092435508", "266617827858878903260923036290000860998", "209484903039847682216310601915076824786", "266325309548746422232961149291378629429", "252684292326872723685814863949595052838" ] }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@2c4adc9b192a0815fe58a62bc0709449416cc884", "id": "CVE-2024-50115-7780b140" }, { "signature_type": "Function", "target": { "file": "arch/x86/kvm/svm/nested.c", "function": "nested_svm_get_tdp_pdptr" }, "signature_version": "v1", "digest": { "length": 287.0, "function_hash": "299529071607363560809733421298292969233" }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@f559b2e9c5c5308850544ab59396b7d53cfc67bd", "id": "CVE-2024-50115-77d95b9d" }, { "signature_type": "Function", "target": { "file": "arch/x86/kvm/svm/nested.c", "function": "nested_svm_get_tdp_pdptr" }, "signature_version": "v1", "digest": { "length": 287.0, "function_hash": "299529071607363560809733421298292969233" }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@76ce386feb14ec9a460784fcd495d8432acce7a5", "id": "CVE-2024-50115-8e757430" }, { "signature_type": "Function", "target": { "file": "arch/x86/kvm/svm/nested.c", "function": "nested_svm_get_tdp_pdptr" }, "signature_version": "v1", "digest": { "length": 287.0, "function_hash": "299529071607363560809733421298292969233" }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@6876793907cbe19d42e9edc8c3315a21e06c32ae", "id": "CVE-2024-50115-a5b38d40" }, { "signature_type": "Function", "target": { "file": "arch/x86/kvm/svm/nested.c", "function": "nested_svm_get_tdp_pdptr" }, "signature_version": "v1", "digest": { "length": 287.0, "function_hash": "299529071607363560809733421298292969233" }, "deprecated": false, "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@2c4adc9b192a0815fe58a62bc0709449416cc884", "id": "CVE-2024-50115-a7635805" } ] }