ghsa-p83g-x445-4qm2
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
RISC-V: KVM: Don't zero-out PMU snapshot area before freeing data
With the latest Linux-6.11-rc3, the below NULL pointer crash is observed when SBI PMU snapshot is enabled for the guest and the guest is forcefully powered-off.
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000508 Oops [#1] Modules linked in: kvm CPU: 0 UID: 0 PID: 61 Comm: term-poll Not tainted 6.11.0-rc3-00018-g44d7178dd77a #3 Hardware name: riscv-virtio,qemu (DT) epc : __kvm_write_guest_page+0x94/0xa6 [kvm] ra : __kvm_write_guest_page+0x54/0xa6 [kvm] epc : ffffffff01590e98 ra : ffffffff01590e58 sp : ffff8f80001f39b0 gp : ffffffff81512a60 tp : ffffaf80024872c0 t0 : ffffaf800247e000 t1 : 00000000000007e0 t2 : 0000000000000000 s0 : ffff8f80001f39f0 s1 : 00007fff89ac4000 a0 : ffffffff015dd7e8 a1 : 0000000000000086 a2 : 0000000000000000 a3 : ffffaf8000000000 a4 : ffffaf80024882c0 a5 : 0000000000000000 a6 : ffffaf800328d780 a7 : 00000000000001cc s2 : ffffaf800197bd00 s3 : 00000000000828c4 s4 : ffffaf800248c000 s5 : ffffaf800247d000 s6 : 0000000000001000 s7 : 0000000000001000 s8 : 0000000000000000 s9 : 00007fff861fd500 s10: 0000000000000001 s11: 0000000000800000 t3 : 00000000000004d3 t4 : 00000000000004d3 t5 : ffffffff814126e0 t6 : ffffffff81412700 status: 0000000200000120 badaddr: 0000000000000508 cause: 000000000000000d [] __kvm_write_guest_page+0x94/0xa6 [kvm] [] kvm_vcpu_write_guest+0x56/0x90 [kvm] [] kvm_pmu_clear_snapshot_area+0x42/0x7e [kvm] [] kvm_riscv_vcpu_pmu_deinit.part.0+0xe0/0x14e [kvm] [] kvm_riscv_vcpu_pmu_deinit+0x1a/0x24 [kvm] [] kvm_arch_vcpu_destroy+0x28/0x4c [kvm] [] kvm_destroy_vcpus+0x5a/0xda [kvm] [] kvm_arch_destroy_vm+0x14/0x28 [kvm] [] kvm_destroy_vm+0x168/0x2a0 [kvm] [] kvm_put_kvm+0x3c/0x58 [kvm] [] kvm_vm_release+0x22/0x2e [kvm]
Clearly, the kvm_vcpu_write_guest() function is crashing because it is being called from kvm_pmu_clear_snapshot_area() upon guest tear down.
To address the above issue, simplify the kvm_pmu_clear_snapshot_area() to not zero-out PMU snapshot area from kvm_pmu_clear_snapshot_area() because the guest is anyway being tore down.
The kvm_pmu_clear_snapshot_area() is also called when guest changes PMU snapshot area of a VCPU but even in this case the previous PMU snaphsot area must not be zeroed-out because the guest might have reclaimed the pervious PMU snapshot area for some other purpose.
{ affected: [], aliases: [ "CVE-2024-47717", ], database_specific: { cwe_ids: [ "CWE-476", ], github_reviewed: false, github_reviewed_at: null, nvd_published_at: "2024-10-21T12:15:08Z", severity: "MODERATE", }, details: "In the Linux kernel, the following vulnerability has been resolved:\n\nRISC-V: KVM: Don't zero-out PMU snapshot area before freeing data\n\nWith the latest Linux-6.11-rc3, the below NULL pointer crash is observed\nwhen SBI PMU snapshot is enabled for the guest and the guest is forcefully\npowered-off.\n\n Unable to handle kernel NULL pointer dereference at virtual address 0000000000000508\n Oops [#1]\n Modules linked in: kvm\n CPU: 0 UID: 0 PID: 61 Comm: term-poll Not tainted 6.11.0-rc3-00018-g44d7178dd77a #3\n Hardware name: riscv-virtio,qemu (DT)\n epc : __kvm_write_guest_page+0x94/0xa6 [kvm]\n ra : __kvm_write_guest_page+0x54/0xa6 [kvm]\n epc : ffffffff01590e98 ra : ffffffff01590e58 sp : ffff8f80001f39b0\n gp : ffffffff81512a60 tp : ffffaf80024872c0 t0 : ffffaf800247e000\n t1 : 00000000000007e0 t2 : 0000000000000000 s0 : ffff8f80001f39f0\n s1 : 00007fff89ac4000 a0 : ffffffff015dd7e8 a1 : 0000000000000086\n a2 : 0000000000000000 a3 : ffffaf8000000000 a4 : ffffaf80024882c0\n a5 : 0000000000000000 a6 : ffffaf800328d780 a7 : 00000000000001cc\n s2 : ffffaf800197bd00 s3 : 00000000000828c4 s4 : ffffaf800248c000\n s5 : ffffaf800247d000 s6 : 0000000000001000 s7 : 0000000000001000\n s8 : 0000000000000000 s9 : 00007fff861fd500 s10: 0000000000000001\n s11: 0000000000800000 t3 : 00000000000004d3 t4 : 00000000000004d3\n t5 : ffffffff814126e0 t6 : ffffffff81412700\n status: 0000000200000120 badaddr: 0000000000000508 cause: 000000000000000d\n [<ffffffff01590e98>] __kvm_write_guest_page+0x94/0xa6 [kvm]\n [<ffffffff015943a6>] kvm_vcpu_write_guest+0x56/0x90 [kvm]\n [<ffffffff015a175c>] kvm_pmu_clear_snapshot_area+0x42/0x7e [kvm]\n [<ffffffff015a1972>] kvm_riscv_vcpu_pmu_deinit.part.0+0xe0/0x14e [kvm]\n [<ffffffff015a2ad0>] kvm_riscv_vcpu_pmu_deinit+0x1a/0x24 [kvm]\n [<ffffffff0159b344>] kvm_arch_vcpu_destroy+0x28/0x4c [kvm]\n [<ffffffff0158e420>] kvm_destroy_vcpus+0x5a/0xda [kvm]\n [<ffffffff0159930c>] kvm_arch_destroy_vm+0x14/0x28 [kvm]\n [<ffffffff01593260>] kvm_destroy_vm+0x168/0x2a0 [kvm]\n [<ffffffff015933d4>] kvm_put_kvm+0x3c/0x58 [kvm]\n [<ffffffff01593412>] kvm_vm_release+0x22/0x2e [kvm]\n\nClearly, the kvm_vcpu_write_guest() function is crashing because it is\nbeing called from kvm_pmu_clear_snapshot_area() upon guest tear down.\n\nTo address the above issue, simplify the kvm_pmu_clear_snapshot_area() to\nnot zero-out PMU snapshot area from kvm_pmu_clear_snapshot_area() because\nthe guest is anyway being tore down.\n\nThe kvm_pmu_clear_snapshot_area() is also called when guest changes\nPMU snapshot area of a VCPU but even in this case the previous PMU\nsnaphsot area must not be zeroed-out because the guest might have\nreclaimed the pervious PMU snapshot area for some other purpose.", id: "GHSA-p83g-x445-4qm2", modified: "2024-10-24T15:31:08Z", published: "2024-10-21T12:30:55Z", references: [ { type: "ADVISORY", url: "https://nvd.nist.gov/vuln/detail/CVE-2024-47717", }, { type: "WEB", url: "https://git.kernel.org/stable/c/47d40d93292d9cff8dabb735bed83d930fa03950", }, { type: "WEB", url: "https://git.kernel.org/stable/c/6d0a5dcfc78bd18f2abb9641f83380135494559b", }, { type: "WEB", url: "https://git.kernel.org/stable/c/81aa95fd5bd14ff49617f07fa79a8d1f1cf2ce9a", }, ], schema_version: "1.4.0", severity: [ { score: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", type: "CVSS_V3", }, ], }
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