Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect() KASAN reports the following issue: BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm] Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798 CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G X --------- --- Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020 Call Trace: dump_stack+0xa5/0xe6 print_address_description.constprop.0+0x18/0x130 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] __kasan_report.cold+0x7f/0x114 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kasan_report+0x38/0x50 kasan_check_range+0xf5/0x1d0 kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm] ? kvm_arch_exit+0x110/0x110 [kvm] ? sched_clock+0x5/0x10 ioapic_write_indirect+0x59f/0x9e0 [kvm] ? static_obj+0xc0/0xc0 ? __lock_acquired+0x1d2/0x8c0 ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm] The problem appears to be that 'vcpu_bitmap' is allocated as a single long on stack and it should really be KVM_MAX_VCPUS long. We also seem to clear the lower 16 bits of it with bitmap_zero() for no particular reason (my guess would be that 'bitmap' and 'vcpu_bitmap' variables in kvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed 16-bit long, the later should accommodate all possible vCPUs).

Severity

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

CVSS 4.0 Severity and Metrics:

NIST: NVD

N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

CVSS 3.x Severity and Metrics:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()

KASAN reports the following issue:

 BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
 Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798

 CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G               X --------- ---
 Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020
 Call Trace:
  dump

kernel.org https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69 [No types assigned]

kernel.org https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792 [No types assigned]

kernel.org https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25b [No types assigned]