Vulnerability 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).
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.5, < 5.10.71 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69Patch
- https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792Patch
- https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25bPatch
- https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69Patch
- https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792Patch
- https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25bPatch
FAQ
What is CVE-2021-47390?
CVE-2021-47390 is a vulnerability with a CVSS score of 7.1 (HIGH). 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: stac...
How severe is CVE-2021-47390?
CVE-2021-47390 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-47390?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.