Stack-based Buffer Overflow Affecting kernel-rt-selftests-internal package, versions *
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Test your applications- Snyk ID SNYK-CENTOS8-KERNELRTSELFTESTSINTERNAL-6982612
- published 22 May 2024
- disclosed 21 May 2024
Introduced: 21 May 2024
CVE-2021-47390 Open this link in a new tabHow to fix?
There is no fixed version for Centos:8 kernel-rt-selftests-internal.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-selftests-internal package and not the kernel-rt-selftests-internal package as distributed by Centos.
See How to fix? for Centos:8 relevant fixed versions and status.
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).