Time-of-check Time-of-use (TOCTOU) Affecting kernel-zfcpdump-devel package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.04% (6th percentile)

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  • Snyk ID SNYK-RHEL8-KERNELZFCPDUMPDEVEL-7823621
  • published 23 Aug 2024
  • disclosed 22 Aug 2024

How to fix?

There is no fixed version for RHEL:8 kernel-zfcpdump-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-devel package and not the kernel-zfcpdump-devel package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

KVM: x86/mmu: make apf token non-zero to fix bug

In current async pagefault logic, when a page is ready, KVM relies on kvm_arch_can_dequeue_async_page_present() to determine whether to deliver a READY event to the Guest. This function test token value of struct kvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a READY event is finished by Guest. If value is zero meaning that a READY event is done, so the KVM can deliver another. But the kvm_arch_setup_async_pf() may produce a valid token with zero value, which is confused with previous mention and may lead the loss of this READY event.

This bug may cause task blocked forever in Guest: INFO: task stress:7532 blocked for more than 1254 seconds. Not tainted 5.10.0 #16 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:stress state:D stack: 0 pid: 7532 ppid: 1409 flags:0x00000080 Call Trace: __schedule+0x1e7/0x650 schedule+0x46/0xb0 kvm_async_pf_task_wait_schedule+0xad/0xe0 ? exit_to_user_mode_prepare+0x60/0x70 __kvm_handle_async_pf+0x4f/0xb0 ? asm_exc_page_fault+0x8/0x30 exc_page_fault+0x6f/0x110 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x402d00 RSP: 002b:00007ffd31912500 EFLAGS: 00010206 RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0 RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0 RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086 R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000 R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000

CVSS Scores

version 3.1
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NVD

7.8 high
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
Expand this section

Red Hat

5.5 medium
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SUSE

4.7 medium