ghsa-crp4-4q2h-fprq
Vulnerability from github
Published
2025-05-01 15:31
Modified
2025-05-01 15:31
Details

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

KVM: x86: Acquire SRCU in KVM_GET_MP_STATE to protect guest memory accesses

Acquire a lock on kvm->srcu when userspace is getting MP state to handle a rather extreme edge case where "accepting" APIC events, i.e. processing pending INIT or SIPI, can trigger accesses to guest memory. If the vCPU is in L2 with INIT and a TRIPLE_FAULT request pending, then getting MP state will trigger a nested VM-Exit by way of ->check_nested_events(), and emuating the nested VM-Exit can access guest memory.

The splat was originally hit by syzkaller on a Google-internal kernel, and reproduced on an upstream kernel by hacking the triple_fault_event_test selftest to stuff a pending INIT, store an MSR on VM-Exit (to generate a memory access on VMX), and do vcpu_mp_state_get() to trigger the scenario.

============================= WARNING: suspicious RCU usage 6.14.0-rc3-b112d356288b-vmx/pi_lockdep_false_pos-lock #3 Not tainted


include/linux/kvm_host.h:1058 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1 1 lock held by triple_fault_ev/1256: #0: ffff88810df5a330 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x8b/0x9a0 [kvm]

stack backtrace: CPU: 11 UID: 1000 PID: 1256 Comm: triple_fault_ev Not tainted 6.14.0-rc3-b112d356288b-vmx #3 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack_lvl+0x7f/0x90 lockdep_rcu_suspicious+0x144/0x190 kvm_vcpu_gfn_to_memslot+0x156/0x180 [kvm] kvm_vcpu_read_guest+0x3e/0x90 [kvm] read_and_check_msr_entry+0x2e/0x180 [kvm_intel] __nested_vmx_vmexit+0x550/0xde0 [kvm_intel] kvm_check_nested_events+0x1b/0x30 [kvm] kvm_apic_accept_events+0x33/0x100 [kvm] kvm_arch_vcpu_ioctl_get_mpstate+0x30/0x1d0 [kvm] kvm_vcpu_ioctl+0x33e/0x9a0 [kvm] __x64_sys_ioctl+0x8b/0xb0 do_syscall_64+0x6c/0x170 entry_SYSCALL_64_after_hwframe+0x4b/0x53

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2025-23141"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-05-01T13:15:49Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Acquire SRCU in KVM_GET_MP_STATE to protect guest memory accesses\n\nAcquire a lock on kvm-\u003esrcu when userspace is getting MP state to handle a\nrather extreme edge case where \"accepting\" APIC events, i.e. processing\npending INIT or SIPI, can trigger accesses to guest memory.  If the vCPU\nis in L2 with INIT *and* a TRIPLE_FAULT request pending, then getting MP\nstate will trigger a nested VM-Exit by way of -\u003echeck_nested_events(), and\nemuating the nested VM-Exit can access guest memory.\n\nThe splat was originally hit by syzkaller on a Google-internal kernel, and\nreproduced on an upstream kernel by hacking the triple_fault_event_test\nselftest to stuff a pending INIT, store an MSR on VM-Exit (to generate a\nmemory access on VMX), and do vcpu_mp_state_get() to trigger the scenario.\n\n  =============================\n  WARNING: suspicious RCU usage\n  6.14.0-rc3-b112d356288b-vmx/pi_lockdep_false_pos-lock #3 Not tainted\n  -----------------------------\n  include/linux/kvm_host.h:1058 suspicious rcu_dereference_check() usage!\n\n  other info that might help us debug this:\n\n  rcu_scheduler_active = 2, debug_locks = 1\n  1 lock held by triple_fault_ev/1256:\n   #0: ffff88810df5a330 (\u0026vcpu-\u003emutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x8b/0x9a0 [kvm]\n\n  stack backtrace:\n  CPU: 11 UID: 1000 PID: 1256 Comm: triple_fault_ev Not tainted 6.14.0-rc3-b112d356288b-vmx #3\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x7f/0x90\n   lockdep_rcu_suspicious+0x144/0x190\n   kvm_vcpu_gfn_to_memslot+0x156/0x180 [kvm]\n   kvm_vcpu_read_guest+0x3e/0x90 [kvm]\n   read_and_check_msr_entry+0x2e/0x180 [kvm_intel]\n   __nested_vmx_vmexit+0x550/0xde0 [kvm_intel]\n   kvm_check_nested_events+0x1b/0x30 [kvm]\n   kvm_apic_accept_events+0x33/0x100 [kvm]\n   kvm_arch_vcpu_ioctl_get_mpstate+0x30/0x1d0 [kvm]\n   kvm_vcpu_ioctl+0x33e/0x9a0 [kvm]\n   __x64_sys_ioctl+0x8b/0xb0\n   do_syscall_64+0x6c/0x170\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n   \u003c/TASK\u003e",
  "id": "GHSA-crp4-4q2h-fprq",
  "modified": "2025-05-01T15:31:39Z",
  "published": "2025-05-01T15:31:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-23141"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0357c8406dfa09430dd9858ebe813feb65524b6e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/592e040572f216d916f465047c8ce4a308fcca44"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7bc5c360375d28ba5ef6298b0d53e735c81d66a1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8a3df0aa1087a89f5ce55f4aba816bfcb1ecf1be"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ef01cac401f18647d62720cf773d7bb0541827da"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5cbe725b7477b4cd677be1b86b4e08f90572997"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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