fkie_cve-2022-50425
Vulnerability from fkie_nvd
Published
2025-10-01 12:15
Modified
2025-10-02 19:12
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Fix copy_xstate_to_uabi() to copy init states correctly When an extended state component is not present in fpstate, but in init state, the function copies from init_fpstate via copy_feature(). But, dynamic states are not present in init_fpstate because of all-zeros init states. Then retrieving them from init_fpstate will explode like this: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:memcpy_erms+0x6/0x10 ? __copy_xstate_to_uabi_buf+0x381/0x870 fpu_copy_guest_fpstate_to_uabi+0x28/0x80 kvm_arch_vcpu_ioctl+0x14c/0x1460 [kvm] ? __this_cpu_preempt_check+0x13/0x20 ? vmx_vcpu_put+0x2e/0x260 [kvm_intel] kvm_vcpu_ioctl+0xea/0x6b0 [kvm] ? kvm_vcpu_ioctl+0xea/0x6b0 [kvm] ? __fget_light+0xd4/0x130 __x64_sys_ioctl+0xe3/0x910 ? debug_smp_processor_id+0x17/0x20 ? fpregs_assert_state_consistent+0x27/0x50 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Adjust the 'mask' to zero out the userspace buffer for the features that are not available both from fpstate and from init_fpstate. The dynamic features depend on the compacted XSAVE format. Ensure it is enabled before reading XCOMP_BV in init_fpstate.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/471f0aa7fa64e23766a1473b32d9ec3f0718895a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6ff29642fd28965a8f8d6d326ac91bf6075f3113
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/fpu: Fix copy_xstate_to_uabi() to copy init states correctly\n\nWhen an extended state component is not present in fpstate, but in init\nstate, the function copies from init_fpstate via copy_feature().\n\nBut, dynamic states are not present in init_fpstate because of all-zeros\ninit states. Then retrieving them from init_fpstate will explode like this:\n\n BUG: kernel NULL pointer dereference, address: 0000000000000000\n ...\n RIP: 0010:memcpy_erms+0x6/0x10\n  ? __copy_xstate_to_uabi_buf+0x381/0x870\n  fpu_copy_guest_fpstate_to_uabi+0x28/0x80\n  kvm_arch_vcpu_ioctl+0x14c/0x1460 [kvm]\n  ? __this_cpu_preempt_check+0x13/0x20\n  ? vmx_vcpu_put+0x2e/0x260 [kvm_intel]\n  kvm_vcpu_ioctl+0xea/0x6b0 [kvm]\n  ? kvm_vcpu_ioctl+0xea/0x6b0 [kvm]\n  ? __fget_light+0xd4/0x130\n  __x64_sys_ioctl+0xe3/0x910\n  ? debug_smp_processor_id+0x17/0x20\n  ? fpregs_assert_state_consistent+0x27/0x50\n  do_syscall_64+0x3f/0x90\n  entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nAdjust the \u0027mask\u0027 to zero out the userspace buffer for the features that\nare not available both from fpstate and from init_fpstate.\n\nThe dynamic features depend on the compacted XSAVE format. Ensure it is\nenabled before reading XCOMP_BV in init_fpstate."
    }
  ],
  "id": "CVE-2022-50425",
  "lastModified": "2025-10-02T19:12:17.160",
  "metrics": {},
  "published": "2025-10-01T12:15:33.987",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/471f0aa7fa64e23766a1473b32d9ec3f0718895a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6ff29642fd28965a8f8d6d326ac91bf6075f3113"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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