linux

iv/linux

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Paolo Bonzini 226b4327ef KVM: avoid NULL pointer dereference in kvm_dirty_ring_push

commit 5593473a1e6c743764b08e3b6071cb43b5cfa6c4 upstream.

kvm_vcpu_release() will call kvm_dirty_ring_free(), freeing
ring->dirty_gfns and setting it to NULL.  Afterwards, it calls
kvm_arch_vcpu_destroy().

However, if closing the file descriptor races with KVM_RUN in such away
that vcpu->arch.st.preempted == 0, the following call stack leads to a
NULL pointer dereference in kvm_dirty_run_push():

 mark_page_dirty_in_slot+0x192/0x270 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3171
 kvm_steal_time_set_preempted arch/x86/kvm/x86.c:4600 [inline]
 kvm_arch_vcpu_put+0x34e/0x5b0 arch/x86/kvm/x86.c:4618
 vcpu_put+0x1b/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:211
 vmx_free_vcpu+0xcb/0x130 arch/x86/kvm/vmx/vmx.c:6985
 kvm_arch_vcpu_destroy+0x76/0x290 arch/x86/kvm/x86.c:11219
 kvm_vcpu_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:441 [inline]

The fix is to release the dirty page ring after kvm_arch_vcpu_destroy
has run.

Reported-by: Qiuhao Li <qiuhao@sysec.org>
Reported-by: Gaoning Pan <pgn@zju.edu.cn>
Reported-by: Yongkang Jia <kangel@zju.edu.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2022-04-13 20:59:26 +02:00

async_pf.c

mm/gup: remove task_struct pointer for all gup code

2020-08-12 10:58:04 -07:00

async_pf.h

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504

2019-06-19 17:09:56 +02:00

binary_stats.c

KVM: stats: remove dead stores

2021-08-13 03:35:15 -04:00

coalesced_mmio.c

KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio