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| author |   Paolo Bonzini <pbonzini@redhat.com> | 2022-04-06 13:13:42 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-04-06 13:26:30 -0400 |
| commit | 5593473a1e6c743764b08e3b6071cb43b5cfa6c4 (patch) | |
| tree | 344aca3aecf659cba08717558f1ada346fcfd371 /virt | |
| parent | Documentation: kvm: Add missing line break in api.rst (diff) | |
| download | linux-dev-5593473a1e6c743764b08e3b6071cb43b5cfa6c4.tar.xz linux-dev-5593473a1e6c743764b08e3b6071cb43b5cfa6c4.zip | |
KVM: avoid NULL pointer dereference in kvm_dirty_ring_push
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>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 70e05af5ebea..b22f380e3347 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -434,8 +434,8 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu) { - kvm_dirty_ring_free(&vcpu->dirty_ring); kvm_arch_vcpu_destroy(vcpu); + kvm_dirty_ring_free(&vcpu->dirty_ring); /* * No need for rcu_read_lock as VCPU_RUN is the only place that changes |