From: Haimin Zhang <tcs_kernel@tencent.com> stable inclusion from stable-v5.10.71 commit deb2949417677649e2413266d7ce8c2ff73952b4 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RFI8 CVE: CVE-2021-47407 -------------------------------- commit eb7511bf9182292ef1df1082d23039e856d1ddfb upstream. Check the return of init_srcu_struct(), which can fail due to OOM, when initializing the page track mechanism. Lack of checking leads to a NULL pointer deref found by a modified syzkaller. Reported-by: TCS Robot <tcs_robot@tencent.com> Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com> Message-Id: <1630636626-12262-1-git-send-email-tcs_kernel@tencent.com> [Move the call towards the beginning of kvm_arch_init_vm. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- arch/x86/include/asm/kvm_page_track.h | 2 +- arch/x86/kvm/page_track.c | 4 ++-- arch/x86/kvm/x86.c | 7 ++++++- 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h index 172f9749dbb2..5986bd4aacd6 100644 --- a/arch/x86/include/asm/kvm_page_track.h +++ b/arch/x86/include/asm/kvm_page_track.h @@ -46,7 +46,7 @@ struct kvm_page_track_notifier_node { struct kvm_page_track_notifier_node *node); }; -void kvm_page_track_init(struct kvm *kvm); +int kvm_page_track_init(struct kvm *kvm); void kvm_page_track_cleanup(struct kvm *kvm); void kvm_page_track_free_memslot(struct kvm_memory_slot *free, diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c index 3052a59a3065..1f6b0d9b0c85 100644 --- a/arch/x86/kvm/page_track.c +++ b/arch/x86/kvm/page_track.c @@ -169,13 +169,13 @@ void kvm_page_track_cleanup(struct kvm *kvm) cleanup_srcu_struct(&head->track_srcu); } -void kvm_page_track_init(struct kvm *kvm) +int kvm_page_track_init(struct kvm *kvm) { struct kvm_page_track_notifier_head *head; head = &kvm->arch.track_notifier_head; - init_srcu_struct(&head->track_srcu); INIT_HLIST_HEAD(&head->track_notifier_list); + return init_srcu_struct(&head->track_srcu); } /* diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 53564a1096c3..6afffdcc656e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9110,9 +9110,15 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) { + int ret; + if (type) return -EINVAL; + ret = kvm_page_track_init(kvm); + if (ret) + return ret; + INIT_HLIST_HEAD(&kvm->arch.mask_notifier_list); INIT_LIST_HEAD(&kvm->arch.active_mmu_pages); INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages); @@ -9139,7 +9145,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn); kvm_hv_init_vm(kvm); - kvm_page_track_init(kvm); kvm_mmu_init_vm(kvm); if (kvm_x86_ops->vm_init) -- 2.34.1