From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C437EC433EF for ; Mon, 4 Oct 2021 13:27:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADB34610A5 for ; Mon, 4 Oct 2021 13:27:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237066AbhJDN3f (ORCPT ); Mon, 4 Oct 2021 09:29:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:43748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236775AbhJDN12 (ORCPT ); Mon, 4 Oct 2021 09:27:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0849A61B7B; Mon, 4 Oct 2021 13:12:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633353123; bh=sbVyS3b/pe/VN4ve5UOz0/7q/rDxrzYHx53sOjsguEw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1tgIgQqylWAKTkDPVNF9ldMtELmgjkozozPh+EBqIYGQXjgiO0T3UUHLhNcI1cYBG caJ05PHgWn5dHpEkh0RTUEQlq571NKsTMeDKwHSsjfYiVweBRr2+ayqSPcSoNUEq4B 5y8NEg0ORxd+xnhMSFpXeD12mjmyQ6FjH+s/nELo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, TCS Robot , Haimin Zhang , Paolo Bonzini Subject: [PATCH 5.10 91/93] KVM: x86: Handle SRCU initialization failure during page track init Date: Mon, 4 Oct 2021 14:53:29 +0200 Message-Id: <20211004125037.599892813@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125034.579439135@linuxfoundation.org> References: <20211004125034.579439135@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Haimin Zhang 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 Signed-off-by: Haimin Zhang 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/kvm_page_track.h | 2 +- arch/x86/kvm/mmu/page_track.c | 4 ++-- arch/x86/kvm/x86.c | 7 ++++++- 3 files changed, 9 insertions(+), 4 deletions(-) --- 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 *slot); --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -163,13 +163,13 @@ void kvm_page_track_cleanup(struct 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); } /* --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10392,9 +10392,15 @@ void kvm_arch_free_vm(struct kvm *kvm) 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); @@ -10421,7 +10427,6 @@ int kvm_arch_init_vm(struct kvm *kvm, un 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); return kvm_x86_ops.vm_init(kvm);