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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90204C433EF for ; Tue, 14 Jun 2022 02:40:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353474AbiFNCjz (ORCPT ); Mon, 13 Jun 2022 22:39:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356815AbiFNCi3 (ORCPT ); Mon, 13 Jun 2022 22:38:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACF5038A; Mon, 13 Jun 2022 19:17:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C2D4FB816A4; Tue, 14 Jun 2022 02:12:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A161FC34114; Tue, 14 Jun 2022 02:12:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655172721; bh=LijSy99pzpSg1iIzbzqZJpsUfznU587YrJg1vozHGAU=; h=From:To:Cc:Subject:Date:From; b=E+5fKuEZIB96bHfxsYSBfHd9fzJFDKPBSV8/2W4MZIw1UyYWGtqmkxWWDoeByOQp/ xQDfQreHaxLSnPMT6fnHeeyNo5UargrYKS3sUg1cq1yeOD/YxHX5rMd4X+lDEs1Rnt zegqaxX9NF7s4w8Do4vwZx+lbohIYghnbFMfAKfkpKqVVMgMoLCEs/Zc2BbG8h0PDj m8G99syV6P8cajGtUOW1aeJWRV1zqqyPktwJgVouau9RZl2iwSBfTZoBb1NjULz5hT r+MG8d0875byGrOd9yazltRttmhGQNk7djBdw7lheQyArfs9hQBSUXn/NGbGDafkFq c6cD/9diTwEtQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Alexey Kardashevskiy , Paolo Bonzini , Sasha Levin , kvm@vger.kernel.org Subject: [PATCH MANUALSEL 5.4] KVM: Don't null dereference ops->destroy Date: Mon, 13 Jun 2022 22:11:58 -0400 Message-Id: <20220614021158.1101574-1-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Alexey Kardashevskiy [ Upstream commit e8bc2427018826e02add7b0ed0fc625a60390ae5 ] A KVM device cleanup happens in either of two callbacks: 1) destroy() which is called when the VM is being destroyed; 2) release() which is called when a device fd is closed. Most KVM devices use 1) but Book3s's interrupt controller KVM devices (XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during the machine execution. The error handling in kvm_ioctl_create_device() assumes destroy() is always defined which leads to NULL dereference as discovered by Syzkaller. This adds a checks for destroy!=NULL and adds a missing release(). This is not changing kvm_destroy_devices() as devices with defined release() should have been removed from the KVM devices list by then. Suggested-by: Paolo Bonzini Signed-off-by: Alexey Kardashevskiy Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- virt/kvm/kvm_main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 287444e52ccf..4b445dddb798 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3329,8 +3329,11 @@ static int kvm_ioctl_create_device(struct kvm *kvm, kvm_put_kvm(kvm); mutex_lock(&kvm->lock); list_del(&dev->vm_node); + if (ops->release) + ops->release(dev); mutex_unlock(&kvm->lock); - ops->destroy(dev); + if (ops->destroy) + ops->destroy(dev); return ret; } -- 2.35.1