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 1F6B5C43334 for ; Tue, 14 Jun 2022 02:32:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355413AbiFNCcY (ORCPT ); Mon, 13 Jun 2022 22:32:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356594AbiFNCbW (ORCPT ); Mon, 13 Jun 2022 22:31:22 -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 13EFB443EA; Mon, 13 Jun 2022 19:12:14 -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 A2E88B816B9; Tue, 14 Jun 2022 02:12:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A01F2C34114; Tue, 14 Jun 2022 02:12:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655172727; bh=vPhUUX8l1Ea5yiw1ssiDDbBvC4xNA/d5bq7xIcMj7wc=; h=From:To:Cc:Subject:Date:From; b=P/flqMww9Dl4G1avSWa9IZMS47+o2UMHEtO3+txWsEGymw5Cd9nr725dZf2oR0ifj odZd+F3ulzqW5d0NEYIIDZ+nlUK7kABP7fZKto1wWHalmuMIxgGQo8l8nDnxlLC9gH LIcVTIWvqR+/drRPKSS84wwyOtVoiZ3T89HCVZj9dJ/Q5n+RhmhtWJbiE+FdDSi8fu HorELledj/wYZDp2EkBH7uCA0JxQI4k/XHdl+I970EghQMd7tep4M2IK5Y+aSXg4l1 iVCd+H/sK2TU1TtGwKHI2bhwrjEC4tLP+8DGrgGL1uONUuYhWaO8PRB2fF68SDw4Kw S+LcdhS3X9kgQ== 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 4.14] KVM: Don't null dereference ops->destroy Date: Mon, 13 Jun 2022 22:12:04 -0400 Message-Id: <20220614021204.1101624-1-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 87d522eefbb4..de6c66521744 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3036,8 +3036,11 @@ 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