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 ADD0EC433EF for ; Tue, 14 Jun 2022 02:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355243AbiFNCcN (ORCPT ); Mon, 13 Jun 2022 22:32:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356842AbiFNCbc (ORCPT ); Mon, 13 Jun 2022 22:31:32 -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 72DC54474F; Mon, 13 Jun 2022 19:12:27 -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 E0BBEB816AA; Tue, 14 Jun 2022 02:12:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA064C3411E; Tue, 14 Jun 2022 02:12:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655172745; bh=QPq4A+MPT7ODraj38T+gaiAyBRab/RGhAAvnfWnRn0M=; h=From:To:Cc:Subject:Date:From; b=YIJ8DM+GKq8jv8n8PMPgZOX8E5loTjw2ghHuQWZ8UQp1p+BoRjdmXhWjF7WElibg7 VZn8ErmHCmo9NCC0uO8f5W8ebr66fnvInUDTbxvgAN+PQeZ0XdPHwLZ6E2ESoF49A4 fmYEbklY8U67bG3wM5+7abGIpC4ARijk10w1HuCnCmuIUXNi19iZ+P7txZBpNA3nlH b5lkRcLFsYD9XVpydyk/OMLsN8Xn+6ZMUVh3LYwnouiaOyT8zV9PsTsbBRXdHJ3tcK h3EMKY28goqq0BocBbjMFvMPnsXwyn1wzMYS8Alc4neOMVVyd+9fqsDhnm+2aFrn3S UelS4HDbksj8A== 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 4.9] KVM: Don't null dereference ops->destroy Date: Mon, 13 Jun 2022 22:12:07 -0400 Message-Id: <20220614021207.1101649-1-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: stable@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 d251b718bf53..5482f47cb07d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2995,8 +2995,11 @@ 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