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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E89CC433E0 for ; Tue, 16 Jun 2020 15:48:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F40E20E65 for ; Tue, 16 Jun 2020 15:48:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322483; bh=5JcNY3+ofa7957DqRCh2OsXj0EcV00v6wRJI0km4tQc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W5u0Q36KF1w/zegOTzHpmTTNkFbgxgI3jZEADm51cuJp0+LRywUXT6xF6kNH6/Pj7 /6WYNpi5lNJvuYz1bCLuL4Q5pcLu1IzHJV51yosg9jGDalA737wSxG5asdqo8fIeJh oydp0ueKjSGpbyHZi4zIs+oB3TBi3N+LhmRm3MvU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732083AbgFPPsB (ORCPT ); Tue, 16 Jun 2020 11:48:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:41674 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732367AbgFPPry (ORCPT ); Tue, 16 Jun 2020 11:47:54 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 79D0D2071A; Tue, 16 Jun 2020 15:47:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322474; bh=5JcNY3+ofa7957DqRCh2OsXj0EcV00v6wRJI0km4tQc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AXOxH4gkVDch+SpgmPUvqV7qnHygyGIxFWbOqx9/7e9AJqLGFu8+jiOlN9U/cl8/l RbCx2g5OehqLuyVN+I9qY9PQLv8fAzLvdeGUtYm1wi2/wNv1GYX8fxfoUQ/tijNDch eP2dDLvpB9U5xgq0Z0p3k5PNoxk/fYVCwmcmMzmA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ezequiel Garcia , Rodrigo Siqueira , Rodrigo Siqueira , syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com Subject: [PATCH 5.7 145/163] drm/vkms: Hold gem object while still in-use Date: Tue, 16 Jun 2020 17:35:19 +0200 Message-Id: <20200616153113.747491695@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200616153106.849127260@linuxfoundation.org> References: <20200616153106.849127260@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ezequiel Garcia commit 0ea2ea42b31abc1141f2fd3911f952a97d401fcb upstream. We need to keep the reference to the drm_gem_object until the last access by vkms_dumb_create. Therefore, the put the object after it is used. This fixes a use-after-free issue reported by syzbot. While here, change vkms_gem_create() symbol to static. Reported-and-tested-by: syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com Signed-off-by: Ezequiel Garcia Reviewed-by: Rodrigo Siqueira Signed-off-by: Rodrigo Siqueira Link: https://patchwork.freedesktop.org/patch/msgid/20200427214405.13069-1-ezequiel@collabora.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/vkms/vkms_drv.h | 5 ----- drivers/gpu/drm/vkms/vkms_gem.c | 11 ++++++----- 2 files changed, 6 insertions(+), 10 deletions(-) --- a/drivers/gpu/drm/vkms/vkms_drv.h +++ b/drivers/gpu/drm/vkms/vkms_drv.h @@ -117,11 +117,6 @@ struct drm_plane *vkms_plane_init(struct enum drm_plane_type type, int index); /* Gem stuff */ -struct drm_gem_object *vkms_gem_create(struct drm_device *dev, - struct drm_file *file, - u32 *handle, - u64 size); - vm_fault_t vkms_gem_fault(struct vm_fault *vmf); int vkms_dumb_create(struct drm_file *file, struct drm_device *dev, --- a/drivers/gpu/drm/vkms/vkms_gem.c +++ b/drivers/gpu/drm/vkms/vkms_gem.c @@ -97,10 +97,10 @@ vm_fault_t vkms_gem_fault(struct vm_faul return ret; } -struct drm_gem_object *vkms_gem_create(struct drm_device *dev, - struct drm_file *file, - u32 *handle, - u64 size) +static struct drm_gem_object *vkms_gem_create(struct drm_device *dev, + struct drm_file *file, + u32 *handle, + u64 size) { struct vkms_gem_object *obj; int ret; @@ -113,7 +113,6 @@ struct drm_gem_object *vkms_gem_create(s return ERR_CAST(obj); ret = drm_gem_handle_create(file, &obj->gem, handle); - drm_gem_object_put_unlocked(&obj->gem); if (ret) return ERR_PTR(ret); @@ -142,6 +141,8 @@ int vkms_dumb_create(struct drm_file *fi args->size = gem_obj->size; args->pitch = pitch; + drm_gem_object_put_unlocked(gem_obj); + DRM_DEBUG_DRIVER("Created object of size %lld\n", size); return 0;