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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 CE45CC43381 for ; Mon, 1 Apr 2019 18:00:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DACB2084B for ; Mon, 1 Apr 2019 18:00:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141626; bh=4ChKukL+wvxdqXaHwo+CWoefDZkX74mYvkyybd56718=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mtkjcJRIaSbiYOEUJfGF391nFrH74imVmqnH9iReCVkWY3BE21G7TmMDX7bvZ3Gfq d5569d1GeQFabwD2kl1Pn/ARMrte5F1/1aETjCOoHcSVQ/GOYnckGqwjQlXY/bhEEt p9JVFG+6bnh71kgAnCrkXwyXFWqzPPDZsrwdgPlE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729517AbfDASAV (ORCPT ); Mon, 1 Apr 2019 14:00:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:43736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730824AbfDARRb (ORCPT ); Mon, 1 Apr 2019 13:17:31 -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 7FBD220883; Mon, 1 Apr 2019 17:17:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139051; bh=4ChKukL+wvxdqXaHwo+CWoefDZkX74mYvkyybd56718=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZFWuIr0Mw0DdwIPjZehalJIns2dwNx0I9vhqz3GxivLb0c2GajKxXD5rKwnmqs2rX Ctn4ydkMVk2/sNaWNIYYfuslfuzfbTsALRREzSazgE4Pvvz1hCG15Ei6TtwWfdznTG ZkvQPUmhZSMLZD5C20RTdTTQ3RL345b67YM75TRk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rodrigo Siqueira , Haneen Mohammed , Daniel Vetter , Chris Wilson , Eric Biggers , Maxime Ripard Subject: [PATCH 4.19 098/134] drm/vkms: fix use-after-free when drm_gem_handle_create() fails Date: Mon, 1 Apr 2019 19:02:14 +0200 Message-Id: <20190401170053.448431437@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170044.243719205@linuxfoundation.org> References: <20190401170044.243719205@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 36b6c9ed45afe89045973e8dee1b004dd5372d40 upstream. If drm_gem_handle_create() fails in vkms_gem_create(), then the vkms_gem_object is freed twice: once when the reference is dropped by drm_gem_object_put_unlocked(), and again by the extra calls to drm_gem_object_release() and kfree(). Fix it by skipping the second release and free. This bug was originally found in the vgem driver by syzkaller using fault injection, but I noticed it's also present in the vkms driver. Fixes: 559e50fd34d1 ("drm/vkms: Add dumb operations") Cc: Rodrigo Siqueira Cc: Haneen Mohammed Cc: Daniel Vetter Cc: Chris Wilson Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Reviewed-by: Chris Wilson Reviewed-by: Rodrigo Siqueira Signed-off-by: Rodrigo Siqueira Link: https://patchwork.freedesktop.org/patch/msgid/20190226220858.214438-1-ebiggers@kernel.org Signed-off-by: Maxime Ripard Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/vkms/vkms_gem.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) --- a/drivers/gpu/drm/vkms/vkms_gem.c +++ b/drivers/gpu/drm/vkms/vkms_gem.c @@ -110,11 +110,8 @@ struct drm_gem_object *vkms_gem_create(s ret = drm_gem_handle_create(file, &obj->gem, handle); drm_gem_object_put_unlocked(&obj->gem); - if (ret) { - drm_gem_object_release(&obj->gem); - kfree(obj); + if (ret) return ERR_PTR(ret); - } return &obj->gem; }