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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 37895C433F4 for ; Sun, 26 Aug 2018 06:48:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F1E5B2170B for ; Sun, 26 Aug 2018 06:48:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F1E5B2170B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728114AbeHZKaQ (ORCPT ); Sun, 26 Aug 2018 06:30:16 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:53994 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726611AbeHZKaP (ORCPT ); Sun, 26 Aug 2018 06:30:15 -0400 Received: from localhost (5355525A.cm-6-6b.dynamic.ziggo.nl [83.85.82.90]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 534F39F0; Sun, 26 Aug 2018 06:48:39 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "linux-kernel@vger.kernel.org, kernel-team@android.com, Daniel Rosenberg" , Daniel Rosenberg Subject: [PATCH 3.18 51/56] staging: android: ion: check for kref overflow Date: Sun, 26 Aug 2018 08:45:12 +0200 Message-Id: <20180826064234.753862394@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180826064232.320669119@linuxfoundation.org> References: <20180826064232.320669119@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Rosenberg This patch is against 4.4. It does not apply to master due to a large rework of ion in 4.12 which removed the affected functions altogther. 4c23cbff073f3b9b ("staging: android: ion: Remove import interface") Userspace can cause the kref to handles to increment arbitrarily high. Ensure it does not overflow. Signed-off-by: Daniel Rosenberg Signed-off-by: Greg Kroah-Hartman --- v2: Fixed patch corruption :( It applies from 3.18 to 4.11, although with a trivial conflict resolution for the later branches. drivers/staging/android/ion/ion.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -15,6 +15,7 @@ * */ +#include #include #include #include @@ -389,6 +390,16 @@ static void ion_handle_get(struct ion_ha kref_get(&handle->ref); } +/* Must hold the client lock */ +static struct ion_handle *ion_handle_get_check_overflow( + struct ion_handle *handle) +{ + if (atomic_read(&handle->ref.refcount) + 1 == 0) + return ERR_PTR(-EOVERFLOW); + ion_handle_get(handle); + return handle; +} + static int ion_handle_put_nolock(struct ion_handle *handle) { int ret; @@ -435,9 +446,9 @@ static struct ion_handle *ion_handle_get handle = idr_find(&client->idr, id); if (handle) - ion_handle_get(handle); + return ion_handle_get_check_overflow(handle); - return handle ? handle : ERR_PTR(-EINVAL); + return ERR_PTR(-EINVAL); } struct ion_handle *ion_handle_get_by_id(struct ion_client *client, @@ -1197,7 +1208,7 @@ struct ion_handle *ion_import_dma_buf(st /* if a handle exists for this buffer just take a reference to it */ handle = ion_handle_lookup(client, buffer); if (!IS_ERR(handle)) { - ion_handle_get(handle); + handle = ion_handle_get_check_overflow(handle); mutex_unlock(&client->lock); goto end; }