From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756852AbbALTN4 (ORCPT ); Mon, 12 Jan 2015 14:13:56 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:57383 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877AbbALSFh (ORCPT ); Mon, 12 Jan 2015 13:05:37 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Ian Abbott , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 3.16.y-ckt 023/216] misc: genwqe: check for error from get_user_pages_fast() Date: Mon, 12 Jan 2015 18:02:20 +0000 Message-Id: <1421085933-32536-24-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1421085933-32536-1-git-send-email-luis.henriques@canonical.com> References: <1421085933-32536-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit cf35d6e0475982667b0d2d318fb27be4b8849827 upstream. `genwqe_user_vmap()` calls `get_user_pages_fast()` and if the return value is less than the number of pages requested, it frees the pages and returns an error (`-EFAULT`). However, it fails to consider a negative error return value from `get_user_pages_fast()`. In that case, the test `if (rc < m->nr_pages)` will be false (due to promotion of `rc` to a large `unsigned int`) and the code will continue on to call `genwqe_map_pages()` with an invalid list of page pointers. Fix it by bailing out if `get_user_pages_fast()` returns a negative error value. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman Signed-off-by: Luis Henriques --- drivers/misc/genwqe/card_utils.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 62cc6bb3f62e..ded1c2507d3d 100644 --- a/drivers/misc/genwqe/card_utils.c +++ b/drivers/misc/genwqe/card_utils.c @@ -580,6 +580,8 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr, m->nr_pages, 1, /* write by caller */ m->page_list); /* ptrs to pages */ + if (rc < 0) + goto fail_get_user_pages; /* assumption: get_user_pages can be killed by signals. */ if (rc < m->nr_pages) { -- 2.1.4