From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757312AbbIUTXH (ORCPT ); Mon, 21 Sep 2015 15:23:07 -0400 Received: from g2t4622.austin.hp.com ([15.73.212.79]:32910 "EHLO g2t4622.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757166AbbIUTWi (ORCPT ); Mon, 21 Sep 2015 15:22:38 -0400 From: Toshi Kani To: mchehab@osg.samsung.com, bp@alien8.de, dougthompson@xmission.com Cc: linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org, elliott@hpe.com, tony.luck@intel.com, Toshi Kani Subject: [PATCH 2/2] EDAC: Fix sysfs dimm_label store operation Date: Mon, 21 Sep 2015 13:19:44 -0600 Message-Id: <1442863184-17935-3-git-send-email-toshi.kani@hpe.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1442863184-17935-1-git-send-email-toshi.kani@hpe.com> References: <1442863184-17935-1-git-send-email-toshi.kani@hpe.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sysfs "dimm_label" and "chX_dimm_label" have the following issues in their store operation. 1) A newline-terminated input string causes redundant newlines # echo "test" > /sys/bus/mc0/devices/dimm0/dimm_label # cat /sys/bus/mc0/devices/dimm0/dimm_label test # od -bc /sys/bus/mc0/devices/dimm0/dimm_label 0000000 164 145 163 164 012 012 t e s t \n \n 0000006 2) The original label string (31 characters) cannot be stored due to an improper size check # echo "CPU_SrcID#0_Ha#0_Chan#0_DIMM#0" \ > /sys/bus/mc0/devices/dimm0/dimm_label # cat /sys/bus/mc0/devices/dimm0/dimm_label # od -bc /sys/bus/mc0/devices/dimm0/dimm_label 0000000 012 012 \n \n 0000002 3) An input string longer than the buffer size results a wrong label info as it allows a retry with the remaining string. # echo "CPU_SrcID#0_Ha#0_Chan#0_DIMM#0_TEST" \ > /sys/bus/mc0/devices/dimm0/dimm_label # cat /sys/bus/mc0/devices/dimm0/dimm_label _TEST Fix these issues by making the following changes: 1) Replace a newline character at the end with a null, if any. 2) Check the label buffer size with 'sizeof(dimm->label)'. 3) Fail a request if its string exceeds the label buffer size. Signed-off-by: Toshi Kani Cc: Mauro Carvalho Chehab Cc: Borislav Petkov Cc: Doug Thompson Cc: Robert Elliott --- drivers/edac/edac_mc_sysfs.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c index 8983755..f2ea914 100644 --- a/drivers/edac/edac_mc_sysfs.c +++ b/drivers/edac/edac_mc_sysfs.c @@ -241,13 +241,14 @@ static ssize_t channel_dimm_label_store(struct device *dev, unsigned chan = to_channel(mattr); struct rank_info *rank = csrow->channels[chan]; - ssize_t max_size = 0; + if (count == 0 || count > sizeof(rank->dimm->label)) + return -EINVAL; - max_size = min((ssize_t) count, (ssize_t) EDAC_MC_LABEL_LEN - 1); - strncpy(rank->dimm->label, data, max_size); - rank->dimm->label[max_size] = '\0'; + strncpy(rank->dimm->label, data, count); + if (rank->dimm->label[count - 1] == '\n') + rank->dimm->label[count - 1] = '\0'; - return max_size; + return count; } /* show function for dynamic chX_ce_count attribute */ @@ -495,13 +496,14 @@ static ssize_t dimmdev_label_store(struct device *dev, { struct dimm_info *dimm = to_dimm(dev); - ssize_t max_size = 0; + if (count == 0 || count > sizeof(dimm->label)) + return -EINVAL; - max_size = min((ssize_t) count, (ssize_t) EDAC_MC_LABEL_LEN - 1); - strncpy(dimm->label, data, max_size); - dimm->label[max_size] = '\0'; + strncpy(dimm->label, data, count); + if (dimm->label[count - 1] == '\n') + dimm->label[count - 1] = '\0'; - return max_size; + return count; } static ssize_t dimmdev_size_show(struct device *dev,