From patchwork Fri Jan 8 10:56:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Shayne Chen X-Patchwork-Id: 359494 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, UNPARSEABLE_RELAY, 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 03D03C433E0 for ; Fri, 8 Jan 2021 10:59:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A284E23976 for ; Fri, 8 Jan 2021 10:59:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726468AbhAHK6t (ORCPT ); Fri, 8 Jan 2021 05:58:49 -0500 Received: from mailgw01.mediatek.com ([210.61.82.183]:44933 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725901AbhAHK6t (ORCPT ); Fri, 8 Jan 2021 05:58:49 -0500 X-UUID: a2812a66070e49b6adf58535417dd9c8-20210108 X-UUID: a2812a66070e49b6adf58535417dd9c8-20210108 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw01.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.14 Build 0819 with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1767557850; Fri, 08 Jan 2021 18:58:04 +0800 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs08n2.mediatek.inc (172.21.101.56) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 8 Jan 2021 18:58:02 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 8 Jan 2021 18:58:01 +0800 From: Shayne Chen To: linux-wireless CC: Johannes Berg , =?utf-8?q?Toke_H=C3=B8iland?= =?utf-8?q?-J=C3=B8rgensen?= , Felix Fietkau , Lorenzo Bianconi , Ryder Lee , linux-mediatek , Shayne Chen , Sujuan Chen Subject: [PATCH] mac80211: fix incorrect strlen of .write in debugfs Date: Fri, 8 Jan 2021 18:56:43 +0800 Message-ID: <20210108105643.10834-1-shayne.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-TM-SNTS-SMTP: ABABAB4B14836EBA9C6DBD0A2BFFC1237D0049382AC8F90DB79B7B7F41F177EA2000:8 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org This fixes strlen mismatch problems happening in some .write callbacks of debugfs. When trying to configure airtime_flags in debugfs, an error appeared: # echo 0 > /sys/kernel/debug/ieee80211/phy0/airtime_flags ash: write error: Invalid argument The error is returned from kstrtou16() since a wrong length makes it miss the real end of input string. To fix this, use count as the string length, and set proper end of string for a char buffer. The debug print is shown - airtime_flags_write: count = 2, len = 8, where the actual length is 2, but "len = strlen(buf)" gets 8. Also cleanup the other similar cases for the sake of consistency. Signed-off-by: Sujuan Chen Signed-off-by: Ryder Lee Signed-off-by: Shayne Chen Acked-by: Toke Høiland-Jørgensen --- This patch is based on the discussion from https://patchwork.kernel.org/project/linux-wireless/list/?series=409693 --- net/mac80211/debugfs.c | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c index 9135b6f..9991a6a 100644 --- a/net/mac80211/debugfs.c +++ b/net/mac80211/debugfs.c @@ -120,7 +120,6 @@ static ssize_t aqm_write(struct file *file, { struct ieee80211_local *local = file->private_data; char buf[100]; - size_t len; if (count > sizeof(buf)) return -EINVAL; @@ -128,10 +127,10 @@ static ssize_t aqm_write(struct file *file, if (copy_from_user(buf, user_buf, count)) return -EFAULT; - buf[sizeof(buf) - 1] = '\0'; - len = strlen(buf); - if (len > 0 && buf[len-1] == '\n') - buf[len-1] = 0; + if (count && buf[count - 1] == '\n') + buf[count - 1] = '\0'; + + buf[count] = '\0'; if (sscanf(buf, "fq_limit %u", &local->fq.limit) == 1) return count; @@ -177,7 +176,6 @@ static ssize_t airtime_flags_write(struct file *file, { struct ieee80211_local *local = file->private_data; char buf[16]; - size_t len; if (count > sizeof(buf)) return -EINVAL; @@ -185,10 +183,10 @@ static ssize_t airtime_flags_write(struct file *file, if (copy_from_user(buf, user_buf, count)) return -EFAULT; - buf[sizeof(buf) - 1] = 0; - len = strlen(buf); - if (len > 0 && buf[len - 1] == '\n') - buf[len - 1] = 0; + if (count && buf[count - 1] == '\n') + buf[count - 1] = '\0'; + + buf[count] = '\0'; if (kstrtou16(buf, 0, &local->airtime_flags)) return -EINVAL; @@ -237,7 +235,6 @@ static ssize_t aql_txq_limit_write(struct file *file, { struct ieee80211_local *local = file->private_data; char buf[100]; - size_t len; u32 ac, q_limit_low, q_limit_high, q_limit_low_old, q_limit_high_old; struct sta_info *sta; @@ -247,10 +244,10 @@ static ssize_t aql_txq_limit_write(struct file *file, if (copy_from_user(buf, user_buf, count)) return -EFAULT; - buf[sizeof(buf) - 1] = 0; - len = strlen(buf); - if (len > 0 && buf[len - 1] == '\n') - buf[len - 1] = 0; + if (count && buf[count - 1] == '\n') + buf[count - 1] = '\0'; + + buf[count] = '\0'; if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3) return -EINVAL; @@ -306,7 +303,6 @@ static ssize_t force_tx_status_write(struct file *file, { struct ieee80211_local *local = file->private_data; char buf[3]; - size_t len; if (count > sizeof(buf)) return -EINVAL; @@ -314,10 +310,10 @@ static ssize_t force_tx_status_write(struct file *file, if (copy_from_user(buf, user_buf, count)) return -EFAULT; - buf[sizeof(buf) - 1] = '\0'; - len = strlen(buf); - if (len > 0 && buf[len - 1] == '\n') - buf[len - 1] = 0; + if (count && buf[count - 1] == '\n') + buf[count - 1] = '\0'; + + buf[count] = '\0'; if (buf[0] == '0' && buf[1] == '\0') local->force_tx_status = 0;