From patchwork Fri Jan 19 00:02:41 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10174331 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2CF9D601E7 for ; Fri, 19 Jan 2018 00:12:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1F89D26E1A for ; Fri, 19 Jan 2018 00:12:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 13BCD283B9; Fri, 19 Jan 2018 00:12:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 101B226E1A for ; Fri, 19 Jan 2018 00:12:45 +0000 (UTC) Received: (qmail 19711 invoked by uid 550); 19 Jan 2018 00:12:01 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 19521 invoked from network); 19 Jan 2018 00:11:59 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,379,1511856000"; d="scan'208";a="24547888" From: Dan Williams To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, gregkh@linuxfoundation.org, Christian Lamparter , linux-wireless@vger.kernel.org, tglx@linutronix.de, Johannes Berg , torvalds@linux-foundation.org, "David S. Miller" , Elena Reshetova , alan@linux.intel.com Date: Thu, 18 Jan 2018 16:02:41 -0800 Message-ID: <151632015637.21271.10452415430644852207.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151632009605.21271.11304291057104672116.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151632009605.21271.11304291057104672116.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Subject: [kernel-hardening] [PATCH v4 10/10] nl80211: sanitize array index in parse_txq_params X-Virus-Scanned: ClamAV using ClamSMTP Wireless drivers rely on parse_txq_params to validate that txq_params->ac is less than NL80211_NUM_ACS by the time the low-level driver's ->conf_tx() handler is called. Use a new helper, 'array_idx', to sanitize txq_params->ac with respect to speculation. I.e. ensure that any speculation into ->conf_tx() handlers is done with a value of txq_params->ac that is within the bounds of [0, NL80211_NUM_ACS). Reported-by: Christian Lamparter Reported-by: Elena Reshetova Cc: Johannes Berg Cc: "David S. Miller" Cc: linux-wireless@vger.kernel.org Signed-off-by: Dan Williams Reviewed-by: Johannes Berg --- include/linux/nospec.h | 21 +++++++++++++++++++++ net/wireless/nl80211.c | 10 +++++++--- 2 files changed, 28 insertions(+), 3 deletions(-) diff --git a/include/linux/nospec.h b/include/linux/nospec.h index f841c11f3f1f..8af35be1869e 100644 --- a/include/linux/nospec.h +++ b/include/linux/nospec.h @@ -41,4 +41,25 @@ static inline unsigned long array_ptr_mask(unsigned long idx, unsigned long sz) __u._bit &= _mask; \ __u._ptr; \ }) + +/** + * array_idx - Generate a pointer to an array index, ensuring the + * pointer is bounded under speculation to NULL. + * + * @idx: the index of the element, must be less than LONG_MAX + * @sz: the number of elements in the array, must be less than LONG_MAX + * + * If @idx falls in the interval [0, @sz), returns &@idx otherwise + * returns NULL. + */ +#define array_idx(idx, sz) \ +({ \ + union { typeof((idx)) *_ptr; unsigned long _bit; } __u; \ + typeof(idx) *_i = &(idx); \ + unsigned long _mask = array_ptr_mask(*_i, (sz)); \ + \ + __u._ptr = _i; \ + __u._bit &= _mask; \ + __u._ptr; \ +}) #endif /* __NOSPEC_H__ */ diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 2b3dbcd40e46..202cb1dc03ee 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -2056,20 +2057,23 @@ static const struct nla_policy txq_params_policy[NL80211_TXQ_ATTR_MAX + 1] = { static int parse_txq_params(struct nlattr *tb[], struct ieee80211_txq_params *txq_params) { + u8 ac, *idx; + if (!tb[NL80211_TXQ_ATTR_AC] || !tb[NL80211_TXQ_ATTR_TXOP] || !tb[NL80211_TXQ_ATTR_CWMIN] || !tb[NL80211_TXQ_ATTR_CWMAX] || !tb[NL80211_TXQ_ATTR_AIFS]) return -EINVAL; - txq_params->ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]); + ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]); txq_params->txop = nla_get_u16(tb[NL80211_TXQ_ATTR_TXOP]); txq_params->cwmin = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMIN]); txq_params->cwmax = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMAX]); txq_params->aifs = nla_get_u8(tb[NL80211_TXQ_ATTR_AIFS]); - if (txq_params->ac >= NL80211_NUM_ACS) + idx = array_idx(ac, NL80211_NUM_ACS); + if (!idx) return -EINVAL; - + txq_params->ac = *idx; return 0; }