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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 07003C388F7 for ; Tue, 10 Nov 2020 03:56:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B525A20663 for ; Tue, 10 Nov 2020 03:56:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="E6KLWDXE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387579AbgKJD4X (ORCPT ); Mon, 9 Nov 2020 22:56:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:58280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387557AbgKJD4W (ORCPT ); Mon, 9 Nov 2020 22:56:22 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 894DF20663; Tue, 10 Nov 2020 03:56:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604980581; bh=vYfmboIzGbBiNDdt8ogPl6hax31zFik+g+zN1Zf1vRI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E6KLWDXETpCrmFyYQYKKALhMkwV8+uJ7kv7tWcdUC/Wb5B8e18iYNLTUz4vC4yzKi 9ozwG8W+72pAVpyWOvI4pqrxwRVMgKOTbfPxz4jzgJyGGTTb86Q/Ybr8MXWbwbscso Z7tVfZ01PkoxuAFA46tYBeJnPDBvguMlTMys4NUM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johannes Berg , syzbot+32fd1a1bfe355e93f1e2@syzkaller.appspotmail.com, Sasha Levin , linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 07/14] mac80211: fix use of skb payload instead of header Date: Mon, 9 Nov 2020 22:56:03 -0500 Message-Id: <20201110035611.424867-7-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201110035611.424867-1-sashal@kernel.org> References: <20201110035611.424867-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Johannes Berg [ Upstream commit 14f46c1e5108696ec1e5a129e838ecedf108c7bf ] When ieee80211_skb_resize() is called from ieee80211_build_hdr() the skb has no 802.11 header yet, in fact it consist only of the payload as the ethernet frame is removed. As such, we're using the payload data for ieee80211_is_mgmt(), which is of course completely wrong. This didn't really hurt us because these are always data frames, so we could only have added more tailroom than we needed if we determined it was a management frame and sdata->crypto_tx_tailroom_needed_cnt was false. However, syzbot found that of course there need not be any payload, so we're using at best uninitialized memory for the check. Fix this to pass explicitly the kind of frame that we have instead of checking there, by replacing the "bool may_encrypt" argument with an argument that can carry the three possible states - it's not going to be encrypted, it's a management frame, or it's a data frame (and then we check sdata->crypto_tx_tailroom_needed_cnt). Reported-by: syzbot+32fd1a1bfe355e93f1e2@syzkaller.appspotmail.com Signed-off-by: Johannes Berg Link: https://lore.kernel.org/r/20201009132538.e1fd7f802947.I799b288466ea2815f9d4c84349fae697dca2f189@changeid Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/tx.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 1b1f2d6cb3f4b..0ab710576673f 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1851,19 +1851,24 @@ static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata, /* device xmit handlers */ +enum ieee80211_encrypt { + ENCRYPT_NO, + ENCRYPT_MGMT, + ENCRYPT_DATA, +}; + static int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb, - int head_need, bool may_encrypt) + int head_need, + enum ieee80211_encrypt encrypt) { struct ieee80211_local *local = sdata->local; - struct ieee80211_hdr *hdr; bool enc_tailroom; int tail_need = 0; - hdr = (struct ieee80211_hdr *) skb->data; - enc_tailroom = may_encrypt && - (sdata->crypto_tx_tailroom_needed_cnt || - ieee80211_is_mgmt(hdr->frame_control)); + enc_tailroom = encrypt == ENCRYPT_MGMT || + (encrypt == ENCRYPT_DATA && + sdata->crypto_tx_tailroom_needed_cnt); if (enc_tailroom) { tail_need = IEEE80211_ENCRYPT_TAILROOM; @@ -1896,21 +1901,27 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; int headroom; - bool may_encrypt; + enum ieee80211_encrypt encrypt; - may_encrypt = !(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT); + if (info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT) + encrypt = ENCRYPT_NO; + else if (ieee80211_is_mgmt(hdr->frame_control)) + encrypt = ENCRYPT_MGMT; + else + encrypt = ENCRYPT_DATA; headroom = local->tx_headroom; - if (may_encrypt) + if (encrypt != ENCRYPT_NO) headroom += sdata->encrypt_headroom; headroom -= skb_headroom(skb); headroom = max_t(int, 0, headroom); - if (ieee80211_skb_resize(sdata, skb, headroom, may_encrypt)) { + if (ieee80211_skb_resize(sdata, skb, headroom, encrypt)) { ieee80211_free_txskb(&local->hw, skb); return; } + /* reload after potential resize */ hdr = (struct ieee80211_hdr *) skb->data; info->control.vif = &sdata->vif; @@ -2692,7 +2703,7 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata, head_need += sdata->encrypt_headroom; head_need += local->tx_headroom; head_need = max_t(int, 0, head_need); - if (ieee80211_skb_resize(sdata, skb, head_need, true)) { + if (ieee80211_skb_resize(sdata, skb, head_need, ENCRYPT_DATA)) { ieee80211_free_txskb(&local->hw, skb); skb = NULL; return ERR_PTR(-ENOMEM); @@ -3352,7 +3363,7 @@ static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata, if (unlikely(ieee80211_skb_resize(sdata, skb, max_t(int, extra_head + hw_headroom - skb_headroom(skb), 0), - false))) { + ENCRYPT_NO))) { kfree_skb(skb); return true; } -- 2.27.0