From patchwork Fri Jul 1 14:54:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddh Raman Pant X-Patchwork-Id: 586520 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2F20C433EF for ; Fri, 1 Jul 2022 15:11:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230039AbiGAPLN (ORCPT ); Fri, 1 Jul 2022 11:11:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229845AbiGAPLM (ORCPT ); Fri, 1 Jul 2022 11:11:12 -0400 X-Greylist: delayed 913 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Fri, 01 Jul 2022 08:11:11 PDT Received: from sender-of-o53.zoho.in (sender-of-o53.zoho.in [103.117.158.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2606723BD5 for ; Fri, 1 Jul 2022 08:11:10 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1656687325; cv=none; d=zohomail.in; s=zohoarc; b=FiEaSlyeB5dJSM7DRWxy7RLVHSOSwxAuUQwWW/z+v3/iTTBRgQqhqjhn8WsmlaiZdMhy0qQ8Wxt4An/fhPhMXhy3gm7t8kCCus+apZY+9UDadMbP05nMLMOoG6dgIlEkm5lrndF7s2iyaQmkpgdN0QDKFwoAImnDTzZNHsSxq5o= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.in; s=zohoarc; t=1656687325; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:MIME-Version:Message-ID:Subject:To; bh=CrcF49UEX8SWd4LvC7g+h7rckFp6IPoWnRfYza7Wpf4=; b=EQJdwhLyt76VZ7lKH/G1DVNEeFyuhp2Kdj4E61jM1HYf/eu/gw1/lcd3LEp9FmCjJjgs0kp60bKQddBpG4NO0EQl7lCabNdTZWEyRWQwUIwinocRC/TWoamlGroVKDrnEC9R6i3uimRN0bEnjct3DWMxjIVjYLXIDiIHzN3i4s0= ARC-Authentication-Results: i=1; mx.zohomail.in; dkim=pass header.i=siddh.me; spf=pass smtp.mailfrom=code@siddh.me; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1656687325; s=zmail; d=siddh.me; i=code@siddh.me; h=From:From:To:To:Cc:Cc:Message-ID:Subject:Subject:Date:Date:MIME-Version:Content-Transfer-Encoding:Content-Type:Message-Id:Reply-To; bh=CrcF49UEX8SWd4LvC7g+h7rckFp6IPoWnRfYza7Wpf4=; b=QB2xsFvTFpkZpGWLYG/6EoL1vFDTxljo0BxBdEabq/ZUrVzoHxexceL2nc4VXXJh UW//enYAdJiTYS7yuE98h10sTM9umYD6qmp8rljEBDEniUJmAUWr7WPmNk2E8B3C9dO 05iAWpaiLEtNxDVZW/OK3q3QB9LZ2+z0tPD6iSTU= Received: from localhost.localdomain (103.250.137.221 [103.250.137.221]) by mx.zoho.in with SMTPS id 1656687324349795.6718155316092; Fri, 1 Jul 2022 20:25:24 +0530 (IST) From: Siddh Raman Pant To: Johannes Berg , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: linux-wireless , netdev , linux-kernel , linux-kernel-mentees Message-ID: <20220701145423.53208-1-code@siddh.me> Subject: [PATCH] net: Fix UAF in ieee80211_scan_rx() Date: Fri, 1 Jul 2022 20:24:23 +0530 X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-ZohoMailClient: External Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org ieee80211_scan_rx() tries to access scan_req->flags after a null check (see line 303 of mac80211/scan.c), but ___cfg80211_scan_done() uses kfree() on the scan_req (see line 991 of wireless/scan.c). This results in a UAF. ieee80211_scan_rx() is called inside a RCU read-critical section initiated by ieee80211_rx_napi() (see line 5043 of mac80211/rx.c). Thus, add an rcu_head to the scan_req struct so as to use kfree_rcu() instead of kfree() so that we don't free during the critical section. Bug report (3): https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com Reported-by: syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com Reported-by: syzbot+9250865a55539d384347@syzkaller.appspotmail.com Signed-off-by: Siddh Raman Pant --- include/net/cfg80211.h | 2 ++ net/wireless/scan.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 6d02e12e4702..ba4a49884de8 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -2368,6 +2368,7 @@ struct cfg80211_scan_6ghz_params { * @n_6ghz_params: number of 6 GHz params * @scan_6ghz_params: 6 GHz params * @bssid: BSSID to scan for (most commonly, the wildcard BSSID) + * @rcu_head: (internal) RCU head to use for freeing */ struct cfg80211_scan_request { struct cfg80211_ssid *ssids; @@ -2397,6 +2398,7 @@ struct cfg80211_scan_request { bool scan_6ghz; u32 n_6ghz_params; struct cfg80211_scan_6ghz_params *scan_6ghz_params; + struct rcu_head rcu_head; /* keep last */ struct ieee80211_channel *channels[]; diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 6d82bd9eaf8c..638b2805222c 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -988,7 +988,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, kfree(rdev->int_scan_req); rdev->int_scan_req = NULL; - kfree(rdev->scan_req); + kfree_rcu(rdev->scan_req, rcu_head); rdev->scan_req = NULL; if (!send_message)