From patchwork Fri Aug 26 17:00:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Prestwood X-Patchwork-Id: 600572 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 7905DECAAA3 for ; Fri, 26 Aug 2022 17:00:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229946AbiHZRAt (ORCPT ); Fri, 26 Aug 2022 13:00:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232426AbiHZRAp (ORCPT ); Fri, 26 Aug 2022 13:00:45 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8742ABC82A for ; Fri, 26 Aug 2022 10:00:43 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id i7-20020a17090adc0700b001fd7ccbec3cso334892pjv.0 for ; Fri, 26 Aug 2022 10:00:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=8Pf6A1jSbfvvNhI6LUD9Fh4Kyvq7BLxYJ5Ca1mFYhBw=; b=lqNIBvI9Y2xOPTiiQ9CpR+X1qBczA2/sPIIl71YUIMQ5zk6sFsupVr38hnJ+BEbJyW OoOrvhcLrJm4uVTEqa+IU0HM68qd+X+kmajDqb2UZa+uThLzzx43Upfeq7WB3lSZRvVj lSwesp+NI17Wk4fIvrGG5jTQyejXwjrIDaxUEbyA0ru5fU8oIaLcqpW1VSzp/0DaX0cc 5i7Q0tg84DAodFQxAuoA4d/qghtVox1oAhfAfHJzIMoW9uRrEGmeowNPlVVBOYmkTUbL RecYUWfB+aZsdiAQTRsNJTt8g2oUk9tWRDsWVzrhw7P6HdPB5JgUkGBrIBCJr6wBTPiE iwBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=8Pf6A1jSbfvvNhI6LUD9Fh4Kyvq7BLxYJ5Ca1mFYhBw=; b=ssBgXCoFZi7Vwa+zjB8PnWOvAkpxHRNGSJMLZBU2MkNt6SNVl9hVJ8AlNIaIqWj7uH MU3dKq4igB0t6neZe5+71fosKxJ4EKpm+sU4iQDNn5MysAII6idJAcbAqHObZAuGiohw aJukiAqsOrZf6K2zJXgb4zqbLg7osUucoZCAtqhZAvCQhmlbHs/xhFnvObs2eq5QuLDb 7lfdUvQ2vrG2CxriOY6927yRdngkFpTktakjdJMSDGTs5J2TCaL7w7wXlXI9zf9NDwr9 lQ1C228hVA8TbyIjl2T2/3OUchyxmkyUpP/UNeyjVrrwBee3A8ci6JgQeuHI4hiTM5pg C6gg== X-Gm-Message-State: ACgBeo3gHOBJaNLgrvl0lwQtxL08HN34fu3EjsCrj4AqY/prxFKhu31y l5xBRdpTyVk4VddPulNdxfJfU7XGh80= X-Google-Smtp-Source: AA6agR7XNBUNaLxeJX3B9B1raulZH/tenMmZAFaZ9IBHUzQs7PiKcFsUFmK0IEOzpRY9vXV08np07g== X-Received: by 2002:a17:902:b68d:b0:172:e973:82b9 with SMTP id c13-20020a170902b68d00b00172e97382b9mr4549608pls.120.1661533242626; Fri, 26 Aug 2022 10:00:42 -0700 (PDT) Received: from jprestwo-xps.none ([50.39.168.145]) by smtp.gmail.com with ESMTPSA id y9-20020a634949000000b0041d322b3bf6sm1685034pgk.77.2022.08.26.10.00.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Aug 2022 10:00:42 -0700 (PDT) From: James Prestwood To: linux-wireless@vger.kernel.org Cc: James Prestwood Subject: [PATCH v3 2/2] mac80211: Support POWERED_ADDR_CHANGE feature Date: Fri, 26 Aug 2022 10:00:32 -0700 Message-Id: <20220826170032.2860883-3-prestwoj@gmail.com> X-Mailer: git-send-email 2.34.3 In-Reply-To: <20220826170032.2860883-1-prestwoj@gmail.com> References: <20220826170032.2860883-1-prestwoj@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Adds support in mac80211 for NL80211_EXT_FEATURE_POWERED_ADDR_CHANGE. The motivation behind this functionality is to fix limitations of address randomization on frequencies which are disallowed in world roaming. The way things work now, if a client wants to randomize their address per-connection it must power down the device, change the MAC, and power back up. Here lies a problem since powering down the device may result in frequencies being disabled (until the regdom is set). If the desired BSS is on one such frequency the client is unable to connect once the phy is powered again. For mac80211 based devices changing the MAC while powered is possible but currently disallowed (-EBUSY). This patch adds some logic to allow a MAC change while powered by removing the interface, changing the MAC, and adding it again. mac80211 will advertise support for this feature so userspace can determine the best course of action e.g. disallow address randomization on certain frequencies if not supported. There are certain limitations put on this which simplify the logic: - No active connection - No offchannel work, including scanning. Signed-off-by: James Prestwood --- net/mac80211/iface.c | 71 ++++++++++++++++++++++++++++++++++++++++++-- net/mac80211/main.c | 2 ++ 2 files changed, 71 insertions(+), 2 deletions(-) diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 1a9ada411879..8bc168339390 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -199,15 +199,73 @@ static int ieee80211_verify_mac(struct ieee80211_sub_if_data *sdata, u8 *addr, return ret; } +static int ieee80211_can_powered_addr_change(struct ieee80211_sub_if_data *sdata) +{ + struct ieee80211_roc_work *roc; + struct ieee80211_local *local = sdata->local; + struct ieee80211_sub_if_data *scan_sdata; + int ret = 0; + + /* To be the most flexible here we want to only limit changing the + * address if the specific interface is doing offchannel work or + * scanning. + */ + if (netif_carrier_ok(sdata->dev)) + return -EBUSY; + + mutex_lock(&local->mtx); + + /* First check no ROC work is happening on this iface */ + list_for_each_entry(roc, &local->roc_list, list) { + if (roc->sdata != sdata) + continue; + + if (roc->started) { + ret = -EBUSY; + goto unlock; + } + } + + /* And if this iface is scanning */ + if (local->scanning) { + scan_sdata = rcu_dereference_protected(local->scan_sdata, + lockdep_is_held(&local->mtx)); + if (sdata == scan_sdata) + ret = -EBUSY; + } + + switch (sdata->vif.type) { + case NL80211_IFTYPE_STATION: + case NL80211_IFTYPE_P2P_CLIENT: + /* More interface types could be added here but changing the + * address while powered makes the most sense in client modes. + */ + break; + default: + return -EOPNOTSUPP; + } + +unlock: + mutex_unlock(&local->mtx); + return ret; +} + static int ieee80211_change_mac(struct net_device *dev, void *addr) { struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); + struct ieee80211_local *local = sdata->local; struct sockaddr *sa = addr; bool check_dup = true; + bool live = false; int ret; - if (ieee80211_sdata_running(sdata)) - return -EBUSY; + if (ieee80211_sdata_running(sdata)) { + ret = ieee80211_can_powered_addr_change(sdata); + if (ret) + return ret; + + live = true; + } if (sdata->vif.type == NL80211_IFTYPE_MONITOR && !(sdata->u.mntr.flags & MONITOR_FLAG_ACTIVE)) @@ -217,11 +275,19 @@ static int ieee80211_change_mac(struct net_device *dev, void *addr) if (ret) return ret; + if (live) + drv_remove_interface(local, sdata); ret = eth_mac_addr(dev, sa); if (ret == 0) memcpy(sdata->vif.addr, sa->sa_data, ETH_ALEN); + /* Regardless of eth_mac_addr() return we still want to add the + * interface back. This should not fail... + */ + if (live) + WARN_ON(drv_add_interface(local, sdata)); + return ret; } @@ -2128,6 +2194,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name, sdata->u.mgd.use_4addr = params->use_4addr; ndev->features |= local->hw.netdev_features; + ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE; ndev->hw_features |= ndev->features & MAC80211_SUPPORTED_FEATURES_TX; diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 5a385d4146b9..3aeb5e598263 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -616,6 +616,8 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len, NL80211_EXT_FEATURE_CONTROL_PORT_OVER_NL80211_TX_STATUS); wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_SCAN_FREQ_KHZ); + wiphy_ext_feature_set(wiphy, + NL80211_EXT_FEATURE_POWERED_ADDR_CHANGE); if (!ops->hw_scan) { wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN |