From patchwork Sat Nov 20 12:39:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 18401 X-Patchwork-Delegate: sw@simonwunderlich.de Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from diktynna.open-mesh.org (localhost [IPv6:::1]) by diktynna.open-mesh.org (Postfix) with ESMTP id DD9B583DF8; Sat, 20 Nov 2021 13:39:47 +0100 (CET) Received: from dvalin.narfation.org (dvalin.narfation.org [213.160.73.56]) by diktynna.open-mesh.org (Postfix) with ESMTPS id 6791C81A7E for ; Sat, 20 Nov 2021 13:39:43 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1637411982; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Tapa3Y205oYvhgGZ3fKaBByTWKzaol61opjN713tCK0=; b=X+c0Qnu4EHuH0UOu5hCC+99WY4p8/yxBnHtHqUIRFddOdGebJ4xCks3cb7OLe/ixpxCL/e bfjdIEo3yXgwEhFOpO2x5q8dz7DpJUM1ZflMY4365deg/fn8aJAyzBAN9sUBm2EfedsLpP NK3LpZt4wH4QO4FFqLbqcqBREkHJ7DU= From: Sven Eckelmann To: stable@vger.kernel.org Subject: [PATCH 4.4 03/11] batman-adv: Prevent duplicated softif_vlan entry Date: Sat, 20 Nov 2021 13:39:31 +0100 Message-Id: <20211120123939.260723-4-sven@narfation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211120123939.260723-1-sven@narfation.org> References: <20211120123939.260723-1-sven@narfation.org> MIME-Version: 1.0 ARC-Seal: i=1; s=20121; d=open-mesh.org; t=1637411983; a=rsa-sha256; cv=none; b=yjrviUrCRqV9qX4P7nARfmEEikLJGouJNQ9P5ZWVVURmorVnnUD6OyCld2sR5epxu1Zjap A4l5busGLX8rdjH9wztVDg5l+QMJVZJ+iS36P92X4HqTfkTPc2E3BbwufhaAS4AeqykqF6 wgydIhskomi7JIsZJXKcZ+JzI8cyPy4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=open-mesh.org; s=20121; t=1637411983; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Tapa3Y205oYvhgGZ3fKaBByTWKzaol61opjN713tCK0=; b=dYO32Ea6hT0c2uB9Pg1bOdBjlD9qlHBCP8ohvCBX35wwkNWVdypzhS+vvxKHtLnbDGLpdl c5DsyWna8Px8Wo7+BOcXMbSbKT1YfRHwgUIE4f7ELwmrjNr8EWTRTWYfGNIylRJRSSlTfs 8OZ5dBegTLF/cw75jDTiA2Cf6vWboJI= ARC-Authentication-Results: i=1; diktynna.open-mesh.org; dkim=pass header.d=narfation.org header.s=20121 header.b=X+c0Qnu4; spf=pass (diktynna.open-mesh.org: domain of sven@narfation.org designates 213.160.73.56 as permitted sender) smtp.mailfrom=sven@narfation.org; dmarc=pass (policy=none) header.from=narfation.org Message-ID-Hash: RM4UBG3CFJWTMDI734E6ASZWU22VYW2Y X-Message-ID-Hash: RM4UBG3CFJWTMDI734E6ASZWU22VYW2Y X-MailFrom: sven@narfation.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-b.a.t.m.a.n.lists.open-mesh.org-0; header-match-b.a.t.m.a.n.lists.open-mesh.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header CC: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 3.2.1 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: commit 94cb82f594ed86be303398d6dfc7640a6f1d45d4 upstream. The function batadv_softif_vlan_get is responsible for adding new softif_vlan to the softif_vlan_list. It first checks whether the entry already is in the list or not. If it is, then the creation of a new entry is aborted. But the lock for the list is only held when the list is really modified. This could lead to duplicated entries because another context could create an entry with the same key between the check and the list manipulation. The check and the manipulation of the list must therefore be in the same locked code section. Fixes: 5d2c05b21337 ("batman-adv: add per VLAN interface attribute framework") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich [ bp: 4.4 backport: switch back to atomic_t based reference counting. ] Signed-off-by: Sven Eckelmann --- net/batman-adv/soft-interface.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index ff693887ea82..f1e2e7e33500 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -539,15 +539,20 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) struct batadv_softif_vlan *vlan; int err; + spin_lock_bh(&bat_priv->softif_vlan_list_lock); + vlan = batadv_softif_vlan_get(bat_priv, vid); if (vlan) { batadv_softif_vlan_free_ref(vlan); + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return -EEXIST; } vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC); - if (!vlan) + if (!vlan) { + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); return -ENOMEM; + } vlan->bat_priv = bat_priv; vlan->vid = vid; @@ -555,16 +560,19 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) atomic_set(&vlan->ap_isolation, 0); + hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list); + spin_unlock_bh(&bat_priv->softif_vlan_list_lock); + + /* batadv_sysfs_add_vlan cannot be in the spinlock section due to the + * sleeping behavior of the sysfs functions and the fs_reclaim lock + */ err = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan); if (err) { - kfree(vlan); + /* ref for the list */ + batadv_softif_vlan_free_ref(vlan); return err; } - spin_lock_bh(&bat_priv->softif_vlan_list_lock); - hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list); - spin_unlock_bh(&bat_priv->softif_vlan_list_lock); - /* add a new TT local entry. This one will be marked with the NOPURGE * flag */