From patchwork Sat Sep 18 19:01:20 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 412 Return-Path: Received: from mail.gmx.net (mailout-de.gmx.net [213.165.64.22]) by open-mesh.org (Postfix) with SMTP id 461E415453D for ; Sat, 18 Sep 2010 21:00:44 +0200 (CEST) Received: (qmail invoked by alias); 18 Sep 2010 19:00:39 -0000 Received: from unknown (EHLO sven-desktop.lazhur.ath.cx) [88.130.165.18] by mail.gmx.net (mp056) with SMTP; 18 Sep 2010 21:00:39 +0200 X-Authenticated: #15668376 X-Provags-ID: V01U2FsdGVkX1/w4y14YsXwx/UE2rXLRNewfuEUWvvq2H31g9Qp// eeofKkjAqM37ER From: Sven Eckelmann To: greg@kroah.com Date: Sat, 18 Sep 2010 21:01:20 +0200 Message-Id: <1284836482-23431-11-git-send-email-sven.eckelmann@gmx.de> X-Mailer: git-send-email 1.7.2.3 In-Reply-To: <1284836482-23431-1-git-send-email-sven.eckelmann@gmx.de> References: <1284836482-23431-1-git-send-email-sven.eckelmann@gmx.de> X-Y-GMX-Trusted: 0 Cc: b.a.t.m.a.n@lists.open-mesh.org Subject: [B.A.T.M.A.N.] [PATCH 10/12] Staging: batman-adv: count batman_if list queries as reference X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.11 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 18 Sep 2010 19:00:45 -0000 The return of get_batman_if_by_netdev and get_active_batman_if leaks a pointer from the rcu protected list of interfaces. We must protect it to prevent a too early release of the memory. Those functions must increase the reference counter before rcu_read_unlock or it may be to late to prevent a free. hardif_add_interface must also increase the reference count for the returned batman_if to make the behaviour consistent. Reported-by: Paul E. McKenney Signed-off-by: Sven Eckelmann --- drivers/staging/batman-adv/TODO | 4 -- drivers/staging/batman-adv/bat_sysfs.c | 42 ++++++++++++++++++++------ drivers/staging/batman-adv/hard-interface.c | 29 +++++++++++++++--- 3 files changed, 56 insertions(+), 19 deletions(-) diff --git a/drivers/staging/batman-adv/TODO b/drivers/staging/batman-adv/TODO index cb6b026..5913731 100644 --- a/drivers/staging/batman-adv/TODO +++ b/drivers/staging/batman-adv/TODO @@ -1,7 +1,3 @@ - * Rework usage of RCU - - don't leak pointers from rcu out of rcu critical area which may - get freed - - go through Documentation/RCU/checklist.txt * Request a new review * Process the comments from the review * Move into mainline proper diff --git a/drivers/staging/batman-adv/bat_sysfs.c b/drivers/staging/batman-adv/bat_sysfs.c index 0610169..bc17fb8 100644 --- a/drivers/staging/batman-adv/bat_sysfs.c +++ b/drivers/staging/batman-adv/bat_sysfs.c @@ -405,13 +405,17 @@ static ssize_t show_mesh_iface(struct kobject *kobj, struct attribute *attr, struct device *dev = to_dev(kobj->parent); struct net_device *net_dev = to_net_dev(dev); struct batman_if *batman_if = get_batman_if_by_netdev(net_dev); + ssize_t length; if (!batman_if) return 0; - return sprintf(buff, "%s\n", - batman_if->if_status == IF_NOT_IN_USE ? - "none" : batman_if->soft_iface->name); + length = sprintf(buff, "%s\n", batman_if->if_status == IF_NOT_IN_USE ? + "none" : batman_if->soft_iface->name); + + hardif_put(batman_if); + + return length; } static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, @@ -421,6 +425,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, struct net_device *net_dev = to_net_dev(dev); struct batman_if *batman_if = get_batman_if_by_netdev(net_dev); int status_tmp = -1; + int ret; if (!batman_if) return count; @@ -431,6 +436,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, if (strlen(buff) >= IFNAMSIZ) { pr_err("Invalid parameter for 'mesh_iface' setting received: " "interface name too long '%s'\n", buff); + hardif_put(batman_if); return -EINVAL; } @@ -440,13 +446,16 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, status_tmp = IF_I_WANT_YOU; if ((batman_if->if_status == status_tmp) || ((batman_if->soft_iface) && - (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0))) + (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0))) { + hardif_put(batman_if); return count; + } if (status_tmp == IF_NOT_IN_USE) { rtnl_lock(); hardif_disable_interface(batman_if); rtnl_unlock(); + hardif_put(batman_if); return count; } @@ -457,7 +466,10 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr, rtnl_unlock(); } - return hardif_enable_interface(batman_if, buff); + ret = hardif_enable_interface(batman_if, buff); + hardif_put(batman_if); + + return ret; } static ssize_t show_iface_status(struct kobject *kobj, struct attribute *attr, @@ -466,23 +478,33 @@ static ssize_t show_iface_status(struct kobject *kobj, struct attribute *attr, struct device *dev = to_dev(kobj->parent); struct net_device *net_dev = to_net_dev(dev); struct batman_if *batman_if = get_batman_if_by_netdev(net_dev); + ssize_t length; if (!batman_if) return 0; switch (batman_if->if_status) { case IF_TO_BE_REMOVED: - return sprintf(buff, "disabling\n"); + length = sprintf(buff, "disabling\n"); + break; case IF_INACTIVE: - return sprintf(buff, "inactive\n"); + length = sprintf(buff, "inactive\n"); + break; case IF_ACTIVE: - return sprintf(buff, "active\n"); + length = sprintf(buff, "active\n"); + break; case IF_TO_BE_ACTIVATED: - return sprintf(buff, "enabling\n"); + length = sprintf(buff, "enabling\n"); + break; case IF_NOT_IN_USE: default: - return sprintf(buff, "not in use\n"); + length = sprintf(buff, "not in use\n"); + break; } + + hardif_put(batman_if); + + return length; } static BAT_ATTR(mesh_iface, S_IRUGO | S_IWUSR, diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c index df6e5bd..eef5631 100644 --- a/drivers/staging/batman-adv/hard-interface.c +++ b/drivers/staging/batman-adv/hard-interface.c @@ -49,6 +49,9 @@ struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev) batman_if = NULL; out: + if (batman_if) + hardif_hold(batman_if); + rcu_read_unlock(); return batman_if; } @@ -96,6 +99,9 @@ static struct batman_if *get_active_batman_if(struct net_device *soft_iface) batman_if = NULL; out: + if (batman_if) + hardif_hold(batman_if); + rcu_read_unlock(); return batman_if; } @@ -292,6 +298,7 @@ int hardif_enable_interface(struct batman_if *batman_if, char *iface_name) batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN); batman_if->batman_adv_ptype.func = batman_skb_recv; batman_if->batman_adv_ptype.dev = batman_if->net_dev; + hardif_hold(batman_if); dev_add_pack(&batman_if->batman_adv_ptype); atomic_set(&batman_if->seqno, 1); @@ -350,13 +357,20 @@ void hardif_disable_interface(struct batman_if *batman_if) bat_info(batman_if->soft_iface, "Removing interface: %s\n", batman_if->net_dev->name); dev_remove_pack(&batman_if->batman_adv_ptype); + hardif_put(batman_if); bat_priv->num_ifaces--; orig_hash_del_if(batman_if, bat_priv->num_ifaces); - if (batman_if == bat_priv->primary_if) - set_primary_if(bat_priv, - get_active_batman_if(batman_if->soft_iface)); + if (batman_if == bat_priv->primary_if) { + struct batman_if *new_if; + + new_if = get_active_batman_if(batman_if->soft_iface); + set_primary_if(bat_priv, new_if); + + if (new_if) + hardif_put(new_if); + } kfree(batman_if->packet_buff); batman_if->packet_buff = NULL; @@ -410,6 +424,8 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev) list_add_tail_rcu(&batman_if->list, &if_list); spin_unlock(&if_list_lock); + /* extra reference for return */ + hardif_hold(batman_if); return batman_if; free_if: @@ -459,7 +475,7 @@ static int hard_if_event(struct notifier_block *this, struct bat_priv *bat_priv; if (!batman_if && event == NETDEV_REGISTER) - batman_if = hardif_add_interface(net_dev); + batman_if = hardif_add_interface(net_dev); if (!batman_if) goto out; @@ -482,8 +498,10 @@ static int hard_if_event(struct notifier_block *this, update_min_mtu(batman_if->soft_iface); break; case NETDEV_CHANGEADDR: - if (batman_if->if_status == IF_NOT_IN_USE) + if (batman_if->if_status == IF_NOT_IN_USE) { + hardif_put(batman_if); goto out; + } check_known_mac_addr(batman_if->net_dev->dev_addr); update_mac_addresses(batman_if); @@ -495,6 +513,7 @@ static int hard_if_event(struct notifier_block *this, default: break; }; + hardif_put(batman_if); out: return NOTIFY_DONE;