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Commit e8a34e5a authored by Tyler Wear's avatar Tyler Wear Committed by Gerrit - the friendly Code Review server
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netfilter: xt_quota2: 4.9 netlink notification fix 



Create a virtual device inside of sysfs.  Use the created
kobject to notify userspace of counter transitions.

CRs-Fixed: 2068778
Change-Id: I06a02a3e6c70160083e17291cf08f1e9b375a26f
Signed-off-by: default avatarTyler Wear <twear@codeaurora.org>
parent 3228fead

net/netfilter/xt_quota2.c

+59 −71
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/proc_fs.h>

#include <linux/skbuff.h>

#include <linux/spinlock.h>

#include <linux/workqueue.h>

#include <asm/atomic.h>

#include <net/netlink.h>
@@ -43,6 +44,8 @@ typedef struct ulog_packet_msg { 
	unsigned char payload[0];

} ulog_packet_msg_t;

#endif

#define QUOTA2_SYSFS_WORK_MAX_SIZE 64

#define QUOTA2_SYSFS_NUM_ENVP 3



/**

 * @lock:	lock to protect quota writers from each other
@@ -54,17 +57,16 @@ struct xt_quota_counter { 
	atomic_t ref;

	char name[sizeof(((struct xt_quota_mtinfo2 *)NULL)->name)];

	struct proc_dir_entry *procfs_entry;

	char last_iface[QUOTA2_SYSFS_WORK_MAX_SIZE];

	char last_prefix[QUOTA2_SYSFS_WORK_MAX_SIZE];

	struct work_struct work;

};



#ifdef CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG

/* Harald's favorite number +1 :D From ipt_ULOG.C */

static int qlog_nl_event = 112;

module_param_named(event_num, qlog_nl_event, uint, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(event_num,

		 "Event number for NETLINK_NFLOG message. 0 disables log."

		 "111 is what ipt_ULOG uses.");

static struct sock *nflognl;

#endif

#define to_quota_counter(x) container_of(x, struct xt_quota_counter, work)



static struct class *quota_class;

static struct device *quota_device;

static struct kobject *quota_kobj;



static LIST_HEAD(counter_list);

static DEFINE_SPINLOCK(counter_list_lock);
@@ -75,68 +77,39 @@ static kuid_t quota_list_uid = KUIDT_INIT(0); 
static kgid_t quota_list_gid = KGIDT_INIT(0);

module_param_named(perms, quota_list_perms, uint, S_IRUGO | S_IWUSR);



#ifdef CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG

static void quota2_log(unsigned int hooknum,

		       const struct sk_buff *skb,

		       const struct net_device *in,

		       const struct net_device *out,

		       const char *prefix)

static void quota2_work(struct work_struct *work)

{

	ulog_packet_msg_t *pm;

	struct sk_buff *log_skb;

	size_t size;

	struct nlmsghdr *nlh;

	char alert_msg[QUOTA2_SYSFS_WORK_MAX_SIZE];

	char iface_name[QUOTA2_SYSFS_WORK_MAX_SIZE];

	char *envp[QUOTA2_SYSFS_NUM_ENVP] = {alert_msg, iface_name,  NULL};

	struct xt_quota_counter *counter = to_quota_counter(work);



	if (!qlog_nl_event)

		return;

	snprintf(alert_msg, sizeof(alert_msg), "ALERT_NAME=%s", counter->name);

	snprintf(iface_name, sizeof(iface_name), "INTERFACE=%s",

		 counter->last_iface);



	size = NLMSG_SPACE(sizeof(*pm));

	size = max(size, (size_t)NLMSG_GOODSIZE);

	log_skb = alloc_skb(size, GFP_ATOMIC);

	if (!log_skb) {

		pr_err("xt_quota2: cannot alloc skb for logging\n");

		return;

	kobject_uevent_env(quota_kobj, KOBJ_CHANGE, envp);

}



	nlh = nlmsg_put(log_skb, /*pid*/0, /*seq*/0, qlog_nl_event,

			sizeof(*pm), 0);

	if (!nlh) {

		pr_err("xt_quota2: nlmsg_put failed\n");

		kfree_skb(log_skb);

static void quota2_log(const struct net_device *in,

		       const struct net_device *out,

		       struct  xt_quota_counter *q,

		       const char *prefix)

{

	if (!prefix)

		return;

	}

	pm = nlmsg_data(nlh);

	if (skb->tstamp.tv64 == 0)

		__net_timestamp((struct sk_buff *)skb);

	pm->data_len = 0;

	pm->hook = hooknum;

	if (prefix != NULL)

		strlcpy(pm->prefix, prefix, sizeof(pm->prefix));

	else

		*(pm->prefix) = '\0';

	if (in)

		strlcpy(pm->indev_name, in->name, sizeof(pm->indev_name));

	else

		pm->indev_name[0] = '\0';



	if (out)

		strlcpy(pm->outdev_name, out->name, sizeof(pm->outdev_name));

	strlcpy(q->last_prefix, prefix, QUOTA2_SYSFS_WORK_MAX_SIZE);



	if (in)

		strlcpy(q->last_iface, in->name, QUOTA2_SYSFS_WORK_MAX_SIZE);

	else if (out)

		strlcpy(q->last_iface, out->name, QUOTA2_SYSFS_WORK_MAX_SIZE);

	else

		pm->outdev_name[0] = '\0';

		strlcpy(q->last_iface, "UNKNOWN", QUOTA2_SYSFS_WORK_MAX_SIZE);



	NETLINK_CB(log_skb).dst_group = 1;

	pr_debug("throwing 1 packets to netlink group 1\n");

	netlink_broadcast(nflognl, log_skb, 0, 1, GFP_ATOMIC);

}

#else

static void quota2_log(unsigned int hooknum,

		       const struct sk_buff *skb,

		       const struct net_device *in,

		       const struct net_device *out,

		       const char *prefix)

{

	schedule_work(&q->work);

}

#endif  /* if+else CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG */



static ssize_t quota_proc_read(struct file *file, char __user *buf,

			   size_t size, loff_t *ppos)
@@ -193,6 +166,9 @@ q2_new_counter(const struct xt_quota_mtinfo2 *q, bool anon) 
		INIT_LIST_HEAD(&e->list);

		atomic_set(&e->ref, 1);

		strlcpy(e->name, q->name, sizeof(e->name));

		strlcpy(e->last_prefix, "UNSET", sizeof(e->last_prefix));

		strlcpy(e->last_iface, "UNSET", sizeof(e->last_iface));

		INIT_WORK(&e->work, quota2_work);

	}

	return e;

}
@@ -326,11 +302,7 @@ quota_mt2(const struct sk_buff *skb, struct xt_action_param *par) 
		} else {

			/* We are transitioning, log that fact. */

			if (e->quota) {

				quota2_log(par->hooknum,

					   skb,

					   par->in,

					   par->out,

					   q->name);

				quota2_log(par->in, par->out, e, q->name);

			}

			/* we do not allow even small packets from now on */

			e->quota = 0;
@@ -368,11 +340,25 @@ static int __init quota_mt2_init(void) 
	int ret;

	pr_debug("xt_quota2: init()");



#ifdef CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG

	nflognl = netlink_kernel_create(&init_net, NETLINK_NFLOG, NULL);

	if (!nflognl)

		return -ENOMEM;

#endif

	quota_class = class_create(THIS_MODULE, "xt_quota2");

	ret = PTR_ERR(quota_class);

	if (IS_ERR(quota_class)) {

		pr_err("xt_quota2: couldn't create class");

		class_destroy(quota_class);

		return ret;

	}



	quota_device = device_create(quota_class, NULL, MKDEV(0, 0), NULL,

				     "counters");

	ret = PTR_ERR(quota_device);

	if (IS_ERR(quota_device)) {

		pr_err("xt_quota2: couldn't create device");

		device_destroy(quota_class, MKDEV(0, 0));

		class_destroy(quota_class);

		return ret;

	}



	quota_kobj = &quota_device->kobj;



	proc_xt_quota = proc_mkdir("xt_quota", init_net.proc_net);

	if (proc_xt_quota == NULL)
@@ -389,6 +375,8 @@ static void __exit quota_mt2_exit(void) 
{

	xt_unregister_matches(quota_mt2_reg, ARRAY_SIZE(quota_mt2_reg));

	remove_proc_entry("xt_quota", init_net.proc_net);

	device_destroy(quota_class, MKDEV(0, 0));

	class_destroy(quota_class);

}



module_init(quota_mt2_init);