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-rw-r--r--net/netfilter/xt_recent.c687
1 files changed, 687 insertions, 0 deletions
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
new file mode 100644
index 0000000..280c471
--- /dev/null
+++ b/net/netfilter/xt_recent.c
@@ -0,0 +1,687 @@
+/*
+ * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
+ * Copyright © CC Computer Consultants GmbH, 2007 - 2008
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This is a replacement of the old ipt_recent module, which carried the
+ * following copyright notice:
+ *
+ * Author: Stephen Frost <sfrost@snowman.net>
+ * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
+ */
+#include <linux/init.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
+#include <linux/bitops.h>
+#include <linux/skbuff.h>
+#include <linux/inet.h>
+#include <net/net_namespace.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_recent.h>
+
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
+MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching for IPv4");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_recent");
+MODULE_ALIAS("ip6t_recent");
+
+static unsigned int ip_list_tot = 100;
+static unsigned int ip_pkt_list_tot = 20;
+static unsigned int ip_list_hash_size = 0;
+static unsigned int ip_list_perms = 0644;
+static unsigned int ip_list_uid = 0;
+static unsigned int ip_list_gid = 0;
+module_param(ip_list_tot, uint, 0400);
+module_param(ip_pkt_list_tot, uint, 0400);
+module_param(ip_list_hash_size, uint, 0400);
+module_param(ip_list_perms, uint, 0400);
+module_param(ip_list_uid, uint, 0400);
+module_param(ip_list_gid, uint, 0400);
+MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
+MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
+MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
+MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
+MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/xt_recent/* files");
+MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/xt_recent/* files");
+
+struct recent_entry {
+ struct list_head list;
+ struct list_head lru_list;
+ union nf_inet_addr addr;
+ u_int16_t family;
+ u_int8_t ttl;
+ u_int8_t index;
+ u_int16_t nstamps;
+ unsigned long stamps[0];
+};
+
+struct recent_table {
+ struct list_head list;
+ char name[XT_RECENT_NAME_LEN];
+#ifdef CONFIG_PROC_FS
+ struct proc_dir_entry *proc_old, *proc;
+#endif
+ unsigned int refcnt;
+ unsigned int entries;
+ struct list_head lru_list;
+ struct list_head iphash[0];
+};
+
+static LIST_HEAD(tables);
+static DEFINE_SPINLOCK(recent_lock);
+static DEFINE_MUTEX(recent_mutex);
+
+#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+static struct proc_dir_entry *proc_old_dir;
+#endif
+static struct proc_dir_entry *recent_proc_dir;
+static const struct file_operations recent_old_fops, recent_mt_fops;
+#endif
+
+static u_int32_t hash_rnd;
+static bool hash_rnd_initted;
+
+static unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
+{
+ if (!hash_rnd_initted) {
+ get_random_bytes(&hash_rnd, sizeof(hash_rnd));
+ hash_rnd_initted = true;
+ }
+ return jhash_1word((__force u32)addr->ip, hash_rnd) &
+ (ip_list_hash_size - 1);
+}
+
+static unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
+{
+ if (!hash_rnd_initted) {
+ get_random_bytes(&hash_rnd, sizeof(hash_rnd));
+ hash_rnd_initted = true;
+ }
+ return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
+ (ip_list_hash_size - 1);
+}
+
+static struct recent_entry *
+recent_entry_lookup(const struct recent_table *table,
+ const union nf_inet_addr *addrp, u_int16_t family,
+ u_int8_t ttl)
+{
+ struct recent_entry *e;
+ unsigned int h;
+
+ if (family == NFPROTO_IPV4)
+ h = recent_entry_hash4(addrp);
+ else
+ h = recent_entry_hash6(addrp);
+
+ list_for_each_entry(e, &table->iphash[h], list)
+ if (e->family == family &&
+ memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
+ (ttl == e->ttl || ttl == 0 || e->ttl == 0))
+ return e;
+ return NULL;
+}
+
+static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
+{
+ list_del(&e->list);
+ list_del(&e->lru_list);
+ kfree(e);
+ t->entries--;
+}
+
+static struct recent_entry *
+recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
+ u_int16_t family, u_int8_t ttl)
+{
+ struct recent_entry *e;
+
+ if (t->entries >= ip_list_tot) {
+ e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
+ recent_entry_remove(t, e);
+ }
+ e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
+ GFP_ATOMIC);
+ if (e == NULL)
+ return NULL;
+ memcpy(&e->addr, addr, sizeof(e->addr));
+ e->ttl = ttl;
+ e->stamps[0] = jiffies;
+ e->nstamps = 1;
+ e->index = 1;
+ e->family = family;
+ if (family == NFPROTO_IPV4)
+ list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
+ else
+ list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
+ list_add_tail(&e->lru_list, &t->lru_list);
+ t->entries++;
+ return e;
+}
+
+static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
+{
+ e->stamps[e->index++] = jiffies;
+ if (e->index > e->nstamps)
+ e->nstamps = e->index;
+ e->index %= ip_pkt_list_tot;
+ list_move_tail(&e->lru_list, &t->lru_list);
+}
+
+static struct recent_table *recent_table_lookup(const char *name)
+{
+ struct recent_table *t;
+
+ list_for_each_entry(t, &tables, list)
+ if (!strcmp(t->name, name))
+ return t;
+ return NULL;
+}
+
+static void recent_table_flush(struct recent_table *t)
+{
+ struct recent_entry *e, *next;
+ unsigned int i;
+
+ for (i = 0; i < ip_list_hash_size; i++)
+ list_for_each_entry_safe(e, next, &t->iphash[i], list)
+ recent_entry_remove(t, e);
+}
+
+static bool
+recent_mt(const struct sk_buff *skb, const struct xt_match_param *par)
+{
+ const struct xt_recent_mtinfo *info = par->matchinfo;
+ struct recent_table *t;
+ struct recent_entry *e;
+ union nf_inet_addr addr = {};
+ u_int8_t ttl;
+ bool ret = info->invert;
+
+ if (par->match->family == NFPROTO_IPV4) {
+ const struct iphdr *iph = ip_hdr(skb);
+
+ if (info->side == XT_RECENT_DEST)
+ addr.ip = iph->daddr;
+ else
+ addr.ip = iph->saddr;
+
+ ttl = iph->ttl;
+ } else {
+ const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+ if (info->side == XT_RECENT_DEST)
+ memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
+ else
+ memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
+
+ ttl = iph->hop_limit;
+ }
+
+ /* use TTL as seen before forwarding */
+ if (par->out != NULL && skb->sk == NULL)
+ ttl++;
+
+ spin_lock_bh(&recent_lock);
+ t = recent_table_lookup(info->name);
+ e = recent_entry_lookup(t, &addr, par->match->family,
+ (info->check_set & XT_RECENT_TTL) ? ttl : 0);
+ if (e == NULL) {
+ if (!(info->check_set & XT_RECENT_SET))
+ goto out;
+ e = recent_entry_init(t, &addr, par->match->family, ttl);
+ if (e == NULL)
+ *par->hotdrop = true;
+ ret = !ret;
+ goto out;
+ }
+
+ if (info->check_set & XT_RECENT_SET)
+ ret = !ret;
+ else if (info->check_set & XT_RECENT_REMOVE) {
+ recent_entry_remove(t, e);
+ ret = !ret;
+ } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
+ unsigned long time = jiffies - info->seconds * HZ;
+ unsigned int i, hits = 0;
+
+ for (i = 0; i < e->nstamps; i++) {
+ if (info->seconds && time_after(time, e->stamps[i]))
+ continue;
+ if (++hits >= info->hit_count) {
+ ret = !ret;
+ break;
+ }
+ }
+ }
+
+ if (info->check_set & XT_RECENT_SET ||
+ (info->check_set & XT_RECENT_UPDATE && ret)) {
+ recent_entry_update(t, e);
+ e->ttl = ttl;
+ }
+out:
+ spin_unlock_bh(&recent_lock);
+ return ret;
+}
+
+static bool recent_mt_check(const struct xt_mtchk_param *par)
+{
+ const struct xt_recent_mtinfo *info = par->matchinfo;
+ struct recent_table *t;
+ unsigned i;
+ bool ret = false;
+
+ if (hweight8(info->check_set &
+ (XT_RECENT_SET | XT_RECENT_REMOVE |
+ XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
+ return false;
+ if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
+ (info->seconds || info->hit_count))
+ return false;
+ if (info->hit_count > ip_pkt_list_tot)
+ return false;
+ if (info->name[0] == '\0' ||
+ strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
+ return false;
+
+ mutex_lock(&recent_mutex);
+ t = recent_table_lookup(info->name);
+ if (t != NULL) {
+ t->refcnt++;
+ ret = true;
+ goto out;
+ }
+
+ t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
+ GFP_KERNEL);
+ if (t == NULL)
+ goto out;
+ t->refcnt = 1;
+ strcpy(t->name, info->name);
+ INIT_LIST_HEAD(&t->lru_list);
+ for (i = 0; i < ip_list_hash_size; i++)
+ INIT_LIST_HEAD(&t->iphash[i]);
+#ifdef CONFIG_PROC_FS
+ t->proc = proc_create_data(t->name, ip_list_perms, recent_proc_dir,
+ &recent_mt_fops, t);
+ if (t->proc == NULL) {
+ kfree(t);
+ goto out;
+ }
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+ t->proc_old = proc_create_data(t->name, ip_list_perms, proc_old_dir,
+ &recent_old_fops, t);
+ if (t->proc_old == NULL) {
+ remove_proc_entry(t->name, proc_old_dir);
+ kfree(t);
+ goto out;
+ }
+ t->proc_old->uid = ip_list_uid;
+ t->proc_old->gid = ip_list_gid;
+#endif
+ t->proc->uid = ip_list_uid;
+ t->proc->gid = ip_list_gid;
+#endif
+ spin_lock_bh(&recent_lock);
+ list_add_tail(&t->list, &tables);
+ spin_unlock_bh(&recent_lock);
+ ret = true;
+out:
+ mutex_unlock(&recent_mutex);
+ return ret;
+}
+
+static void recent_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_recent_mtinfo *info = par->matchinfo;
+ struct recent_table *t;
+
+ mutex_lock(&recent_mutex);
+ t = recent_table_lookup(info->name);
+ if (--t->refcnt == 0) {
+ spin_lock_bh(&recent_lock);
+ list_del(&t->list);
+ spin_unlock_bh(&recent_lock);
+#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+ remove_proc_entry(t->name, proc_old_dir);
+#endif
+ remove_proc_entry(t->name, recent_proc_dir);
+#endif
+ recent_table_flush(t);
+ kfree(t);
+ }
+ mutex_unlock(&recent_mutex);
+}
+
+#ifdef CONFIG_PROC_FS
+struct recent_iter_state {
+ const struct recent_table *table;
+ unsigned int bucket;
+};
+
+static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
+ __acquires(recent_lock)
+{
+ struct recent_iter_state *st = seq->private;
+ const struct recent_table *t = st->table;
+ struct recent_entry *e;
+ loff_t p = *pos;
+
+ spin_lock_bh(&recent_lock);
+
+ for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
+ list_for_each_entry(e, &t->iphash[st->bucket], list)
+ if (p-- == 0)
+ return e;
+ return NULL;
+}
+
+static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct recent_iter_state *st = seq->private;
+ const struct recent_table *t = st->table;
+ const struct recent_entry *e = v;
+ const struct list_head *head = e->list.next;
+
+ while (head == &t->iphash[st->bucket]) {
+ if (++st->bucket >= ip_list_hash_size)
+ return NULL;
+ head = t->iphash[st->bucket].next;
+ }
+ (*pos)++;
+ return list_entry(head, struct recent_entry, list);
+}
+
+static void recent_seq_stop(struct seq_file *s, void *v)
+ __releases(recent_lock)
+{
+ spin_unlock_bh(&recent_lock);
+}
+
+static int recent_seq_show(struct seq_file *seq, void *v)
+{
+ const struct recent_entry *e = v;
+ unsigned int i;
+
+ i = (e->index - 1) % ip_pkt_list_tot;
+ if (e->family == NFPROTO_IPV4)
+ seq_printf(seq, "src=" NIPQUAD_FMT " ttl: %u last_seen: %lu "
+ "oldest_pkt: %u", NIPQUAD(e->addr.ip), e->ttl,
+ e->stamps[i], e->index);
+ else
+ seq_printf(seq, "src=" NIP6_FMT " ttl: %u last_seen: %lu "
+ "oldest_pkt: %u", NIP6(e->addr.in6), e->ttl,
+ e->stamps[i], e->index);
+ for (i = 0; i < e->nstamps; i++)
+ seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
+ seq_printf(seq, "\n");
+ return 0;
+}
+
+static const struct seq_operations recent_seq_ops = {
+ .start = recent_seq_start,
+ .next = recent_seq_next,
+ .stop = recent_seq_stop,
+ .show = recent_seq_show,
+};
+
+static int recent_seq_open(struct inode *inode, struct file *file)
+{
+ struct proc_dir_entry *pde = PDE(inode);
+ struct recent_iter_state *st;
+
+ st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
+ if (st == NULL)
+ return -ENOMEM;
+
+ st->table = pde->data;
+ return 0;
+}
+
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+static int recent_old_seq_open(struct inode *inode, struct file *filp)
+{
+ static bool warned_of_old;
+
+ if (unlikely(!warned_of_old)) {
+ printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
+ " is deprecated; use /proc/net/xt_recent.\n");
+ warned_of_old = true;
+ }
+ return recent_seq_open(inode, filp);
+}
+
+static ssize_t recent_old_proc_write(struct file *file,
+ const char __user *input,
+ size_t size, loff_t *loff)
+{
+ const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
+ struct recent_table *t = pde->data;
+ struct recent_entry *e;
+ char buf[sizeof("+255.255.255.255")], *c = buf;
+ __be32 addr;
+ int add;
+
+ if (size > sizeof(buf))
+ size = sizeof(buf);
+ if (copy_from_user(buf, input, size))
+ return -EFAULT;
+
+ while (isspace(*c))
+ c++;
+
+ if (size - (c - buf) < 5)
+ return c - buf;
+ if (!strncmp(c, "clear", 5)) {
+ c += 5;
+ spin_lock_bh(&recent_lock);
+ recent_table_flush(t);
+ spin_unlock_bh(&recent_lock);
+ return c - buf;
+ }
+
+ switch (*c) {
+ case '-':
+ add = 0;
+ c++;
+ break;
+ case '+':
+ c++;
+ default:
+ add = 1;
+ break;
+ }
+ addr = in_aton(c);
+
+ spin_lock_bh(&recent_lock);
+ e = recent_entry_lookup(t, (const void *)&addr, NFPROTO_IPV4, 0);
+ if (e == NULL) {
+ if (add)
+ recent_entry_init(t, (const void *)&addr,
+ NFPROTO_IPV4, 0);
+ } else {
+ if (add)
+ recent_entry_update(t, e);
+ else
+ recent_entry_remove(t, e);
+ }
+ spin_unlock_bh(&recent_lock);
+ return size;
+}
+
+static const struct file_operations recent_old_fops = {
+ .open = recent_old_seq_open,
+ .read = seq_read,
+ .write = recent_old_proc_write,
+ .release = seq_release_private,
+ .owner = THIS_MODULE,
+};
+#endif
+
+static ssize_t
+recent_mt_proc_write(struct file *file, const char __user *input,
+ size_t size, loff_t *loff)
+{
+ const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
+ struct recent_table *t = pde->data;
+ struct recent_entry *e;
+ char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
+ const char *c = buf;
+ union nf_inet_addr addr;
+ u_int16_t family;
+ bool add, succ;
+
+ if (size == 0)
+ return 0;
+ if (size > sizeof(buf))
+ size = sizeof(buf);
+ if (copy_from_user(buf, input, size) != 0)
+ return -EFAULT;
+
+ /* Strict protocol! */
+ if (*loff != 0)
+ return -ESPIPE;
+ switch (*c) {
+ case '/': /* flush table */
+ spin_lock_bh(&recent_lock);
+ recent_table_flush(t);
+ spin_unlock_bh(&recent_lock);
+ return size;
+ case '-': /* remove address */
+ add = false;
+ break;
+ case '+': /* add address */
+ add = true;
+ break;
+ default:
+ printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
+ return -EINVAL;
+ }
+
+ ++c;
+ --size;
+ if (strnchr(c, size, ':') != NULL) {
+ family = NFPROTO_IPV6;
+ succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
+ } else {
+ family = NFPROTO_IPV4;
+ succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
+ }
+
+ if (!succ) {
+ printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
+ "to procfs\n");
+ return -EINVAL;
+ }
+
+ spin_lock_bh(&recent_lock);
+ e = recent_entry_lookup(t, &addr, family, 0);
+ if (e == NULL) {
+ if (add)
+ recent_entry_init(t, &addr, family, 0);
+ } else {
+ if (add)
+ recent_entry_update(t, e);
+ else
+ recent_entry_remove(t, e);
+ }
+ spin_unlock_bh(&recent_lock);
+ /* Note we removed one above */
+ *loff += size + 1;
+ return size + 1;
+}
+
+static const struct file_operations recent_mt_fops = {
+ .open = recent_seq_open,
+ .read = seq_read,
+ .write = recent_mt_proc_write,
+ .release = seq_release_private,
+ .owner = THIS_MODULE,
+};
+#endif /* CONFIG_PROC_FS */
+
+static struct xt_match recent_mt_reg[] __read_mostly = {
+ {
+ .name = "recent",
+ .revision = 0,
+ .family = NFPROTO_IPV4,
+ .match = recent_mt,
+ .matchsize = sizeof(struct xt_recent_mtinfo),
+ .checkentry = recent_mt_check,
+ .destroy = recent_mt_destroy,
+ .me = THIS_MODULE,
+ },
+ {
+ .name = "recent",
+ .revision = 0,
+ .family = NFPROTO_IPV6,
+ .match = recent_mt,
+ .matchsize = sizeof(struct xt_recent_mtinfo),
+ .checkentry = recent_mt_check,
+ .destroy = recent_mt_destroy,
+ .me = THIS_MODULE,
+ },
+};
+
+static int __init recent_mt_init(void)
+{
+ int err;
+
+ if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
+ return -EINVAL;
+ ip_list_hash_size = 1 << fls(ip_list_tot);
+
+ err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
+#ifdef CONFIG_PROC_FS
+ if (err)
+ return err;
+ recent_proc_dir = proc_mkdir("xt_recent", init_net.proc_net);
+ if (recent_proc_dir == NULL) {
+ xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
+ err = -ENOMEM;
+ }
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+ if (err < 0)
+ return err;
+ proc_old_dir = proc_mkdir("ipt_recent", init_net.proc_net);
+ if (proc_old_dir == NULL) {
+ remove_proc_entry("xt_recent", init_net.proc_net);
+ xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
+ err = -ENOMEM;
+ }
+#endif
+#endif
+ return err;
+}
+
+static void __exit recent_mt_exit(void)
+{
+ BUG_ON(!list_empty(&tables));
+ xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
+#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
+ remove_proc_entry("ipt_recent", init_net.proc_net);
+#endif
+ remove_proc_entry("xt_recent", init_net.proc_net);
+#endif
+}
+
+module_init(recent_mt_init);
+module_exit(recent_mt_exit);
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