| /* |
| * 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 |
| */ |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| #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 <net/netns/generic.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@medozas.de>"); |
| MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching"); |
| 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, S_IRUGO | S_IWUSR); |
| module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR); |
| 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 address 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, "default owner of /proc/net/xt_recent/* files"); |
| MODULE_PARM_DESC(ip_list_gid, "default 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]; |
| unsigned int refcnt; |
| unsigned int entries; |
| struct list_head lru_list; |
| struct list_head iphash[0]; |
| }; |
| |
| struct recent_net { |
| struct list_head tables; |
| #ifdef CONFIG_PROC_FS |
| struct proc_dir_entry *xt_recent; |
| #endif |
| }; |
| |
| static int recent_net_id; |
| static inline struct recent_net *recent_pernet(struct net *net) |
| { |
| return net_generic(net, recent_net_id); |
| } |
| |
| static DEFINE_SPINLOCK(recent_lock); |
| static DEFINE_MUTEX(recent_mutex); |
| |
| #ifdef CONFIG_PROC_FS |
| static const struct file_operations recent_old_fops, recent_mt_fops; |
| #endif |
| |
| static u_int32_t hash_rnd __read_mostly; |
| static bool hash_rnd_inited __read_mostly; |
| |
| static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr) |
| { |
| return jhash_1word((__force u32)addr->ip, hash_rnd) & |
| (ip_list_hash_size - 1); |
| } |
| |
| static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr) |
| { |
| 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--; |
| } |
| |
| /* |
| * Drop entries with timestamps older then 'time'. |
| */ |
| static void recent_entry_reap(struct recent_table *t, unsigned long time) |
| { |
| struct recent_entry *e; |
| |
| /* |
| * The head of the LRU list is always the oldest entry. |
| */ |
| e = list_entry(t->lru_list.next, struct recent_entry, lru_list); |
| |
| /* |
| * The last time stamp is the most recent. |
| */ |
| if (time_after(time, e->stamps[e->index-1])) |
| recent_entry_remove(t, e); |
| } |
| |
| 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->index %= ip_pkt_list_tot; |
| e->stamps[e->index++] = jiffies; |
| if (e->index > e->nstamps) |
| e->nstamps = e->index; |
| list_move_tail(&e->lru_list, &t->lru_list); |
| } |
| |
| static struct recent_table *recent_table_lookup(struct recent_net *recent_net, |
| const char *name) |
| { |
| struct recent_table *t; |
| |
| list_for_each_entry(t, &recent_net->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) |
| { |
| struct net *net = dev_net(par->in ? par->in : par->out); |
| struct recent_net *recent_net = recent_pernet(net); |
| 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->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(recent_net, info->name); |
| e = recent_entry_lookup(t, &addr, par->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->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 (info->hit_count && ++hits >= info->hit_count) { |
| ret = !ret; |
| break; |
| } |
| } |
| |
| /* info->seconds must be non-zero */ |
| if (info->check_set & XT_RECENT_REAP) |
| recent_entry_reap(t, time); |
| } |
| |
| 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 int recent_mt_check(const struct xt_mtchk_param *par) |
| { |
| struct recent_net *recent_net = recent_pernet(par->net); |
| const struct xt_recent_mtinfo *info = par->matchinfo; |
| struct recent_table *t; |
| #ifdef CONFIG_PROC_FS |
| struct proc_dir_entry *pde; |
| #endif |
| unsigned i; |
| int ret = -EINVAL; |
| |
| if (unlikely(!hash_rnd_inited)) { |
| get_random_bytes(&hash_rnd, sizeof(hash_rnd)); |
| hash_rnd_inited = true; |
| } |
| if (info->check_set & ~XT_RECENT_VALID_FLAGS) { |
| pr_info("Unsupported user space flags (%08x)\n", |
| info->check_set); |
| return -EINVAL; |
| } |
| if (hweight8(info->check_set & |
| (XT_RECENT_SET | XT_RECENT_REMOVE | |
| XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1) |
| return -EINVAL; |
| if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) && |
| (info->seconds || info->hit_count || |
| (info->check_set & XT_RECENT_MODIFIERS))) |
| return -EINVAL; |
| if ((info->check_set & XT_RECENT_REAP) && !info->seconds) |
| return -EINVAL; |
| if (info->hit_count > ip_pkt_list_tot) { |
| pr_info("hitcount (%u) is larger than " |
| "packets to be remembered (%u)\n", |
| info->hit_count, ip_pkt_list_tot); |
| return -EINVAL; |
| } |
| if (info->name[0] == '\0' || |
| strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN) |
| return -EINVAL; |
| |
| mutex_lock(&recent_mutex); |
| t = recent_table_lookup(recent_net, info->name); |
| if (t != NULL) { |
| t->refcnt++; |
| ret = 0; |
| 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 |
| pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent, |
| &recent_mt_fops, t); |
| if (pde == NULL) { |
| kfree(t); |
| goto out; |
| } |
| pde->uid = ip_list_uid; |
| pde->gid = ip_list_gid; |
| #endif |
| spin_lock_bh(&recent_lock); |
| list_add_tail(&t->list, &recent_net->tables); |
| spin_unlock_bh(&recent_lock); |
| ret = 0; |
| out: |
| mutex_unlock(&recent_mutex); |
| return ret; |
| } |
| |
| static void recent_mt_destroy(const struct xt_mtdtor_param *par) |
| { |
| struct recent_net *recent_net = recent_pernet(par->net); |
| const struct xt_recent_mtinfo *info = par->matchinfo; |
| struct recent_table *t; |
| |
| mutex_lock(&recent_mutex); |
| t = recent_table_lookup(recent_net, info->name); |
| if (--t->refcnt == 0) { |
| spin_lock_bh(&recent_lock); |
| list_del(&t->list); |
| spin_unlock_bh(&recent_lock); |
| #ifdef CONFIG_PROC_FS |
| remove_proc_entry(t->name, recent_net->xt_recent); |
| #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=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u", |
| &e->addr.ip, e->ttl, e->stamps[i], e->index); |
| else |
| seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u", |
| &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; |
| } |
| |
| 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: |
| pr_info("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) { |
| pr_info("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, |
| }; |
| |
| static int __net_init recent_proc_net_init(struct net *net) |
| { |
| struct recent_net *recent_net = recent_pernet(net); |
| |
| recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net); |
| if (!recent_net->xt_recent) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| static void __net_exit recent_proc_net_exit(struct net *net) |
| { |
| proc_net_remove(net, "xt_recent"); |
| } |
| #else |
| static inline int recent_proc_net_init(struct net *net) |
| { |
| return 0; |
| } |
| |
| static inline void recent_proc_net_exit(struct net *net) |
| { |
| } |
| #endif /* CONFIG_PROC_FS */ |
| |
| static int __net_init recent_net_init(struct net *net) |
| { |
| struct recent_net *recent_net = recent_pernet(net); |
| |
| INIT_LIST_HEAD(&recent_net->tables); |
| return recent_proc_net_init(net); |
| } |
| |
| static void __net_exit recent_net_exit(struct net *net) |
| { |
| struct recent_net *recent_net = recent_pernet(net); |
| |
| BUG_ON(!list_empty(&recent_net->tables)); |
| recent_proc_net_exit(net); |
| } |
| |
| static struct pernet_operations recent_net_ops = { |
| .init = recent_net_init, |
| .exit = recent_net_exit, |
| .id = &recent_net_id, |
| .size = sizeof(struct recent_net), |
| }; |
| |
| 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 = register_pernet_subsys(&recent_net_ops); |
| if (err) |
| return err; |
| err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg)); |
| if (err) |
| unregister_pernet_subsys(&recent_net_ops); |
| return err; |
| } |
| |
| static void __exit recent_mt_exit(void) |
| { |
| xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg)); |
| unregister_pernet_subsys(&recent_net_ops); |
| } |
| |
| module_init(recent_mt_init); |
| module_exit(recent_mt_exit); |