From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- net/netfilter/xt_recent.c | 769 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 769 insertions(+) create mode 100644 net/netfilter/xt_recent.c (limited to 'net/netfilter/xt_recent.c') diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c new file mode 100644 index 000000000..45e1b30e4 --- /dev/null +++ b/net/netfilter/xt_recent.c @@ -0,0 +1,769 @@ +/* + * Copyright (c) 2006 Patrick McHardy + * 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 + * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +MODULE_AUTHOR("Patrick McHardy "); +MODULE_AUTHOR("Jan Engelhardt "); +MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ipt_recent"); +MODULE_ALIAS("ip6t_recent"); + +static unsigned int ip_list_tot __read_mostly = 100; +static unsigned int ip_list_hash_size __read_mostly; +static unsigned int ip_list_perms __read_mostly = 0644; +static unsigned int ip_list_uid __read_mostly; +static unsigned int ip_list_gid __read_mostly; +module_param(ip_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_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"); + +/* retained for backwards compatibility */ +static unsigned int ip_pkt_list_tot __read_mostly; +module_param(ip_pkt_list_tot, uint, 0400); +MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)"); + +#define XT_RECENT_MAX_NSTAMPS 256 + +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]; + union nf_inet_addr mask; + unsigned int refcnt; + unsigned int entries; + u8 nstamps_max_mask; + 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 __read_mostly; + +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; + unsigned int nstamps_max = t->nstamps_max_mask; + + if (t->entries >= ip_list_tot) { + e = list_entry(t->lru_list.next, struct recent_entry, lru_list); + recent_entry_remove(t, e); + } + + nstamps_max += 1; + e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * nstamps_max, + 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 &= t->nstamps_max_mask; + 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, struct xt_action_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_v1 *info = par->matchinfo; + struct recent_table *t; + struct recent_entry *e; + union nf_inet_addr addr = {}, addr_mask; + 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); + + nf_inet_addr_mask(&addr, &addr_mask, &t->mask); + + e = recent_entry_lookup(t, &addr_mask, 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_mask, 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 void recent_table_free(void *addr) +{ + kvfree(addr); +} + +static int recent_mt_check(const struct xt_mtchk_param *par, + const struct xt_recent_mtinfo_v1 *info) +{ + struct recent_net *recent_net = recent_pernet(par->net); + struct recent_table *t; +#ifdef CONFIG_PROC_FS + struct proc_dir_entry *pde; + kuid_t uid; + kgid_t gid; +#endif + unsigned int nstamp_mask; + unsigned int i; + int ret = -EINVAL; + size_t sz; + + 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 >= XT_RECENT_MAX_NSTAMPS) { + pr_info("hitcount (%u) is larger than allowed maximum (%u)\n", + info->hit_count, XT_RECENT_MAX_NSTAMPS - 1); + return -EINVAL; + } + if (info->name[0] == '\0' || + strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN) + return -EINVAL; + + if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot) + nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1; + else if (info->hit_count) + nstamp_mask = roundup_pow_of_two(info->hit_count) - 1; + else + nstamp_mask = 32 - 1; + + mutex_lock(&recent_mutex); + t = recent_table_lookup(recent_net, info->name); + if (t != NULL) { + if (nstamp_mask > t->nstamps_max_mask) { + spin_lock_bh(&recent_lock); + recent_table_flush(t); + t->nstamps_max_mask = nstamp_mask; + spin_unlock_bh(&recent_lock); + } + + t->refcnt++; + ret = 0; + goto out; + } + + sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size; + if (sz <= PAGE_SIZE) + t = kzalloc(sz, GFP_KERNEL); + else + t = vzalloc(sz); + if (t == NULL) { + ret = -ENOMEM; + goto out; + } + t->refcnt = 1; + t->nstamps_max_mask = nstamp_mask; + + memcpy(&t->mask, &info->mask, sizeof(t->mask)); + 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 + uid = make_kuid(&init_user_ns, ip_list_uid); + gid = make_kgid(&init_user_ns, ip_list_gid); + if (!uid_valid(uid) || !gid_valid(gid)) { + recent_table_free(t); + ret = -EINVAL; + goto out; + } + pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent, + &recent_mt_fops, t); + if (pde == NULL) { + recent_table_free(t); + ret = -ENOMEM; + goto out; + } + proc_set_user(pde, uid, 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 int recent_mt_check_v0(const struct xt_mtchk_param *par) +{ + const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo; + struct xt_recent_mtinfo_v1 info_v1; + + /* Copy revision 0 structure to revision 1 */ + memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo)); + /* Set default mask to ensure backward compatible behaviour */ + memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all)); + + return recent_mt_check(par, &info_v1); +} + +static int recent_mt_check_v1(const struct xt_mtchk_param *par) +{ + return recent_mt_check(par, par->matchinfo); +} + +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_v1 *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 + if (recent_net->xt_recent != NULL) + remove_proc_entry(t->name, recent_net->xt_recent); +#endif + recent_table_flush(t); + recent_table_free(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; + struct recent_iter_state *st = seq->private; + const struct recent_table *t = st->table; + unsigned int i; + + i = (e->index - 1) & t->nstamps_max_mask; + + 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 recent_iter_state *st; + + st = __seq_open_private(file, &recent_seq_ops, sizeof(*st)); + if (st == NULL) + return -ENOMEM; + + st->table = PDE_DATA(inode); + return 0; +} + +static ssize_t +recent_mt_proc_write(struct file *file, const char __user *input, + size_t size, loff_t *loff) +{ + struct recent_table *t = PDE_DATA(file_inode(file)); + 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, + .llseek = seq_lseek, +}; + +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) +{ + struct recent_net *recent_net = recent_pernet(net); + struct recent_table *t; + + /* recent_net_exit() is called before recent_mt_destroy(). Make sure + * that the parent xt_recent proc entry is is empty before trying to + * remove it. + */ + spin_lock_bh(&recent_lock); + list_for_each_entry(t, &recent_net->tables, list) + remove_proc_entry(t->name, recent_net->xt_recent); + + recent_net->xt_recent = NULL; + spin_unlock_bh(&recent_lock); + + remove_proc_entry("xt_recent", net->proc_net); +} +#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) +{ + 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_v0, + .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_v0, + .destroy = recent_mt_destroy, + .me = THIS_MODULE, + }, + { + .name = "recent", + .revision = 1, + .family = NFPROTO_IPV4, + .match = recent_mt, + .matchsize = sizeof(struct xt_recent_mtinfo_v1), + .checkentry = recent_mt_check_v1, + .destroy = recent_mt_destroy, + .me = THIS_MODULE, + }, + { + .name = "recent", + .revision = 1, + .family = NFPROTO_IPV6, + .match = recent_mt, + .matchsize = sizeof(struct xt_recent_mtinfo_v1), + .checkentry = recent_mt_check_v1, + .destroy = recent_mt_destroy, + .me = THIS_MODULE, + } +}; + +static int __init recent_mt_init(void) +{ + int err; + + BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS); + + if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS) + 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); -- cgit v1.2.3-54-g00ecf