diff options
Diffstat (limited to 'net/netfilter/x_tables.c')
| -rw-r--r-- | net/netfilter/x_tables.c | 1395 |
1 files changed, 1395 insertions, 0 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c new file mode 100644 index 00000000..b0869fe3 --- /dev/null +++ b/net/netfilter/x_tables.c @@ -0,0 +1,1395 @@ +/* + * x_tables core - Backend for {ip,ip6,arp}_tables + * + * Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org> + * + * Based on existing ip_tables code which is + * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling + * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org> + * + * 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. + * + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/kernel.h> +#include <linux/socket.h> +#include <linux/net.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/string.h> +#include <linux/vmalloc.h> +#include <linux/mutex.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/audit.h> +#include <net/net_namespace.h> + +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter_arp.h> +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv6/ip6_tables.h> +#include <linux/netfilter_arp/arp_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); +MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module"); + +#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) + +struct compat_delta { + unsigned int offset; /* offset in kernel */ + int delta; /* delta in 32bit user land */ +}; + +struct xt_af { + struct mutex mutex; + struct list_head match; + struct list_head target; +#ifdef CONFIG_COMPAT + struct mutex compat_mutex; + struct compat_delta *compat_tab; + unsigned int number; /* number of slots in compat_tab[] */ + unsigned int cur; /* number of used slots in compat_tab[] */ +#endif +}; + +static struct xt_af *xt; + +static const char *const xt_prefix[NFPROTO_NUMPROTO] = { + [NFPROTO_UNSPEC] = "x", + [NFPROTO_IPV4] = "ip", + [NFPROTO_ARP] = "arp", + [NFPROTO_BRIDGE] = "eb", + [NFPROTO_IPV6] = "ip6", +}; + +/* Allow this many total (re)entries. */ +static const unsigned int xt_jumpstack_multiplier = 2; + +/* Registration hooks for targets. */ +int +xt_register_target(struct xt_target *target) +{ + u_int8_t af = target->family; + int ret; + + ret = mutex_lock_interruptible(&xt[af].mutex); + if (ret != 0) + return ret; + list_add(&target->list, &xt[af].target); + mutex_unlock(&xt[af].mutex); + return ret; +} +EXPORT_SYMBOL(xt_register_target); + +void +xt_unregister_target(struct xt_target *target) +{ + u_int8_t af = target->family; + + mutex_lock(&xt[af].mutex); + list_del(&target->list); + mutex_unlock(&xt[af].mutex); +} +EXPORT_SYMBOL(xt_unregister_target); + +int +xt_register_targets(struct xt_target *target, unsigned int n) +{ + unsigned int i; + int err = 0; + + for (i = 0; i < n; i++) { + err = xt_register_target(&target[i]); + if (err) + goto err; + } + return err; + +err: + if (i > 0) + xt_unregister_targets(target, i); + return err; +} +EXPORT_SYMBOL(xt_register_targets); + +void +xt_unregister_targets(struct xt_target *target, unsigned int n) +{ + while (n-- > 0) + xt_unregister_target(&target[n]); +} +EXPORT_SYMBOL(xt_unregister_targets); + +int +xt_register_match(struct xt_match *match) +{ + u_int8_t af = match->family; + int ret; + + ret = mutex_lock_interruptible(&xt[af].mutex); + if (ret != 0) + return ret; + + list_add(&match->list, &xt[af].match); + mutex_unlock(&xt[af].mutex); + + return ret; +} +EXPORT_SYMBOL(xt_register_match); + +void +xt_unregister_match(struct xt_match *match) +{ + u_int8_t af = match->family; + + mutex_lock(&xt[af].mutex); + list_del(&match->list); + mutex_unlock(&xt[af].mutex); +} +EXPORT_SYMBOL(xt_unregister_match); + +int +xt_register_matches(struct xt_match *match, unsigned int n) +{ + unsigned int i; + int err = 0; + + for (i = 0; i < n; i++) { + err = xt_register_match(&match[i]); + if (err) + goto err; + } + return err; + +err: + if (i > 0) + xt_unregister_matches(match, i); + return err; +} +EXPORT_SYMBOL(xt_register_matches); + +void +xt_unregister_matches(struct xt_match *match, unsigned int n) +{ + while (n-- > 0) + xt_unregister_match(&match[n]); +} +EXPORT_SYMBOL(xt_unregister_matches); + + +/* + * These are weird, but module loading must not be done with mutex + * held (since they will register), and we have to have a single + * function to use. + */ + +/* Find match, grabs ref. Returns ERR_PTR() on error. */ +struct xt_match *xt_find_match(u8 af, const char *name, u8 revision) +{ + struct xt_match *m; + int err = -ENOENT; + + if (mutex_lock_interruptible(&xt[af].mutex) != 0) + return ERR_PTR(-EINTR); + + list_for_each_entry(m, &xt[af].match, list) { + if (strcmp(m->name, name) == 0) { + if (m->revision == revision) { + if (try_module_get(m->me)) { + mutex_unlock(&xt[af].mutex); + return m; + } + } else + err = -EPROTOTYPE; /* Found something. */ + } + } + mutex_unlock(&xt[af].mutex); + + if (af != NFPROTO_UNSPEC) + /* Try searching again in the family-independent list */ + return xt_find_match(NFPROTO_UNSPEC, name, revision); + + return ERR_PTR(err); +} +EXPORT_SYMBOL(xt_find_match); + +struct xt_match * +xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision) +{ + struct xt_match *match; + + match = xt_find_match(nfproto, name, revision); + if (IS_ERR(match)) { + request_module("%st_%s", xt_prefix[nfproto], name); + match = xt_find_match(nfproto, name, revision); + } + + return match; +} +EXPORT_SYMBOL_GPL(xt_request_find_match); + +/* Find target, grabs ref. Returns ERR_PTR() on error. */ +struct xt_target *xt_find_target(u8 af, const char *name, u8 revision) +{ + struct xt_target *t; + int err = -ENOENT; + + if (mutex_lock_interruptible(&xt[af].mutex) != 0) + return ERR_PTR(-EINTR); + + list_for_each_entry(t, &xt[af].target, list) { + if (strcmp(t->name, name) == 0) { + if (t->revision == revision) { + if (try_module_get(t->me)) { + mutex_unlock(&xt[af].mutex); + return t; + } + } else + err = -EPROTOTYPE; /* Found something. */ + } + } + mutex_unlock(&xt[af].mutex); + + if (af != NFPROTO_UNSPEC) + /* Try searching again in the family-independent list */ + return xt_find_target(NFPROTO_UNSPEC, name, revision); + + return ERR_PTR(err); +} +EXPORT_SYMBOL(xt_find_target); + +struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision) +{ + struct xt_target *target; + + target = xt_find_target(af, name, revision); + if (IS_ERR(target)) { + request_module("%st_%s", xt_prefix[af], name); + target = xt_find_target(af, name, revision); + } + + return target; +} +EXPORT_SYMBOL_GPL(xt_request_find_target); + +static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) +{ + const struct xt_match *m; + int have_rev = 0; + + list_for_each_entry(m, &xt[af].match, list) { + if (strcmp(m->name, name) == 0) { + if (m->revision > *bestp) + *bestp = m->revision; + if (m->revision == revision) + have_rev = 1; + } + } + + if (af != NFPROTO_UNSPEC && !have_rev) + return match_revfn(NFPROTO_UNSPEC, name, revision, bestp); + + return have_rev; +} + +static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) +{ + const struct xt_target *t; + int have_rev = 0; + + list_for_each_entry(t, &xt[af].target, list) { + if (strcmp(t->name, name) == 0) { + if (t->revision > *bestp) + *bestp = t->revision; + if (t->revision == revision) + have_rev = 1; + } + } + + if (af != NFPROTO_UNSPEC && !have_rev) + return target_revfn(NFPROTO_UNSPEC, name, revision, bestp); + + return have_rev; +} + +/* Returns true or false (if no such extension at all) */ +int xt_find_revision(u8 af, const char *name, u8 revision, int target, + int *err) +{ + int have_rev, best = -1; + + if (mutex_lock_interruptible(&xt[af].mutex) != 0) { + *err = -EINTR; + return 1; + } + if (target == 1) + have_rev = target_revfn(af, name, revision, &best); + else + have_rev = match_revfn(af, name, revision, &best); + mutex_unlock(&xt[af].mutex); + + /* Nothing at all? Return 0 to try loading module. */ + if (best == -1) { + *err = -ENOENT; + return 0; + } + + *err = best; + if (!have_rev) + *err = -EPROTONOSUPPORT; + return 1; +} +EXPORT_SYMBOL_GPL(xt_find_revision); + +static char *textify_hooks(char *buf, size_t size, unsigned int mask) +{ + static const char *const names[] = { + "PREROUTING", "INPUT", "FORWARD", + "OUTPUT", "POSTROUTING", "BROUTING", + }; + unsigned int i; + char *p = buf; + bool np = false; + int res; + + *p = '\0'; + for (i = 0; i < ARRAY_SIZE(names); ++i) { + if (!(mask & (1 << i))) + continue; + res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]); + if (res > 0) { + size -= res; + p += res; + } + np = true; + } + + return buf; +} + +int xt_check_match(struct xt_mtchk_param *par, + unsigned int size, u_int8_t proto, bool inv_proto) +{ + int ret; + + if (XT_ALIGN(par->match->matchsize) != size && + par->match->matchsize != -1) { + /* + * ebt_among is exempt from centralized matchsize checking + * because it uses a dynamic-size data set. + */ + pr_err("%s_tables: %s.%u match: invalid size " + "%u (kernel) != (user) %u\n", + xt_prefix[par->family], par->match->name, + par->match->revision, + XT_ALIGN(par->match->matchsize), size); + return -EINVAL; + } + if (par->match->table != NULL && + strcmp(par->match->table, par->table) != 0) { + pr_err("%s_tables: %s match: only valid in %s table, not %s\n", + xt_prefix[par->family], par->match->name, + par->match->table, par->table); + return -EINVAL; + } + if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) { + char used[64], allow[64]; + + pr_err("%s_tables: %s match: used from hooks %s, but only " + "valid from %s\n", + xt_prefix[par->family], par->match->name, + textify_hooks(used, sizeof(used), par->hook_mask), + textify_hooks(allow, sizeof(allow), par->match->hooks)); + return -EINVAL; + } + if (par->match->proto && (par->match->proto != proto || inv_proto)) { + pr_err("%s_tables: %s match: only valid for protocol %u\n", + xt_prefix[par->family], par->match->name, + par->match->proto); + return -EINVAL; + } + if (par->match->checkentry != NULL) { + ret = par->match->checkentry(par); + if (ret < 0) + return ret; + else if (ret > 0) + /* Flag up potential errors. */ + return -EIO; + } + return 0; +} +EXPORT_SYMBOL_GPL(xt_check_match); + +#ifdef CONFIG_COMPAT +int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta) +{ + struct xt_af *xp = &xt[af]; + + if (!xp->compat_tab) { + if (!xp->number) + return -EINVAL; + xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number); + if (!xp->compat_tab) + return -ENOMEM; + xp->cur = 0; + } + + if (xp->cur >= xp->number) + return -EINVAL; + + if (xp->cur) + delta += xp->compat_tab[xp->cur - 1].delta; + xp->compat_tab[xp->cur].offset = offset; + xp->compat_tab[xp->cur].delta = delta; + xp->cur++; + return 0; +} +EXPORT_SYMBOL_GPL(xt_compat_add_offset); + +void xt_compat_flush_offsets(u_int8_t af) +{ + if (xt[af].compat_tab) { + vfree(xt[af].compat_tab); + xt[af].compat_tab = NULL; + xt[af].number = 0; + xt[af].cur = 0; + } +} +EXPORT_SYMBOL_GPL(xt_compat_flush_offsets); + +int xt_compat_calc_jump(u_int8_t af, unsigned int offset) +{ + struct compat_delta *tmp = xt[af].compat_tab; + int mid, left = 0, right = xt[af].cur - 1; + + while (left <= right) { + mid = (left + right) >> 1; + if (offset > tmp[mid].offset) + left = mid + 1; + else if (offset < tmp[mid].offset) + right = mid - 1; + else + return mid ? tmp[mid - 1].delta : 0; + } + return left ? tmp[left - 1].delta : 0; +} +EXPORT_SYMBOL_GPL(xt_compat_calc_jump); + +void xt_compat_init_offsets(u_int8_t af, unsigned int number) +{ + xt[af].number = number; + xt[af].cur = 0; +} +EXPORT_SYMBOL(xt_compat_init_offsets); + +int xt_compat_match_offset(const struct xt_match *match) +{ + u_int16_t csize = match->compatsize ? : match->matchsize; + return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize); +} +EXPORT_SYMBOL_GPL(xt_compat_match_offset); + +int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, + unsigned int *size) +{ + const struct xt_match *match = m->u.kernel.match; + struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m; + int pad, off = xt_compat_match_offset(match); + u_int16_t msize = cm->u.user.match_size; + + m = *dstptr; + memcpy(m, cm, sizeof(*cm)); + if (match->compat_from_user) + match->compat_from_user(m->data, cm->data); + else + memcpy(m->data, cm->data, msize - sizeof(*cm)); + pad = XT_ALIGN(match->matchsize) - match->matchsize; + if (pad > 0) + memset(m->data + match->matchsize, 0, pad); + + msize += off; + m->u.user.match_size = msize; + + *size += off; + *dstptr += msize; + return 0; +} +EXPORT_SYMBOL_GPL(xt_compat_match_from_user); + +int xt_compat_match_to_user(const struct xt_entry_match *m, + void __user **dstptr, unsigned int *size) +{ + const struct xt_match *match = m->u.kernel.match; + struct compat_xt_entry_match __user *cm = *dstptr; + int off = xt_compat_match_offset(match); + u_int16_t msize = m->u.user.match_size - off; + + if (copy_to_user(cm, m, sizeof(*cm)) || + put_user(msize, &cm->u.user.match_size) || + copy_to_user(cm->u.user.name, m->u.kernel.match->name, + strlen(m->u.kernel.match->name) + 1)) + return -EFAULT; + + if (match->compat_to_user) { + if (match->compat_to_user((void __user *)cm->data, m->data)) + return -EFAULT; + } else { + if (copy_to_user(cm->data, m->data, msize - sizeof(*cm))) + return -EFAULT; + } + + *size -= off; + *dstptr += msize; + return 0; +} +EXPORT_SYMBOL_GPL(xt_compat_match_to_user); +#endif /* CONFIG_COMPAT */ + +int xt_check_target(struct xt_tgchk_param *par, + unsigned int size, u_int8_t proto, bool inv_proto) +{ + int ret; + + if (XT_ALIGN(par->target->targetsize) != size) { + pr_err("%s_tables: %s.%u target: invalid size " + "%u (kernel) != (user) %u\n", + xt_prefix[par->family], par->target->name, + par->target->revision, + XT_ALIGN(par->target->targetsize), size); + return -EINVAL; + } + if (par->target->table != NULL && + strcmp(par->target->table, par->table) != 0) { + pr_err("%s_tables: %s target: only valid in %s table, not %s\n", + xt_prefix[par->family], par->target->name, + par->target->table, par->table); + return -EINVAL; + } + if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) { + char used[64], allow[64]; + + pr_err("%s_tables: %s target: used from hooks %s, but only " + "usable from %s\n", + xt_prefix[par->family], par->target->name, + textify_hooks(used, sizeof(used), par->hook_mask), + textify_hooks(allow, sizeof(allow), par->target->hooks)); + return -EINVAL; + } + if (par->target->proto && (par->target->proto != proto || inv_proto)) { + pr_err("%s_tables: %s target: only valid for protocol %u\n", + xt_prefix[par->family], par->target->name, + par->target->proto); + return -EINVAL; + } + if (par->target->checkentry != NULL) { + ret = par->target->checkentry(par); + if (ret < 0) + return ret; + else if (ret > 0) + /* Flag up potential errors. */ + return -EIO; + } + return 0; +} +EXPORT_SYMBOL_GPL(xt_check_target); + +#ifdef CONFIG_COMPAT +int xt_compat_target_offset(const struct xt_target *target) +{ + u_int16_t csize = target->compatsize ? : target->targetsize; + return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize); +} +EXPORT_SYMBOL_GPL(xt_compat_target_offset); + +void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, + unsigned int *size) +{ + const struct xt_target *target = t->u.kernel.target; + struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t; + int pad, off = xt_compat_target_offset(target); + u_int16_t tsize = ct->u.user.target_size; + + t = *dstptr; + memcpy(t, ct, sizeof(*ct)); + if (target->compat_from_user) + target->compat_from_user(t->data, ct->data); + else + memcpy(t->data, ct->data, tsize - sizeof(*ct)); + pad = XT_ALIGN(target->targetsize) - target->targetsize; + if (pad > 0) + memset(t->data + target->targetsize, 0, pad); + + tsize += off; + t->u.user.target_size = tsize; + + *size += off; + *dstptr += tsize; +} +EXPORT_SYMBOL_GPL(xt_compat_target_from_user); + +int xt_compat_target_to_user(const struct xt_entry_target *t, + void __user **dstptr, unsigned int *size) +{ + const struct xt_target *target = t->u.kernel.target; + struct compat_xt_entry_target __user *ct = *dstptr; + int off = xt_compat_target_offset(target); + u_int16_t tsize = t->u.user.target_size - off; + + if (copy_to_user(ct, t, sizeof(*ct)) || + put_user(tsize, &ct->u.user.target_size) || + copy_to_user(ct->u.user.name, t->u.kernel.target->name, + strlen(t->u.kernel.target->name) + 1)) + return -EFAULT; + + if (target->compat_to_user) { + if (target->compat_to_user((void __user *)ct->data, t->data)) + return -EFAULT; + } else { + if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct))) + return -EFAULT; + } + + *size -= off; + *dstptr += tsize; + return 0; +} +EXPORT_SYMBOL_GPL(xt_compat_target_to_user); +#endif + +struct xt_table_info *xt_alloc_table_info(unsigned int size) +{ + struct xt_table_info *newinfo; + int cpu; + + /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ + if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages) + return NULL; + + newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL); + if (!newinfo) + return NULL; + + newinfo->size = size; + + for_each_possible_cpu(cpu) { + if (size <= PAGE_SIZE) + newinfo->entries[cpu] = kmalloc_node(size, + GFP_KERNEL, + cpu_to_node(cpu)); + else + newinfo->entries[cpu] = vmalloc_node(size, + cpu_to_node(cpu)); + + if (newinfo->entries[cpu] == NULL) { + xt_free_table_info(newinfo); + return NULL; + } + } + + return newinfo; +} +EXPORT_SYMBOL(xt_alloc_table_info); + +void xt_free_table_info(struct xt_table_info *info) +{ + int cpu; + + for_each_possible_cpu(cpu) { + if (info->size <= PAGE_SIZE) + kfree(info->entries[cpu]); + else + vfree(info->entries[cpu]); + } + + if (info->jumpstack != NULL) { + if (sizeof(void *) * info->stacksize > PAGE_SIZE) { + for_each_possible_cpu(cpu) + vfree(info->jumpstack[cpu]); + } else { + for_each_possible_cpu(cpu) + kfree(info->jumpstack[cpu]); + } + } + + if (sizeof(void **) * nr_cpu_ids > PAGE_SIZE) + vfree(info->jumpstack); + else + kfree(info->jumpstack); + + free_percpu(info->stackptr); + + kfree(info); +} +EXPORT_SYMBOL(xt_free_table_info); + +/* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */ +struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, + const char *name) +{ + struct xt_table *t; + + if (mutex_lock_interruptible(&xt[af].mutex) != 0) + return ERR_PTR(-EINTR); + + list_for_each_entry(t, &net->xt.tables[af], list) + if (strcmp(t->name, name) == 0 && try_module_get(t->me)) + return t; + mutex_unlock(&xt[af].mutex); + return NULL; +} +EXPORT_SYMBOL_GPL(xt_find_table_lock); + +void xt_table_unlock(struct xt_table *table) +{ + mutex_unlock(&xt[table->af].mutex); +} +EXPORT_SYMBOL_GPL(xt_table_unlock); + +#ifdef CONFIG_COMPAT +void xt_compat_lock(u_int8_t af) +{ + mutex_lock(&xt[af].compat_mutex); +} +EXPORT_SYMBOL_GPL(xt_compat_lock); + +void xt_compat_unlock(u_int8_t af) +{ + mutex_unlock(&xt[af].compat_mutex); +} +EXPORT_SYMBOL_GPL(xt_compat_unlock); +#endif + +DEFINE_PER_CPU(seqcount_t, xt_recseq); +EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq); + +static int xt_jumpstack_alloc(struct xt_table_info *i) +{ + unsigned int size; + int cpu; + + i->stackptr = alloc_percpu(unsigned int); + if (i->stackptr == NULL) + return -ENOMEM; + + size = sizeof(void **) * nr_cpu_ids; + if (size > PAGE_SIZE) + i->jumpstack = vmalloc(size); + else + i->jumpstack = kmalloc(size, GFP_KERNEL); + if (i->jumpstack == NULL) + return -ENOMEM; + memset(i->jumpstack, 0, size); + + i->stacksize *= xt_jumpstack_multiplier; + size = sizeof(void *) * i->stacksize; + for_each_possible_cpu(cpu) { + if (size > PAGE_SIZE) + i->jumpstack[cpu] = vmalloc_node(size, + cpu_to_node(cpu)); + else + i->jumpstack[cpu] = kmalloc_node(size, + GFP_KERNEL, cpu_to_node(cpu)); + if (i->jumpstack[cpu] == NULL) + /* + * Freeing will be done later on by the callers. The + * chain is: xt_replace_table -> __do_replace -> + * do_replace -> xt_free_table_info. + */ + return -ENOMEM; + } + + return 0; +} + +struct xt_table_info * +xt_replace_table(struct xt_table *table, + unsigned int num_counters, + struct xt_table_info *newinfo, + int *error) +{ + struct xt_table_info *private; + int ret; + + ret = xt_jumpstack_alloc(newinfo); + if (ret < 0) { + *error = ret; + return NULL; + } + + /* Do the substitution. */ + local_bh_disable(); + private = table->private; + + /* Check inside lock: is the old number correct? */ + if (num_counters != private->number) { + pr_debug("num_counters != table->private->number (%u/%u)\n", + num_counters, private->number); + local_bh_enable(); + *error = -EAGAIN; + return NULL; + } + + table->private = newinfo; + newinfo->initial_entries = private->initial_entries; + + /* + * Even though table entries have now been swapped, other CPU's + * may still be using the old entries. This is okay, because + * resynchronization happens because of the locking done + * during the get_counters() routine. + */ + local_bh_enable(); + +#ifdef CONFIG_AUDIT + if (audit_enabled) { + struct audit_buffer *ab; + + ab = audit_log_start(current->audit_context, GFP_KERNEL, + AUDIT_NETFILTER_CFG); + if (ab) { + audit_log_format(ab, "table=%s family=%u entries=%u", + table->name, table->af, + private->number); + audit_log_end(ab); + } + } +#endif + + return private; +} +EXPORT_SYMBOL_GPL(xt_replace_table); + +struct xt_table *xt_register_table(struct net *net, + const struct xt_table *input_table, + struct xt_table_info *bootstrap, + struct xt_table_info *newinfo) +{ + int ret; + struct xt_table_info *private; + struct xt_table *t, *table; + + /* Don't add one object to multiple lists. */ + table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL); + if (!table) { + ret = -ENOMEM; + goto out; + } + + ret = mutex_lock_interruptible(&xt[table->af].mutex); + if (ret != 0) + goto out_free; + + /* Don't autoload: we'd eat our tail... */ + list_for_each_entry(t, &net->xt.tables[table->af], list) { + if (strcmp(t->name, table->name) == 0) { + ret = -EEXIST; + goto unlock; + } + } + + /* Simplifies replace_table code. */ + table->private = bootstrap; + + if (!xt_replace_table(table, 0, newinfo, &ret)) + goto unlock; + + private = table->private; + pr_debug("table->private->number = %u\n", private->number); + + /* save number of initial entries */ + private->initial_entries = private->number; + + list_add(&table->list, &net->xt.tables[table->af]); + mutex_unlock(&xt[table->af].mutex); + return table; + + unlock: + mutex_unlock(&xt[table->af].mutex); +out_free: + kfree(table); +out: + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(xt_register_table); + +void *xt_unregister_table(struct xt_table *table) +{ + struct xt_table_info *private; + + mutex_lock(&xt[table->af].mutex); + private = table->private; + list_del(&table->list); + mutex_unlock(&xt[table->af].mutex); + kfree(table); + + return private; +} +EXPORT_SYMBOL_GPL(xt_unregister_table); + +#ifdef CONFIG_PROC_FS +struct xt_names_priv { + struct seq_net_private p; + u_int8_t af; +}; +static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct xt_names_priv *priv = seq->private; + struct net *net = seq_file_net(seq); + u_int8_t af = priv->af; + + mutex_lock(&xt[af].mutex); + return seq_list_start(&net->xt.tables[af], *pos); +} + +static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct xt_names_priv *priv = seq->private; + struct net *net = seq_file_net(seq); + u_int8_t af = priv->af; + + return seq_list_next(v, &net->xt.tables[af], pos); +} + +static void xt_table_seq_stop(struct seq_file *seq, void *v) +{ + struct xt_names_priv *priv = seq->private; + u_int8_t af = priv->af; + + mutex_unlock(&xt[af].mutex); +} + +static int xt_table_seq_show(struct seq_file *seq, void *v) +{ + struct xt_table *table = list_entry(v, struct xt_table, list); + + if (strlen(table->name)) + return seq_printf(seq, "%s\n", table->name); + else + return 0; +} + +static const struct seq_operations xt_table_seq_ops = { + .start = xt_table_seq_start, + .next = xt_table_seq_next, + .stop = xt_table_seq_stop, + .show = xt_table_seq_show, +}; + +static int xt_table_open(struct inode *inode, struct file *file) +{ + int ret; + struct xt_names_priv *priv; + + ret = seq_open_net(inode, file, &xt_table_seq_ops, + sizeof(struct xt_names_priv)); + if (!ret) { + priv = ((struct seq_file *)file->private_data)->private; + priv->af = (unsigned long)PDE(inode)->data; + } + return ret; +} + +static const struct file_operations xt_table_ops = { + .owner = THIS_MODULE, + .open = xt_table_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net, +}; + +/* + * Traverse state for ip{,6}_{tables,matches} for helping crossing + * the multi-AF mutexes. + */ +struct nf_mttg_trav { + struct list_head *head, *curr; + uint8_t class, nfproto; +}; + +enum { + MTTG_TRAV_INIT, + MTTG_TRAV_NFP_UNSPEC, + MTTG_TRAV_NFP_SPEC, + MTTG_TRAV_DONE, +}; + +static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos, + bool is_target) +{ + static const uint8_t next_class[] = { + [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC, + [MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE, + }; + struct nf_mttg_trav *trav = seq->private; + + switch (trav->class) { + case MTTG_TRAV_INIT: + trav->class = MTTG_TRAV_NFP_UNSPEC; + mutex_lock(&xt[NFPROTO_UNSPEC].mutex); + trav->head = trav->curr = is_target ? + &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match; + break; + case MTTG_TRAV_NFP_UNSPEC: + trav->curr = trav->curr->next; + if (trav->curr != trav->head) + break; + mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); + mutex_lock(&xt[trav->nfproto].mutex); + trav->head = trav->curr = is_target ? + &xt[trav->nfproto].target : &xt[trav->nfproto].match; + trav->class = next_class[trav->class]; + break; + case MTTG_TRAV_NFP_SPEC: + trav->curr = trav->curr->next; + if (trav->curr != trav->head) + break; + /* fallthru, _stop will unlock */ + default: + return NULL; + } + + if (ppos != NULL) + ++*ppos; + return trav; +} + +static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos, + bool is_target) +{ + struct nf_mttg_trav *trav = seq->private; + unsigned int j; + + trav->class = MTTG_TRAV_INIT; + for (j = 0; j < *pos; ++j) + if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL) + return NULL; + return trav; +} + +static void xt_mttg_seq_stop(struct seq_file *seq, void *v) +{ + struct nf_mttg_trav *trav = seq->private; + + switch (trav->class) { + case MTTG_TRAV_NFP_UNSPEC: + mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); + break; + case MTTG_TRAV_NFP_SPEC: + mutex_unlock(&xt[trav->nfproto].mutex); + break; + } +} + +static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos) +{ + return xt_mttg_seq_start(seq, pos, false); +} + +static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos) +{ + return xt_mttg_seq_next(seq, v, ppos, false); +} + +static int xt_match_seq_show(struct seq_file *seq, void *v) +{ + const struct nf_mttg_trav *trav = seq->private; + const struct xt_match *match; + + switch (trav->class) { + case MTTG_TRAV_NFP_UNSPEC: + case MTTG_TRAV_NFP_SPEC: + if (trav->curr == trav->head) + return 0; + match = list_entry(trav->curr, struct xt_match, list); + return (*match->name == '\0') ? 0 : + seq_printf(seq, "%s\n", match->name); + } + return 0; +} + +static const struct seq_operations xt_match_seq_ops = { + .start = xt_match_seq_start, + .next = xt_match_seq_next, + .stop = xt_mttg_seq_stop, + .show = xt_match_seq_show, +}; + +static int xt_match_open(struct inode *inode, struct file *file) +{ + struct seq_file *seq; + struct nf_mttg_trav *trav; + int ret; + + trav = kmalloc(sizeof(*trav), GFP_KERNEL); + if (trav == NULL) + return -ENOMEM; + + ret = seq_open(file, &xt_match_seq_ops); + if (ret < 0) { + kfree(trav); + return ret; + } + + seq = file->private_data; + seq->private = trav; + trav->nfproto = (unsigned long)PDE(inode)->data; + return 0; +} + +static const struct file_operations xt_match_ops = { + .owner = THIS_MODULE, + .open = xt_match_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; + +static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos) +{ + return xt_mttg_seq_start(seq, pos, true); +} + +static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos) +{ + return xt_mttg_seq_next(seq, v, ppos, true); +} + +static int xt_target_seq_show(struct seq_file *seq, void *v) +{ + const struct nf_mttg_trav *trav = seq->private; + const struct xt_target *target; + + switch (trav->class) { + case MTTG_TRAV_NFP_UNSPEC: + case MTTG_TRAV_NFP_SPEC: + if (trav->curr == trav->head) + return 0; + target = list_entry(trav->curr, struct xt_target, list); + return (*target->name == '\0') ? 0 : + seq_printf(seq, "%s\n", target->name); + } + return 0; +} + +static const struct seq_operations xt_target_seq_ops = { + .start = xt_target_seq_start, + .next = xt_target_seq_next, + .stop = xt_mttg_seq_stop, + .show = xt_target_seq_show, +}; + +static int xt_target_open(struct inode *inode, struct file *file) +{ + struct seq_file *seq; + struct nf_mttg_trav *trav; + int ret; + + trav = kmalloc(sizeof(*trav), GFP_KERNEL); + if (trav == NULL) + return -ENOMEM; + + ret = seq_open(file, &xt_target_seq_ops); + if (ret < 0) { + kfree(trav); + return ret; + } + + seq = file->private_data; + seq->private = trav; + trav->nfproto = (unsigned long)PDE(inode)->data; + return 0; +} + +static const struct file_operations xt_target_ops = { + .owner = THIS_MODULE, + .open = xt_target_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; + +#define FORMAT_TABLES "_tables_names" +#define FORMAT_MATCHES "_tables_matches" +#define FORMAT_TARGETS "_tables_targets" + +#endif /* CONFIG_PROC_FS */ + +/** + * xt_hook_link - set up hooks for a new table + * @table: table with metadata needed to set up hooks + * @fn: Hook function + * + * This function will take care of creating and registering the necessary + * Netfilter hooks for XT tables. + */ +struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn) +{ + unsigned int hook_mask = table->valid_hooks; + uint8_t i, num_hooks = hweight32(hook_mask); + uint8_t hooknum; + struct nf_hook_ops *ops; + int ret; + + ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); + if (ops == NULL) + return ERR_PTR(-ENOMEM); + + for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0; + hook_mask >>= 1, ++hooknum) { + if (!(hook_mask & 1)) + continue; + ops[i].hook = fn; + ops[i].owner = table->me; + ops[i].pf = table->af; + ops[i].hooknum = hooknum; + ops[i].priority = table->priority; + ++i; + } + + ret = nf_register_hooks(ops, num_hooks); + if (ret < 0) { + kfree(ops); + return ERR_PTR(ret); + } + + return ops; +} +EXPORT_SYMBOL_GPL(xt_hook_link); + +/** + * xt_hook_unlink - remove hooks for a table + * @ops: nf_hook_ops array as returned by nf_hook_link + * @hook_mask: the very same mask that was passed to nf_hook_link + */ +void xt_hook_unlink(const struct xt_table *table, struct nf_hook_ops *ops) +{ + nf_unregister_hooks(ops, hweight32(table->valid_hooks)); + kfree(ops); +} +EXPORT_SYMBOL_GPL(xt_hook_unlink); + +int xt_proto_init(struct net *net, u_int8_t af) +{ +#ifdef CONFIG_PROC_FS + char buf[XT_FUNCTION_MAXNAMELEN]; + struct proc_dir_entry *proc; +#endif + + if (af >= ARRAY_SIZE(xt_prefix)) + return -EINVAL; + + +#ifdef CONFIG_PROC_FS + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_TABLES, sizeof(buf)); + proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops, + (void *)(unsigned long)af); + if (!proc) + goto out; + + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_MATCHES, sizeof(buf)); + proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops, + (void *)(unsigned long)af); + if (!proc) + goto out_remove_tables; + + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_TARGETS, sizeof(buf)); + proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops, + (void *)(unsigned long)af); + if (!proc) + goto out_remove_matches; +#endif + + return 0; + +#ifdef CONFIG_PROC_FS +out_remove_matches: + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_MATCHES, sizeof(buf)); + proc_net_remove(net, buf); + +out_remove_tables: + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_TABLES, sizeof(buf)); + proc_net_remove(net, buf); +out: + return -1; +#endif +} +EXPORT_SYMBOL_GPL(xt_proto_init); + +void xt_proto_fini(struct net *net, u_int8_t af) +{ +#ifdef CONFIG_PROC_FS + char buf[XT_FUNCTION_MAXNAMELEN]; + + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_TABLES, sizeof(buf)); + proc_net_remove(net, buf); + + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_TARGETS, sizeof(buf)); + proc_net_remove(net, buf); + + strlcpy(buf, xt_prefix[af], sizeof(buf)); + strlcat(buf, FORMAT_MATCHES, sizeof(buf)); + proc_net_remove(net, buf); +#endif /*CONFIG_PROC_FS*/ +} +EXPORT_SYMBOL_GPL(xt_proto_fini); + +static int __net_init xt_net_init(struct net *net) +{ + int i; + + for (i = 0; i < NFPROTO_NUMPROTO; i++) + INIT_LIST_HEAD(&net->xt.tables[i]); + return 0; +} + +static struct pernet_operations xt_net_ops = { + .init = xt_net_init, +}; + +static int __init xt_init(void) +{ + unsigned int i; + int rv; + + for_each_possible_cpu(i) { + seqcount_init(&per_cpu(xt_recseq, i)); + } + + xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL); + if (!xt) + return -ENOMEM; + + for (i = 0; i < NFPROTO_NUMPROTO; i++) { + mutex_init(&xt[i].mutex); +#ifdef CONFIG_COMPAT + mutex_init(&xt[i].compat_mutex); + xt[i].compat_tab = NULL; +#endif + INIT_LIST_HEAD(&xt[i].target); + INIT_LIST_HEAD(&xt[i].match); + } + rv = register_pernet_subsys(&xt_net_ops); + if (rv < 0) + kfree(xt); + return rv; +} + +static void __exit xt_fini(void) +{ + unregister_pernet_subsys(&xt_net_ops); + kfree(xt); +} + +module_init(xt_init); +module_exit(xt_fini); + |