/* * x_tables core - Backend for {ip,ip6,arp}_tables * * Copyright (C) 2006-2006 Harald Welte * * Based on existing ip_tables code which is * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling * Copyright (C) 2000-2005 Netfilter Core Team * * 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. * */ #include #include #include #include #include #include #include #include #include #include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte "); MODULE_DESCRIPTION("[ip,ip6,arp]_tables backend module"); #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) struct xt_af { struct mutex mutex; struct list_head match; struct list_head target; struct list_head tables; struct mutex compat_mutex; }; static struct xt_af *xt; #ifdef DEBUG_IP_FIREWALL_USER #define duprintf(format, args...) printk(format , ## args) #else #define duprintf(format, args...) #endif enum { TABLE, TARGET, MATCH, }; static const char *xt_prefix[NPROTO] = { [AF_INET] = "ip", [AF_INET6] = "ip6", [NF_ARP] = "arp", }; /* Registration hooks for targets. */ int xt_register_target(struct xt_target *target) { int ret, af = target->family; 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) { int af = target->family; mutex_lock(&xt[af].mutex); LIST_DELETE(&xt[af].target, target); mutex_unlock(&xt[af].mutex); } EXPORT_SYMBOL(xt_unregister_target); int xt_register_match(struct xt_match *match) { int ret, af = match->family; 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) { int af = match->family; mutex_lock(&xt[af].mutex); LIST_DELETE(&xt[af].match, match); mutex_unlock(&xt[af].mutex); } EXPORT_SYMBOL(xt_unregister_match); /* * 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 try_then_request_module(). */ /* Find match, grabs ref. Returns ERR_PTR() on error. */ struct xt_match *xt_find_match(int af, const char *name, u8 revision) { struct xt_match *m; int err = 0; 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); return ERR_PTR(err); } EXPORT_SYMBOL(xt_find_match); /* Find target, grabs ref. Returns ERR_PTR() on error. */ struct xt_target *xt_find_target(int af, const char *name, u8 revision) { struct xt_target *t; int err = 0; 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); return ERR_PTR(err); } EXPORT_SYMBOL(xt_find_target); struct xt_target *xt_request_find_target(int af, const char *name, u8 revision) { struct xt_target *target; target = try_then_request_module(xt_find_target(af, name, revision), "%st_%s", xt_prefix[af], name); if (IS_ERR(target) || !target) return NULL; return target; } EXPORT_SYMBOL_GPL(xt_request_find_target); static int match_revfn(int af, const char *name, u8 revision, int *bestp) { 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; } } return have_rev; } static int target_revfn(int af, const char *name, u8 revision, int *bestp) { 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; } } return have_rev; } /* Returns true or false (if no such extension at all) */ int xt_find_revision(int 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); int xt_check_match(const struct xt_match *match, unsigned short family, unsigned int size, const char *table, unsigned int hook_mask, unsigned short proto, int inv_proto) { if (XT_ALIGN(match->matchsize) != size) { printk("%s_tables: %s match: invalid size %Zu != %u\n", xt_prefix[family], match->name, XT_ALIGN(match->matchsize), size); return -EINVAL; } if (match->table && strcmp(match->table, table)) { printk("%s_tables: %s match: only valid in %s table, not %s\n", xt_prefix[family], match->name, match->table, table); return -EINVAL; } if (match->hooks && (hook_mask & ~match->hooks) != 0) { printk("%s_tables: %s match: bad hook_mask %u\n", xt_prefix[family], match->name, hook_mask); return -EINVAL; } if (match->proto && (match->proto != proto || inv_proto)) { printk("%s_tables: %s match: only valid for protocol %u\n", xt_prefix[family], match->name, match->proto); return -EINVAL; } return 0; } EXPORT_SYMBOL_GPL(xt_check_match); #ifdef CONFIG_COMPAT int xt_compat_match(void *match, void **dstptr, int *size, int convert) { struct xt_match *m; struct compat_xt_entry_match *pcompat_m; struct xt_entry_match *pm; u_int16_t msize; int off, ret; ret = 0; m = ((struct xt_entry_match *)match)->u.kernel.match; off = XT_ALIGN(m->matchsize) - COMPAT_XT_ALIGN(m->matchsize); switch (convert) { case COMPAT_TO_USER: pm = (struct xt_entry_match *)match; msize = pm->u.user.match_size; if (copy_to_user(*dstptr, pm, msize)) { ret = -EFAULT; break; } msize -= off; if (put_user(msize, (u_int16_t *)*dstptr)) ret = -EFAULT; *size -= off; *dstptr += msize; break; case COMPAT_FROM_USER: pcompat_m = (struct compat_xt_entry_match *)match; pm = (struct xt_entry_match *)*dstptr; msize = pcompat_m->u.user.match_size; memcpy(pm, pcompat_m, msize); msize += off; pm->u.user.match_size = msize; *size += off; *dstptr += msize; break; case COMPAT_CALC_SIZE: *size += off; break; default: ret = -ENOPROTOOPT; break; } return ret; } EXPORT_SYMBOL_GPL(xt_compat_match); #endif int xt_check_target(const struct xt_target *target, unsigned short family, unsigned int size, const char *table, unsigned int hook_mask, unsigned short proto, int inv_proto) { if (XT_ALIGN(target->targetsize) != size) { printk("%s_tables: %s target: invalid size %Zu != %u\n", xt_prefix[family], target->name, XT_ALIGN(target->targetsize), size); return -EINVAL; } if (target->table && strcmp(target->table, table)) { printk("%s_tables: %s target: only valid in %s table, not %s\n", xt_prefix[family], target->name, target->table, table); return -EINVAL; } if (target->hooks && (hook_mask & ~target->hooks) != 0) { printk("%s_tables: %s target: bad hook_mask %u\n", xt_prefix[family], target->name, hook_mask); return -EINVAL; } if (target->proto && (target->proto != proto || inv_proto)) { printk("%s_tables: %s target: only valid for protocol %u\n", xt_prefix[family], target->name, target->proto); return -EINVAL; } return 0; } EXPORT_SYMBOL_GPL(xt_check_target); #ifdef CONFIG_COMPAT int xt_compat_target(void *target, void **dstptr, int *size, int convert) { struct xt_target *t; struct compat_xt_entry_target *pcompat; struct xt_entry_target *pt; u_int16_t tsize; int off, ret; ret = 0; t = ((struct xt_entry_target *)target)->u.kernel.target; off = XT_ALIGN(t->targetsize) - COMPAT_XT_ALIGN(t->targetsize); switch (convert) { case COMPAT_TO_USER: pt = (struct xt_entry_target *)target; tsize = pt->u.user.target_size; if (copy_to_user(*dstptr, pt, tsize)) { ret = -EFAULT; break; } tsize -= off; if (put_user(tsize, (u_int16_t *)*dstptr)) ret = -EFAULT; *size -= off; *dstptr += tsize; break; case COMPAT_FROM_USER: pcompat = (struct compat_xt_entry_target *)target; pt = (struct xt_entry_target *)*dstptr; tsize = pcompat->u.user.target_size; memcpy(pt, pcompat, tsize); tsize += off; pt->u.user.target_size = tsize; *size += off; *dstptr += tsize; break; case COMPAT_CALC_SIZE: *size += off; break; default: ret = -ENOPROTOOPT; break; } return ret; } EXPORT_SYMBOL_GPL(xt_compat_target); #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 > num_physpages) return NULL; newinfo = kzalloc(sizeof(struct xt_table_info), 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]); } 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(int 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, &xt[af].tables, 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(int af) { mutex_lock(&xt[af].compat_mutex); } EXPORT_SYMBOL_GPL(xt_compat_lock); void xt_compat_unlock(int af) { mutex_unlock(&xt[af].compat_mutex); } EXPORT_SYMBOL_GPL(xt_compat_unlock); #endif 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 *oldinfo, *private; /* Do the substitution. */ write_lock_bh(&table->lock); private = table->private; /* Check inside lock: is the old number correct? */ if (num_counters != private->number) { duprintf("num_counters != table->private->number (%u/%u)\n", num_counters, private->number); write_unlock_bh(&table->lock); *error = -EAGAIN; return NULL; } oldinfo = private; table->private = newinfo; newinfo->initial_entries = oldinfo->initial_entries; write_unlock_bh(&table->lock); return oldinfo; } EXPORT_SYMBOL_GPL(xt_replace_table); int xt_register_table(struct xt_table *table, struct xt_table_info *bootstrap, struct xt_table_info *newinfo) { int ret; struct xt_table_info *private; ret = mutex_lock_interruptible(&xt[table->af].mutex); if (ret != 0) return ret; /* Don't autoload: we'd eat our tail... */ if (list_named_find(&xt[table->af].tables, table->name)) { ret = -EEXIST; goto unlock; } /* Simplifies replace_table code. */ table->private = bootstrap; rwlock_init(&table->lock); if (!xt_replace_table(table, 0, newinfo, &ret)) goto unlock; private = table->private; duprintf("table->private->number = %u\n", private->number); /* save number of initial entries */ private->initial_entries = private->number; list_prepend(&xt[table->af].tables, table); ret = 0; unlock: mutex_unlock(&xt[table->af].mutex); return 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_DELETE(&xt[table->af].tables, table); mutex_unlock(&xt[table->af].mutex); return private; } EXPORT_SYMBOL_GPL(xt_unregister_table); #ifdef CONFIG_PROC_FS static char *xt_proto_prefix[NPROTO] = { [AF_INET] = "ip", [AF_INET6] = "ip6", [NF_ARP] = "arp", }; static struct list_head *xt_get_idx(struct list_head *list, struct seq_file *seq, loff_t pos) { struct list_head *head = list->next; if (!head || list_empty(list)) return NULL; while (pos && (head = head->next)) { if (head == list) return NULL; pos--; } return pos ? NULL : head; } static struct list_head *type2list(u_int16_t af, u_int16_t type) { struct list_head *list; switch (type) { case TARGET: list = &xt[af].target; break; case MATCH: list = &xt[af].match; break; case TABLE: list = &xt[af].tables; break; default: list = NULL; break; } return list; } static void *xt_tgt_seq_start(struct seq_file *seq, loff_t *pos) { struct proc_dir_entry *pde = (struct proc_dir_entry *) seq->private; u_int16_t af = (unsigned long)pde->data & 0xffff; u_int16_t type = (unsigned long)pde->data >> 16; struct list_head *list; if (af >= NPROTO) return NULL; list = type2list(af, type); if (!list) return NULL; if (mutex_lock_interruptible(&xt[af].mutex) != 0) return NULL; return xt_get_idx(list, seq, *pos); } static void *xt_tgt_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct proc_dir_entry *pde = seq->private; u_int16_t af = (unsigned long)pde->data & 0xffff; u_int16_t type = (unsigned long)pde->data >> 16; struct list_head *list; if (af >= NPROTO) return NULL; list = type2list(af, type); if (!list) return NULL; (*pos)++; return xt_get_idx(list, seq, *pos); } static void xt_tgt_seq_stop(struct seq_file *seq, void *v) { struct proc_dir_entry *pde = seq->private; u_int16_t af = (unsigned long)pde->data & 0xffff; mutex_unlock(&xt[af].mutex); } static int xt_name_seq_show(struct seq_file *seq, void *v) { char *name = (char *)v + sizeof(struct list_head); if (strlen(name)) return seq_printf(seq, "%s\n", name); else return 0; } static struct seq_operations xt_tgt_seq_ops = { .start = xt_tgt_seq_start, .next = xt_tgt_seq_next, .stop = xt_tgt_seq_stop, .show = xt_name_seq_show, }; static int xt_tgt_open(struct inode *inode, struct file *file) { int ret; ret = seq_open(file, &xt_tgt_seq_ops); if (!ret) { struct seq_file *seq = file->private_data; struct proc_dir_entry *pde = PDE(inode); seq->private = pde; } return ret; } static struct file_operations xt_file_ops = { .owner = THIS_MODULE, .open = xt_tgt_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; #define FORMAT_TABLES "_tables_names" #define FORMAT_MATCHES "_tables_matches" #define FORMAT_TARGETS "_tables_targets" #endif /* CONFIG_PROC_FS */ int xt_proto_init(int af) { #ifdef CONFIG_PROC_FS char buf[XT_FUNCTION_MAXNAMELEN]; struct proc_dir_entry *proc; #endif if (af >= NPROTO) return -EINVAL; #ifdef CONFIG_PROC_FS strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TABLES, sizeof(buf)); proc = proc_net_fops_create(buf, 0440, &xt_file_ops); if (!proc) goto out; proc->data = (void *) ((unsigned long) af | (TABLE << 16)); strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_MATCHES, sizeof(buf)); proc = proc_net_fops_create(buf, 0440, &xt_file_ops); if (!proc) goto out_remove_tables; proc->data = (void *) ((unsigned long) af | (MATCH << 16)); strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TARGETS, sizeof(buf)); proc = proc_net_fops_create(buf, 0440, &xt_file_ops); if (!proc) goto out_remove_matches; proc->data = (void *) ((unsigned long) af | (TARGET << 16)); #endif return 0; #ifdef CONFIG_PROC_FS out_remove_matches: strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_MATCHES, sizeof(buf)); proc_net_remove(buf); out_remove_tables: strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TABLES, sizeof(buf)); proc_net_remove(buf); out: return -1; #endif } EXPORT_SYMBOL_GPL(xt_proto_init); void xt_proto_fini(int af) { #ifdef CONFIG_PROC_FS char buf[XT_FUNCTION_MAXNAMELEN]; strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TABLES, sizeof(buf)); proc_net_remove(buf); strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_TARGETS, sizeof(buf)); proc_net_remove(buf); strlcpy(buf, xt_proto_prefix[af], sizeof(buf)); strlcat(buf, FORMAT_MATCHES, sizeof(buf)); proc_net_remove(buf); #endif /*CONFIG_PROC_FS*/ } EXPORT_SYMBOL_GPL(xt_proto_fini); static int __init xt_init(void) { int i; xt = kmalloc(sizeof(struct xt_af) * NPROTO, GFP_KERNEL); if (!xt) return -ENOMEM; for (i = 0; i < NPROTO; i++) { mutex_init(&xt[i].mutex); #ifdef CONFIG_COMPAT mutex_init(&xt[i].compat_mutex); #endif INIT_LIST_HEAD(&xt[i].target); INIT_LIST_HEAD(&xt[i].match); INIT_LIST_HEAD(&xt[i].tables); } return 0; } static void __exit xt_fini(void) { kfree(xt); } module_init(xt_init); module_exit(xt_fini);