diff options
Diffstat (limited to 'net/bridge/netfilter/ebtables.c')
| -rw-r--r-- | net/bridge/netfilter/ebtables.c | 1507 |
1 files changed, 1507 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c new file mode 100644 index 00000000000..18ebc664769 --- /dev/null +++ b/net/bridge/netfilter/ebtables.c @@ -0,0 +1,1507 @@ +/* + * ebtables + * + * Author: + * Bart De Schuymer <bdschuym@pandora.be> + * + * ebtables.c,v 2.0, July, 2002 + * + * This code is stongly inspired on the iptables code which is + * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +/* used for print_string */ +#include <linux/sched.h> +#include <linux/tty.h> + +#include <linux/kmod.h> +#include <linux/module.h> +#include <linux/vmalloc.h> +#include <linux/netfilter_bridge/ebtables.h> +#include <linux/spinlock.h> +#include <asm/uaccess.h> +#include <linux/smp.h> +#include <net/sock.h> +/* needed for logical [in,out]-dev filtering */ +#include "../br_private.h" + +/* list_named_find */ +#define ASSERT_READ_LOCK(x) +#define ASSERT_WRITE_LOCK(x) +#include <linux/netfilter_ipv4/listhelp.h> + +#if 0 +/* use this for remote debugging + * Copyright (C) 1998 by Ori Pomerantz + * Print the string to the appropriate tty, the one + * the current task uses + */ +static void print_string(char *str) +{ + struct tty_struct *my_tty; + + /* The tty for the current task */ + my_tty = current->signal->tty; + if (my_tty != NULL) { + my_tty->driver->write(my_tty, 0, str, strlen(str)); + my_tty->driver->write(my_tty, 0, "\015\012", 2); + } +} + +#define BUGPRINT(args) print_string(args); +#else +#define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\ + "report to author: "format, ## args) +/* #define BUGPRINT(format, args...) */ +#endif +#define MEMPRINT(format, args...) printk("kernel msg: ebtables "\ + ": out of memory: "format, ## args) +/* #define MEMPRINT(format, args...) */ + + + +/* + * Each cpu has its own set of counters, so there is no need for write_lock in + * the softirq + * For reading or updating the counters, the user context needs to + * get a write_lock + */ + +/* The size of each set of counters is altered to get cache alignment */ +#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) +#define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter))) +#define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \ + COUNTER_OFFSET(n) * cpu)) + + + +static DECLARE_MUTEX(ebt_mutex); +static LIST_HEAD(ebt_tables); +static LIST_HEAD(ebt_targets); +static LIST_HEAD(ebt_matches); +static LIST_HEAD(ebt_watchers); + +static struct ebt_target ebt_standard_target = +{ {NULL, NULL}, EBT_STANDARD_TARGET, NULL, NULL, NULL, NULL}; + +static inline int ebt_do_watcher (struct ebt_entry_watcher *w, + const struct sk_buff *skb, unsigned int hooknr, const struct net_device *in, + const struct net_device *out) +{ + w->u.watcher->watcher(skb, hooknr, in, out, w->data, + w->watcher_size); + /* watchers don't give a verdict */ + return 0; +} + +static inline int ebt_do_match (struct ebt_entry_match *m, + const struct sk_buff *skb, const struct net_device *in, + const struct net_device *out) +{ + return m->u.match->match(skb, in, out, m->data, + m->match_size); +} + +static inline int ebt_dev_check(char *entry, const struct net_device *device) +{ + int i = 0; + char *devname = device->name; + + if (*entry == '\0') + return 0; + if (!device) + return 1; + /* 1 is the wildcard token */ + while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i]) + i++; + return (devname[i] != entry[i] && entry[i] != 1); +} + +#define FWINV2(bool,invflg) ((bool) ^ !!(e->invflags & invflg)) +/* process standard matches */ +static inline int ebt_basic_match(struct ebt_entry *e, struct ethhdr *h, + const struct net_device *in, const struct net_device *out) +{ + int verdict, i; + + if (e->bitmask & EBT_802_3) { + if (FWINV2(ntohs(h->h_proto) >= 1536, EBT_IPROTO)) + return 1; + } else if (!(e->bitmask & EBT_NOPROTO) && + FWINV2(e->ethproto != h->h_proto, EBT_IPROTO)) + return 1; + + if (FWINV2(ebt_dev_check(e->in, in), EBT_IIN)) + return 1; + if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT)) + return 1; + if ((!in || !in->br_port) ? 0 : FWINV2(ebt_dev_check( + e->logical_in, in->br_port->br->dev), EBT_ILOGICALIN)) + return 1; + if ((!out || !out->br_port) ? 0 : FWINV2(ebt_dev_check( + e->logical_out, out->br_port->br->dev), EBT_ILOGICALOUT)) + return 1; + + if (e->bitmask & EBT_SOURCEMAC) { + verdict = 0; + for (i = 0; i < 6; i++) + verdict |= (h->h_source[i] ^ e->sourcemac[i]) & + e->sourcemsk[i]; + if (FWINV2(verdict != 0, EBT_ISOURCE) ) + return 1; + } + if (e->bitmask & EBT_DESTMAC) { + verdict = 0; + for (i = 0; i < 6; i++) + verdict |= (h->h_dest[i] ^ e->destmac[i]) & + e->destmsk[i]; + if (FWINV2(verdict != 0, EBT_IDEST) ) + return 1; + } + return 0; +} + +/* Do some firewalling */ +unsigned int ebt_do_table (unsigned int hook, struct sk_buff **pskb, + const struct net_device *in, const struct net_device *out, + struct ebt_table *table) +{ + int i, nentries; + struct ebt_entry *point; + struct ebt_counter *counter_base, *cb_base; + struct ebt_entry_target *t; + int verdict, sp = 0; + struct ebt_chainstack *cs; + struct ebt_entries *chaininfo; + char *base; + struct ebt_table_info *private; + + read_lock_bh(&table->lock); + private = table->private; + cb_base = COUNTER_BASE(private->counters, private->nentries, + smp_processor_id()); + if (private->chainstack) + cs = private->chainstack[smp_processor_id()]; + else + cs = NULL; + chaininfo = private->hook_entry[hook]; + nentries = private->hook_entry[hook]->nentries; + point = (struct ebt_entry *)(private->hook_entry[hook]->data); + counter_base = cb_base + private->hook_entry[hook]->counter_offset; + /* base for chain jumps */ + base = private->entries; + i = 0; + while (i < nentries) { + if (ebt_basic_match(point, eth_hdr(*pskb), in, out)) + goto letscontinue; + + if (EBT_MATCH_ITERATE(point, ebt_do_match, *pskb, in, out) != 0) + goto letscontinue; + + /* increase counter */ + (*(counter_base + i)).pcnt++; + (*(counter_base + i)).bcnt+=(**pskb).len; + + /* these should only watch: not modify, nor tell us + what to do with the packet */ + EBT_WATCHER_ITERATE(point, ebt_do_watcher, *pskb, hook, in, + out); + + t = (struct ebt_entry_target *) + (((char *)point) + point->target_offset); + /* standard target */ + if (!t->u.target->target) + verdict = ((struct ebt_standard_target *)t)->verdict; + else + verdict = t->u.target->target(pskb, hook, + in, out, t->data, t->target_size); + if (verdict == EBT_ACCEPT) { + read_unlock_bh(&table->lock); + return NF_ACCEPT; + } + if (verdict == EBT_DROP) { + read_unlock_bh(&table->lock); + return NF_DROP; + } + if (verdict == EBT_RETURN) { +letsreturn: +#ifdef CONFIG_NETFILTER_DEBUG + if (sp == 0) { + BUGPRINT("RETURN on base chain"); + /* act like this is EBT_CONTINUE */ + goto letscontinue; + } +#endif + sp--; + /* put all the local variables right */ + i = cs[sp].n; + chaininfo = cs[sp].chaininfo; + nentries = chaininfo->nentries; + point = cs[sp].e; + counter_base = cb_base + + chaininfo->counter_offset; + continue; + } + if (verdict == EBT_CONTINUE) + goto letscontinue; +#ifdef CONFIG_NETFILTER_DEBUG + if (verdict < 0) { + BUGPRINT("bogus standard verdict\n"); + read_unlock_bh(&table->lock); + return NF_DROP; + } +#endif + /* jump to a udc */ + cs[sp].n = i + 1; + cs[sp].chaininfo = chaininfo; + cs[sp].e = (struct ebt_entry *) + (((char *)point) + point->next_offset); + i = 0; + chaininfo = (struct ebt_entries *) (base + verdict); +#ifdef CONFIG_NETFILTER_DEBUG + if (chaininfo->distinguisher) { + BUGPRINT("jump to non-chain\n"); + read_unlock_bh(&table->lock); + return NF_DROP; + } +#endif + nentries = chaininfo->nentries; + point = (struct ebt_entry *)chaininfo->data; + counter_base = cb_base + chaininfo->counter_offset; + sp++; + continue; +letscontinue: + point = (struct ebt_entry *) + (((char *)point) + point->next_offset); + i++; + } + + /* I actually like this :) */ + if (chaininfo->policy == EBT_RETURN) + goto letsreturn; + if (chaininfo->policy == EBT_ACCEPT) { + read_unlock_bh(&table->lock); + return NF_ACCEPT; + } + read_unlock_bh(&table->lock); + return NF_DROP; +} + +/* If it succeeds, returns element and locks mutex */ +static inline void * +find_inlist_lock_noload(struct list_head *head, const char *name, int *error, + struct semaphore *mutex) +{ + void *ret; + + *error = down_interruptible(mutex); + if (*error != 0) + return NULL; + + ret = list_named_find(head, name); + if (!ret) { + *error = -ENOENT; + up(mutex); + } + return ret; +} + +#ifndef CONFIG_KMOD +#define find_inlist_lock(h,n,p,e,m) find_inlist_lock_noload((h),(n),(e),(m)) +#else +static void * +find_inlist_lock(struct list_head *head, const char *name, const char *prefix, + int *error, struct semaphore *mutex) +{ + void *ret; + + ret = find_inlist_lock_noload(head, name, error, mutex); + if (!ret) { + request_module("%s%s", prefix, name); + ret = find_inlist_lock_noload(head, name, error, mutex); + } + return ret; +} +#endif + +static inline struct ebt_table * +find_table_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ebt_tables, name, "ebtable_", error, mutex); +} + +static inline struct ebt_match * +find_match_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ebt_matches, name, "ebt_", error, mutex); +} + +static inline struct ebt_watcher * +find_watcher_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ebt_watchers, name, "ebt_", error, mutex); +} + +static inline struct ebt_target * +find_target_lock(const char *name, int *error, struct semaphore *mutex) +{ + return find_inlist_lock(&ebt_targets, name, "ebt_", error, mutex); +} + +static inline int +ebt_check_match(struct ebt_entry_match *m, struct ebt_entry *e, + const char *name, unsigned int hookmask, unsigned int *cnt) +{ + struct ebt_match *match; + int ret; + + if (((char *)m) + m->match_size + sizeof(struct ebt_entry_match) > + ((char *)e) + e->watchers_offset) + return -EINVAL; + match = find_match_lock(m->u.name, &ret, &ebt_mutex); + if (!match) + return ret; + m->u.match = match; + if (!try_module_get(match->me)) { + up(&ebt_mutex); + return -ENOENT; + } + up(&ebt_mutex); + if (match->check && + match->check(name, hookmask, e, m->data, m->match_size) != 0) { + BUGPRINT("match->check failed\n"); + module_put(match->me); + return -EINVAL; + } + (*cnt)++; + return 0; +} + +static inline int +ebt_check_watcher(struct ebt_entry_watcher *w, struct ebt_entry *e, + const char *name, unsigned int hookmask, unsigned int *cnt) +{ + struct ebt_watcher *watcher; + int ret; + + if (((char *)w) + w->watcher_size + sizeof(struct ebt_entry_watcher) > + ((char *)e) + e->target_offset) + return -EINVAL; + watcher = find_watcher_lock(w->u.name, &ret, &ebt_mutex); + if (!watcher) + return ret; + w->u.watcher = watcher; + if (!try_module_get(watcher->me)) { + up(&ebt_mutex); + return -ENOENT; + } + up(&ebt_mutex); + if (watcher->check && + watcher->check(name, hookmask, e, w->data, w->watcher_size) != 0) { + BUGPRINT("watcher->check failed\n"); + module_put(watcher->me); + return -EINVAL; + } + (*cnt)++; + return 0; +} + +/* + * this one is very careful, as it is the first function + * to parse the userspace data + */ +static inline int +ebt_check_entry_size_and_hooks(struct ebt_entry *e, + struct ebt_table_info *newinfo, char *base, char *limit, + struct ebt_entries **hook_entries, unsigned int *n, unsigned int *cnt, + unsigned int *totalcnt, unsigned int *udc_cnt, unsigned int valid_hooks) +{ + int i; + + for (i = 0; i < NF_BR_NUMHOOKS; i++) { + if ((valid_hooks & (1 << i)) == 0) + continue; + if ( (char *)hook_entries[i] - base == + (char *)e - newinfo->entries) + break; + } + /* beginning of a new chain + if i == NF_BR_NUMHOOKS it must be a user defined chain */ + if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) { + if ((e->bitmask & EBT_ENTRY_OR_ENTRIES) != 0) { + /* we make userspace set this right, + so there is no misunderstanding */ + BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set " + "in distinguisher\n"); + return -EINVAL; + } + /* this checks if the previous chain has as many entries + as it said it has */ + if (*n != *cnt) { + BUGPRINT("nentries does not equal the nr of entries " + "in the chain\n"); + return -EINVAL; + } + /* before we look at the struct, be sure it is not too big */ + if ((char *)hook_entries[i] + sizeof(struct ebt_entries) + > limit) { + BUGPRINT("entries_size too small\n"); + return -EINVAL; + } + if (((struct ebt_entries *)e)->policy != EBT_DROP && + ((struct ebt_entries *)e)->policy != EBT_ACCEPT) { + /* only RETURN from udc */ + if (i != NF_BR_NUMHOOKS || + ((struct ebt_entries *)e)->policy != EBT_RETURN) { + BUGPRINT("bad policy\n"); + return -EINVAL; + } + } + if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ + (*udc_cnt)++; + else + newinfo->hook_entry[i] = (struct ebt_entries *)e; + if (((struct ebt_entries *)e)->counter_offset != *totalcnt) { + BUGPRINT("counter_offset != totalcnt"); + return -EINVAL; + } + *n = ((struct ebt_entries *)e)->nentries; + *cnt = 0; + return 0; + } + /* a plain old entry, heh */ + if (sizeof(struct ebt_entry) > e->watchers_offset || + e->watchers_offset > e->target_offset || + e->target_offset >= e->next_offset) { + BUGPRINT("entry offsets not in right order\n"); + return -EINVAL; + } + /* this is not checked anywhere else */ + if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) { + BUGPRINT("target size too small\n"); + return -EINVAL; + } + + (*cnt)++; + (*totalcnt)++; + return 0; +} + +struct ebt_cl_stack +{ + struct ebt_chainstack cs; + int from; + unsigned int hookmask; +}; + +/* + * we need these positions to check that the jumps to a different part of the + * entries is a jump to the beginning of a new chain. + */ +static inline int +ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo, + struct ebt_entries **hook_entries, unsigned int *n, unsigned int valid_hooks, + struct ebt_cl_stack *udc) +{ + int i; + + /* we're only interested in chain starts */ + if (e->bitmask & EBT_ENTRY_OR_ENTRIES) + return 0; + for (i = 0; i < NF_BR_NUMHOOKS; i++) { + if ((valid_hooks & (1 << i)) == 0) + continue; + if (newinfo->hook_entry[i] == (struct ebt_entries *)e) + break; + } + /* only care about udc */ + if (i != NF_BR_NUMHOOKS) + return 0; + + udc[*n].cs.chaininfo = (struct ebt_entries *)e; + /* these initialisations are depended on later in check_chainloops() */ + udc[*n].cs.n = 0; + udc[*n].hookmask = 0; + + (*n)++; + return 0; +} + +static inline int +ebt_cleanup_match(struct ebt_entry_match *m, unsigned int *i) +{ + if (i && (*i)-- == 0) + return 1; + if (m->u.match->destroy) + m->u.match->destroy(m->data, m->match_size); + module_put(m->u.match->me); + + return 0; +} + +static inline int +ebt_cleanup_watcher(struct ebt_entry_watcher *w, unsigned int *i) +{ + if (i && (*i)-- == 0) + return 1; + if (w->u.watcher->destroy) + w->u.watcher->destroy(w->data, w->watcher_size); + module_put(w->u.watcher->me); + + return 0; +} + +static inline int +ebt_cleanup_entry(struct ebt_entry *e, unsigned int *cnt) +{ + struct ebt_entry_target *t; + + if ((e->bitmask & EBT_ENTRY_OR_ENTRIES) == 0) + return 0; + /* we're done */ + if (cnt && (*cnt)-- == 0) + return 1; + EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, NULL); + EBT_MATCH_ITERATE(e, ebt_cleanup_match, NULL); + t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); + if (t->u.target->destroy) + t->u.target->destroy(t->data, t->target_size); + module_put(t->u.target->me); + + return 0; +} + +static inline int +ebt_check_entry(struct ebt_entry *e, struct ebt_table_info *newinfo, + const char *name, unsigned int *cnt, unsigned int valid_hooks, + struct ebt_cl_stack *cl_s, unsigned int udc_cnt) +{ + struct ebt_entry_target *t; + struct ebt_target *target; + unsigned int i, j, hook = 0, hookmask = 0; + int ret; + + /* don't mess with the struct ebt_entries */ + if ((e->bitmask & EBT_ENTRY_OR_ENTRIES) == 0) + return 0; + + if (e->bitmask & ~EBT_F_MASK) { + BUGPRINT("Unknown flag for bitmask\n"); + return -EINVAL; + } + if (e->invflags & ~EBT_INV_MASK) { + BUGPRINT("Unknown flag for inv bitmask\n"); + return -EINVAL; + } + if ( (e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3) ) { + BUGPRINT("NOPROTO & 802_3 not allowed\n"); + return -EINVAL; + } + /* what hook do we belong to? */ + for (i = 0; i < NF_BR_NUMHOOKS; i++) { + if ((valid_hooks & (1 << i)) == 0) + continue; + if ((char *)newinfo->hook_entry[i] < (char *)e) + hook = i; + else + break; + } + /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on + a base chain */ + if (i < NF_BR_NUMHOOKS) + hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); + else { + for (i = 0; i < udc_cnt; i++) + if ((char *)(cl_s[i].cs.chaininfo) > (char *)e) + break; + if (i == 0) + hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); + else + hookmask = cl_s[i - 1].hookmask; + } + i = 0; + ret = EBT_MATCH_ITERATE(e, ebt_check_match, e, name, hookmask, &i); + if (ret != 0) + goto cleanup_matches; + j = 0; + ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, e, name, hookmask, &j); + if (ret != 0) + goto cleanup_watchers; + t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); + target = find_target_lock(t->u.name, &ret, &ebt_mutex); + if (!target) + goto cleanup_watchers; + if (!try_module_get(target->me)) { + up(&ebt_mutex); + ret = -ENOENT; + goto cleanup_watchers; + } + up(&ebt_mutex); + + t->u.target = target; + if (t->u.target == &ebt_standard_target) { + if (e->target_offset + sizeof(struct ebt_standard_target) > + e->next_offset) { + BUGPRINT("Standard target size too big\n"); + ret = -EFAULT; + goto cleanup_watchers; + } + if (((struct ebt_standard_target *)t)->verdict < + -NUM_STANDARD_TARGETS) { + BUGPRINT("Invalid standard target\n"); + ret = -EFAULT; + goto cleanup_watchers; + } + } else if ((e->target_offset + t->target_size + + sizeof(struct ebt_entry_target) > e->next_offset) || + (t->u.target->check && + t->u.target->check(name, hookmask, e, t->data, t->target_size) != 0)){ + module_put(t->u.target->me); + ret = -EFAULT; + goto cleanup_watchers; + } + (*cnt)++; + return 0; +cleanup_watchers: + EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, &j); +cleanup_matches: + EBT_MATCH_ITERATE(e, ebt_cleanup_match, &i); + return ret; +} + +/* + * checks for loops and sets the hook mask for udc + * the hook mask for udc tells us from which base chains the udc can be + * accessed. This mask is a parameter to the check() functions of the extensions + */ +static int check_chainloops(struct ebt_entries *chain, struct ebt_cl_stack *cl_s, + unsigned int udc_cnt, unsigned int hooknr, char *base) +{ + int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict; + struct ebt_entry *e = (struct ebt_entry *)chain->data; + struct ebt_entry_target *t; + + while (pos < nentries || chain_nr != -1) { + /* end of udc, go back one 'recursion' step */ + if (pos == nentries) { + /* put back values of the time when this chain was called */ + e = cl_s[chain_nr].cs.e; + if (cl_s[chain_nr].from != -1) + nentries = + cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries; + else + nentries = chain->nentries; + pos = cl_s[chain_nr].cs.n; + /* make sure we won't see a loop that isn't one */ + cl_s[chain_nr].cs.n = 0; + chain_nr = cl_s[chain_nr].from; + if (pos == nentries) + continue; + } + t = (struct ebt_entry_target *) + (((char *)e) + e->target_offset); + if (strcmp(t->u.name, EBT_STANDARD_TARGET)) + goto letscontinue; + if (e->target_offset + sizeof(struct ebt_standard_target) > + e->next_offset) { + BUGPRINT("Standard target size too big\n"); + return -1; + } + verdict = ((struct ebt_standard_target *)t)->verdict; + if (verdict >= 0) { /* jump to another chain */ + struct ebt_entries *hlp2 = + (struct ebt_entries *)(base + verdict); + for (i = 0; i < udc_cnt; i++) + if (hlp2 == cl_s[i].cs.chaininfo) + break; + /* bad destination or loop */ + if (i == udc_cnt) { + BUGPRINT("bad destination\n"); + return -1; + } + if (cl_s[i].cs.n) { + BUGPRINT("loop\n"); + return -1; + } + /* this can't be 0, so the above test is correct */ + cl_s[i].cs.n = pos + 1; + pos = 0; + cl_s[i].cs.e = ((void *)e + e->next_offset); + e = (struct ebt_entry *)(hlp2->data); + nentries = hlp2->nentries; + cl_s[i].from = chain_nr; + chain_nr = i; + /* this udc is accessible from the base chain for hooknr */ + cl_s[i].hookmask |= (1 << hooknr); + continue; + } +letscontinue: + e = (void *)e + e->next_offset; + pos++; + } + return 0; +} + +/* do the parsing of the table/chains/entries/matches/watchers/targets, heh */ +static int translate_table(struct ebt_replace *repl, + struct ebt_table_info *newinfo) +{ + unsigned int i, j, k, udc_cnt; + int ret; + struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */ + + i = 0; + while (i < NF_BR_NUMHOOKS && !(repl->valid_hooks & (1 << i))) + i++; + if (i == NF_BR_NUMHOOKS) { + BUGPRINT("No valid hooks specified\n"); + return -EINVAL; + } + if (repl->hook_entry[i] != (struct ebt_entries *)repl->entries) { + BUGPRINT("Chains don't start at beginning\n"); + return -EINVAL; + } + /* make sure chains are ordered after each other in same order + as their corresponding hooks */ + for (j = i + 1; j < NF_BR_NUMHOOKS; j++) { + if (!(repl->valid_hooks & (1 << j))) + continue; + if ( repl->hook_entry[j] <= repl->hook_entry[i] ) { + BUGPRINT("Hook order must be followed\n"); + return -EINVAL; + } + i = j; + } + + for (i = 0; i < NF_BR_NUMHOOKS; i++) + newinfo->hook_entry[i] = NULL; + + newinfo->entries_size = repl->entries_size; + newinfo->nentries = repl->nentries; + + /* do some early checkings and initialize some things */ + i = 0; /* holds the expected nr. of entries for the chain */ + j = 0; /* holds the up to now counted entries for the chain */ + k = 0; /* holds the total nr. of entries, should equal + newinfo->nentries afterwards */ + udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */ + ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, + ebt_check_entry_size_and_hooks, newinfo, repl->entries, + repl->entries + repl->entries_size, repl->hook_entry, &i, &j, &k, + &udc_cnt, repl->valid_hooks); + + if (ret != 0) + return ret; + + if (i != j) { + BUGPRINT("nentries does not equal the nr of entries in the " + "(last) chain\n"); + return -EINVAL; + } + if (k != newinfo->nentries) { + BUGPRINT("Total nentries is wrong\n"); + return -EINVAL; + } + + /* check if all valid hooks have a chain */ + for (i = 0; i < NF_BR_NUMHOOKS; i++) { + if (newinfo->hook_entry[i] == NULL && + (repl->valid_hooks & (1 << i))) { + BUGPRINT("Valid hook without chain\n"); + return -EINVAL; + } + } + + /* get the location of the udc, put them in an array + while we're at it, allocate the chainstack */ + if (udc_cnt) { + /* this will get free'd in do_replace()/ebt_register_table() + if an error occurs */ + newinfo->chainstack = (struct ebt_chainstack **) + vmalloc(num_possible_cpus() * sizeof(struct ebt_chainstack)); + if (!newinfo->chainstack) + return -ENOMEM; + for (i = 0; i < num_possible_cpus(); i++) { + newinfo->chainstack[i] = + vmalloc(udc_cnt * sizeof(struct ebt_chainstack)); + if (!newinfo->chainstack[i]) { + while (i) + vfree(newinfo->chainstack[--i]); + vfree(newinfo->chainstack); + newinfo->chainstack = NULL; + return -ENOMEM; + } + } + + cl_s = (struct ebt_cl_stack *) + vmalloc(udc_cnt * sizeof(struct ebt_cl_stack)); + if (!cl_s) + return -ENOMEM; + i = 0; /* the i'th udc */ + EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, + ebt_get_udc_positions, newinfo, repl->hook_entry, &i, + repl->valid_hooks, cl_s); + /* sanity check */ + if (i != udc_cnt) { + BUGPRINT("i != udc_cnt\n"); + vfree(cl_s); + return -EFAULT; + } + } + + /* Check for loops */ + for (i = 0; i < NF_BR_NUMHOOKS; i++) + if (repl->valid_hooks & (1 << i)) + if (check_chainloops(newinfo->hook_entry[i], + cl_s, udc_cnt, i, newinfo->entries)) { + if (cl_s) + vfree(cl_s); + return -EINVAL; + } + + /* we now know the following (along with E=mc˛): + - the nr of entries in each chain is right + - the size of the allocated space is right + - all valid hooks have a corresponding chain + - there are no loops + - wrong data can still be on the level of a single entry + - could be there are jumps to places that are not the + beginning of a chain. This can only occur in chains that + are not accessible from any base chains, so we don't care. */ + + /* used to know what we need to clean up if something goes wrong */ + i = 0; + ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, + ebt_check_entry, newinfo, repl->name, &i, repl->valid_hooks, + cl_s, udc_cnt); + if (ret != 0) { + EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, + ebt_cleanup_entry, &i); + } + if (cl_s) + vfree(cl_s); + return ret; +} + +/* called under write_lock */ +static void get_counters(struct ebt_counter *oldcounters, + struct ebt_counter *counters, unsigned int nentries) +{ + int i, cpu; + struct ebt_counter *counter_base; + + /* counters of cpu 0 */ + memcpy(counters, oldcounters, + sizeof(struct ebt_counter) * nentries); + /* add other counters to those of cpu 0 */ + for (cpu = 1; cpu < num_possible_cpus(); cpu++) { + counter_base = COUNTER_BASE(oldcounters, nentries, cpu); + for (i = 0; i < nentries; i++) { + counters[i].pcnt += counter_base[i].pcnt; + counters[i].bcnt += counter_base[i].bcnt; + } + } +} + +/* replace the table */ +static int do_replace(void __user *user, unsigned int len) +{ + int ret, i, countersize; + struct ebt_table_info *newinfo; + struct ebt_replace tmp; + struct ebt_table *t; + struct ebt_counter *counterstmp = NULL; + /* used to be able to unlock earlier */ + struct ebt_table_info *table; + + if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) + return -EFAULT; + + if (len != sizeof(tmp) + tmp.entries_size) { + BUGPRINT("Wrong len argument\n"); + return -EINVAL; + } + + if (tmp.entries_size == 0) { + BUGPRINT("Entries_size never zero\n"); + return -EINVAL; + } + countersize = COUNTER_OFFSET(tmp.nentries) * num_possible_cpus(); + newinfo = (struct ebt_table_info *) + vmalloc(sizeof(struct ebt_table_info) + countersize); + if (!newinfo) + return -ENOMEM; + + if (countersize) + memset(newinfo->counters, 0, countersize); + + newinfo->entries = (char *)vmalloc(tmp.entries_size); + if (!newinfo->entries) { + ret = -ENOMEM; + goto free_newinfo; + } + if (copy_from_user( + newinfo->entries, tmp.entries, tmp.entries_size) != 0) { + BUGPRINT("Couldn't copy entries from userspace\n"); + ret = -EFAULT; + goto free_entries; + } + + /* the user wants counters back + the check on the size is done later, when we have the lock */ + if (tmp.num_counters) { + counterstmp = (struct ebt_counter *) + vmalloc(tmp.num_counters * sizeof(struct ebt_counter)); + if (!counterstmp) { + ret = -ENOMEM; + goto free_entries; + } + } + else + counterstmp = NULL; + + /* this can get initialized by translate_table() */ + newinfo->chainstack = NULL; + ret = translate_table(&tmp, newinfo); + + if (ret != 0) + goto free_counterstmp; + + t = find_table_lock(tmp.name, &ret, &ebt_mutex); + if (!t) { + ret = -ENOENT; + goto free_iterate; + } + + /* the table doesn't like it */ + if (t->check && (ret = t->check(newinfo, tmp.valid_hooks))) + goto free_unlock; + + if (tmp.num_counters && tmp.num_counters != t->private->nentries) { + BUGPRINT("Wrong nr. of counters requested\n"); + ret = -EINVAL; + goto free_unlock; + } + + /* we have the mutex lock, so no danger in reading this pointer */ + table = t->private; + /* make sure the table can only be rmmod'ed if it contains no rules */ + if (!table->nentries && newinfo->nentries && !try_module_get(t->me)) { + ret = -ENOENT; + goto free_unlock; + } else if (table->nentries && !newinfo->nentries) + module_put(t->me); + /* we need an atomic snapshot of the counters */ + write_lock_bh(&t->lock); + if (tmp.num_counters) + get_counters(t->private->counters, counterstmp, + t->private->nentries); + + t->private = newinfo; + write_unlock_bh(&t->lock); + up(&ebt_mutex); + /* so, a user can change the chains while having messed up her counter + allocation. Only reason why this is done is because this way the lock + is held only once, while this doesn't bring the kernel into a + dangerous state. */ + if (tmp.num_counters && + copy_to_user(tmp.counters, counterstmp, + tmp.num_counters * sizeof(struct ebt_counter))) { + BUGPRINT("Couldn't copy counters to userspace\n"); + ret = -EFAULT; + } + else + ret = 0; + + /* decrease module count and free resources */ + EBT_ENTRY_ITERATE(table->entries, table->entries_size, + ebt_cleanup_entry, NULL); + + vfree(table->entries); + if (table->chainstack) { + for (i = 0; i < num_possible_cpus(); i++) + vfree(table->chainstack[i]); + vfree(table->chainstack); + } + vfree(table); + + if (counterstmp) + vfree(counterstmp); + return ret; + +free_unlock: + up(&ebt_mutex); +free_iterate: + EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, + ebt_cleanup_entry, NULL); +free_counterstmp: + if (counterstmp) + vfree(counterstmp); + /* can be initialized in translate_table() */ + if (newinfo->chainstack) { + for (i = 0; i < num_possible_cpus(); i++) + vfree(newinfo->chainstack[i]); + vfree(newinfo->chainstack); + } +free_entries: + if (newinfo->entries) + vfree(newinfo->entries); +free_newinfo: + if (newinfo) + vfree(newinfo); + return ret; +} + +int ebt_register_target(struct ebt_target *target) +{ + int ret; + + ret = down_interruptible(&ebt_mutex); + if (ret != 0) + return ret; + if (!list_named_insert(&ebt_targets, target)) { + up(&ebt_mutex); + return -EEXIST; + } + up(&ebt_mutex); + + return 0; +} + +void ebt_unregister_target(struct ebt_target *target) +{ + down(&ebt_mutex); + LIST_DELETE(&ebt_targets, target); + up(&ebt_mutex); +} + +int ebt_register_match(struct ebt_match *match) +{ + int ret; + + ret = down_interruptible(&ebt_mutex); + if (ret != 0) + return ret; + if (!list_named_insert(&ebt_matches, match)) { + up(&ebt_mutex); + return -EEXIST; + } + up(&ebt_mutex); + + return 0; +} + +void ebt_unregister_match(struct ebt_match *match) +{ + down(&ebt_mutex); + LIST_DELETE(&ebt_matches, match); + up(&ebt_mutex); +} + +int ebt_register_watcher(struct ebt_watcher *watcher) +{ + int ret; + + ret = down_interruptible(&ebt_mutex); + if (ret != 0) + return ret; + if (!list_named_insert(&ebt_watchers, watcher)) { + up(&ebt_mutex); + return -EEXIST; + } + up(&ebt_mutex); + + return 0; +} + +void ebt_unregister_watcher(struct ebt_watcher *watcher) +{ + down(&ebt_mutex); + LIST_DELETE(&ebt_watchers, watcher); + up(&ebt_mutex); +} + +int ebt_register_table(struct ebt_table *table) +{ + struct ebt_table_info *newinfo; + int ret, i, countersize; + + if (!table || !table->table ||!table->table->entries || + table->table->entries_size == 0 || + table->table->counters || table->private) { + BUGPRINT("Bad table data for ebt_register_table!!!\n"); + return -EINVAL; + } + + countersize = COUNTER_OFFSET(table->table->nentries) * num_possible_cpus(); + newinfo = (struct ebt_table_info *) + vmalloc(sizeof(struct ebt_table_info) + countersize); + ret = -ENOMEM; + if (!newinfo) + return -ENOMEM; + + newinfo->entries = (char *)vmalloc(table->table->entries_size); + if (!(newinfo->entries)) + goto free_newinfo; + + memcpy(newinfo->entries, table->table->entries, + table->table->entries_size); + + if (countersize) + memset(newinfo->counters, 0, countersize); + + /* fill in newinfo and parse the entries */ + newinfo->chainstack = NULL; + ret = translate_table(table->table, newinfo); + if (ret != 0) { + BUGPRINT("Translate_table failed\n"); + goto free_chainstack; + } + + if (table->check && table->check(newinfo, table->valid_hooks)) { + BUGPRINT("The table doesn't like its own initial data, lol\n"); + return -EINVAL; + } + + table->private = newinfo; + rwlock_init(&table->lock); + ret = down_interruptible(&ebt_mutex); + if (ret != 0) + goto free_chainstack; + + if (list_named_find(&ebt_tables, table->name)) { + ret = -EEXIST; + BUGPRINT("Table name already exists\n"); + goto free_unlock; + } + + /* Hold a reference count if the chains aren't empty */ + if (newinfo->nentries && !try_module_get(table->me)) { + ret = -ENOENT; + goto free_unlock; + } + list_prepend(&ebt_tables, table); + up(&ebt_mutex); + return 0; +free_unlock: + up(&ebt_mutex); +free_chainstack: + if (newinfo->chainstack) { + for (i = 0; i < num_possible_cpus(); i++) + vfree(newinfo->chainstack[i]); + vfree(newinfo->chainstack); + } + vfree(newinfo->entries); +free_newinfo: + vfree(newinfo); + return ret; +} + +void ebt_unregister_table(struct ebt_table *table) +{ + int i; + + if (!table) { + BUGPRINT("Request to unregister NULL table!!!\n"); + return; + } + down(&ebt_mutex); + LIST_DELETE(&ebt_tables, table); + up(&ebt_mutex); + if (table->private->entries) + vfree(table->private->entries); + if (table->private->chainstack) { + for (i = 0; i < num_possible_cpus(); i++) + vfree(table->private->chainstack[i]); + vfree(table->private->chainstack); + } + vfree(table->private); +} + +/* userspace just supplied us with counters */ +static int update_counters(void __user *user, unsigned int len) +{ + int i, ret; + struct ebt_counter *tmp; + struct ebt_replace hlp; + struct ebt_table *t; + + if (copy_from_user(&hlp, user, sizeof(hlp))) + return -EFAULT; + + if (len != sizeof(hlp) + hlp.num_counters * sizeof(struct ebt_counter)) + return -EINVAL; + if (hlp.num_counters == 0) + return -EINVAL; + + if ( !(tmp = (struct ebt_counter *) + vmalloc(hlp.num_counters * sizeof(struct ebt_counter))) ){ + MEMPRINT("Update_counters && nomemory\n"); + return -ENOMEM; + } + + t = find_table_lock(hlp.name, &ret, &ebt_mutex); + if (!t) + goto free_tmp; + + if (hlp.num_counters != t->private->nentries) { + BUGPRINT("Wrong nr of counters\n"); + ret = -EINVAL; + goto unlock_mutex; + } + + if ( copy_from_user(tmp, hlp.counters, + hlp.num_counters * sizeof(struct ebt_counter)) ) { + BUGPRINT("Updata_counters && !cfu\n"); + ret = -EFAULT; + goto unlock_mutex; + } + + /* we want an atomic add of the counters */ + write_lock_bh(&t->lock); + + /* we add to the counters of the first cpu */ + for (i = 0; i < hlp.num_counters; i++) { + t->private->counters[i].pcnt += tmp[i].pcnt; + t->private->counters[i].bcnt += tmp[i].bcnt; + } + + write_unlock_bh(&t->lock); + ret = 0; +unlock_mutex: + up(&ebt_mutex); +free_tmp: + vfree(tmp); + return ret; +} + +static inline int ebt_make_matchname(struct ebt_entry_match *m, + char *base, char *ubase) +{ + char *hlp = ubase - base + (char *)m; + if (copy_to_user(hlp, m->u.match->name, EBT_FUNCTION_MAXNAMELEN)) + return -EFAULT; + return 0; +} + +static inline int ebt_make_watchername(struct ebt_entry_watcher *w, + char *base, char *ubase) +{ + char *hlp = ubase - base + (char *)w; + if (copy_to_user(hlp , w->u.watcher->name, EBT_FUNCTION_MAXNAMELEN)) + return -EFAULT; + return 0; +} + +static inline int ebt_make_names(struct ebt_entry *e, char *base, char *ubase) +{ + int ret; + char *hlp; + struct ebt_entry_target *t; + + if ((e->bitmask & EBT_ENTRY_OR_ENTRIES) == 0) + return 0; + + hlp = ubase - base + (char *)e + e->target_offset; + t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); + + ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase); + if (ret != 0) + return ret; + ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase); + if (ret != 0) + return ret; + if (copy_to_user(hlp, t->u.target->name, EBT_FUNCTION_MAXNAMELEN)) + return -EFAULT; + return 0; +} + +/* called with ebt_mutex down */ +static int copy_everything_to_user(struct ebt_table *t, void __user *user, + int *len, int cmd) +{ + struct ebt_replace tmp; + struct ebt_counter *counterstmp, *oldcounters; + unsigned int entries_size, nentries; + char *entries; + + if (cmd == EBT_SO_GET_ENTRIES) { + entries_size = t->private->entries_size; + nentries = t->private->nentries; + entries = t->private->entries; + oldcounters = t->private->counters; + } else { + entries_size = t->table->entries_size; + nentries = t->table->nentries; + entries = t->table->entries; + oldcounters = t->table->counters; + } + + if (copy_from_user(&tmp, user, sizeof(tmp))) { + BUGPRINT("Cfu didn't work\n"); + return -EFAULT; + } + + if (*len != sizeof(struct ebt_replace) + entries_size + + (tmp.num_counters? nentries * sizeof(struct ebt_counter): 0)) { + BUGPRINT("Wrong size\n"); + return -EINVAL; + } + + if (tmp.nentries != nentries) { + BUGPRINT("Nentries wrong\n"); + return -EINVAL; + } + + if (tmp.entries_size != entries_size) { + BUGPRINT("Wrong size\n"); + return -EINVAL; + } + + /* userspace might not need the counters */ + if (tmp.num_counters) { + if (tmp.num_counters != nentries) { + BUGPRINT("Num_counters wrong\n"); + return -EINVAL; + } + counterstmp = (struct ebt_counter *) + vmalloc(nentries * sizeof(struct ebt_counter)); + if (!counterstmp) { + MEMPRINT("Couldn't copy counters, out of memory\n"); + return -ENOMEM; + } + write_lock_bh(&t->lock); + get_counters(oldcounters, counterstmp, nentries); + write_unlock_bh(&t->lock); + + if (copy_to_user(tmp.counters, counterstmp, + nentries * sizeof(struct ebt_counter))) { + BUGPRINT("Couldn't copy counters to userspace\n"); + vfree(counterstmp); + return -EFAULT; + } + vfree(counterstmp); + } + + if (copy_to_user(tmp.entries, entries, entries_size)) { + BUGPRINT("Couldn't copy entries to userspace\n"); + return -EFAULT; + } + /* set the match/watcher/target names right */ + return EBT_ENTRY_ITERATE(entries, entries_size, + ebt_make_names, entries, tmp.entries); +} + +static int do_ebt_set_ctl(struct sock *sk, + int cmd, void __user *user, unsigned int len) +{ + int ret; + + switch(cmd) { + case EBT_SO_SET_ENTRIES: + ret = do_replace(user, len); + break; + case EBT_SO_SET_COUNTERS: + ret = update_counters(user, len); + break; + default: + ret = -EINVAL; + } + return ret; +} + +static int do_ebt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) +{ + int ret; + struct ebt_replace tmp; + struct ebt_table *t; + + if (copy_from_user(&tmp, user, sizeof(tmp))) + return -EFAULT; + + t = find_table_lock(tmp.name, &ret, &ebt_mutex); + if (!t) + return ret; + + switch(cmd) { + case EBT_SO_GET_INFO: + case EBT_SO_GET_INIT_INFO: + if (*len != sizeof(struct ebt_replace)){ + ret = -EINVAL; + up(&ebt_mutex); + break; + } + if (cmd == EBT_SO_GET_INFO) { + tmp.nentries = t->private->nentries; + tmp.entries_size = t->private->entries_size; + tmp.valid_hooks = t->valid_hooks; + } else { + tmp.nentries = t->table->nentries; + tmp.entries_size = t->table->entries_size; + tmp.valid_hooks = t->table->valid_hooks; + } + up(&ebt_mutex); + if (copy_to_user(user, &tmp, *len) != 0){ + BUGPRINT("c2u Didn't work\n"); + ret = -EFAULT; + break; + } + ret = 0; + break; + + case EBT_SO_GET_ENTRIES: + case EBT_SO_GET_INIT_ENTRIES: + ret = copy_everything_to_user(t, user, len, cmd); + up(&ebt_mutex); + break; + + default: + up(&ebt_mutex); + ret = -EINVAL; + } + + return ret; +} + +static struct nf_sockopt_ops ebt_sockopts = +{ { NULL, NULL }, PF_INET, EBT_BASE_CTL, EBT_SO_SET_MAX + 1, do_ebt_set_ctl, + EBT_BASE_CTL, EBT_SO_GET_MAX + 1, do_ebt_get_ctl, 0, NULL +}; + +static int __init init(void) +{ + int ret; + + down(&ebt_mutex); + list_named_insert(&ebt_targets, &ebt_standard_target); + up(&ebt_mutex); + if ((ret = nf_register_sockopt(&ebt_sockopts)) < 0) + return ret; + + printk(KERN_NOTICE "Ebtables v2.0 registered\n"); + return 0; +} + +static void __exit fini(void) +{ + nf_unregister_sockopt(&ebt_sockopts); + printk(KERN_NOTICE "Ebtables v2.0 unregistered\n"); +} + +EXPORT_SYMBOL(ebt_register_table); +EXPORT_SYMBOL(ebt_unregister_table); +EXPORT_SYMBOL(ebt_register_match); +EXPORT_SYMBOL(ebt_unregister_match); +EXPORT_SYMBOL(ebt_register_watcher); +EXPORT_SYMBOL(ebt_unregister_watcher); +EXPORT_SYMBOL(ebt_register_target); +EXPORT_SYMBOL(ebt_unregister_target); +EXPORT_SYMBOL(ebt_do_table); +module_init(init); +module_exit(fini); +MODULE_LICENSE("GPL"); |