android_kernel_samsung_msm8976/net/ipv6/netfilter/ip6_tables.c
Kirill Korotaev ee4bb818ae [NETFILTER]: Fix possible overflow in netfilters do_replace()
netfilter's do_replace() can overflow on addition within SMP_ALIGN()
and/or on multiplication by NR_CPUS, resulting in a buffer overflow on
the copy_from_user().  In practice, the overflow on addition is
triggerable on all systems, whereas the multiplication one might require
much physical memory to be present due to the check above.  Either is
sufficient to overwrite arbitrary amounts of kernel memory.

I really hate adding the same check to all 4 versions of do_replace(),
but the code is duplicate...

Found by Solar Designer during security audit of OpenVZ.org

Signed-Off-By: Kirill Korotaev <dev@openvz.org>
Signed-Off-By: Solar Designer <solar@openwall.com>
Signed-off-by: Patrck McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-04 23:51:25 -08:00

1521 lines
37 KiB
C

/*
* Packet matching code.
*
* 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.
*
* 19 Jan 2002 Harald Welte <laforge@gnumonks.org>
* - increase module usage count as soon as we have rules inside
* a table
* 06 Jun 2002 Andras Kis-Szabo <kisza@sch.bme.hu>
* - new extension header parser code
* 15 Oct 2005 Harald Welte <laforge@netfilter.org>
* - Unification of {ip,ip6}_tables into x_tables
* - Removed tcp and udp code, since it's not ipv6 specific
*/
#include <linux/capability.h>
#include <linux/config.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/kmod.h>
#include <linux/vmalloc.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <linux/icmpv6.h>
#include <net/ipv6.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
#include <linux/proc_fs.h>
#include <linux/cpumask.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter/x_tables.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("IPv6 packet filter");
#define IPV6_HDR_LEN (sizeof(struct ipv6hdr))
#define IPV6_OPTHDR_LEN (sizeof(struct ipv6_opt_hdr))
/*#define DEBUG_IP_FIREWALL*/
/*#define DEBUG_ALLOW_ALL*/ /* Useful for remote debugging */
/*#define DEBUG_IP_FIREWALL_USER*/
#ifdef DEBUG_IP_FIREWALL
#define dprintf(format, args...) printk(format , ## args)
#else
#define dprintf(format, args...)
#endif
#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif
#ifdef CONFIG_NETFILTER_DEBUG
#define IP_NF_ASSERT(x) \
do { \
if (!(x)) \
printk("IP_NF_ASSERT: %s:%s:%u\n", \
__FUNCTION__, __FILE__, __LINE__); \
} while(0)
#else
#define IP_NF_ASSERT(x)
#endif
#include <linux/netfilter_ipv4/listhelp.h>
#if 0
/* All the better to debug you with... */
#define static
#define inline
#endif
/*
We keep a set of rules for each CPU, so we can avoid write-locking
them in the softirq when updating the counters and therefore
only need to read-lock in the softirq; doing a write_lock_bh() in user
context stops packets coming through and allows user context to read
the counters or update the rules.
Hence the start of any table is given by get_table() below. */
#if 0
#define down(x) do { printk("DOWN:%u:" #x "\n", __LINE__); down(x); } while(0)
#define down_interruptible(x) ({ int __r; printk("DOWNi:%u:" #x "\n", __LINE__); __r = down_interruptible(x); if (__r != 0) printk("ABORT-DOWNi:%u\n", __LINE__); __r; })
#define up(x) do { printk("UP:%u:" #x "\n", __LINE__); up(x); } while(0)
#endif
int
ip6_masked_addrcmp(const struct in6_addr *addr1, const struct in6_addr *mask,
const struct in6_addr *addr2)
{
int i;
for( i = 0; i < 16; i++){
if((addr1->s6_addr[i] & mask->s6_addr[i]) !=
(addr2->s6_addr[i] & mask->s6_addr[i]))
return 1;
}
return 0;
}
/* Check for an extension */
int
ip6t_ext_hdr(u8 nexthdr)
{
return ( (nexthdr == IPPROTO_HOPOPTS) ||
(nexthdr == IPPROTO_ROUTING) ||
(nexthdr == IPPROTO_FRAGMENT) ||
(nexthdr == IPPROTO_ESP) ||
(nexthdr == IPPROTO_AH) ||
(nexthdr == IPPROTO_NONE) ||
(nexthdr == IPPROTO_DSTOPTS) );
}
/* Returns whether matches rule or not. */
static inline int
ip6_packet_match(const struct sk_buff *skb,
const char *indev,
const char *outdev,
const struct ip6t_ip6 *ip6info,
unsigned int *protoff,
int *fragoff)
{
size_t i;
unsigned long ret;
const struct ipv6hdr *ipv6 = skb->nh.ipv6h;
#define FWINV(bool,invflg) ((bool) ^ !!(ip6info->invflags & invflg))
if (FWINV(ip6_masked_addrcmp(&ipv6->saddr, &ip6info->smsk,
&ip6info->src), IP6T_INV_SRCIP)
|| FWINV(ip6_masked_addrcmp(&ipv6->daddr, &ip6info->dmsk,
&ip6info->dst), IP6T_INV_DSTIP)) {
dprintf("Source or dest mismatch.\n");
/*
dprintf("SRC: %u. Mask: %u. Target: %u.%s\n", ip->saddr,
ipinfo->smsk.s_addr, ipinfo->src.s_addr,
ipinfo->invflags & IP6T_INV_SRCIP ? " (INV)" : "");
dprintf("DST: %u. Mask: %u. Target: %u.%s\n", ip->daddr,
ipinfo->dmsk.s_addr, ipinfo->dst.s_addr,
ipinfo->invflags & IP6T_INV_DSTIP ? " (INV)" : "");*/
return 0;
}
/* Look for ifname matches; this should unroll nicely. */
for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
ret |= (((const unsigned long *)indev)[i]
^ ((const unsigned long *)ip6info->iniface)[i])
& ((const unsigned long *)ip6info->iniface_mask)[i];
}
if (FWINV(ret != 0, IP6T_INV_VIA_IN)) {
dprintf("VIA in mismatch (%s vs %s).%s\n",
indev, ip6info->iniface,
ip6info->invflags&IP6T_INV_VIA_IN ?" (INV)":"");
return 0;
}
for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
ret |= (((const unsigned long *)outdev)[i]
^ ((const unsigned long *)ip6info->outiface)[i])
& ((const unsigned long *)ip6info->outiface_mask)[i];
}
if (FWINV(ret != 0, IP6T_INV_VIA_OUT)) {
dprintf("VIA out mismatch (%s vs %s).%s\n",
outdev, ip6info->outiface,
ip6info->invflags&IP6T_INV_VIA_OUT ?" (INV)":"");
return 0;
}
/* ... might want to do something with class and flowlabel here ... */
/* look for the desired protocol header */
if((ip6info->flags & IP6T_F_PROTO)) {
int protohdr;
unsigned short _frag_off;
protohdr = ipv6_find_hdr(skb, protoff, -1, &_frag_off);
if (protohdr < 0)
return 0;
*fragoff = _frag_off;
dprintf("Packet protocol %hi ?= %s%hi.\n",
protohdr,
ip6info->invflags & IP6T_INV_PROTO ? "!":"",
ip6info->proto);
if (ip6info->proto == protohdr) {
if(ip6info->invflags & IP6T_INV_PROTO) {
return 0;
}
return 1;
}
/* We need match for the '-p all', too! */
if ((ip6info->proto != 0) &&
!(ip6info->invflags & IP6T_INV_PROTO))
return 0;
}
return 1;
}
/* should be ip6 safe */
static inline int
ip6_checkentry(const struct ip6t_ip6 *ipv6)
{
if (ipv6->flags & ~IP6T_F_MASK) {
duprintf("Unknown flag bits set: %08X\n",
ipv6->flags & ~IP6T_F_MASK);
return 0;
}
if (ipv6->invflags & ~IP6T_INV_MASK) {
duprintf("Unknown invflag bits set: %08X\n",
ipv6->invflags & ~IP6T_INV_MASK);
return 0;
}
return 1;
}
static unsigned int
ip6t_error(struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const void *targinfo,
void *userinfo)
{
if (net_ratelimit())
printk("ip6_tables: error: `%s'\n", (char *)targinfo);
return NF_DROP;
}
static inline
int do_match(struct ip6t_entry_match *m,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
int offset,
unsigned int protoff,
int *hotdrop)
{
/* Stop iteration if it doesn't match */
if (!m->u.kernel.match->match(skb, in, out, m->data,
offset, protoff, hotdrop))
return 1;
else
return 0;
}
static inline struct ip6t_entry *
get_entry(void *base, unsigned int offset)
{
return (struct ip6t_entry *)(base + offset);
}
/* Returns one of the generic firewall policies, like NF_ACCEPT. */
unsigned int
ip6t_do_table(struct sk_buff **pskb,
unsigned int hook,
const struct net_device *in,
const struct net_device *out,
struct xt_table *table,
void *userdata)
{
static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
int offset = 0;
unsigned int protoff = 0;
int hotdrop = 0;
/* Initializing verdict to NF_DROP keeps gcc happy. */
unsigned int verdict = NF_DROP;
const char *indev, *outdev;
void *table_base;
struct ip6t_entry *e, *back;
struct xt_table_info *private;
/* Initialization */
indev = in ? in->name : nulldevname;
outdev = out ? out->name : nulldevname;
/* We handle fragments by dealing with the first fragment as
* if it was a normal packet. All other fragments are treated
* normally, except that they will NEVER match rules that ask
* things we don't know, ie. tcp syn flag or ports). If the
* rule is also a fragment-specific rule, non-fragments won't
* match it. */
read_lock_bh(&table->lock);
private = table->private;
IP_NF_ASSERT(table->valid_hooks & (1 << hook));
table_base = (void *)private->entries[smp_processor_id()];
e = get_entry(table_base, private->hook_entry[hook]);
#ifdef CONFIG_NETFILTER_DEBUG
/* Check noone else using our table */
if (((struct ip6t_entry *)table_base)->comefrom != 0xdead57ac
&& ((struct ip6t_entry *)table_base)->comefrom != 0xeeeeeeec) {
printk("ASSERT: CPU #%u, %s comefrom(%p) = %X\n",
smp_processor_id(),
table->name,
&((struct ip6t_entry *)table_base)->comefrom,
((struct ip6t_entry *)table_base)->comefrom);
}
((struct ip6t_entry *)table_base)->comefrom = 0x57acc001;
#endif
/* For return from builtin chain */
back = get_entry(table_base, private->underflow[hook]);
do {
IP_NF_ASSERT(e);
IP_NF_ASSERT(back);
if (ip6_packet_match(*pskb, indev, outdev, &e->ipv6,
&protoff, &offset)) {
struct ip6t_entry_target *t;
if (IP6T_MATCH_ITERATE(e, do_match,
*pskb, in, out,
offset, protoff, &hotdrop) != 0)
goto no_match;
ADD_COUNTER(e->counters,
ntohs((*pskb)->nh.ipv6h->payload_len)
+ IPV6_HDR_LEN,
1);
t = ip6t_get_target(e);
IP_NF_ASSERT(t->u.kernel.target);
/* Standard target? */
if (!t->u.kernel.target->target) {
int v;
v = ((struct ip6t_standard_target *)t)->verdict;
if (v < 0) {
/* Pop from stack? */
if (v != IP6T_RETURN) {
verdict = (unsigned)(-v) - 1;
break;
}
e = back;
back = get_entry(table_base,
back->comefrom);
continue;
}
if (table_base + v != (void *)e + e->next_offset
&& !(e->ipv6.flags & IP6T_F_GOTO)) {
/* Save old back ptr in next entry */
struct ip6t_entry *next
= (void *)e + e->next_offset;
next->comefrom
= (void *)back - table_base;
/* set back pointer to next entry */
back = next;
}
e = get_entry(table_base, v);
} else {
/* Targets which reenter must return
abs. verdicts */
#ifdef CONFIG_NETFILTER_DEBUG
((struct ip6t_entry *)table_base)->comefrom
= 0xeeeeeeec;
#endif
verdict = t->u.kernel.target->target(pskb,
in, out,
hook,
t->data,
userdata);
#ifdef CONFIG_NETFILTER_DEBUG
if (((struct ip6t_entry *)table_base)->comefrom
!= 0xeeeeeeec
&& verdict == IP6T_CONTINUE) {
printk("Target %s reentered!\n",
t->u.kernel.target->name);
verdict = NF_DROP;
}
((struct ip6t_entry *)table_base)->comefrom
= 0x57acc001;
#endif
if (verdict == IP6T_CONTINUE)
e = (void *)e + e->next_offset;
else
/* Verdict */
break;
}
} else {
no_match:
e = (void *)e + e->next_offset;
}
} while (!hotdrop);
#ifdef CONFIG_NETFILTER_DEBUG
((struct ip6t_entry *)table_base)->comefrom = 0xdead57ac;
#endif
read_unlock_bh(&table->lock);
#ifdef DEBUG_ALLOW_ALL
return NF_ACCEPT;
#else
if (hotdrop)
return NF_DROP;
else return verdict;
#endif
}
/* All zeroes == unconditional rule. */
static inline int
unconditional(const struct ip6t_ip6 *ipv6)
{
unsigned int i;
for (i = 0; i < sizeof(*ipv6); i++)
if (((char *)ipv6)[i])
break;
return (i == sizeof(*ipv6));
}
/* Figures out from what hook each rule can be called: returns 0 if
there are loops. Puts hook bitmask in comefrom. */
static int
mark_source_chains(struct xt_table_info *newinfo,
unsigned int valid_hooks, void *entry0)
{
unsigned int hook;
/* No recursion; use packet counter to save back ptrs (reset
to 0 as we leave), and comefrom to save source hook bitmask */
for (hook = 0; hook < NF_IP6_NUMHOOKS; hook++) {
unsigned int pos = newinfo->hook_entry[hook];
struct ip6t_entry *e
= (struct ip6t_entry *)(entry0 + pos);
if (!(valid_hooks & (1 << hook)))
continue;
/* Set initial back pointer. */
e->counters.pcnt = pos;
for (;;) {
struct ip6t_standard_target *t
= (void *)ip6t_get_target(e);
if (e->comefrom & (1 << NF_IP6_NUMHOOKS)) {
printk("iptables: loop hook %u pos %u %08X.\n",
hook, pos, e->comefrom);
return 0;
}
e->comefrom
|= ((1 << hook) | (1 << NF_IP6_NUMHOOKS));
/* Unconditional return/END. */
if (e->target_offset == sizeof(struct ip6t_entry)
&& (strcmp(t->target.u.user.name,
IP6T_STANDARD_TARGET) == 0)
&& t->verdict < 0
&& unconditional(&e->ipv6)) {
unsigned int oldpos, size;
/* Return: backtrack through the last
big jump. */
do {
e->comefrom ^= (1<<NF_IP6_NUMHOOKS);
#ifdef DEBUG_IP_FIREWALL_USER
if (e->comefrom
& (1 << NF_IP6_NUMHOOKS)) {
duprintf("Back unset "
"on hook %u "
"rule %u\n",
hook, pos);
}
#endif
oldpos = pos;
pos = e->counters.pcnt;
e->counters.pcnt = 0;
/* We're at the start. */
if (pos == oldpos)
goto next;
e = (struct ip6t_entry *)
(entry0 + pos);
} while (oldpos == pos + e->next_offset);
/* Move along one */
size = e->next_offset;
e = (struct ip6t_entry *)
(entry0 + pos + size);
e->counters.pcnt = pos;
pos += size;
} else {
int newpos = t->verdict;
if (strcmp(t->target.u.user.name,
IP6T_STANDARD_TARGET) == 0
&& newpos >= 0) {
/* This a jump; chase it. */
duprintf("Jump rule %u -> %u\n",
pos, newpos);
} else {
/* ... this is a fallthru */
newpos = pos + e->next_offset;
}
e = (struct ip6t_entry *)
(entry0 + newpos);
e->counters.pcnt = pos;
pos = newpos;
}
}
next:
duprintf("Finished chain %u\n", hook);
}
return 1;
}
static inline int
cleanup_match(struct ip6t_entry_match *m, unsigned int *i)
{
if (i && (*i)-- == 0)
return 1;
if (m->u.kernel.match->destroy)
m->u.kernel.match->destroy(m->data,
m->u.match_size - sizeof(*m));
module_put(m->u.kernel.match->me);
return 0;
}
static inline int
standard_check(const struct ip6t_entry_target *t,
unsigned int max_offset)
{
struct ip6t_standard_target *targ = (void *)t;
/* Check standard info. */
if (t->u.target_size
!= IP6T_ALIGN(sizeof(struct ip6t_standard_target))) {
duprintf("standard_check: target size %u != %u\n",
t->u.target_size,
IP6T_ALIGN(sizeof(struct ip6t_standard_target)));
return 0;
}
if (targ->verdict >= 0
&& targ->verdict > max_offset - sizeof(struct ip6t_entry)) {
duprintf("ip6t_standard_check: bad verdict (%i)\n",
targ->verdict);
return 0;
}
if (targ->verdict < -NF_MAX_VERDICT - 1) {
duprintf("ip6t_standard_check: bad negative verdict (%i)\n",
targ->verdict);
return 0;
}
return 1;
}
static inline int
check_match(struct ip6t_entry_match *m,
const char *name,
const struct ip6t_ip6 *ipv6,
unsigned int hookmask,
unsigned int *i)
{
struct ip6t_match *match;
match = try_then_request_module(xt_find_match(AF_INET6, m->u.user.name,
m->u.user.revision),
"ip6t_%s", m->u.user.name);
if (IS_ERR(match) || !match) {
duprintf("check_match: `%s' not found\n", m->u.user.name);
return match ? PTR_ERR(match) : -ENOENT;
}
m->u.kernel.match = match;
if (m->u.kernel.match->checkentry
&& !m->u.kernel.match->checkentry(name, ipv6, m->data,
m->u.match_size - sizeof(*m),
hookmask)) {
module_put(m->u.kernel.match->me);
duprintf("ip_tables: check failed for `%s'.\n",
m->u.kernel.match->name);
return -EINVAL;
}
(*i)++;
return 0;
}
static struct ip6t_target ip6t_standard_target;
static inline int
check_entry(struct ip6t_entry *e, const char *name, unsigned int size,
unsigned int *i)
{
struct ip6t_entry_target *t;
struct ip6t_target *target;
int ret;
unsigned int j;
if (!ip6_checkentry(&e->ipv6)) {
duprintf("ip_tables: ip check failed %p %s.\n", e, name);
return -EINVAL;
}
j = 0;
ret = IP6T_MATCH_ITERATE(e, check_match, name, &e->ipv6, e->comefrom, &j);
if (ret != 0)
goto cleanup_matches;
t = ip6t_get_target(e);
target = try_then_request_module(xt_find_target(AF_INET6,
t->u.user.name,
t->u.user.revision),
"ip6t_%s", t->u.user.name);
if (IS_ERR(target) || !target) {
duprintf("check_entry: `%s' not found\n", t->u.user.name);
ret = target ? PTR_ERR(target) : -ENOENT;
goto cleanup_matches;
}
t->u.kernel.target = target;
if (t->u.kernel.target == &ip6t_standard_target) {
if (!standard_check(t, size)) {
ret = -EINVAL;
goto cleanup_matches;
}
} else if (t->u.kernel.target->checkentry
&& !t->u.kernel.target->checkentry(name, e, t->data,
t->u.target_size
- sizeof(*t),
e->comefrom)) {
module_put(t->u.kernel.target->me);
duprintf("ip_tables: check failed for `%s'.\n",
t->u.kernel.target->name);
ret = -EINVAL;
goto cleanup_matches;
}
(*i)++;
return 0;
cleanup_matches:
IP6T_MATCH_ITERATE(e, cleanup_match, &j);
return ret;
}
static inline int
check_entry_size_and_hooks(struct ip6t_entry *e,
struct xt_table_info *newinfo,
unsigned char *base,
unsigned char *limit,
const unsigned int *hook_entries,
const unsigned int *underflows,
unsigned int *i)
{
unsigned int h;
if ((unsigned long)e % __alignof__(struct ip6t_entry) != 0
|| (unsigned char *)e + sizeof(struct ip6t_entry) >= limit) {
duprintf("Bad offset %p\n", e);
return -EINVAL;
}
if (e->next_offset
< sizeof(struct ip6t_entry) + sizeof(struct ip6t_entry_target)) {
duprintf("checking: element %p size %u\n",
e, e->next_offset);
return -EINVAL;
}
/* Check hooks & underflows */
for (h = 0; h < NF_IP6_NUMHOOKS; h++) {
if ((unsigned char *)e - base == hook_entries[h])
newinfo->hook_entry[h] = hook_entries[h];
if ((unsigned char *)e - base == underflows[h])
newinfo->underflow[h] = underflows[h];
}
/* FIXME: underflows must be unconditional, standard verdicts
< 0 (not IP6T_RETURN). --RR */
/* Clear counters and comefrom */
e->counters = ((struct xt_counters) { 0, 0 });
e->comefrom = 0;
(*i)++;
return 0;
}
static inline int
cleanup_entry(struct ip6t_entry *e, unsigned int *i)
{
struct ip6t_entry_target *t;
if (i && (*i)-- == 0)
return 1;
/* Cleanup all matches */
IP6T_MATCH_ITERATE(e, cleanup_match, NULL);
t = ip6t_get_target(e);
if (t->u.kernel.target->destroy)
t->u.kernel.target->destroy(t->data,
t->u.target_size - sizeof(*t));
module_put(t->u.kernel.target->me);
return 0;
}
/* Checks and translates the user-supplied table segment (held in
newinfo) */
static int
translate_table(const char *name,
unsigned int valid_hooks,
struct xt_table_info *newinfo,
void *entry0,
unsigned int size,
unsigned int number,
const unsigned int *hook_entries,
const unsigned int *underflows)
{
unsigned int i;
int ret;
newinfo->size = size;
newinfo->number = number;
/* Init all hooks to impossible value. */
for (i = 0; i < NF_IP6_NUMHOOKS; i++) {
newinfo->hook_entry[i] = 0xFFFFFFFF;
newinfo->underflow[i] = 0xFFFFFFFF;
}
duprintf("translate_table: size %u\n", newinfo->size);
i = 0;
/* Walk through entries, checking offsets. */
ret = IP6T_ENTRY_ITERATE(entry0, newinfo->size,
check_entry_size_and_hooks,
newinfo,
entry0,
entry0 + size,
hook_entries, underflows, &i);
if (ret != 0)
return ret;
if (i != number) {
duprintf("translate_table: %u not %u entries\n",
i, number);
return -EINVAL;
}
/* Check hooks all assigned */
for (i = 0; i < NF_IP6_NUMHOOKS; i++) {
/* Only hooks which are valid */
if (!(valid_hooks & (1 << i)))
continue;
if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
duprintf("Invalid hook entry %u %u\n",
i, hook_entries[i]);
return -EINVAL;
}
if (newinfo->underflow[i] == 0xFFFFFFFF) {
duprintf("Invalid underflow %u %u\n",
i, underflows[i]);
return -EINVAL;
}
}
if (!mark_source_chains(newinfo, valid_hooks, entry0))
return -ELOOP;
/* Finally, each sanity check must pass */
i = 0;
ret = IP6T_ENTRY_ITERATE(entry0, newinfo->size,
check_entry, name, size, &i);
if (ret != 0) {
IP6T_ENTRY_ITERATE(entry0, newinfo->size,
cleanup_entry, &i);
return ret;
}
/* And one copy for every other CPU */
for_each_cpu(i) {
if (newinfo->entries[i] && newinfo->entries[i] != entry0)
memcpy(newinfo->entries[i], entry0, newinfo->size);
}
return ret;
}
/* Gets counters. */
static inline int
add_entry_to_counter(const struct ip6t_entry *e,
struct xt_counters total[],
unsigned int *i)
{
ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
(*i)++;
return 0;
}
static inline int
set_entry_to_counter(const struct ip6t_entry *e,
struct ip6t_counters total[],
unsigned int *i)
{
SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
(*i)++;
return 0;
}
static void
get_counters(const struct xt_table_info *t,
struct xt_counters counters[])
{
unsigned int cpu;
unsigned int i;
unsigned int curcpu;
/* Instead of clearing (by a previous call to memset())
* the counters and using adds, we set the counters
* with data used by 'current' CPU
* We dont care about preemption here.
*/
curcpu = raw_smp_processor_id();
i = 0;
IP6T_ENTRY_ITERATE(t->entries[curcpu],
t->size,
set_entry_to_counter,
counters,
&i);
for_each_cpu(cpu) {
if (cpu == curcpu)
continue;
i = 0;
IP6T_ENTRY_ITERATE(t->entries[cpu],
t->size,
add_entry_to_counter,
counters,
&i);
}
}
static int
copy_entries_to_user(unsigned int total_size,
struct xt_table *table,
void __user *userptr)
{
unsigned int off, num, countersize;
struct ip6t_entry *e;
struct xt_counters *counters;
struct xt_table_info *private = table->private;
int ret = 0;
void *loc_cpu_entry;
/* We need atomic snapshot of counters: rest doesn't change
(other than comefrom, which userspace doesn't care
about). */
countersize = sizeof(struct xt_counters) * private->number;
counters = vmalloc(countersize);
if (counters == NULL)
return -ENOMEM;
/* First, sum counters... */
write_lock_bh(&table->lock);
get_counters(private, counters);
write_unlock_bh(&table->lock);
/* choose the copy that is on ourc node/cpu */
loc_cpu_entry = private->entries[raw_smp_processor_id()];
if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
ret = -EFAULT;
goto free_counters;
}
/* FIXME: use iterator macros --RR */
/* ... then go back and fix counters and names */
for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
unsigned int i;
struct ip6t_entry_match *m;
struct ip6t_entry_target *t;
e = (struct ip6t_entry *)(loc_cpu_entry + off);
if (copy_to_user(userptr + off
+ offsetof(struct ip6t_entry, counters),
&counters[num],
sizeof(counters[num])) != 0) {
ret = -EFAULT;
goto free_counters;
}
for (i = sizeof(struct ip6t_entry);
i < e->target_offset;
i += m->u.match_size) {
m = (void *)e + i;
if (copy_to_user(userptr + off + i
+ offsetof(struct ip6t_entry_match,
u.user.name),
m->u.kernel.match->name,
strlen(m->u.kernel.match->name)+1)
!= 0) {
ret = -EFAULT;
goto free_counters;
}
}
t = ip6t_get_target(e);
if (copy_to_user(userptr + off + e->target_offset
+ offsetof(struct ip6t_entry_target,
u.user.name),
t->u.kernel.target->name,
strlen(t->u.kernel.target->name)+1) != 0) {
ret = -EFAULT;
goto free_counters;
}
}
free_counters:
vfree(counters);
return ret;
}
static int
get_entries(const struct ip6t_get_entries *entries,
struct ip6t_get_entries __user *uptr)
{
int ret;
struct xt_table *t;
t = xt_find_table_lock(AF_INET6, entries->name);
if (t && !IS_ERR(t)) {
struct xt_table_info *private = t->private;
duprintf("t->private->number = %u\n", private->number);
if (entries->size == private->size)
ret = copy_entries_to_user(private->size,
t, uptr->entrytable);
else {
duprintf("get_entries: I've got %u not %u!\n",
private->size, entries->size);
ret = -EINVAL;
}
module_put(t->me);
xt_table_unlock(t);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
return ret;
}
static int
do_replace(void __user *user, unsigned int len)
{
int ret;
struct ip6t_replace tmp;
struct xt_table *t;
struct xt_table_info *newinfo, *oldinfo;
struct xt_counters *counters;
void *loc_cpu_entry, *loc_cpu_old_entry;
if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
return -EFAULT;
/* overflow check */
if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
SMP_CACHE_BYTES)
return -ENOMEM;
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo)
return -ENOMEM;
/* choose the copy that is on our node/cpu */
loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
counters = vmalloc(tmp.num_counters * sizeof(struct xt_counters));
if (!counters) {
ret = -ENOMEM;
goto free_newinfo;
}
ret = translate_table(tmp.name, tmp.valid_hooks,
newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
tmp.hook_entry, tmp.underflow);
if (ret != 0)
goto free_newinfo_counters;
duprintf("ip_tables: Translated table\n");
t = try_then_request_module(xt_find_table_lock(AF_INET6, tmp.name),
"ip6table_%s", tmp.name);
if (!t || IS_ERR(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free_newinfo_counters_untrans;
}
/* You lied! */
if (tmp.valid_hooks != t->valid_hooks) {
duprintf("Valid hook crap: %08X vs %08X\n",
tmp.valid_hooks, t->valid_hooks);
ret = -EINVAL;
goto put_module;
}
oldinfo = xt_replace_table(t, tmp.num_counters, newinfo, &ret);
if (!oldinfo)
goto put_module;
/* Update module usage count based on number of rules */
duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
oldinfo->number, oldinfo->initial_entries, newinfo->number);
if ((oldinfo->number > oldinfo->initial_entries) ||
(newinfo->number <= oldinfo->initial_entries))
module_put(t->me);
if ((oldinfo->number > oldinfo->initial_entries) &&
(newinfo->number <= oldinfo->initial_entries))
module_put(t->me);
/* Get the old counters. */
get_counters(oldinfo, counters);
/* Decrease module usage counts and free resource */
loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
IP6T_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,NULL);
xt_free_table_info(oldinfo);
if (copy_to_user(tmp.counters, counters,
sizeof(struct xt_counters) * tmp.num_counters) != 0)
ret = -EFAULT;
vfree(counters);
xt_table_unlock(t);
return ret;
put_module:
module_put(t->me);
xt_table_unlock(t);
free_newinfo_counters_untrans:
IP6T_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry,NULL);
free_newinfo_counters:
vfree(counters);
free_newinfo:
xt_free_table_info(newinfo);
return ret;
}
/* We're lazy, and add to the first CPU; overflow works its fey magic
* and everything is OK. */
static inline int
add_counter_to_entry(struct ip6t_entry *e,
const struct xt_counters addme[],
unsigned int *i)
{
#if 0
duprintf("add_counter: Entry %u %lu/%lu + %lu/%lu\n",
*i,
(long unsigned int)e->counters.pcnt,
(long unsigned int)e->counters.bcnt,
(long unsigned int)addme[*i].pcnt,
(long unsigned int)addme[*i].bcnt);
#endif
ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
(*i)++;
return 0;
}
static int
do_add_counters(void __user *user, unsigned int len)
{
unsigned int i;
struct xt_counters_info tmp, *paddc;
struct xt_table_info *private;
struct xt_table *t;
int ret = 0;
void *loc_cpu_entry;
if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
return -EFAULT;
if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct xt_counters))
return -EINVAL;
paddc = vmalloc(len);
if (!paddc)
return -ENOMEM;
if (copy_from_user(paddc, user, len) != 0) {
ret = -EFAULT;
goto free;
}
t = xt_find_table_lock(AF_INET6, tmp.name);
if (!t || IS_ERR(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free;
}
write_lock_bh(&t->lock);
private = t->private;
if (private->number != paddc->num_counters) {
ret = -EINVAL;
goto unlock_up_free;
}
i = 0;
/* Choose the copy that is on our node */
loc_cpu_entry = private->entries[smp_processor_id()];
IP6T_ENTRY_ITERATE(loc_cpu_entry,
private->size,
add_counter_to_entry,
paddc->counters,
&i);
unlock_up_free:
write_unlock_bh(&t->lock);
xt_table_unlock(t);
module_put(t->me);
free:
vfree(paddc);
return ret;
}
static int
do_ip6t_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
{
int ret;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
switch (cmd) {
case IP6T_SO_SET_REPLACE:
ret = do_replace(user, len);
break;
case IP6T_SO_SET_ADD_COUNTERS:
ret = do_add_counters(user, len);
break;
default:
duprintf("do_ip6t_set_ctl: unknown request %i\n", cmd);
ret = -EINVAL;
}
return ret;
}
static int
do_ip6t_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
{
int ret;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
switch (cmd) {
case IP6T_SO_GET_INFO: {
char name[IP6T_TABLE_MAXNAMELEN];
struct xt_table *t;
if (*len != sizeof(struct ip6t_getinfo)) {
duprintf("length %u != %u\n", *len,
sizeof(struct ip6t_getinfo));
ret = -EINVAL;
break;
}
if (copy_from_user(name, user, sizeof(name)) != 0) {
ret = -EFAULT;
break;
}
name[IP6T_TABLE_MAXNAMELEN-1] = '\0';
t = try_then_request_module(xt_find_table_lock(AF_INET6, name),
"ip6table_%s", name);
if (t && !IS_ERR(t)) {
struct ip6t_getinfo info;
struct xt_table_info *private = t->private;
info.valid_hooks = t->valid_hooks;
memcpy(info.hook_entry, private->hook_entry,
sizeof(info.hook_entry));
memcpy(info.underflow, private->underflow,
sizeof(info.underflow));
info.num_entries = private->number;
info.size = private->size;
memcpy(info.name, name, sizeof(info.name));
if (copy_to_user(user, &info, *len) != 0)
ret = -EFAULT;
else
ret = 0;
xt_table_unlock(t);
module_put(t->me);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
}
break;
case IP6T_SO_GET_ENTRIES: {
struct ip6t_get_entries get;
if (*len < sizeof(get)) {
duprintf("get_entries: %u < %u\n", *len, sizeof(get));
ret = -EINVAL;
} else if (copy_from_user(&get, user, sizeof(get)) != 0) {
ret = -EFAULT;
} else if (*len != sizeof(struct ip6t_get_entries) + get.size) {
duprintf("get_entries: %u != %u\n", *len,
sizeof(struct ip6t_get_entries) + get.size);
ret = -EINVAL;
} else
ret = get_entries(&get, user);
break;
}
case IP6T_SO_GET_REVISION_MATCH:
case IP6T_SO_GET_REVISION_TARGET: {
struct ip6t_get_revision rev;
int target;
if (*len != sizeof(rev)) {
ret = -EINVAL;
break;
}
if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
ret = -EFAULT;
break;
}
if (cmd == IP6T_SO_GET_REVISION_TARGET)
target = 1;
else
target = 0;
try_then_request_module(xt_find_revision(AF_INET6, rev.name,
rev.revision,
target, &ret),
"ip6t_%s", rev.name);
break;
}
default:
duprintf("do_ip6t_get_ctl: unknown request %i\n", cmd);
ret = -EINVAL;
}
return ret;
}
int ip6t_register_table(struct xt_table *table,
const struct ip6t_replace *repl)
{
int ret;
struct xt_table_info *newinfo;
static struct xt_table_info bootstrap
= { 0, 0, 0, { 0 }, { 0 }, { } };
void *loc_cpu_entry;
newinfo = xt_alloc_table_info(repl->size);
if (!newinfo)
return -ENOMEM;
/* choose the copy on our node/cpu */
loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
memcpy(loc_cpu_entry, repl->entries, repl->size);
ret = translate_table(table->name, table->valid_hooks,
newinfo, loc_cpu_entry, repl->size,
repl->num_entries,
repl->hook_entry,
repl->underflow);
if (ret != 0) {
xt_free_table_info(newinfo);
return ret;
}
if (xt_register_table(table, &bootstrap, newinfo) != 0) {
xt_free_table_info(newinfo);
return ret;
}
return 0;
}
void ip6t_unregister_table(struct xt_table *table)
{
struct xt_table_info *private;
void *loc_cpu_entry;
private = xt_unregister_table(table);
/* Decrease module usage counts and free resources */
loc_cpu_entry = private->entries[raw_smp_processor_id()];
IP6T_ENTRY_ITERATE(loc_cpu_entry, private->size, cleanup_entry, NULL);
xt_free_table_info(private);
}
/* Returns 1 if the type and code is matched by the range, 0 otherwise */
static inline int
icmp6_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code,
u_int8_t type, u_int8_t code,
int invert)
{
return (type == test_type && code >= min_code && code <= max_code)
^ invert;
}
static int
icmp6_match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
struct icmp6hdr _icmp, *ic;
const struct ip6t_icmp *icmpinfo = matchinfo;
/* Must not be a fragment. */
if (offset)
return 0;
ic = skb_header_pointer(skb, protoff, sizeof(_icmp), &_icmp);
if (ic == NULL) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
duprintf("Dropping evil ICMP tinygram.\n");
*hotdrop = 1;
return 0;
}
return icmp6_type_code_match(icmpinfo->type,
icmpinfo->code[0],
icmpinfo->code[1],
ic->icmp6_type, ic->icmp6_code,
!!(icmpinfo->invflags&IP6T_ICMP_INV));
}
/* Called when user tries to insert an entry of this type. */
static int
icmp6_checkentry(const char *tablename,
const void *entry,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
const struct ip6t_ip6 *ipv6 = entry;
const struct ip6t_icmp *icmpinfo = matchinfo;
/* Must specify proto == ICMP, and no unknown invflags */
return ipv6->proto == IPPROTO_ICMPV6
&& !(ipv6->invflags & IP6T_INV_PROTO)
&& matchsize == IP6T_ALIGN(sizeof(struct ip6t_icmp))
&& !(icmpinfo->invflags & ~IP6T_ICMP_INV);
}
/* The built-in targets: standard (NULL) and error. */
static struct ip6t_target ip6t_standard_target = {
.name = IP6T_STANDARD_TARGET,
};
static struct ip6t_target ip6t_error_target = {
.name = IP6T_ERROR_TARGET,
.target = ip6t_error,
};
static struct nf_sockopt_ops ip6t_sockopts = {
.pf = PF_INET6,
.set_optmin = IP6T_BASE_CTL,
.set_optmax = IP6T_SO_SET_MAX+1,
.set = do_ip6t_set_ctl,
.get_optmin = IP6T_BASE_CTL,
.get_optmax = IP6T_SO_GET_MAX+1,
.get = do_ip6t_get_ctl,
};
static struct ip6t_match icmp6_matchstruct = {
.name = "icmp6",
.match = &icmp6_match,
.checkentry = &icmp6_checkentry,
};
static int __init init(void)
{
int ret;
xt_proto_init(AF_INET6);
/* Noone else will be downing sem now, so we won't sleep */
xt_register_target(AF_INET6, &ip6t_standard_target);
xt_register_target(AF_INET6, &ip6t_error_target);
xt_register_match(AF_INET6, &icmp6_matchstruct);
/* Register setsockopt */
ret = nf_register_sockopt(&ip6t_sockopts);
if (ret < 0) {
duprintf("Unable to register sockopts.\n");
xt_proto_fini(AF_INET6);
return ret;
}
printk("ip6_tables: (C) 2000-2006 Netfilter Core Team\n");
return 0;
}
static void __exit fini(void)
{
nf_unregister_sockopt(&ip6t_sockopts);
xt_unregister_match(AF_INET6, &icmp6_matchstruct);
xt_unregister_target(AF_INET6, &ip6t_error_target);
xt_unregister_target(AF_INET6, &ip6t_standard_target);
xt_proto_fini(AF_INET6);
}
/*
* find the offset to specified header or the protocol number of last header
* if target < 0. "last header" is transport protocol header, ESP, or
* "No next header".
*
* If target header is found, its offset is set in *offset and return protocol
* number. Otherwise, return -1.
*
* Note that non-1st fragment is special case that "the protocol number
* of last header" is "next header" field in Fragment header. In this case,
* *offset is meaningless and fragment offset is stored in *fragoff if fragoff
* isn't NULL.
*
*/
int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
int target, unsigned short *fragoff)
{
unsigned int start = (u8*)(skb->nh.ipv6h + 1) - skb->data;
u8 nexthdr = skb->nh.ipv6h->nexthdr;
unsigned int len = skb->len - start;
if (fragoff)
*fragoff = 0;
while (nexthdr != target) {
struct ipv6_opt_hdr _hdr, *hp;
unsigned int hdrlen;
if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) {
if (target < 0)
break;
return -1;
}
hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
if (hp == NULL)
return -1;
if (nexthdr == NEXTHDR_FRAGMENT) {
unsigned short _frag_off, *fp;
fp = skb_header_pointer(skb,
start+offsetof(struct frag_hdr,
frag_off),
sizeof(_frag_off),
&_frag_off);
if (fp == NULL)
return -1;
_frag_off = ntohs(*fp) & ~0x7;
if (_frag_off) {
if (target < 0 &&
((!ipv6_ext_hdr(hp->nexthdr)) ||
nexthdr == NEXTHDR_NONE)) {
if (fragoff)
*fragoff = _frag_off;
return hp->nexthdr;
}
return -1;
}
hdrlen = 8;
} else if (nexthdr == NEXTHDR_AUTH)
hdrlen = (hp->hdrlen + 2) << 2;
else
hdrlen = ipv6_optlen(hp);
nexthdr = hp->nexthdr;
len -= hdrlen;
start += hdrlen;
}
*offset = start;
return nexthdr;
}
EXPORT_SYMBOL(ip6t_register_table);
EXPORT_SYMBOL(ip6t_unregister_table);
EXPORT_SYMBOL(ip6t_do_table);
EXPORT_SYMBOL(ip6t_ext_hdr);
EXPORT_SYMBOL(ipv6_find_hdr);
EXPORT_SYMBOL(ip6_masked_addrcmp);
module_init(init);
module_exit(fini);