- 根目录:
- net
- ipv4
- netfilter
- ip_tables.c
/*
* Packet matching code.
*
* Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
* Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
* Copyright (C) 2006-2010 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cache.h>
#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/kmod.h>
#include <linux/vmalloc.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <linux/icmp.h>
#include <net/ip.h>
#include <net/compat.h>
#include <asm/uaccess.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/err.h>
#include <linux/cpumask.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <net/netfilter/nf_log.h>
#include "../../netfilter/xt_repldata.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("IPv4 packet filter");
/*#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...) pr_info(format , ## args)
#else
#define dprintf(format, args...)
#endif
#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) pr_info(format , ## args)
#else
#define duprintf(format, args...)
#endif
#ifdef CONFIG_NETFILTER_DEBUG
#define IP_NF_ASSERT(x) WARN_ON(!(x))
#else
#define IP_NF_ASSERT(x)
#endif
#if 0
/* All the better to debug you with... */
#define static
#define inline
#endif
void *ipt_alloc_initial_table(const struct xt_table *info)
{
return xt_alloc_initial_table(ipt, IPT);
}
EXPORT_SYMBOL_GPL(ipt_alloc_initial_table);
/* Returns whether matches rule or not. */
/* Performance critical - called for every packet */
static inline bool
ip_packet_match(const struct iphdr *ip,
const char *indev,
const char *outdev,
const struct ipt_ip *ipinfo,
int isfrag)
{
unsigned long ret;
#define FWINV(bool, invflg) ((bool) ^ !!(ipinfo->invflags & (invflg)))
if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr,
IPT_INV_SRCIP) ||
FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr,
IPT_INV_DSTIP)) {
dprintf("Source or dest mismatch.\n");
dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
&ip->saddr, &ipinfo->smsk.s_addr, &ipinfo->src.s_addr,
ipinfo->invflags & IPT_INV_SRCIP ? " (INV)" : "");
dprintf("DST: %pI4 Mask: %pI4 Target: %pI4.%s\n",
&ip->daddr, &ipinfo->dmsk.s_addr, &ipinfo->dst.s_addr,
ipinfo->invflags & IPT_INV_DSTIP ? " (INV)" : "");
return false;
}
ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask);
if (FWINV(ret != 0, IPT_INV_VIA_IN)) {
dprintf("VIA in mismatch (%s vs %s).%s\n",
indev, ipinfo->iniface,
ipinfo->invflags & IPT_INV_VIA_IN ? " (INV)" : "");
return false;
}
ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask);
if (FWINV(ret != 0, IPT_INV_VIA_OUT)) {
dprintf("VIA out mismatch (%s vs %s).%s\n",
outdev, ipinfo->outiface,
ipinfo->invflags & IPT_INV_VIA_OUT ? " (INV)" : "");
return false;
}
/* Check specific protocol */
if (ipinfo->proto &&
FWINV(ip->protocol != ipinfo->proto, IPT_INV_PROTO)) {
dprintf("Packet protocol %hi does not match %hi.%s\n",
ip->protocol, ipinfo->proto,
ipinfo->invflags & IPT_INV_PROTO ? " (INV)" : "");
return false;
}
/* If we have a fragment rule but the packet is not a fragment
* then we return zero */
if (FWINV((ipinfo->flags&IPT_F_FRAG) && !isfrag, IPT_INV_FRAG)) {
dprintf("Fragment rule but not fragment.%s\n",
ipinfo->invflags & IPT_INV_FRAG ? " (INV)" : "");
return false;
}
return true;
}
static bool
ip_checkentry(const struct ipt_ip *ip)
{
if (ip->flags & ~IPT_F_MASK) {
duprintf("Unknown flag bits set: %08X\n",
ip->flags & ~IPT_F_MASK);
return false;
}
if (ip->invflags & ~IPT_INV_MASK) {
duprintf("Unknown invflag bits set: %08X\n",
ip->invflags & ~IPT_INV_MASK);
return false;
}
return true;
}
static unsigned int
ipt_error(struct sk_buff *skb, const struct xt_action_param *par)
{
net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo);
return NF_DROP;
}
/* Performance critical */
static inline struct ipt_entry *
get_entry(const void *base, unsigned int offset)
{
return (struct ipt_entry *)(base + offset);
}
/* All zeroes == unconditional rule. */
/* Mildly perf critical (only if packet tracing is on) */
static inline bool unconditional(const struct ipt_ip *ip)
{
static const struct ipt_ip uncond;
return memcmp(ip, &uncond, sizeof(uncond)) == 0;
#undef FWINV
}
/* for const-correctness */
static inline const struct xt_entry_target *
ipt_get_target_c(const struct ipt_entry *e)
{
return ipt_get_target((struct ipt_entry *)e);
}
#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
static const char *const hooknames[] = {
[NF_INET_PRE_ROUTING] = "PREROUTING",
[NF_INET_LOCAL_IN] = "INPUT",
[NF_INET_FORWARD] = "FORWARD",
[NF_INET_LOCAL_OUT] = "OUTPUT",
[NF_INET_POST_ROUTING] = "POSTROUTING",
};
enum nf_ip_trace_comments {
NF_IP_TRACE_COMMENT_RULE,
NF_IP_TRACE_COMMENT_RETURN,
NF_IP_TRACE_COMMENT_POLICY,
};
static const char *const comments[] = {
[NF_IP_TRACE_COMMENT_RULE] = "rule",
[NF_IP_TRACE_COMMENT_RETURN] = "return",
[NF_IP_TRACE_COMMENT_POLICY] = "policy",
};
static struct nf_loginfo trace_loginfo = {
.type = NF_LOG_TYPE_LOG,
.u = {
.log = {
.level = 4,
.logflags = NF_LOG_MASK,
},
},
};
/* Mildly perf critical (only if packet tracing is on) */
static inline int
get_chainname_rulenum(const struct ipt_entry *s, const struct ipt_entry *e,
const char *hookname, const char **chainname,
const char **comment, unsigned int *rulenum)
{
const struct xt_standard_target *t = (void *)ipt_get_target_c(s);
if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) {
/* Head of user chain: ERROR target with chainname */
*chainname = t->target.data;
(*rulenum) = 0;
} else if (s == e) {
(*rulenum)++;
if (s->target_offset == sizeof(struct ipt_entry) &&
strcmp(t->target.u.kernel.target->name,
XT_STANDARD_TARGET) == 0 &&
t->verdict < 0 &&
unconditional(&s->ip)) {
/* Tail of chains: STANDARD target (return/policy) */
*comment = *chainname == hookname
? comments[NF_IP_TRACE_COMMENT_POLICY]
: comments[NF_IP_TRACE_COMMENT_RETURN];
}
return 1;
} else
(*rulenum)++;
return 0;
}
static void trace_packet(struct net *net,
const struct sk_buff *skb,
unsigned int hook,
const struct net_device *in,
const struct net_device *out,
const char *tablename,
const struct xt_table_info *private,
const struct ipt_entry *e)
{
const struct ipt_entry *root;
const char *hookname, *chainname, *comment;
const struct ipt_entry *iter;
unsigned int rulenum = 0;
root = get_entry(private->entries, private->hook_entry[hook]);
hookname = chainname = hooknames[hook];
comment = comments[NF_IP_TRACE_COMMENT_RULE];
xt_entry_foreach(iter, root, private->size - private->hook_entry[hook])
if (get_chainname_rulenum(iter, e, hookname,
&chainname, &comment, &rulenum) != 0)
break;
nf_log_trace(net, AF_INET, hook, skb, in, out, &trace_loginfo,
"TRACE: %s:%s:%s:%u ",
tablename, chainname, comment, rulenum);
}
#endif
static inline
struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry)
{
return (void *)entry + entry->next_offset;
}
/* Returns one of the generic firewall policies, like NF_ACCEPT. */
unsigned int
ipt_do_table(struct sk_buff *skb,
const struct nf_hook_state *state,
struct xt_table *table)
{
unsigned int hook = state->hook;
static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
const struct iphdr *ip;
/* Initializing verdict to NF_DROP keeps gcc happy. */
unsigned int verdict = NF_DROP;
const char *indev, *outdev;
const void *table_base;
struct ipt_entry *e, **jumpstack;
unsigned int stackidx, cpu;
const struct xt_table_info *private;
struct xt_action_param acpar;
unsigned int addend;
/* Initialization */
stackidx = 0;
ip = ip_hdr(skb);
indev = state->in ? state->in->name : nulldevname;
outdev = state->out ? state->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. */
acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
acpar.thoff = ip_hdrlen(skb);
acpar.hotdrop = false;
acpar.net = state->net;
acpar.in = state->in;
acpar.out = state->out;
acpar.family = NFPROTO_IPV4;
acpar.hooknum = hook;
IP_NF_ASSERT(table->valid_hooks & (1 << hook));
local_bh_disable();
addend = xt_write_recseq_begin();
private = table->private;
cpu = smp_processor_id();
/*
* Ensure we load private-> members after we've fetched the base
* pointer.
*/
smp_read_barrier_depends();
table_base = private->entries;
jumpstack = (struct ipt_entry **)private->jumpstack[cpu];
/* Switch to alternate jumpstack if we're being invoked via TEE.
* TEE issues XT_CONTINUE verdict on original skb so we must not
* clobber the jumpstack.
*
* For recursion via REJECT or SYNPROXY the stack will be clobbered
* but it is no problem since absolute verdict is issued by these.
*/
if (static_key_false(&xt_tee_enabled))
jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
e = get_entry(table_base, private->hook_entry[hook]);
pr_debug("Entering %s(hook %u), UF %p\n",
table->name, hook,
get_entry(table_base, private->underflow[hook]));
do {
const struct xt_entry_target *t;
const struct xt_entry_match *ematch;
struct xt_counters *counter;
IP_NF_ASSERT(e);
if (!ip_packet_match(ip, indev, outdev,
&e->ip, acpar.fragoff)) {
no_match:
e = ipt_next_entry(e);
continue;
}
xt_ematch_foreach(ematch, e) {
acpar.match = ematch->u.kernel.match;
acpar.matchinfo = ematch->data;
if (!acpar.match->match(skb, &acpar))
goto no_match;
}
counter = xt_get_this_cpu_counter(&e->counters);
ADD_COUNTER(*counter, skb->len, 1);
t = ipt_get_target(e);
IP_NF_ASSERT(t->u.kernel.target);
#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
/* The packet is traced: log it */
if (unlikely(skb->nf_trace))
trace_packet(state->net, skb, hook, state->in,
state->out, table->name, private, e);
#endif
/* Standard target? */
if (!t->u.kernel.target->target) {
int v;
v = ((struct xt_standard_target *)t)->verdict;
if (v < 0) {
/* Pop from stack? */
if (v != XT_RETURN) {
verdict = (unsigned int)(-v) - 1;
break;
}
if (stackidx == 0) {
e = get_entry(table_base,
private->underflow[hook]);
pr_debug("Underflow (this is normal) "
"to %p\n", e);
} else {
e = jumpstack[--stackidx];
pr_debug("Pulled %p out from pos %u\n",
e, stackidx);
e = ipt_next_entry(e);
}
continue;
}
if (table_base + v != ipt_next_entry(e) &&
!(e->ip.flags & IPT_F_GOTO)) {
jumpstack[stackidx++] = e;
pr_debug("Pushed %p into pos %u\n",
e, stackidx - 1);
}
e = get_entry(table_base, v);
continue;
}
acpar.target = t->u.kernel.target;
acpar.targinfo = t->data;
verdict = t->u.kernel.target->target(skb, &acpar);
/* Target might have changed stuff. */
ip = ip_hdr(skb);
if (verdict == XT_CONTINUE)
e = ipt_next_entry(e);
else
/* Verdict */
break;
} while (!acpar.hotdrop);
pr_debug("Exiting %s; sp at %u\n", __func__, stackidx);
xt_write_recseq_end(addend);
local_bh_enable();
#ifdef DEBUG_ALLOW_ALL
return NF_ACCEPT;
#else
if (acpar.hotdrop)
return NF_DROP;
else return verdict;
#endif
}
/* 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(const 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_INET_NUMHOOKS; hook++) {
unsigned int pos = newinfo->hook_entry[hook];
struct ipt_entry *e = (struct ipt_entry *)(entry0 + pos);
if (!(valid_hooks & (1 << hook)))
continue;
/* Set initial back pointer. */
e->counters.pcnt = pos;
for (;;) {
const struct xt_standard_target *t
= (void *)ipt_get_target_c(e);
int visited = e->comefrom & (1 << hook);
if (e->comefrom & (1 << NF_INET_NUMHOOKS)) {
pr_err("iptables: loop hook %u pos %u %08X.\n",
hook, pos, e->comefrom);
return 0;
}
e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS));
/* Unconditional return/END. */
if ((e->target_offset == sizeof(struct ipt_entry) &&
(strcmp(t->target.u.user.name,
XT_STANDARD_TARGET) == 0) &&
t->verdict < 0 && unconditional(&e->ip)) ||
visited) {
unsigned int oldpos, size;
if ((strcmp(t->target.u.user.name,
XT_STANDARD_TARGET) == 0) &&
t->verdict < -NF_MAX_VERDICT - 1) {
duprintf("mark_source_chains: bad "
"negative verdict (%i)\n",
t->verdict);
return 0;
}
/* Return: backtrack through the last
big jump. */
do {
e->comefrom ^= (1<<NF_INET_NUMHOOKS);
#ifdef DEBUG_IP_FIREWALL_USER
if (e->comefrom
& (1 << NF_INET_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 ipt_entry *)
(entry0 + pos);
} while (oldpos == pos + e->next_offset);
/* Move along one */
size = e->next_offset;
e = (struct ipt_entry *)
(entry0 + pos + size);
e->counters.pcnt = pos;
pos += size;
} else {
int newpos = t->verdict;
if (strcmp(t->target.u.user.name,
XT_STANDARD_TARGET) == 0 &&
newpos >= 0) {
if (newpos > newinfo->size -
sizeof(struct ipt_entry)) {
duprintf("mark_source_chains: "
"bad verdict (%i)\n",
newpos);
return 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 ipt_entry *)
(entry0 + newpos);
e->counters.pcnt = pos;
pos = newpos;
}
}
next:
duprintf("Finished chain %u\n", hook);
}
return 1;
}
static void cleanup_match(struct xt_entry_match *m, struct net *net)
{
struct xt_mtdtor_param par;
par.net = net;
par.match = m->u.kernel.match;
par.matchinfo = m->data;
par.family = NFPROTO_IPV4;
if (par.match->destroy != NULL)
par.match->destroy(&par);
module_put(par.match->me);
}
static int
check_entry(const struct ipt_entry *e, const char *name)
{
const struct xt_entry_target *t;
if (!ip_checkentry(&e->ip)) {
duprintf("ip check failed %p %s.\n", e, name);
return -EINVAL;
}
if (e->target_offset + sizeof(struct xt_entry_target) >
e->next_offset)
return -EINVAL;
t = ipt_get_target_c(e);
if (e->target_offset + t->u.target_size > e->next_offset)
return -EINVAL;
return 0;
}
static int
check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
{
const struct ipt_ip *ip = par->entryinfo;
int ret;
par->match = m->u.kernel.match;
par->matchinfo = m->data;
ret = xt_check_match(par, m->u.match_size - sizeof(*m),
ip->proto, ip->invflags & IPT_INV_PROTO);
if (ret < 0) {
duprintf("check failed for `%s'.\n", par->match->name);
return ret;
}
return 0;
}
static int
find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
{
struct xt_match *match;
int ret;
match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
m->u.user.revision);
if (IS_ERR(match)) {
duprintf("find_check_match: `%s' not found\n", m->u.user.name);
return PTR_ERR(match);
}
m->u.kernel.match = match;
ret = check_match(m, par);
if (ret)
goto err;
return 0;
err:
module_put(m->u.kernel.match->me);
return ret;
}
static int check_target(struct ipt_entry *e, struct net *net, const char *name)
{
struct xt_entry_target *t = ipt_get_target(e);
struct xt_tgchk_param par = {
.net = net,
.table = name,
.entryinfo = e,
.target = t->u.kernel.target,
.targinfo = t->data,
.hook_mask = e->comefrom,
.family = NFPROTO_IPV4,
};
int ret;
ret = xt_check_target(&par, t->u.target_size - sizeof(*t),
e->ip.proto, e->ip.invflags & IPT_INV_PROTO);
if (ret < 0) {
duprintf("check failed for `%s'.\n",
t->u.kernel.target->name);
return ret;
}
return 0;
}
static int
find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
unsigned int size)
{
struct xt_entry_target *t;
struct xt_target *target;
int ret;
unsigned int j;
struct xt_mtchk_param mtpar;
struct xt_entry_match *ematch;
ret = check_entry(e, name);
if (ret)
return ret;
e->counters.pcnt = xt_percpu_counter_alloc();
if (IS_ERR_VALUE(e->counters.pcnt))
return -ENOMEM;
j = 0;
mtpar.net = net;
mtpar.table = name;
mtpar.entryinfo = &e->ip;
mtpar.hook_mask = e->comefrom;
mtpar.family = NFPROTO_IPV4;
xt_ematch_foreach(ematch, e) {
ret = find_check_match(ematch, &mtpar);
if (ret != 0)
goto cleanup_matches;
++j;
}
t = ipt_get_target(e);
target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
t->u.user.revision);
if (IS_ERR(target)) {
duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
ret = PTR_ERR(target);
goto cleanup_matches;
}
t->u.kernel.target = target;
ret = check_target(e, net, name);
if (ret)
goto err;
return 0;
err:
module_put(t->u.kernel.target->me);
cleanup_matches:
xt_ematch_foreach(ematch, e) {
if (j-- == 0)
break;
cleanup_match(ematch, net);
}
xt_percpu_counter_free(e->counters.pcnt);
return ret;
}
static bool check_underflow(const struct ipt_entry *e)
{
const struct xt_entry_target *t;
unsigned int verdict;
if (!unconditional(&e->ip))
return false;
t = ipt_get_target_c(e);
if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
return false;
verdict = ((struct xt_standard_target *)t)->verdict;
verdict = -verdict - 1;
return verdict == NF_DROP || verdict == NF_ACCEPT;
}
static int
check_entry_size_and_hooks(struct ipt_entry *e,
struct xt_table_info *newinfo,
const unsigned char *base,
const unsigned char *limit,
const unsigned int *hook_entries,
const unsigned int *underflows,
unsigned int valid_hooks)
{
unsigned int h;
if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 ||
(unsigned char *)e + sizeof(struct ipt_entry) >= limit) {
duprintf("Bad offset %p\n", e);
return -EINVAL;
}
if (e->next_offset
< sizeof(struct ipt_entry) + sizeof(struct xt_entry_target)) {
duprintf("checking: element %p size %u\n",
e, e->next_offset);
return -EINVAL;
}
/* Check hooks & underflows */
for (h = 0; h < NF_INET_NUMHOOKS; h++) {
if (!(valid_hooks & (1 << h)))
continue;
if ((unsigned char *)e - base == hook_entries[h])
newinfo->hook_entry[h] = hook_entries[h];
if ((unsigned char *)e - base == underflows[h]) {
if (!check_underflow(e)) {
pr_err("Underflows must be unconditional and "
"use the STANDARD target with "
"ACCEPT/DROP\n");
return -EINVAL;
}
newinfo->underflow[h] = underflows[h];
}
}
/* Clear counters and comefrom */
e->counters = ((struct xt_counters) { 0, 0 });
e->comefrom = 0;
return 0;
}
static void
cleanup_entry(struct ipt_entry *e, struct net *net)
{
struct xt_tgdtor_param par;
struct xt_entry_target *t;
struct xt_entry_match *ematch;
/* Cleanup all matches */
xt_ematch_foreach(ematch, e)
cleanup_match(ematch, net);
t = ipt_get_target(e);
par.net = net;
par.target = t->u.kernel.target;
par.targinfo = t->data;
par.family = NFPROTO_IPV4;
if (par.target->destroy != NULL)
par.target->destroy(&par);
module_put(par.target->me);
xt_percpu_counter_free(e->counters.pcnt);
}
/* Checks and translates the user-supplied table segment (held in
newinfo) */
static int
translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0,
const struct ipt_replace *repl)
{
struct ipt_entry *iter;
unsigned int i;
int ret = 0;
newinfo->size = repl->size;
newinfo->number = repl->num_entries;
/* Init all hooks to impossible value. */
for (i = 0; i < NF_INET_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. */
xt_entry_foreach(iter, entry0, newinfo->size) {
ret = check_entry_size_and_hooks(iter, newinfo, entry0,
entry0 + repl->size,
repl->hook_entry,
repl->underflow,
repl->valid_hooks);
if (ret != 0)
return ret;
++i;
if (strcmp(ipt_get_target(iter)->u.user.name,
XT_ERROR_TARGET) == 0)
++newinfo->stacksize;
}
if (i != repl->num_entries) {
duprintf("translate_table: %u not %u entries\n",
i, repl->num_entries);
return -EINVAL;
}
/* Check hooks all assigned */
for (i = 0; i < NF_INET_NUMHOOKS; i++) {
/* Only hooks which are valid */
if (!(repl->valid_hooks & (1 << i)))
continue;
if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
duprintf("Invalid hook entry %u %u\n",
i, repl->hook_entry[i]);
return -EINVAL;
}
if (newinfo->underflow[i] == 0xFFFFFFFF) {
duprintf("Invalid underflow %u %u\n",
i, repl->underflow[i]);
return -EINVAL;
}
}
if (!mark_source_chains(newinfo, repl->valid_hooks, entry0))
return -ELOOP;
/* Finally, each sanity check must pass */
i = 0;
xt_entry_foreach(iter, entry0, newinfo->size) {
ret = find_check_entry(iter, net, repl->name, repl->size);
if (ret != 0)
break;
++i;
}
if (ret != 0) {
xt_entry_foreach(iter, entry0, newinfo->size) {
if (i-- == 0)
break;
cleanup_entry(iter, net);
}
return ret;
}
return ret;
}
static void
get_counters(const struct xt_table_info *t,
struct xt_counters counters[])
{
struct ipt_entry *iter;
unsigned int cpu;
unsigned int i;
for_each_possible_cpu(cpu) {
seqcount_t *s = &per_cpu(xt_recseq, cpu);
i = 0;
xt_entry_foreach(iter, t->entries, t->size) {
struct xt_counters *tmp;
u64 bcnt, pcnt;
unsigned int start;
tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
do {
start = read_seqcount_begin(s);
bcnt = tmp->bcnt;
pcnt = tmp->pcnt;
} while (read_seqcount_retry(s, start));
ADD_COUNTER(counters[i], bcnt, pcnt);
++i; /* macro does multi eval of i */
}
}
}
static struct xt_counters *alloc_counters(const struct xt_table *table)
{
unsigned int countersize;
struct xt_counters *counters;
const struct xt_table_info *private = table->private;
/* 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 = vzalloc(countersize);
if (counters == NULL)
return ERR_PTR(-ENOMEM);
get_counters(private, counters);
return counters;
}
static int
copy_entries_to_user(unsigned int total_size,
const struct xt_table *table,
void __user *userptr)
{
unsigned int off, num;
const struct ipt_entry *e;
struct xt_counters *counters;
const struct xt_table_info *private = table->private;
int ret = 0;
const void *loc_cpu_entry;
counters = alloc_counters(table);
if (IS_ERR(counters))
return PTR_ERR(counters);
loc_cpu_entry = private->entries;
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;
const struct xt_entry_match *m;
const struct xt_entry_target *t;
e = (struct ipt_entry *)(loc_cpu_entry + off);
if (copy_to_user(userptr + off
+ offsetof(struct ipt_entry, counters),
&counters[num],
sizeof(counters[num])) != 0) {
ret = -EFAULT;
goto free_counters;
}
for (i = sizeof(struct ipt_entry);
i < e->target_offset;
i += m->u.match_size) {
m = (void *)e + i;
if (copy_to_user(userptr + off + i
+ offsetof(struct xt_entry_match,
u.user.name),
m->u.kernel.match->name,
strlen(m->u.kernel.match->name)+1)
!= 0) {
ret = -EFAULT;
goto free_counters;
}
}
t = ipt_get_target_c(e);
if (copy_to_user(userptr + off + e->target_offset
+ offsetof(struct xt_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;
}
#ifdef CONFIG_COMPAT
static void compat_standard_from_user(void *dst, const void *src)
{
int v = *(compat_int_t *)src;
if (v > 0)
v += xt_compat_calc_jump(AF_INET, v);
memcpy(dst, &v, sizeof(v));
}
static int compat_standard_to_user(void __user *dst, const void *src)
{
compat_int_t cv = *(int *)src;
if (cv > 0)
cv -= xt_compat_calc_jump(AF_INET, cv);
return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
}
static int compat_calc_entry(const struct ipt_entry *e,
const struct xt_table_info *info,
const void *base, struct xt_table_info *newinfo)
{
const struct xt_entry_match *ematch;
const struct xt_entry_target *t;
unsigned int entry_offset;
int off, i, ret;
off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
entry_offset = (void *)e - base;
xt_ematch_foreach(ematch, e)
off += xt_compat_match_offset(ematch->u.kernel.match);
t = ipt_get_target_c(e);
off += xt_compat_target_offset(t->u.kernel.target);
newinfo->size -= off;
ret = xt_compat_add_offset(AF_INET, entry_offset, off);
if (ret)
return ret;
for (i = 0; i < NF_INET_NUMHOOKS; i++) {
if (info->hook_entry[i] &&
(e < (struct ipt_entry *)(base + info->hook_entry[i])))
newinfo->hook_entry[i] -= off;
if (info->underflow[i] &&
(e < (struct ipt_entry *)(base + info->underflow[i])))
newinfo->underflow[i] -= off;
}
return 0;
}
static int compat_table_info(const struct xt_table_info *info,
struct xt_table_info *newinfo)
{
struct ipt_entry *iter;
const void *loc_cpu_entry;
int ret;
if (!newinfo || !info)
return -EINVAL;
/* we dont care about newinfo->entries */
memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
newinfo->initial_entries = 0;
loc_cpu_entry = info->entries;
xt_compat_init_offsets(AF_INET, info->number);
xt_entry_foreach(iter, loc_cpu_entry, info->size) {
ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
if (ret != 0)
return ret;
}
return 0;
}
#endif
static int get_info(struct net *net, void __user *user,
const int *len, int compat)
{
char name[XT_TABLE_MAXNAMELEN];
struct xt_table *t;
int ret;
if (*len != sizeof(struct ipt_getinfo)) {
duprintf("length %u != %zu\n", *len,
sizeof(struct ipt_getinfo));
return -EINVAL;
}
if (copy_from_user(name, user, sizeof(name)) != 0)
return -EFAULT;
name[XT_TABLE_MAXNAMELEN-1] = '\0';
#ifdef CONFIG_COMPAT
if (compat)
xt_compat_lock(AF_INET);
#endif
t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
"iptable_%s", name);
if (!IS_ERR_OR_NULL(t)) {
struct ipt_getinfo info;
const struct xt_table_info *private = t->private;
#ifdef CONFIG_COMPAT
struct xt_table_info tmp;
if (compat) {
ret = compat_table_info(private, &tmp);
xt_compat_flush_offsets(AF_INET);
private = &tmp;
}
#endif
memset(&info, 0, sizeof(info));
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;
strcpy(info.name, 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;
#ifdef CONFIG_COMPAT
if (compat)
xt_compat_unlock(AF_INET);
#endif
return ret;
}
static int
get_entries(struct net *net, struct ipt_get_entries __user *uptr,
const int *len)
{
int ret;
struct ipt_get_entries get;
struct xt_table *t;
if (*len < sizeof(get)) {
duprintf("get_entries: %u < %zu\n", *len, sizeof(get));
return -EINVAL;
}
if (copy_from_user(&get, uptr, sizeof(get)) != 0)
return -EFAULT;
if (*len != sizeof(struct ipt_get_entries) + get.size) {
duprintf("get_entries: %u != %zu\n",
*len, sizeof(get) + get.size);
return -EINVAL;
}
t = xt_find_table_lock(net, AF_INET, get.name);
if (!IS_ERR_OR_NULL(t)) {
const struct xt_table_info *private = t->private;
duprintf("t->private->number = %u\n", private->number);
if (get.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, get.size);
ret = -EAGAIN;
}
module_put(t->me);
xt_table_unlock(t);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
return ret;
}
static int
__do_replace(struct net *net, const char *name, unsigned int valid_hooks,
struct xt_table_info *newinfo, unsigned int num_counters,
void __user *counters_ptr)
{
int ret;
struct xt_table *t;
struct xt_table_info *oldinfo;
struct xt_counters *counters;
struct ipt_entry *iter;
ret = 0;
counters = vzalloc(num_counters * sizeof(struct xt_counters));
if (!counters) {
ret = -ENOMEM;
goto out;
}
t = try_then_request_module(xt_find_table_lock(net, AF_INET, name),
"iptable_%s", name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free_newinfo_counters_untrans;
}
/* You lied! */
if (valid_hooks != t->valid_hooks) {
duprintf("Valid hook crap: %08X vs %08X\n",
valid_hooks, t->valid_hooks);
ret = -EINVAL;
goto put_module;
}
oldinfo = xt_replace_table(t, 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, and synchronize with replace */
get_counters(oldinfo, counters);
/* Decrease module usage counts and free resource */
xt_entry_foreach(iter, oldinfo->entries, oldinfo->size)
cleanup_entry(iter, net);
xt_free_table_info(oldinfo);
if (copy_to_user(counters_ptr, counters,
sizeof(struct xt_counters) * num_counters) != 0) {
/* Silent error, can't fail, new table is already in place */
net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n");
}
vfree(counters);
xt_table_unlock(t);
return ret;
put_module:
module_put(t->me);
xt_table_unlock(t);
free_newinfo_counters_untrans:
vfree(counters);
out:
return ret;
}
static int
do_replace(struct net *net, const void __user *user, unsigned int len)
{
int ret;
struct ipt_replace tmp;
struct xt_table_info *newinfo;
void *loc_cpu_entry;
struct ipt_entry *iter;
if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
return -EFAULT;
/* overflow check */
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
if (tmp.num_counters == 0)
return -EINVAL;
tmp.name[sizeof(tmp.name)-1] = 0;
newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo)
return -ENOMEM;
loc_cpu_entry = newinfo->entries;
if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
if (ret != 0)
goto free_newinfo;
duprintf("Translated table\n");
ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
tmp.num_counters, tmp.counters);
if (ret)
goto free_newinfo_untrans;
return 0;
free_newinfo_untrans:
xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
cleanup_entry(iter, net);
free_newinfo:
xt_free_table_info(newinfo);
return ret;
}
static int
do_add_counters(struct net *net, const void __user *user,
unsigned int len, int compat)
{
unsigned int i;
struct xt_counters_info tmp;
struct xt_counters *paddc;
unsigned int num_counters;
const char *name;
int size;
void *ptmp;
struct xt_table *t;
const struct xt_table_info *private;
int ret = 0;
struct ipt_entry *iter;
unsigned int addend;
#ifdef CONFIG_COMPAT
struct compat_xt_counters_info compat_tmp;
if (compat) {
ptmp = &compat_tmp;
size = sizeof(struct compat_xt_counters_info);
} else
#endif
{
ptmp = &tmp;
size = sizeof(struct xt_counters_info);
}
if (copy_from_user(ptmp, user, size) != 0)
return -EFAULT;
#ifdef CONFIG_COMPAT
if (compat) {
num_counters = compat_tmp.num_counters;
name = compat_tmp.name;
} else
#endif
{
num_counters = tmp.num_counters;
name = tmp.name;
}
if (len != size + num_counters * sizeof(struct xt_counters))
return -EINVAL;
paddc = vmalloc(len - size);
if (!paddc)
return -ENOMEM;
if (copy_from_user(paddc, user + size, len - size) != 0) {
ret = -EFAULT;
goto free;
}
t = xt_find_table_lock(net, AF_INET, name);
if (IS_ERR_OR_NULL(t)) {
ret = t ? PTR_ERR(t) : -ENOENT;
goto free;
}
local_bh_disable();
private = t->private;
if (private->number != num_counters) {
ret = -EINVAL;
goto unlock_up_free;
}
i = 0;
addend = xt_write_recseq_begin();
xt_entry_foreach(iter, private->entries, private->size) {
struct xt_counters *tmp;
tmp = xt_get_this_cpu_counter(&iter->counters);
ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
++i;
}
xt_write_recseq_end(addend);
unlock_up_free:
local_bh_enable();
xt_table_unlock(t);
module_put(t->me);
free:
vfree(paddc);
return ret;
}
#ifdef CONFIG_COMPAT
struct compat_ipt_replace {
char name[XT_TABLE_MAXNAMELEN];
u32 valid_hooks;
u32 num_entries;
u32 size;
u32 hook_entry[NF_INET_NUMHOOKS];
u32 underflow[NF_INET_NUMHOOKS];
u32 num_counters;
compat_uptr_t counters; /* struct xt_counters * */
struct compat_ipt_entry entries[0];
};
static int
compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr,
unsigned int *size, struct xt_counters *counters,
unsigned int i)
{
struct xt_entry_target *t;
struct compat_ipt_entry __user *ce;
u_int16_t target_offset, next_offset;
compat_uint_t origsize;
const struct xt_entry_match *ematch;
int ret = 0;
origsize = *size;
ce = (struct compat_ipt_entry __user *)*dstptr;
if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 ||
copy_to_user(&ce->counters, &counters[i],
sizeof(counters[i])) != 0)
return -EFAULT;
*dstptr += sizeof(struct compat_ipt_entry);
*size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
xt_ematch_foreach(ematch, e) {
ret = xt_compat_match_to_user(ematch, dstptr, size);
if (ret != 0)
return ret;
}
target_offset = e->target_offset - (origsize - *size);
t = ipt_get_target(e);
ret = xt_compat_target_to_user(t, dstptr, size);
if (ret)
return ret;
next_offset = e->next_offset - (origsize - *size);
if (put_user(target_offset, &ce->target_offset) != 0 ||
put_user(next_offset, &ce->next_offset) != 0)
return -EFAULT;
return 0;
}
static int
compat_find_calc_match(struct xt_entry_match *m,
const char *name,
const struct ipt_ip *ip,
int *size)
{
struct xt_match *match;
match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
m->u.user.revision);
if (IS_ERR(match)) {
duprintf("compat_check_calc_match: `%s' not found\n",
m->u.user.name);
return PTR_ERR(match);
}
m->u.kernel.match = match;
*size += xt_compat_match_offset(match);
return 0;
}
static void compat_release_entry(struct compat_ipt_entry *e)
{
struct xt_entry_target *t;
struct xt_entry_match *ematch;
/* Cleanup all matches */
xt_ematch_foreach(ematch, e)
module_put(ematch->u.kernel.match->me);
t = compat_ipt_get_target(e);
module_put(t->u.kernel.target->me);
}
static int
check_compat_entry_size_and_hooks(struct compat_ipt_entry *e,
struct xt_table_info *newinfo,
unsigned int *size,
const unsigned char *base,
const unsigned char *limit,
const unsigned int *hook_entries,
const unsigned int *underflows,
const char *name)
{
struct xt_entry_match *ematch;
struct xt_entry_target *t;
struct xt_target *target;
unsigned int entry_offset;
unsigned int j;
int ret, off, h;
duprintf("check_compat_entry_size_and_hooks %p\n", e);
if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 ||
(unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit) {
duprintf("Bad offset %p, limit = %p\n", e, limit);
return -EINVAL;
}
if (e->next_offset < sizeof(struct compat_ipt_entry) +
sizeof(struct compat_xt_entry_target)) {
duprintf("checking: element %p size %u\n",
e, e->next_offset);
return -EINVAL;
}
/* For purposes of check_entry casting the compat entry is fine */
ret = check_entry((struct ipt_entry *)e, name);
if (ret)
return ret;
off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
entry_offset = (void *)e - (void *)base;
j = 0;
xt_ematch_foreach(ematch, e) {
ret = compat_find_calc_match(ematch, name, &e->ip, &off);
if (ret != 0)
goto release_matches;
++j;
}
t = compat_ipt_get_target(e);
target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
t->u.user.revision);
if (IS_ERR(target)) {
duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
t->u.user.name);
ret = PTR_ERR(target);
goto release_matches;
}
t->u.kernel.target = target;
off += xt_compat_target_offset(target);
*size += off;
ret = xt_compat_add_offset(AF_INET, entry_offset, off);
if (ret)
goto out;
/* Check hooks & underflows */
for (h = 0; h < NF_INET_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];
}
/* Clear counters and comefrom */
memset(&e->counters, 0, sizeof(e->counters));
e->comefrom = 0;
return 0;
out:
module_put(t->u.kernel.target->me);
release_matches:
xt_ematch_foreach(ematch, e) {
if (j-- == 0)
break;
module_put(ematch->u.kernel.match->me);
}
return ret;
}
static int
compat_copy_entry_from_user(struct compat_ipt_entry *e, void **dstptr,
unsigned int *size, const char *name,
struct xt_table_info *newinfo, unsigned char *base)
{
struct xt_entry_target *t;
struct xt_target *target;
struct ipt_entry *de;
unsigned int origsize;
int ret, h;
struct xt_entry_match *ematch;
ret = 0;
origsize = *size;
de = (struct ipt_entry *)*dstptr;
memcpy(de, e, sizeof(struct ipt_entry));
memcpy(&de->counters, &e->counters, sizeof(e->counters));
*dstptr += sizeof(struct ipt_entry);
*size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
xt_ematch_foreach(ematch, e) {
ret = xt_compat_match_from_user(ematch, dstptr, size);
if (ret != 0)
return ret;
}
de->target_offset = e->target_offset - (origsize - *size);
t = compat_ipt_get_target(e);
target = t->u.kernel.target;
xt_compat_target_from_user(t, dstptr, size);
de->next_offset = e->next_offset - (origsize - *size);
for (h = 0; h < NF_INET_NUMHOOKS; h++) {
if ((unsigned char *)de - base < newinfo->hook_entry[h])
newinfo->hook_entry[h] -= origsize - *size;
if ((unsigned char *)de - base < newinfo->underflow[h])
newinfo->underflow[h] -= origsize - *size;
}
return ret;
}
static int
compat_check_entry(struct ipt_entry *e, struct net *net, const char *name)
{
struct xt_entry_match *ematch;
struct xt_mtchk_param mtpar;
unsigned int j;
int ret = 0;
e->counters.pcnt = xt_percpu_counter_alloc();
if (IS_ERR_VALUE(e->counters.pcnt))
return -ENOMEM;
j = 0;
mtpar.net = net;
mtpar.table = name;
mtpar.entryinfo = &e->ip;
mtpar.hook_mask = e->comefrom;
mtpar.family = NFPROTO_IPV4;
xt_ematch_foreach(ematch, e) {
ret = check_match(ematch, &mtpar);
if (ret != 0)
goto cleanup_matches;
++j;
}
ret = check_target(e, net, name);
if (ret)
goto cleanup_matches;
return 0;
cleanup_matches:
xt_ematch_foreach(ematch, e) {
if (j-- == 0)
break;
cleanup_match(ematch, net);
}
xt_percpu_counter_free(e->counters.pcnt);
return ret;
}
static int
translate_compat_table(struct net *net,
const char *name,
unsigned int valid_hooks,
struct xt_table_info **pinfo,
void **pentry0,
unsigned int total_size,
unsigned int number,
unsigned int *hook_entries,
unsigned int *underflows)
{
unsigned int i, j;
struct xt_table_info *newinfo, *info;
void *pos, *entry0, *entry1;
struct compat_ipt_entry *iter0;
struct ipt_entry *iter1;
unsigned int size;
int ret;
info = *pinfo;
entry0 = *pentry0;
size = total_size;
info->number = number;
/* Init all hooks to impossible value. */
for (i = 0; i < NF_INET_NUMHOOKS; i++) {
info->hook_entry[i] = 0xFFFFFFFF;
info->underflow[i] = 0xFFFFFFFF;
}
duprintf("translate_compat_table: size %u\n", info->size);
j = 0;
xt_compat_lock(AF_INET);
xt_compat_init_offsets(AF_INET, number);
/* Walk through entries, checking offsets. */
xt_entry_foreach(iter0, entry0, total_size) {
ret = check_compat_entry_size_and_hooks(iter0, info, &size,
entry0,
entry0 + total_size,
hook_entries,
underflows,
name);
if (ret != 0)
goto out_unlock;
++j;
}
ret = -EINVAL;
if (j != number) {
duprintf("translate_compat_table: %u not %u entries\n",
j, number);
goto out_unlock;
}
/* Check hooks all assigned */
for (i = 0; i < NF_INET_NUMHOOKS; i++) {
/* Only hooks which are valid */
if (!(valid_hooks & (1 << i)))
continue;
if (info->hook_entry[i] == 0xFFFFFFFF) {
duprintf("Invalid hook entry %u %u\n",
i, hook_entries[i]);
goto out_unlock;
}
if (info->underflow[i] == 0xFFFFFFFF) {
duprintf("Invalid underflow %u %u\n",
i, underflows[i]);
goto out_unlock;
}
}
ret = -ENOMEM;
newinfo = xt_alloc_table_info(size);
if (!newinfo)
goto out_unlock;
newinfo->number = number;
for (i = 0; i < NF_INET_NUMHOOKS; i++) {
newinfo->hook_entry[i] = info->hook_entry[i];
newinfo->underflow[i] = info->underflow[i];
}
entry1 = newinfo->entries;
pos = entry1;
size = total_size;
xt_entry_foreach(iter0, entry0, total_size) {
ret = compat_copy_entry_from_user(iter0, &pos, &size,
name, newinfo, entry1);
if (ret != 0)
break;
}
xt_compat_flush_offsets(AF_INET);
xt_compat_unlock(AF_INET);
if (ret)
goto free_newinfo;
ret = -ELOOP;
if (!mark_source_chains(newinfo, valid_hooks, entry1))
goto free_newinfo;
i = 0;
xt_entry_foreach(iter1, entry1, newinfo->size) {
ret = compat_check_entry(iter1, net, name);
if (ret != 0)
break;
++i;
if (strcmp(ipt_get_target(iter1)->u.user.name,
XT_ERROR_TARGET) == 0)
++newinfo->stacksize;
}
if (ret) {
/*
* The first i matches need cleanup_entry (calls ->destroy)
* because they had called ->check already. The other j-i
* entries need only release.
*/
int skip = i;
j -= i;
xt_entry_foreach(iter0, entry0, newinfo->size) {
if (skip-- > 0)
continue;
if (j-- == 0)
break;
compat_release_entry(iter0);
}
xt_entry_foreach(iter1, entry1, newinfo->size) {
if (i-- == 0)
break;
cleanup_entry(iter1, net);
}
xt_free_table_info(newinfo);
return ret;
}
*pinfo = newinfo;
*pentry0 = entry1;
xt_free_table_info(info);
return 0;
free_newinfo:
xt_free_table_info(newinfo);
out:
xt_entry_foreach(iter0, entry0, total_size) {
if (j-- == 0)
break;
compat_release_entry(iter0);
}
return ret;
out_unlock:
xt_compat_flush_offsets(AF_INET);
xt_compat_unlock(AF_INET);
goto out;
}
static int
compat_do_replace(struct net *net, void __user *user, unsigned int len)
{
int ret;
struct compat_ipt_replace tmp;
struct xt_table_info *newinfo;
void *loc_cpu_entry;
struct ipt_entry *iter;
if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
return -EFAULT;
/* overflow check */
if (tmp.size >= INT_MAX / num_possible_cpus())
return -ENOMEM;
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
if (tmp.num_counters == 0)
return -EINVAL;
tmp.name[sizeof(tmp.name)-1] = 0;
newinfo = xt_alloc_table_info(tmp.size);
if (!newinfo)
return -ENOMEM;
loc_cpu_entry = newinfo->entries;
if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
ret = translate_compat_table(net, 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;
duprintf("compat_do_replace: Translated table\n");
ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
tmp.num_counters, compat_ptr(tmp.counters));
if (ret)
goto free_newinfo_untrans;
return 0;
free_newinfo_untrans:
xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
cleanup_entry(iter, net);
free_newinfo:
xt_free_table_info(newinfo);
return ret;
}
static int
compat_do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user,
unsigned int len)
{
int ret;
if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
return -EPERM;
switch (cmd) {
case IPT_SO_SET_REPLACE:
ret = compat_do_replace(sock_net(sk), user, len);
break;
case IPT_SO_SET_ADD_COUNTERS:
ret = do_add_counters(sock_net(sk), user, len, 1);
break;
default:
duprintf("do_ipt_set_ctl: unknown request %i\n", cmd);
ret = -EINVAL;
}
return ret;
}
struct compat_ipt_get_entries {
char name[XT_TABLE_MAXNAMELEN];
compat_uint_t size;
struct compat_ipt_entry entrytable[0];
};
static int
compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table,
void __user *userptr)
{
struct xt_counters *counters;
const struct xt_table_info *private = table->private;
void __user *pos;
unsigned int size;
int ret = 0;
unsigned int i = 0;
struct ipt_entry *iter;
counters = alloc_counters(table);
if (IS_ERR(counters))
return PTR_ERR(counters);
pos = userptr;
size = total_size;
xt_entry_foreach(iter, private->entries, total_size) {
ret = compat_copy_entry_to_user(iter, &pos,
&size, counters, i++);
if (ret != 0)
break;
}
vfree(counters);
return ret;
}
static int
compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr,
int *len)
{
int ret;
struct compat_ipt_get_entries get;
struct xt_table *t;
if (*len < sizeof(get)) {
duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
return -EINVAL;
}
if (copy_from_user(&get, uptr, sizeof(get)) != 0)
return -EFAULT;
if (*len != sizeof(struct compat_ipt_get_entries) + get.size) {
duprintf("compat_get_entries: %u != %zu\n",
*len, sizeof(get) + get.size);
return -EINVAL;
}
xt_compat_lock(AF_INET);
t = xt_find_table_lock(net, AF_INET, get.name);
if (!IS_ERR_OR_NULL(t)) {
const struct xt_table_info *private = t->private;
struct xt_table_info info;
duprintf("t->private->number = %u\n", private->number);
ret = compat_table_info(private, &info);
if (!ret && get.size == info.size) {
ret = compat_copy_entries_to_user(private->size,
t, uptr->entrytable);
} else if (!ret) {
duprintf("compat_get_entries: I've got %u not %u!\n",
private->size, get.size);
ret = -EAGAIN;
}
xt_compat_flush_offsets(AF_INET);
module_put(t->me);
xt_table_unlock(t);
} else
ret = t ? PTR_ERR(t) : -ENOENT;
xt_compat_unlock(AF_INET);
return ret;
}
static int do_ipt_get_ctl(struct sock *, int, void __user *, int *);
static int
compat_do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
{
int ret;
if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
return -EPERM;
switch (cmd) {
case IPT_SO_GET_INFO:
ret = get_info(sock_net(sk), user, len, 1);
break;
case IPT_SO_GET_ENTRIES:
ret = compat_get_entries(sock_net(sk), user, len);
break;
default:
ret = do_ipt_get_ctl(sk, cmd, user, len);
}
return ret;
}
#endif
static int
do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
{
int ret;
if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
return -EPERM;
switch (cmd) {
case IPT_SO_SET_REPLACE:
ret = do_replace(sock_net(sk), user, len);
break;
case IPT_SO_SET_ADD_COUNTERS:
ret = do_add_counters(sock_net(sk), user, len, 0);
break;
default:
duprintf("do_ipt_set_ctl: unknown request %i\n", cmd);
ret = -EINVAL;
}
return ret;
}
static int
do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
{
int ret;
if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
return -EPERM;
switch (cmd) {
case IPT_SO_GET_INFO:
ret = get_info(sock_net(sk), user, len, 0);
break;
case IPT_SO_GET_ENTRIES:
ret = get_entries(sock_net(sk), user, len);
break;
case IPT_SO_GET_REVISION_MATCH:
case IPT_SO_GET_REVISION_TARGET: {
struct xt_get_revision rev;
int target;
if (*len != sizeof(rev)) {
ret = -EINVAL;
break;
}
if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
ret = -EFAULT;
break;
}
rev.name[sizeof(rev.name)-1] = 0;
if (cmd == IPT_SO_GET_REVISION_TARGET)
target = 1;
else
target = 0;
try_then_request_module(xt_find_revision(AF_INET, rev.name,
rev.revision,
target, &ret),
"ipt_%s", rev.name);
break;
}
default:
duprintf("do_ipt_get_ctl: unknown request %i\n", cmd);
ret = -EINVAL;
}
return ret;
}
struct xt_table *ipt_register_table(struct net *net,
const struct xt_table *table,
const struct ipt_replace *repl)
{
int ret;
struct xt_table_info *newinfo;
struct xt_table_info bootstrap = {0};
void *loc_cpu_entry;
struct xt_table *new_table;
newinfo = xt_alloc_table_info(repl->size);
if (!newinfo) {
ret = -ENOMEM;
goto out;
}
loc_cpu_entry = newinfo->entries;
memcpy(loc_cpu_entry, repl->entries, repl->size);
ret = translate_table(net, newinfo, loc_cpu_entry, repl);
if (ret != 0)
goto out_free;
new_table = xt_register_table(net, table, &bootstrap, newinfo);
if (IS_ERR(new_table)) {
ret = PTR_ERR(new_table);
goto out_free;
}
return new_table;
out_free:
xt_free_table_info(newinfo);
out:
return ERR_PTR(ret);
}
void ipt_unregister_table(struct net *net, struct xt_table *table)
{
struct xt_table_info *private;
void *loc_cpu_entry;
struct module *table_owner = table->me;
struct ipt_entry *iter;
private = xt_unregister_table(table);
/* Decrease module usage counts and free resources */
loc_cpu_entry = private->entries;
xt_entry_foreach(iter, loc_cpu_entry, private->size)
cleanup_entry(iter, net);
if (private->number > private->initial_entries)
module_put(table_owner);
xt_free_table_info(private);
}
/* Returns 1 if the type and code is matched by the range, 0 otherwise */
static inline bool
icmp_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,
bool invert)
{
return ((test_type == 0xFF) ||
(type == test_type && code >= min_code && code <= max_code))
^ invert;
}
static bool
icmp_match(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct icmphdr *ic;
struct icmphdr _icmph;
const struct ipt_icmp *icmpinfo = par->matchinfo;
/* Must not be a fragment. */
if (par->fragoff != 0)
return false;
ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
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");
par->hotdrop = true;
return false;
}
return icmp_type_code_match(icmpinfo->type,
icmpinfo->code[0],
icmpinfo->code[1],
ic->type, ic->code,
!!(icmpinfo->invflags&IPT_ICMP_INV));
}
static int icmp_checkentry(const struct xt_mtchk_param *par)
{
const struct ipt_icmp *icmpinfo = par->matchinfo;
/* Must specify no unknown invflags */
return (icmpinfo->invflags & ~IPT_ICMP_INV) ? -EINVAL : 0;
}
static struct xt_target ipt_builtin_tg[] __read_mostly = {
{
.name = XT_STANDARD_TARGET,
.targetsize = sizeof(int),
.family = NFPROTO_IPV4,
#ifdef CONFIG_COMPAT
.compatsize = sizeof(compat_int_t),
.compat_from_user = compat_standard_from_user,
.compat_to_user = compat_standard_to_user,
#endif
},
{
.name = XT_ERROR_TARGET,
.target = ipt_error,
.targetsize = XT_FUNCTION_MAXNAMELEN,
.family = NFPROTO_IPV4,
},
};
static struct nf_sockopt_ops ipt_sockopts = {
.pf = PF_INET,
.set_optmin = IPT_BASE_CTL,
.set_optmax = IPT_SO_SET_MAX+1,
.set = do_ipt_set_ctl,
#ifdef CONFIG_COMPAT
.compat_set = compat_do_ipt_set_ctl,
#endif
.get_optmin = IPT_BASE_CTL,
.get_optmax = IPT_SO_GET_MAX+1,
.get = do_ipt_get_ctl,
#ifdef CONFIG_COMPAT
.compat_get = compat_do_ipt_get_ctl,
#endif
.owner = THIS_MODULE,
};
static struct xt_match ipt_builtin_mt[] __read_mostly = {
{
.name = "icmp",
.match = icmp_match,
.matchsize = sizeof(struct ipt_icmp),
.checkentry = icmp_checkentry,
.proto = IPPROTO_ICMP,
.family = NFPROTO_IPV4,
},
};
static int __net_init ip_tables_net_init(struct net *net)
{
return xt_proto_init(net, NFPROTO_IPV4);
}
static void __net_exit ip_tables_net_exit(struct net *net)
{
xt_proto_fini(net, NFPROTO_IPV4);
}
static struct pernet_operations ip_tables_net_ops = {
.init = ip_tables_net_init,
.exit = ip_tables_net_exit,
};
static int __init ip_tables_init(void)
{
int ret;
ret = register_pernet_subsys(&ip_tables_net_ops);
if (ret < 0)
goto err1;
/* No one else will be downing sem now, so we won't sleep */
ret = xt_register_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
if (ret < 0)
goto err2;
ret = xt_register_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
if (ret < 0)
goto err4;
/* Register setsockopt */
ret = nf_register_sockopt(&ipt_sockopts);
if (ret < 0)
goto err5;
pr_info("(C) 2000-2006 Netfilter Core Team\n");
return 0;
err5:
xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
err4:
xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
err2:
unregister_pernet_subsys(&ip_tables_net_ops);
err1:
return ret;
}
static void __exit ip_tables_fini(void)
{
nf_unregister_sockopt(&ipt_sockopts);
xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
unregister_pernet_subsys(&ip_tables_net_ops);
}
EXPORT_SYMBOL(ipt_register_table);
EXPORT_SYMBOL(ipt_unregister_table);
EXPORT_SYMBOL(ipt_do_table);
module_init(ip_tables_init);
module_exit(ip_tables_fini);