blob: bb25d4c794c78a63fb899df6257b919261184804 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/seq_file.h>
#include <net/protocol.h>
#include <net/netfilter/nf_log.h>
#include "nf_internals.h"
/* Internal logging interface, which relies on the real
LOG target modules */
#define NFLOGGER_NAME_LEN 64
int sysctl_nf_log_all_netns __read_mostly;
EXPORT_SYMBOL(sysctl_nf_log_all_netns);
static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
static DEFINE_MUTEX(nf_log_mutex);
#define nft_log_dereference(logger) \
rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))
static struct nf_logger *__find_logger(int pf, const char *str_logger)
{
struct nf_logger *log;
int i;
for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
if (loggers[pf][i] == NULL)
continue;
log = nft_log_dereference(loggers[pf][i]);
if (!strncasecmp(str_logger, log->name, strlen(log->name)))
return log;
}
return NULL;
}
int nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
{
const struct nf_logger *log;
if (pf == NFPROTO_UNSPEC || pf >= ARRAY_SIZE(net->nf.nf_loggers))
return -EOPNOTSUPP;
mutex_lock(&nf_log_mutex);
log = nft_log_dereference(net->nf.nf_loggers[pf]);
if (log == NULL)
rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
mutex_unlock(&nf_log_mutex);
return 0;
}
EXPORT_SYMBOL(nf_log_set);
void nf_log_unset(struct net *net, const struct nf_logger *logger)
{
int i;
const struct nf_logger *log;
mutex_lock(&nf_log_mutex);
for (i = 0; i < NFPROTO_NUMPROTO; i++) {
log = nft_log_dereference(net->nf.nf_loggers[i]);
if (log == logger)
RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
}
mutex_unlock(&nf_log_mutex);
}
EXPORT_SYMBOL(nf_log_unset);
/* return EEXIST if the same logger is registered, 0 on success. */
int nf_log_register(u_int8_t pf, struct nf_logger *logger)
{
int i;
int ret = 0;
if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
return -EINVAL;
mutex_lock(&nf_log_mutex);
if (pf == NFPROTO_UNSPEC) {
for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
if (rcu_access_pointer(loggers[i][logger->type])) {
ret = -EEXIST;
goto unlock;
}
}
for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
rcu_assign_pointer(loggers[i][logger->type], logger);
} else {
if (rcu_access_pointer(loggers[pf][logger->type])) {
ret = -EEXIST;
goto unlock;
}
rcu_assign_pointer(loggers[pf][logger->type], logger);
}
unlock:
mutex_unlock(&nf_log_mutex);
return ret;
}
EXPORT_SYMBOL(nf_log_register);
void nf_log_unregister(struct nf_logger *logger)
{
const struct nf_logger *log;
int i;
mutex_lock(&nf_log_mutex);
for (i = 0; i < NFPROTO_NUMPROTO; i++) {
log = nft_log_dereference(loggers[i][logger->type]);
if (log == logger)
RCU_INIT_POINTER(loggers[i][logger->type], NULL);
}
mutex_unlock(&nf_log_mutex);
synchronize_rcu();
}
EXPORT_SYMBOL(nf_log_unregister);
int nf_log_bind_pf(struct net *net, u_int8_t pf,
const struct nf_logger *logger)
{
if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
return -EINVAL;
mutex_lock(&nf_log_mutex);
if (__find_logger(pf, logger->name) == NULL) {
mutex_unlock(&nf_log_mutex);
return -ENOENT;
}
rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
mutex_unlock(&nf_log_mutex);
return 0;
}
EXPORT_SYMBOL(nf_log_bind_pf);
void nf_log_unbind_pf(struct net *net, u_int8_t pf)
{
if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
return;
mutex_lock(&nf_log_mutex);
RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
mutex_unlock(&nf_log_mutex);
}
EXPORT_SYMBOL(nf_log_unbind_pf);
void nf_logger_request_module(int pf, enum nf_log_type type)
{
if (loggers[pf][type] == NULL)
request_module("nf-logger-%u-%u", pf, type);
}
EXPORT_SYMBOL_GPL(nf_logger_request_module);
int nf_logger_find_get(int pf, enum nf_log_type type)
{
struct nf_logger *logger;
int ret = -ENOENT;
if (pf == NFPROTO_INET) {
ret = nf_logger_find_get(NFPROTO_IPV4, type);
if (ret < 0)
return ret;
ret = nf_logger_find_get(NFPROTO_IPV6, type);
if (ret < 0) {
nf_logger_put(NFPROTO_IPV4, type);
return ret;
}
return 0;
}
if (rcu_access_pointer(loggers[pf][type]) == NULL)
request_module("nf-logger-%u-%u", pf, type);
rcu_read_lock();
logger = rcu_dereference(loggers[pf][type]);
if (logger == NULL)
goto out;
if (try_module_get(logger->me))
ret = 0;
out:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(nf_logger_find_get);
void nf_logger_put(int pf, enum nf_log_type type)
{
struct nf_logger *logger;
if (pf == NFPROTO_INET) {
nf_logger_put(NFPROTO_IPV4, type);
nf_logger_put(NFPROTO_IPV6, type);
return;
}
BUG_ON(loggers[pf][type] == NULL);
rcu_read_lock();
logger = rcu_dereference(loggers[pf][type]);
module_put(logger->me);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(nf_logger_put);
void nf_log_packet(struct net *net,
u_int8_t pf,
unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct nf_loginfo *loginfo,
const char *fmt, ...)
{
va_list args;
char prefix[NF_LOG_PREFIXLEN];
const struct nf_logger *logger;
rcu_read_lock();
if (loginfo != NULL)
logger = rcu_dereference(loggers[pf][loginfo->type]);
else
logger = rcu_dereference(net->nf.nf_loggers[pf]);
if (logger) {
va_start(args, fmt);
vsnprintf(prefix, sizeof(prefix), fmt, args);
va_end(args);
logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
}
rcu_read_unlock();
}
EXPORT_SYMBOL(nf_log_packet);
void nf_log_trace(struct net *net,
u_int8_t pf,
unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct nf_loginfo *loginfo, const char *fmt, ...)
{
va_list args;
char prefix[NF_LOG_PREFIXLEN];
const struct nf_logger *logger;
rcu_read_lock();
logger = rcu_dereference(net->nf.nf_loggers[pf]);
if (logger) {
va_start(args, fmt);
vsnprintf(prefix, sizeof(prefix), fmt, args);
va_end(args);
logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
}
rcu_read_unlock();
}
EXPORT_SYMBOL(nf_log_trace);
#define S_SIZE (1024 - (sizeof(unsigned int) + 1))
struct nf_log_buf {
unsigned int count;
char buf[S_SIZE + 1];
};
static struct nf_log_buf emergency, *emergency_ptr = &emergency;
__printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
{
va_list args;
int len;
if (likely(m->count < S_SIZE)) {
va_start(args, f);
len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
va_end(args);
if (likely(m->count + len < S_SIZE)) {
m->count += len;
return 0;
}
}
m->count = S_SIZE;
printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
return -1;
}
EXPORT_SYMBOL_GPL(nf_log_buf_add);
struct nf_log_buf *nf_log_buf_open(void)
{
struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);
if (unlikely(!m)) {
local_bh_disable();
do {
m = xchg(&emergency_ptr, NULL);
} while (!m);
}
m->count = 0;
return m;
}
EXPORT_SYMBOL_GPL(nf_log_buf_open);
void nf_log_buf_close(struct nf_log_buf *m)
{
m->buf[m->count] = 0;
printk("%s\n", m->buf);
if (likely(m != &emergency))
kfree(m);
else {
emergency_ptr = m;
local_bh_enable();
}
}
EXPORT_SYMBOL_GPL(nf_log_buf_close);
#ifdef CONFIG_PROC_FS
static void *seq_start(struct seq_file *seq, loff_t *pos)
{
struct net *net = seq_file_net(seq);
mutex_lock(&nf_log_mutex);
if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
return NULL;
return pos;
}
static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct net *net = seq_file_net(s);
(*pos)++;
if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
return NULL;
return pos;
}
static void seq_stop(struct seq_file *s, void *v)
{
mutex_unlock(&nf_log_mutex);
}
static int seq_show(struct seq_file *s, void *v)
{
loff_t *pos = v;
const struct nf_logger *logger;
int i;
struct net *net = seq_file_net(s);
logger = nft_log_dereference(net->nf.nf_loggers[*pos]);
if (!logger)
seq_printf(s, "%2lld NONE (", *pos);
else
seq_printf(s, "%2lld %s (", *pos, logger->name);
if (seq_has_overflowed(s))
return -ENOSPC;
for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
if (loggers[*pos][i] == NULL)
continue;
logger = nft_log_dereference(loggers[*pos][i]);
seq_puts(s, logger->name);
if (i == 0 && loggers[*pos][i + 1] != NULL)
seq_puts(s, ",");
if (seq_has_overflowed(s))
return -ENOSPC;
}
seq_puts(s, ")\n");
if (seq_has_overflowed(s))
return -ENOSPC;
return 0;
}
static const struct seq_operations nflog_seq_ops = {
.start = seq_start,
.next = seq_next,
.stop = seq_stop,
.show = seq_show,
};
#endif /* PROC_FS */
#ifdef CONFIG_SYSCTL
static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
static struct ctl_table_header *nf_log_sysctl_fhdr;
static struct ctl_table nf_log_sysctl_ftable[] = {
{
.procname = "nf_log_all_netns",
.data = &sysctl_nf_log_all_netns,
.maxlen = sizeof(sysctl_nf_log_all_netns),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static int nf_log_proc_dostring(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
const struct nf_logger *logger;
char buf[NFLOGGER_NAME_LEN];
int r = 0;
int tindex = (unsigned long)table->extra1;
struct net *net = table->extra2;
if (write) {
struct ctl_table tmp = *table;
/* proc_dostring() can append to existing strings, so we need to
* initialize it as an empty string.
*/
buf[0] = '\0';
tmp.data = buf;
r = proc_dostring(&tmp, write, buffer, lenp, ppos);
if (r)
return r;
if (!strcmp(buf, "NONE")) {
nf_log_unbind_pf(net, tindex);
return 0;
}
mutex_lock(&nf_log_mutex);
logger = __find_logger(tindex, buf);
if (logger == NULL) {
mutex_unlock(&nf_log_mutex);
return -ENOENT;
}
rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
mutex_unlock(&nf_log_mutex);
} else {
struct ctl_table tmp = *table;
tmp.data = buf;
mutex_lock(&nf_log_mutex);
logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
if (!logger)
strlcpy(buf, "NONE", sizeof(buf));
else
strlcpy(buf, logger->name, sizeof(buf));
mutex_unlock(&nf_log_mutex);
r = proc_dostring(&tmp, write, buffer, lenp, ppos);
}
return r;
}
static int netfilter_log_sysctl_init(struct net *net)
{
int i;
struct ctl_table *table;
table = nf_log_sysctl_table;
if (!net_eq(net, &init_net)) {
table = kmemdup(nf_log_sysctl_table,
sizeof(nf_log_sysctl_table),
GFP_KERNEL);
if (!table)
goto err_alloc;
} else {
for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
snprintf(nf_log_sysctl_fnames[i],
3, "%d", i);
nf_log_sysctl_table[i].procname =
nf_log_sysctl_fnames[i];
nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN;
nf_log_sysctl_table[i].mode = 0644;
nf_log_sysctl_table[i].proc_handler =
nf_log_proc_dostring;
nf_log_sysctl_table[i].extra1 =
(void *)(unsigned long) i;
}
nf_log_sysctl_fhdr = register_net_sysctl(net, "net/netfilter",
nf_log_sysctl_ftable);
if (!nf_log_sysctl_fhdr)
goto err_freg;
}
for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
table[i].extra2 = net;
net->nf.nf_log_dir_header = register_net_sysctl(net,
"net/netfilter/nf_log",
table);
if (!net->nf.nf_log_dir_header)
goto err_reg;
return 0;
err_reg:
if (!net_eq(net, &init_net))
kfree(table);
else
unregister_net_sysctl_table(nf_log_sysctl_fhdr);
err_freg:
err_alloc:
return -ENOMEM;
}
static void netfilter_log_sysctl_exit(struct net *net)
{
struct ctl_table *table;
table = net->nf.nf_log_dir_header->ctl_table_arg;
unregister_net_sysctl_table(net->nf.nf_log_dir_header);
if (!net_eq(net, &init_net))
kfree(table);
else
unregister_net_sysctl_table(nf_log_sysctl_fhdr);
}
#else
static int netfilter_log_sysctl_init(struct net *net)
{
return 0;
}
static void netfilter_log_sysctl_exit(struct net *net)
{
}
#endif /* CONFIG_SYSCTL */
static int __net_init nf_log_net_init(struct net *net)
{
int ret = -ENOMEM;
#ifdef CONFIG_PROC_FS
if (!proc_create_net("nf_log", 0444, net->nf.proc_netfilter,
&nflog_seq_ops, sizeof(struct seq_net_private)))
return ret;
#endif
ret = netfilter_log_sysctl_init(net);
if (ret < 0)
goto out_sysctl;
return 0;
out_sysctl:
#ifdef CONFIG_PROC_FS
remove_proc_entry("nf_log", net->nf.proc_netfilter);
#endif
return ret;
}
static void __net_exit nf_log_net_exit(struct net *net)
{
netfilter_log_sysctl_exit(net);
#ifdef CONFIG_PROC_FS
remove_proc_entry("nf_log", net->nf.proc_netfilter);
#endif
}
static struct pernet_operations nf_log_net_ops = {
.init = nf_log_net_init,
.exit = nf_log_net_exit,
};
int __init netfilter_log_init(void)
{
return register_pernet_subsys(&nf_log_net_ops);
}