diff options
Diffstat (limited to 'net/netfilter/nf_log.c')
| -rw-r--r-- | net/netfilter/nf_log.c | 568 |
1 files changed, 568 insertions, 0 deletions
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c new file mode 100644 index 000000000..8a2929014 --- /dev/null +++ b/net/netfilter/nf_log.c @@ -0,0 +1,568 @@ +// 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); + +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; + } + + 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 *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) + strscpy(buf, "NONE", sizeof(buf)); + else + strscpy(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); +} |