From 08010a21602678932894c5e87014a282af0079cf Mon Sep 17 00:00:00 2001 From: Flavio Leitner Date: Wed, 17 Apr 2019 11:46:15 -0300 Subject: netfilter: add API to manage NAT helpers. The API allows a conntrack helper to indicate its corresponding NAT helper which then can be loaded and reference counted. Signed-off-by: Flavio Leitner Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_amanda.c | 8 +++- net/netfilter/nf_conntrack_ftp.c | 18 +++++--- net/netfilter/nf_conntrack_helper.c | 86 +++++++++++++++++++++++++++++++++++++ net/netfilter/nf_conntrack_irc.c | 6 ++- net/netfilter/nf_conntrack_sane.c | 12 +++--- net/netfilter/nf_conntrack_sip.c | 28 ++++++------ net/netfilter/nf_conntrack_tftp.c | 18 +++++--- 7 files changed, 140 insertions(+), 36 deletions(-) (limited to 'net/netfilter') diff --git a/net/netfilter/nf_conntrack_amanda.c b/net/netfilter/nf_conntrack_amanda.c index f2681ec5b5f6..dbec6fca0d9e 100644 --- a/net/netfilter/nf_conntrack_amanda.c +++ b/net/netfilter/nf_conntrack_amanda.c @@ -28,11 +28,13 @@ static unsigned int master_timeout __read_mostly = 300; static char *ts_algo = "kmp"; +#define HELPER_NAME "amanda" + MODULE_AUTHOR("Brian J. Murrell "); MODULE_DESCRIPTION("Amanda connection tracking module"); MODULE_LICENSE("GPL"); MODULE_ALIAS("ip_conntrack_amanda"); -MODULE_ALIAS_NFCT_HELPER("amanda"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); module_param(master_timeout, uint, 0600); MODULE_PARM_DESC(master_timeout, "timeout for the master connection"); @@ -179,13 +181,14 @@ static const struct nf_conntrack_expect_policy amanda_exp_policy = { static struct nf_conntrack_helper amanda_helper[2] __read_mostly = { { - .name = "amanda", + .name = HELPER_NAME, .me = THIS_MODULE, .help = amanda_help, .tuple.src.l3num = AF_INET, .tuple.src.u.udp.port = cpu_to_be16(10080), .tuple.dst.protonum = IPPROTO_UDP, .expect_policy = &amanda_exp_policy, + .nat_mod_name = NF_NAT_HELPER_NAME(HELPER_NAME), }, { .name = "amanda", @@ -195,6 +198,7 @@ static struct nf_conntrack_helper amanda_helper[2] __read_mostly = { .tuple.src.u.udp.port = cpu_to_be16(10080), .tuple.dst.protonum = IPPROTO_UDP, .expect_policy = &amanda_exp_policy, + .nat_mod_name = NF_NAT_HELPER_NAME(HELPER_NAME), }, }; diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c index a11c304fb771..32aeac1c4760 100644 --- a/net/netfilter/nf_conntrack_ftp.c +++ b/net/netfilter/nf_conntrack_ftp.c @@ -29,11 +29,13 @@ #include #include +#define HELPER_NAME "ftp" + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Rusty Russell "); MODULE_DESCRIPTION("ftp connection tracking helper"); MODULE_ALIAS("ip_conntrack_ftp"); -MODULE_ALIAS_NFCT_HELPER("ftp"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); /* This is slow, but it's simple. --RR */ static char *ftp_buffer; @@ -588,12 +590,14 @@ static int __init nf_conntrack_ftp_init(void) /* FIXME should be configurable whether IPv4 and IPv6 FTP connections are tracked or not - YK */ for (i = 0; i < ports_c; i++) { - nf_ct_helper_init(&ftp[2 * i], AF_INET, IPPROTO_TCP, "ftp", - FTP_PORT, ports[i], ports[i], &ftp_exp_policy, - 0, help, nf_ct_ftp_from_nlattr, THIS_MODULE); - nf_ct_helper_init(&ftp[2 * i + 1], AF_INET6, IPPROTO_TCP, "ftp", - FTP_PORT, ports[i], ports[i], &ftp_exp_policy, - 0, help, nf_ct_ftp_from_nlattr, THIS_MODULE); + nf_ct_helper_init(&ftp[2 * i], AF_INET, IPPROTO_TCP, + HELPER_NAME, FTP_PORT, ports[i], ports[i], + &ftp_exp_policy, 0, help, + nf_ct_ftp_from_nlattr, THIS_MODULE); + nf_ct_helper_init(&ftp[2 * i + 1], AF_INET6, IPPROTO_TCP, + HELPER_NAME, FTP_PORT, ports[i], ports[i], + &ftp_exp_policy, 0, help, + nf_ct_ftp_from_nlattr, THIS_MODULE); } ret = nf_conntrack_helpers_register(ftp, ports_c * 2); diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index 274baf1dab87..918df7f71c8f 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -42,6 +42,9 @@ module_param_named(nf_conntrack_helper, nf_ct_auto_assign_helper, bool, 0644); MODULE_PARM_DESC(nf_conntrack_helper, "Enable automatic conntrack helper assignment (default 0)"); +static DEFINE_MUTEX(nf_ct_nat_helpers_mutex); +static struct list_head nf_ct_nat_helpers __read_mostly; + /* Stupid hash, but collision free for the default registrations of the * helpers currently in the kernel. */ static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple) @@ -130,6 +133,70 @@ void nf_conntrack_helper_put(struct nf_conntrack_helper *helper) } EXPORT_SYMBOL_GPL(nf_conntrack_helper_put); +static struct nf_conntrack_nat_helper * +nf_conntrack_nat_helper_find(const char *mod_name) +{ + struct nf_conntrack_nat_helper *cur; + bool found = false; + + list_for_each_entry_rcu(cur, &nf_ct_nat_helpers, list) { + if (!strcmp(cur->mod_name, mod_name)) { + found = true; + break; + } + } + return found ? cur : NULL; +} + +int +nf_nat_helper_try_module_get(const char *name, u16 l3num, u8 protonum) +{ + struct nf_conntrack_helper *h; + struct nf_conntrack_nat_helper *nat; + char mod_name[NF_CT_HELPER_NAME_LEN]; + int ret = 0; + + rcu_read_lock(); + h = __nf_conntrack_helper_find(name, l3num, protonum); + if (!h) { + rcu_read_unlock(); + return -ENOENT; + } + + nat = nf_conntrack_nat_helper_find(h->nat_mod_name); + if (!nat) { + snprintf(mod_name, sizeof(mod_name), "%s", h->nat_mod_name); + rcu_read_unlock(); + request_module(mod_name); + + rcu_read_lock(); + nat = nf_conntrack_nat_helper_find(mod_name); + if (!nat) { + rcu_read_unlock(); + return -ENOENT; + } + } + + if (!try_module_get(nat->module)) + ret = -ENOENT; + + rcu_read_unlock(); + return ret; +} +EXPORT_SYMBOL_GPL(nf_nat_helper_try_module_get); + +void nf_nat_helper_put(struct nf_conntrack_helper *helper) +{ + struct nf_conntrack_nat_helper *nat; + + nat = nf_conntrack_nat_helper_find(helper->nat_mod_name); + if (WARN_ON_ONCE(!nat)) + return; + + module_put(nat->module); +} +EXPORT_SYMBOL_GPL(nf_nat_helper_put); + struct nf_conn_help * nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp) { @@ -430,6 +497,8 @@ void nf_ct_helper_init(struct nf_conntrack_helper *helper, helper->help = help; helper->from_nlattr = from_nlattr; helper->me = module; + snprintf(helper->nat_mod_name, sizeof(helper->nat_mod_name), + NF_NAT_HELPER_PREFIX "%s", name); if (spec_port == default_port) snprintf(helper->name, sizeof(helper->name), "%s", name); @@ -466,6 +535,22 @@ void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *helper, } EXPORT_SYMBOL_GPL(nf_conntrack_helpers_unregister); +void nf_nat_helper_register(struct nf_conntrack_nat_helper *nat) +{ + mutex_lock(&nf_ct_nat_helpers_mutex); + list_add_rcu(&nat->list, &nf_ct_nat_helpers); + mutex_unlock(&nf_ct_nat_helpers_mutex); +} +EXPORT_SYMBOL_GPL(nf_nat_helper_register); + +void nf_nat_helper_unregister(struct nf_conntrack_nat_helper *nat) +{ + mutex_lock(&nf_ct_nat_helpers_mutex); + list_del_rcu(&nat->list); + mutex_unlock(&nf_ct_nat_helpers_mutex); +} +EXPORT_SYMBOL_GPL(nf_nat_helper_unregister); + static const struct nf_ct_ext_type helper_extend = { .len = sizeof(struct nf_conn_help), .align = __alignof__(struct nf_conn_help), @@ -493,6 +578,7 @@ int nf_conntrack_helper_init(void) goto out_extend; } + INIT_LIST_HEAD(&nf_ct_nat_helpers); return 0; out_extend: kvfree(nf_ct_helper_hash); diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c index 4099f4d79bae..79e5014b3b0d 100644 --- a/net/netfilter/nf_conntrack_irc.c +++ b/net/netfilter/nf_conntrack_irc.c @@ -42,11 +42,13 @@ unsigned int (*nf_nat_irc_hook)(struct sk_buff *skb, struct nf_conntrack_expect *exp) __read_mostly; EXPORT_SYMBOL_GPL(nf_nat_irc_hook); +#define HELPER_NAME "irc" + MODULE_AUTHOR("Harald Welte "); MODULE_DESCRIPTION("IRC (DCC) connection tracking helper"); MODULE_LICENSE("GPL"); MODULE_ALIAS("ip_conntrack_irc"); -MODULE_ALIAS_NFCT_HELPER("irc"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); module_param_array(ports, ushort, &ports_c, 0400); MODULE_PARM_DESC(ports, "port numbers of IRC servers"); @@ -259,7 +261,7 @@ static int __init nf_conntrack_irc_init(void) ports[ports_c++] = IRC_PORT; for (i = 0; i < ports_c; i++) { - nf_ct_helper_init(&irc[i], AF_INET, IPPROTO_TCP, "irc", + nf_ct_helper_init(&irc[i], AF_INET, IPPROTO_TCP, HELPER_NAME, IRC_PORT, ports[i], i, &irc_exp_policy, 0, help, NULL, THIS_MODULE); } diff --git a/net/netfilter/nf_conntrack_sane.c b/net/netfilter/nf_conntrack_sane.c index 5072ff96ab33..83306648dd0f 100644 --- a/net/netfilter/nf_conntrack_sane.c +++ b/net/netfilter/nf_conntrack_sane.c @@ -30,10 +30,12 @@ #include #include +#define HELPER_NAME "sane" + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Michal Schmidt "); MODULE_DESCRIPTION("SANE connection tracking helper"); -MODULE_ALIAS_NFCT_HELPER("sane"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); static char *sane_buffer; @@ -195,12 +197,12 @@ static int __init nf_conntrack_sane_init(void) /* FIXME should be configurable whether IPv4 and IPv6 connections are tracked or not - YK */ for (i = 0; i < ports_c; i++) { - nf_ct_helper_init(&sane[2 * i], AF_INET, IPPROTO_TCP, "sane", - SANE_PORT, ports[i], ports[i], + nf_ct_helper_init(&sane[2 * i], AF_INET, IPPROTO_TCP, + HELPER_NAME, SANE_PORT, ports[i], ports[i], &sane_exp_policy, 0, help, NULL, THIS_MODULE); - nf_ct_helper_init(&sane[2 * i + 1], AF_INET6, IPPROTO_TCP, "sane", - SANE_PORT, ports[i], ports[i], + nf_ct_helper_init(&sane[2 * i + 1], AF_INET6, IPPROTO_TCP, + HELPER_NAME, SANE_PORT, ports[i], ports[i], &sane_exp_policy, 0, help, NULL, THIS_MODULE); } diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index d5454d1031a3..c30c883c370b 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -30,11 +30,13 @@ #include #include +#define HELPER_NAME "sip" + MODULE_LICENSE("GPL"); MODULE_AUTHOR("Christian Hentschel "); MODULE_DESCRIPTION("SIP connection tracking helper"); MODULE_ALIAS("ip_conntrack_sip"); -MODULE_ALIAS_NFCT_HELPER("sip"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); #define MAX_PORTS 8 static unsigned short ports[MAX_PORTS]; @@ -1669,21 +1671,21 @@ static int __init nf_conntrack_sip_init(void) ports[ports_c++] = SIP_PORT; for (i = 0; i < ports_c; i++) { - nf_ct_helper_init(&sip[4 * i], AF_INET, IPPROTO_UDP, "sip", - SIP_PORT, ports[i], i, sip_exp_policy, - SIP_EXPECT_MAX, sip_help_udp, + nf_ct_helper_init(&sip[4 * i], AF_INET, IPPROTO_UDP, + HELPER_NAME, SIP_PORT, ports[i], i, + sip_exp_policy, SIP_EXPECT_MAX, sip_help_udp, NULL, THIS_MODULE); - nf_ct_helper_init(&sip[4 * i + 1], AF_INET, IPPROTO_TCP, "sip", - SIP_PORT, ports[i], i, sip_exp_policy, - SIP_EXPECT_MAX, sip_help_tcp, + nf_ct_helper_init(&sip[4 * i + 1], AF_INET, IPPROTO_TCP, + HELPER_NAME, SIP_PORT, ports[i], i, + sip_exp_policy, SIP_EXPECT_MAX, sip_help_tcp, NULL, THIS_MODULE); - nf_ct_helper_init(&sip[4 * i + 2], AF_INET6, IPPROTO_UDP, "sip", - SIP_PORT, ports[i], i, sip_exp_policy, - SIP_EXPECT_MAX, sip_help_udp, + nf_ct_helper_init(&sip[4 * i + 2], AF_INET6, IPPROTO_UDP, + HELPER_NAME, SIP_PORT, ports[i], i, + sip_exp_policy, SIP_EXPECT_MAX, sip_help_udp, NULL, THIS_MODULE); - nf_ct_helper_init(&sip[4 * i + 3], AF_INET6, IPPROTO_TCP, "sip", - SIP_PORT, ports[i], i, sip_exp_policy, - SIP_EXPECT_MAX, sip_help_tcp, + nf_ct_helper_init(&sip[4 * i + 3], AF_INET6, IPPROTO_TCP, + HELPER_NAME, SIP_PORT, ports[i], i, + sip_exp_policy, SIP_EXPECT_MAX, sip_help_tcp, NULL, THIS_MODULE); } diff --git a/net/netfilter/nf_conntrack_tftp.c b/net/netfilter/nf_conntrack_tftp.c index 548b673b3625..6977cb91ae9a 100644 --- a/net/netfilter/nf_conntrack_tftp.c +++ b/net/netfilter/nf_conntrack_tftp.c @@ -20,11 +20,13 @@ #include #include +#define HELPER_NAME "tftp" + MODULE_AUTHOR("Magnus Boden "); MODULE_DESCRIPTION("TFTP connection tracking helper"); MODULE_LICENSE("GPL"); MODULE_ALIAS("ip_conntrack_tftp"); -MODULE_ALIAS_NFCT_HELPER("tftp"); +MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); #define MAX_PORTS 8 static unsigned short ports[MAX_PORTS]; @@ -119,12 +121,14 @@ static int __init nf_conntrack_tftp_init(void) ports[ports_c++] = TFTP_PORT; for (i = 0; i < ports_c; i++) { - nf_ct_helper_init(&tftp[2 * i], AF_INET, IPPROTO_UDP, "tftp", - TFTP_PORT, ports[i], i, &tftp_exp_policy, - 0, tftp_help, NULL, THIS_MODULE); - nf_ct_helper_init(&tftp[2 * i + 1], AF_INET6, IPPROTO_UDP, "tftp", - TFTP_PORT, ports[i], i, &tftp_exp_policy, - 0, tftp_help, NULL, THIS_MODULE); + nf_ct_helper_init(&tftp[2 * i], AF_INET, IPPROTO_UDP, + HELPER_NAME, TFTP_PORT, ports[i], i, + &tftp_exp_policy, 0, tftp_help, NULL, + THIS_MODULE); + nf_ct_helper_init(&tftp[2 * i + 1], AF_INET6, IPPROTO_UDP, + HELPER_NAME, TFTP_PORT, ports[i], i, + &tftp_exp_policy, 0, tftp_help, NULL, + THIS_MODULE); } ret = nf_conntrack_helpers_register(tftp, ports_c * 2); -- cgit v1.2.3