diff options
| -rw-r--r-- | include/linux/netfilter/nf_conntrack_ftp.h | 20 | ||||
| -rw-r--r-- | include/linux/netfilter_ipv4/ip_conntrack_ftp.h | 40 | ||||
| -rw-r--r-- | include/net/netfilter/nf_conntrack.h | 2 | ||||
| -rw-r--r-- | net/ipv4/netfilter/Kconfig | 25 | ||||
| -rw-r--r-- | net/ipv4/netfilter/Makefile | 5 | ||||
| -rw-r--r-- | net/ipv4/netfilter/nf_nat_ftp.c | 179 | ||||
| -rw-r--r-- | net/netfilter/nf_conntrack_ftp.c | 20 |
7 files changed, 260 insertions, 31 deletions
diff --git a/include/linux/netfilter/nf_conntrack_ftp.h b/include/linux/netfilter/nf_conntrack_ftp.h index ad4a41c9ce93..81453ea7e4c2 100644 --- a/include/linux/netfilter/nf_conntrack_ftp.h +++ b/include/linux/netfilter/nf_conntrack_ftp.h @@ -3,16 +3,16 @@ /* FTP tracking. */ /* This enum is exposed to userspace */ -enum ip_ct_ftp_type +enum nf_ct_ftp_type { /* PORT command from client */ - IP_CT_FTP_PORT, + NF_CT_FTP_PORT, /* PASV response from server */ - IP_CT_FTP_PASV, + NF_CT_FTP_PASV, /* EPRT command from client */ - IP_CT_FTP_EPRT, + NF_CT_FTP_EPRT, /* EPSV response from server */ - IP_CT_FTP_EPSV, + NF_CT_FTP_EPSV, }; #ifdef __KERNEL__ @@ -21,23 +21,23 @@ enum ip_ct_ftp_type #define NUM_SEQ_TO_REMEMBER 2 /* This structure exists only once per master */ -struct ip_ct_ftp_master { +struct nf_ct_ftp_master { /* Valid seq positions for cmd matching after newline */ u_int32_t seq_aft_nl[IP_CT_DIR_MAX][NUM_SEQ_TO_REMEMBER]; /* 0 means seq_match_aft_nl not set */ int seq_aft_nl_num[IP_CT_DIR_MAX]; }; -struct ip_conntrack_expect; +struct nf_conntrack_expect; /* For NAT to hook in when we find a packet which describes what other * connection we should expect. */ -extern unsigned int (*ip_nat_ftp_hook)(struct sk_buff **pskb, +extern unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb, enum ip_conntrack_info ctinfo, - enum ip_ct_ftp_type type, + enum nf_ct_ftp_type type, unsigned int matchoff, unsigned int matchlen, - struct ip_conntrack_expect *exp, + struct nf_conntrack_expect *exp, u32 *seq); #endif /* __KERNEL__ */ diff --git a/include/linux/netfilter_ipv4/ip_conntrack_ftp.h b/include/linux/netfilter_ipv4/ip_conntrack_ftp.h index 63811934de4d..2129fc3972ac 100644 --- a/include/linux/netfilter_ipv4/ip_conntrack_ftp.h +++ b/include/linux/netfilter_ipv4/ip_conntrack_ftp.h @@ -1,6 +1,44 @@ #ifndef _IP_CONNTRACK_FTP_H #define _IP_CONNTRACK_FTP_H +/* FTP tracking. */ -#include <linux/netfilter/nf_conntrack_ftp.h> +/* This enum is exposed to userspace */ +enum ip_ct_ftp_type +{ + /* PORT command from client */ + IP_CT_FTP_PORT, + /* PASV response from server */ + IP_CT_FTP_PASV, + /* EPRT command from client */ + IP_CT_FTP_EPRT, + /* EPSV response from server */ + IP_CT_FTP_EPSV, +}; + +#ifdef __KERNEL__ + +#define FTP_PORT 21 + +#define NUM_SEQ_TO_REMEMBER 2 +/* This structure exists only once per master */ +struct ip_ct_ftp_master { + /* Valid seq positions for cmd matching after newline */ + u_int32_t seq_aft_nl[IP_CT_DIR_MAX][NUM_SEQ_TO_REMEMBER]; + /* 0 means seq_match_aft_nl not set */ + int seq_aft_nl_num[IP_CT_DIR_MAX]; +}; + +struct ip_conntrack_expect; + +/* For NAT to hook in when we find a packet which describes what other + * connection we should expect. */ +extern unsigned int (*ip_nat_ftp_hook)(struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + enum ip_ct_ftp_type type, + unsigned int matchoff, + unsigned int matchlen, + struct ip_conntrack_expect *exp, + u32 *seq); +#endif /* __KERNEL__ */ #endif /* _IP_CONNTRACK_FTP_H */ diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index 9948af068688..83694cfdfa8f 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -45,7 +45,7 @@ union nf_conntrack_expect_proto { /* per conntrack: application helper private data */ union nf_conntrack_help { /* insert conntrack helper private data (master) here */ - struct ip_ct_ftp_master ct_ftp_info; + struct nf_ct_ftp_master ct_ftp_info; }; #include <linux/types.h> diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig index 01789aeaeb5f..52f876db68f4 100644 --- a/net/ipv4/netfilter/Kconfig +++ b/net/ipv4/netfilter/Kconfig @@ -477,20 +477,29 @@ config IP_NF_NAT_SNMP_BASIC To compile it as a module, choose M here. If unsure, say N. +# If they want FTP, set to $CONFIG_IP_NF_NAT (m or y), +# or $CONFIG_IP_NF_FTP (m or y), whichever is weaker. +# From kconfig-language.txt: +# +# <expr> '&&' <expr> (6) +# +# (6) Returns the result of min(/expr/, /expr/). +config IP_NF_NAT_FTP + tristate + depends on IP_NF_IPTABLES && IP_NF_CONNTRACK && IP_NF_NAT + default IP_NF_NAT && IP_NF_FTP + +config NF_NAT_FTP + tristate + depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT + default NF_NAT && NF_CONNTRACK_FTP + config IP_NF_NAT_IRC tristate depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n default IP_NF_NAT if IP_NF_IRC=y default m if IP_NF_IRC=m -# If they want FTP, set to $CONFIG_IP_NF_NAT (m or y), -# or $CONFIG_IP_NF_FTP (m or y), whichever is weaker. Argh. -config IP_NF_NAT_FTP - tristate - depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n - default IP_NF_NAT if IP_NF_FTP=y - default m if IP_NF_FTP=m - config IP_NF_NAT_TFTP tristate depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile index ec31690764ac..c0c6194bb275 100644 --- a/net/ipv4/netfilter/Makefile +++ b/net/ipv4/netfilter/Makefile @@ -40,7 +40,7 @@ obj-$(CONFIG_IP_NF_IRC) += ip_conntrack_irc.o obj-$(CONFIG_IP_NF_SIP) += ip_conntrack_sip.o obj-$(CONFIG_IP_NF_NETBIOS_NS) += ip_conntrack_netbios_ns.o -# NAT helpers +# NAT helpers (ip_conntrack) obj-$(CONFIG_IP_NF_NAT_H323) += ip_nat_h323.o obj-$(CONFIG_IP_NF_NAT_PPTP) += ip_nat_pptp.o obj-$(CONFIG_IP_NF_NAT_AMANDA) += ip_nat_amanda.o @@ -49,6 +49,9 @@ obj-$(CONFIG_IP_NF_NAT_FTP) += ip_nat_ftp.o obj-$(CONFIG_IP_NF_NAT_IRC) += ip_nat_irc.o obj-$(CONFIG_IP_NF_NAT_SIP) += ip_nat_sip.o +# NAT helpers (nf_conntrack) +obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o + # generic IP tables obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o diff --git a/net/ipv4/netfilter/nf_nat_ftp.c b/net/ipv4/netfilter/nf_nat_ftp.c new file mode 100644 index 000000000000..751b59801755 --- /dev/null +++ b/net/ipv4/netfilter/nf_nat_ftp.c @@ -0,0 +1,179 @@ +/* FTP extension for TCP NAT alteration. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2006 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. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/ip.h> +#include <linux/tcp.h> +#include <linux/netfilter_ipv4.h> +#include <net/netfilter/nf_nat.h> +#include <net/netfilter/nf_nat_helper.h> +#include <net/netfilter/nf_nat_rule.h> +#include <net/netfilter/nf_conntrack_helper.h> +#include <net/netfilter/nf_conntrack_expect.h> +#include <linux/netfilter/nf_conntrack_ftp.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); +MODULE_DESCRIPTION("ftp NAT helper"); +MODULE_ALIAS("ip_nat_ftp"); + +#if 0 +#define DEBUGP printk +#else +#define DEBUGP(format, args...) +#endif + +/* FIXME: Time out? --RR */ + +static int +mangle_rfc959_packet(struct sk_buff **pskb, + __be32 newip, + u_int16_t port, + unsigned int matchoff, + unsigned int matchlen, + struct nf_conn *ct, + enum ip_conntrack_info ctinfo, + u32 *seq) +{ + char buffer[sizeof("nnn,nnn,nnn,nnn,nnn,nnn")]; + + sprintf(buffer, "%u,%u,%u,%u,%u,%u", + NIPQUAD(newip), port>>8, port&0xFF); + + DEBUGP("calling nf_nat_mangle_tcp_packet\n"); + + *seq += strlen(buffer) - matchlen; + return nf_nat_mangle_tcp_packet(pskb, ct, ctinfo, matchoff, + matchlen, buffer, strlen(buffer)); +} + +/* |1|132.235.1.2|6275| */ +static int +mangle_eprt_packet(struct sk_buff **pskb, + __be32 newip, + u_int16_t port, + unsigned int matchoff, + unsigned int matchlen, + struct nf_conn *ct, + enum ip_conntrack_info ctinfo, + u32 *seq) +{ + char buffer[sizeof("|1|255.255.255.255|65535|")]; + + sprintf(buffer, "|1|%u.%u.%u.%u|%u|", NIPQUAD(newip), port); + + DEBUGP("calling nf_nat_mangle_tcp_packet\n"); + + *seq += strlen(buffer) - matchlen; + return nf_nat_mangle_tcp_packet(pskb, ct, ctinfo, matchoff, + matchlen, buffer, strlen(buffer)); +} + +/* |1|132.235.1.2|6275| */ +static int +mangle_epsv_packet(struct sk_buff **pskb, + __be32 newip, + u_int16_t port, + unsigned int matchoff, + unsigned int matchlen, + struct nf_conn *ct, + enum ip_conntrack_info ctinfo, + u32 *seq) +{ + char buffer[sizeof("|||65535|")]; + + sprintf(buffer, "|||%u|", port); + + DEBUGP("calling nf_nat_mangle_tcp_packet\n"); + + *seq += strlen(buffer) - matchlen; + return nf_nat_mangle_tcp_packet(pskb, ct, ctinfo, matchoff, + matchlen, buffer, strlen(buffer)); +} + +static int (*mangle[])(struct sk_buff **, __be32, u_int16_t, + unsigned int, unsigned int, struct nf_conn *, + enum ip_conntrack_info, u32 *seq) += { + [NF_CT_FTP_PORT] = mangle_rfc959_packet, + [NF_CT_FTP_PASV] = mangle_rfc959_packet, + [NF_CT_FTP_EPRT] = mangle_eprt_packet, + [NF_CT_FTP_EPSV] = mangle_epsv_packet +}; + +/* So, this packet has hit the connection tracking matching code. + Mangle it, and change the expectation to match the new version. */ +static unsigned int nf_nat_ftp(struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + enum nf_ct_ftp_type type, + unsigned int matchoff, + unsigned int matchlen, + struct nf_conntrack_expect *exp, + u32 *seq) +{ + __be32 newip; + u_int16_t port; + int dir = CTINFO2DIR(ctinfo); + struct nf_conn *ct = exp->master; + + DEBUGP("FTP_NAT: type %i, off %u len %u\n", type, matchoff, matchlen); + + /* Connection will come from wherever this packet goes, hence !dir */ + newip = ct->tuplehash[!dir].tuple.dst.u3.ip; + exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; + exp->dir = !dir; + + /* When you see the packet, we need to NAT it the same as the + * this one. */ + exp->expectfn = nf_nat_follow_master; + + /* Try to get same port: if not, try to change it. */ + for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) { + exp->tuple.dst.u.tcp.port = htons(port); + if (nf_conntrack_expect_related(exp) == 0) + break; + } + + if (port == 0) + return NF_DROP; + + if (!mangle[type](pskb, newip, port, matchoff, matchlen, ct, ctinfo, + seq)) { + nf_conntrack_unexpect_related(exp); + return NF_DROP; + } + return NF_ACCEPT; +} + +static void __exit nf_nat_ftp_fini(void) +{ + rcu_assign_pointer(nf_nat_ftp_hook, NULL); + synchronize_rcu(); +} + +static int __init nf_nat_ftp_init(void) +{ + BUG_ON(rcu_dereference(nf_nat_ftp_hook)); + rcu_assign_pointer(nf_nat_ftp_hook, nf_nat_ftp); + return 0; +} + +/* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */ +static int warn_set(const char *val, struct kernel_param *kp) +{ + printk(KERN_INFO KBUILD_MODNAME + ": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n"); + return 0; +} +module_param_call(ports, warn_set, NULL, NULL, 0); + +module_init(nf_nat_ftp_init); +module_exit(nf_nat_ftp_fini); diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c index e299d657e4fc..92a947168761 100644 --- a/net/netfilter/nf_conntrack_ftp.c +++ b/net/netfilter/nf_conntrack_ftp.c @@ -51,7 +51,7 @@ module_param(loose, bool, 0600); unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb, enum ip_conntrack_info ctinfo, - enum ip_ct_ftp_type type, + enum nf_ct_ftp_type type, unsigned int matchoff, unsigned int matchlen, struct nf_conntrack_expect *exp, @@ -74,7 +74,7 @@ static struct ftp_search { size_t plen; char skip; char term; - enum ip_ct_ftp_type ftptype; + enum nf_ct_ftp_type ftptype; int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char); } search[IP_CT_DIR_MAX][2] = { [IP_CT_DIR_ORIGINAL] = { @@ -83,7 +83,7 @@ static struct ftp_search { .plen = sizeof("PORT") - 1, .skip = ' ', .term = '\r', - .ftptype = IP_CT_FTP_PORT, + .ftptype = NF_CT_FTP_PORT, .getnum = try_rfc959, }, { @@ -91,7 +91,7 @@ static struct ftp_search { .plen = sizeof("EPRT") - 1, .skip = ' ', .term = '\r', - .ftptype = IP_CT_FTP_EPRT, + .ftptype = NF_CT_FTP_EPRT, .getnum = try_eprt, }, }, @@ -101,7 +101,7 @@ static struct ftp_search { .plen = sizeof("227 ") - 1, .skip = '(', .term = ')', - .ftptype = IP_CT_FTP_PASV, + .ftptype = NF_CT_FTP_PASV, .getnum = try_rfc959, }, { @@ -109,7 +109,7 @@ static struct ftp_search { .plen = sizeof("229 ") - 1, .skip = '(', .term = ')', - .ftptype = IP_CT_FTP_EPSV, + .ftptype = NF_CT_FTP_EPSV, .getnum = try_epsv_response, }, }, @@ -320,7 +320,7 @@ static int find_pattern(const char *data, size_t dlen, } /* Look up to see if we're just after a \n. */ -static int find_nl_seq(u32 seq, const struct ip_ct_ftp_master *info, int dir) +static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir) { unsigned int i; @@ -331,7 +331,7 @@ static int find_nl_seq(u32 seq, const struct ip_ct_ftp_master *info, int dir) } /* We don't update if it's older than what we have. */ -static void update_nl_seq(u32 nl_seq, struct ip_ct_ftp_master *info, int dir, +static void update_nl_seq(u32 nl_seq, struct nf_ct_ftp_master *info, int dir, struct sk_buff *skb) { unsigned int i, oldest = NUM_SEQ_TO_REMEMBER; @@ -367,7 +367,7 @@ static int help(struct sk_buff **pskb, u32 seq; int dir = CTINFO2DIR(ctinfo); unsigned int matchlen, matchoff; - struct ip_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info; + struct nf_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info; struct nf_conntrack_expect *exp; struct nf_conntrack_man cmd = {}; unsigned int i; @@ -523,7 +523,7 @@ static int help(struct sk_buff **pskb, /* Now, NAT might want to mangle the packet, and register the * (possibly changed) expectation itself. */ nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook); - if (nf_nat_ftp) + if (nf_nat_ftp && ct->status & IPS_NAT_MASK) ret = nf_nat_ftp(pskb, ctinfo, search[dir][i].ftptype, matchoff, matchlen, exp, &seq); else { |
