[thirdparty/linux.git] / net / netfilter / nf_conntrack_ftp.c

// SPDX-License-Identifier: GPL-2.0-only
/* FTP extension for connection tracking. */

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netfilter.h>
#include <linux/ip.h>
#include <linux/slab.h>
#include <linux/ipv6.h>
#include <linux/ctype.h>
#include <linux/inet.h>
#include <net/checksum.h>
#include <net/tcp.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <linux/netfilter/nf_conntrack_ftp.h>

#define HELPER_NAME "ftp"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
MODULE_DESCRIPTION("ftp connection tracking helper");
MODULE_ALIAS("ip_conntrack_ftp");
MODULE_ALIAS_NFCT_HELPER(HELPER_NAME);

/* This is slow, but it's simple. --RR */
static char *ftp_buffer;

static DEFINE_SPINLOCK(nf_ftp_lock);

#define MAX_PORTS 8
static u_int16_t ports[MAX_PORTS];
static unsigned int ports_c;
module_param_array(ports, ushort, &ports_c, 0400);

static bool loose;
module_param(loose, bool, 0600);

unsigned int (*nf_nat_ftp_hook)(struct sk_buff *skb,
				enum ip_conntrack_info ctinfo,
				enum nf_ct_ftp_type type,
				unsigned int protoff,
				unsigned int matchoff,
				unsigned int matchlen,
				struct nf_conntrack_expect *exp);
EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);

static int try_rfc959(const char *, size_t, struct nf_conntrack_man *,
		      char, unsigned int *);
static int try_rfc1123(const char *, size_t, struct nf_conntrack_man *,
		       char, unsigned int *);
static int try_eprt(const char *, size_t, struct nf_conntrack_man *,
		    char, unsigned int *);
static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
			     char, unsigned int *);

static struct ftp_search {
	const char *pattern;
	size_t plen;
	char skip;
	char term;
	enum nf_ct_ftp_type ftptype;
	int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char, unsigned int *);
} search[IP_CT_DIR_MAX][2] = {
	[IP_CT_DIR_ORIGINAL] = {
		{
			.pattern	= "PORT",
			.plen		= sizeof("PORT") - 1,
			.skip		= ' ',
			.term		= '\r',
			.ftptype	= NF_CT_FTP_PORT,
			.getnum		= try_rfc959,
		},
		{
			.pattern	= "EPRT",
			.plen		= sizeof("EPRT") - 1,
			.skip		= ' ',
			.term		= '\r',
			.ftptype	= NF_CT_FTP_EPRT,
			.getnum		= try_eprt,
		},
	},
	[IP_CT_DIR_REPLY] = {
		{
			.pattern	= "227 ",
			.plen		= sizeof("227 ") - 1,
			.ftptype	= NF_CT_FTP_PASV,
			.getnum		= try_rfc1123,
		},
		{
			.pattern	= "229 ",
			.plen		= sizeof("229 ") - 1,
			.skip		= '(',
			.term		= ')',
			.ftptype	= NF_CT_FTP_EPSV,
			.getnum		= try_epsv_response,
		},
	},
};

static int
get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
{
	const char *end;
	int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
	if (ret > 0)
		return (int)(end - src);
	return 0;
}

static int try_number(const char *data, size_t dlen, u_int32_t array[],
		      int array_size, char sep, char term)
{
	u_int32_t i, len;

	memset(array, 0, sizeof(array[0])*array_size);

	/* Keep data pointing at next char. */
	for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
		if (*data >= '0' && *data <= '9') {
			array[i] = array[i]*10 + *data - '0';
		}
		else if (*data == sep)
			i++;
		else {
			/* Unexpected character; true if it's the
			   terminator (or we don't care about one)
			   and we're finished. */
			if ((*data == term || !term) && i == array_size - 1)
				return len;

			pr_debug("Char %u (got %u nums) `%u' unexpected\n",
				 len, i, *data);
			return 0;
		}
	}
	pr_debug("Failed to fill %u numbers separated by %c\n",
		 array_size, sep);
	return 0;
}

/* Returns 0, or length of numbers: 192,168,1,1,5,6 */
static int try_rfc959(const char *data, size_t dlen,
		      struct nf_conntrack_man *cmd, char term,
		      unsigned int *offset)
{
	int length;
	u_int32_t array[6];

	length = try_number(data, dlen, array, 6, ',', term);
	if (length == 0)
		return 0;

	cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
				    (array[2] << 8) | array[3]);
	cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
	return length;
}

/*
 * From RFC 1123:
 * The format of the 227 reply to a PASV command is not
 * well standardized.  In particular, an FTP client cannot
 * assume that the parentheses shown on page 40 of RFC-959
 * will be present (and in fact, Figure 3 on page 43 omits
 * them).  Therefore, a User-FTP program that interprets
 * the PASV reply must scan the reply for the first digit
 * of the host and port numbers.
 */
static int try_rfc1123(const char *data, size_t dlen,
		       struct nf_conntrack_man *cmd, char term,
		       unsigned int *offset)
{
	int i;
	for (i = 0; i < dlen; i++)
		if (isdigit(data[i]))
			break;

	if (i == dlen)
		return 0;

	*offset += i;

	return try_rfc959(data + i, dlen - i, cmd, 0, offset);
}

/* Grab port: number up to delimiter */
static int get_port(const char *data, int start, size_t dlen, char delim,
		    __be16 *port)
{
	u_int16_t tmp_port = 0;
	int i;

	for (i = start; i < dlen; i++) {
		/* Finished? */
		if (data[i] == delim) {
			if (tmp_port == 0)
				break;
			*port = htons(tmp_port);
			pr_debug("get_port: return %d\n", tmp_port);
			return i + 1;
		}
		else if (data[i] >= '0' && data[i] <= '9')
			tmp_port = tmp_port*10 + data[i] - '0';
		else { /* Some other crap */
			pr_debug("get_port: invalid char.\n");
			break;
		}
	}
	return 0;
}

/* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
		    char term, unsigned int *offset)
{
	char delim;
	int length;

	/* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
	   then delimiter again. */
	if (dlen <= 3) {
		pr_debug("EPRT: too short\n");
		return 0;
	}
	delim = data[0];
	if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
		pr_debug("try_eprt: invalid delimiter.\n");
		return 0;
	}

	if ((cmd->l3num == PF_INET && data[1] != '1') ||
	    (cmd->l3num == PF_INET6 && data[1] != '2')) {
		pr_debug("EPRT: invalid protocol number.\n");
		return 0;
	}

	pr_debug("EPRT: Got %c%c%c\n", delim, data[1], delim);

	if (data[1] == '1') {
		u_int32_t array[4];

		/* Now we have IP address. */
		length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
		if (length != 0)
			cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
					   | (array[2] << 8) | array[3]);
	} else {
		/* Now we have IPv6 address. */
		length = get_ipv6_addr(data + 3, dlen - 3,
				       (struct in6_addr *)cmd->u3.ip6, delim);
	}

	if (length == 0)
		return 0;
	pr_debug("EPRT: Got IP address!\n");
	/* Start offset includes initial "|1|", and trailing delimiter */
	return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
}

/* Returns 0, or length of numbers: |||6446| */
static int try_epsv_response(const char *data, size_t dlen,
			     struct nf_conntrack_man *cmd, char term,
			     unsigned int *offset)
{
	char delim;

	/* Three delimiters. */
	if (dlen <= 3) return 0;
	delim = data[0];
	if (isdigit(delim) || delim < 33 || delim > 126 ||
	    data[1] != delim || data[2] != delim)
		return 0;

	return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
}

/* Return 1 for match, 0 for accept, -1 for partial. */
static int find_pattern(const char *data, size_t dlen,
			const char *pattern, size_t plen,
			char skip, char term,
			unsigned int *numoff,
			unsigned int *numlen,
			struct nf_conntrack_man *cmd,
			int (*getnum)(const char *, size_t,
				      struct nf_conntrack_man *, char,
				      unsigned int *))
{
	size_t i = plen;

	pr_debug("find_pattern `%s': dlen = %zu\n", pattern, dlen);

	if (dlen <= plen) {
		/* Short packet: try for partial? */
		if (strncasecmp(data, pattern, dlen) == 0)
			return -1;
		else return 0;
	}

	if (strncasecmp(data, pattern, plen) != 0)
		return 0;

	pr_debug("Pattern matches!\n");
	/* Now we've found the constant string, try to skip
	   to the 'skip' character */
	if (skip) {
		for (i = plen; data[i] != skip; i++)
			if (i == dlen - 1) return -1;

		/* Skip over the last character */
		i++;
	}

	pr_debug("Skipped up to `%c'!\n", skip);

	*numoff = i;
	*numlen = getnum(data + i, dlen - i, cmd, term, numoff);
	if (!*numlen)
		return -1;

	pr_debug("Match succeeded!\n");
	return 1;
}

/* Look up to see if we're just after a \n. */
static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir)
{
	unsigned int i;

	for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
		if (info->seq_aft_nl[dir][i] == seq)
			return 1;
	return 0;
}

/* We don't update if it's older than what we have. */
static void update_nl_seq(struct nf_conn *ct, u32 nl_seq,
			  struct nf_ct_ftp_master *info, int dir,
			  struct sk_buff *skb)
{
	unsigned int i, oldest;

	/* Look for oldest: if we find exact match, we're done. */
	for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
		if (info->seq_aft_nl[dir][i] == nl_seq)
			return;
	}

	if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
		info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
	} else {
		if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1]))
			oldest = 0;
		else
			oldest = 1;

		if (after(nl_seq, info->seq_aft_nl[dir][oldest]))
			info->seq_aft_nl[dir][oldest] = nl_seq;
	}
}

static int help(struct sk_buff *skb,
		unsigned int protoff,
		struct nf_conn *ct,
		enum ip_conntrack_info ctinfo)
{
	unsigned int dataoff, datalen;
	const struct tcphdr *th;
	struct tcphdr _tcph;
	const char *fb_ptr;
	int ret;
	u32 seq;
	int dir = CTINFO2DIR(ctinfo);
	unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff);
	struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct);
	struct nf_conntrack_expect *exp;
	union nf_inet_addr *daddr;
	struct nf_conntrack_man cmd = {};
	unsigned int i;
	int found = 0, ends_in_nl;
	typeof(nf_nat_ftp_hook) nf_nat_ftp;

	/* Until there's been traffic both ways, don't look in packets. */
	if (ctinfo != IP_CT_ESTABLISHED &&
	    ctinfo != IP_CT_ESTABLISHED_REPLY) {
		pr_debug("ftp: Conntrackinfo = %u\n", ctinfo);
		return NF_ACCEPT;
	}

	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
	if (th == NULL)
		return NF_ACCEPT;

	dataoff = protoff + th->doff * 4;
	/* No data? */
	if (dataoff >= skb->len) {
		pr_debug("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
			 skb->len);
		return NF_ACCEPT;
	}
	datalen = skb->len - dataoff;

	spin_lock_bh(&nf_ftp_lock);
	fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer);
	BUG_ON(fb_ptr == NULL);

	ends_in_nl = (fb_ptr[datalen - 1] == '\n');
	seq = ntohl(th->seq) + datalen;

	/* Look up to see if we're just after a \n. */
	if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
		/* We're picking up this, clear flags and let it continue */
		if (unlikely(ct_ftp_info->flags[dir] & NF_CT_FTP_SEQ_PICKUP)) {
			ct_ftp_info->flags[dir] ^= NF_CT_FTP_SEQ_PICKUP;
			goto skip_nl_seq;
		}

		/* Now if this ends in \n, update ftp info. */
		pr_debug("nf_conntrack_ftp: wrong seq pos %s(%u) or %s(%u)\n",
			 ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
			 ct_ftp_info->seq_aft_nl[dir][0],
			 ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
			 ct_ftp_info->seq_aft_nl[dir][1]);
		ret = NF_ACCEPT;
		goto out_update_nl;
	}

skip_nl_seq:
	/* Initialize IP/IPv6 addr to expected address (it's not mentioned
	   in EPSV responses) */
	cmd.l3num = nf_ct_l3num(ct);
	memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
	       sizeof(cmd.u3.all));

	for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
		found = find_pattern(fb_ptr, datalen,
				     search[dir][i].pattern,
				     search[dir][i].plen,
				     search[dir][i].skip,
				     search[dir][i].term,
				     &matchoff, &matchlen,
				     &cmd,
				     search[dir][i].getnum);
		if (found) break;
	}
	if (found == -1) {
		/* We don't usually drop packets.  After all, this is
		   connection tracking, not packet filtering.
		   However, it is necessary for accurate tracking in
		   this case. */
		nf_ct_helper_log(skb, ct, "partial matching of `%s'",
			         search[dir][i].pattern);
		ret = NF_DROP;
		goto out;
	} else if (found == 0) { /* No match */
		ret = NF_ACCEPT;
		goto out_update_nl;
	}

	pr_debug("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
		 matchlen, fb_ptr + matchoff,
		 matchlen, ntohl(th->seq) + matchoff);

	exp = nf_ct_expect_alloc(ct);
	if (exp == NULL) {
		nf_ct_helper_log(skb, ct, "cannot alloc expectation");
		ret = NF_DROP;
		goto out;
	}

	/* We refer to the reverse direction ("!dir") tuples here,
	 * because we're expecting something in the other direction.
	 * Doesn't matter unless NAT is happening.  */
	daddr = &ct->tuplehash[!dir].tuple.dst.u3;

	/* Update the ftp info */
	if ((cmd.l3num == nf_ct_l3num(ct)) &&
	    memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
		     sizeof(cmd.u3.all))) {
		/* Enrico Scholz's passive FTP to partially RNAT'd ftp
		   server: it really wants us to connect to a
		   different IP address.  Simply don't record it for
		   NAT. */
		if (cmd.l3num == PF_INET) {
			pr_debug("NOT RECORDING: %pI4 != %pI4\n",
				 &cmd.u3.ip,
				 &ct->tuplehash[dir].tuple.src.u3.ip);
		} else {
			pr_debug("NOT RECORDING: %pI6 != %pI6\n",
				 cmd.u3.ip6,
				 ct->tuplehash[dir].tuple.src.u3.ip6);
		}

		/* Thanks to Cristiano Lincoln Mattos
		   <lincoln@cesar.org.br> for reporting this potential
		   problem (DMZ machines opening holes to internal
		   networks, or the packet filter itself). */
		if (!loose) {
			ret = NF_ACCEPT;
			goto out_put_expect;
		}
		daddr = &cmd.u3;
	}

	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, cmd.l3num,
			  &ct->tuplehash[!dir].tuple.src.u3, daddr,
			  IPPROTO_TCP, NULL, &cmd.u.tcp.port);

	/* 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 && ct->status & IPS_NAT_MASK)
		ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype,
				 protoff, matchoff, matchlen, exp);
	else {
		/* Can't expect this?  Best to drop packet now. */
		if (nf_ct_expect_related(exp, 0) != 0) {
			nf_ct_helper_log(skb, ct, "cannot add expectation");
			ret = NF_DROP;
		} else
			ret = NF_ACCEPT;
	}

out_put_expect:
	nf_ct_expect_put(exp);

out_update_nl:
	/* Now if this ends in \n, update ftp info.  Seq may have been
	 * adjusted by NAT code. */
	if (ends_in_nl)
		update_nl_seq(ct, seq, ct_ftp_info, dir, skb);
 out:
	spin_unlock_bh(&nf_ftp_lock);
	return ret;
}

static int nf_ct_ftp_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
{
	struct nf_ct_ftp_master *ftp = nfct_help_data(ct);

	/* This conntrack has been injected from user-space, always pick up
	 * sequence tracking. Otherwise, the first FTP command after the
	 * failover breaks.
	 */
	ftp->flags[IP_CT_DIR_ORIGINAL] |= NF_CT_FTP_SEQ_PICKUP;
	ftp->flags[IP_CT_DIR_REPLY] |= NF_CT_FTP_SEQ_PICKUP;
	return 0;
}

static struct nf_conntrack_helper ftp[MAX_PORTS * 2] __read_mostly;

static const struct nf_conntrack_expect_policy ftp_exp_policy = {
	.max_expected	= 1,
	.timeout	= 5 * 60,
};

static void __exit nf_conntrack_ftp_fini(void)
{
	nf_conntrack_helpers_unregister(ftp, ports_c * 2);
	kfree(ftp_buffer);
}

static int __init nf_conntrack_ftp_init(void)
{
	int i, ret = 0;

	NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_ftp_master));

	ftp_buffer = kmalloc(65536, GFP_KERNEL);
	if (!ftp_buffer)
		return -ENOMEM;

	if (ports_c == 0)
		ports[ports_c++] = FTP_PORT;

	/* 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,
				  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);
	if (ret < 0) {
		pr_err("failed to register helpers\n");
		kfree(ftp_buffer);
		return ret;
	}

	return 0;
}

module_init(nf_conntrack_ftp_init);
module_exit(nf_conntrack_ftp_fini);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
9fb9cbb1 YK	2	/* FTP extension for connection tracking. */
	3
	4	/* (C) 1999-2001 Paul `Rusty' Russell
	5	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	6	* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
f229f6ce	7	* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
9fb9cbb1 YK	8	*/
9fb9cbb1 YK	9
ad6d9503 PNA	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
ad6d9503 PNA	11
9fb9cbb1 YK	12	#include <linux/module.h>
	13	#include <linux/moduleparam.h>
	14	#include <linux/netfilter.h>
	15	#include <linux/ip.h>
5a0e3ad6	16	#include <linux/slab.h>
9fb9cbb1 YK	17	#include <linux/ipv6.h>
9fb9cbb1 YK	18	#include <linux/ctype.h>
6a28ec8c	19	#include <linux/inet.h>
9fb9cbb1 YK	20	#include <net/checksum.h>
	21	#include <net/tcp.h>
	22
	23	#include <net/netfilter/nf_conntrack.h>
77ab9cff	24	#include <net/netfilter/nf_conntrack_expect.h>
f6180121	25	#include <net/netfilter/nf_conntrack_ecache.h>
9fb9cbb1 YK	26	#include <net/netfilter/nf_conntrack_helper.h>
	27	#include <linux/netfilter/nf_conntrack_ftp.h>
	28
08010a21 FL	29	#define HELPER_NAME "ftp"
08010a21 FL	30
9fb9cbb1 YK	31	MODULE_LICENSE("GPL");
	32	MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
	33	MODULE_DESCRIPTION("ftp connection tracking helper");
d2483dde	34	MODULE_ALIAS("ip_conntrack_ftp");
08010a21	35	MODULE_ALIAS_NFCT_HELPER(HELPER_NAME);
9fb9cbb1 YK	36
	37	/* This is slow, but it's simple. --RR */
	38	static char *ftp_buffer;
	39
	40	static DEFINE_SPINLOCK(nf_ftp_lock);
	41
	42	#define MAX_PORTS 8
	43	static u_int16_t ports[MAX_PORTS];
	44	static unsigned int ports_c;
	45	module_param_array(ports, ushort, &ports_c, 0400);
	46
eb939922	47	static bool loose;
e7be6994	48	module_param(loose, bool, 0600);
9fb9cbb1	49
3db05fea	50	unsigned int (nf_nat_ftp_hook)(struct sk_buff skb,
9fb9cbb1	51	enum ip_conntrack_info ctinfo,
55a73324	52	enum nf_ct_ftp_type type,
051966c0	53	unsigned int protoff,
9fb9cbb1 YK	54	unsigned int matchoff,
9fb9cbb1 YK	55	unsigned int matchlen,
25b86e05	56	struct nf_conntrack_expect *exp);
9fb9cbb1 YK	57	EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
9fb9cbb1 YK	58
4e7dba99 JM	59	static int try_rfc959(const char , size_t, struct nf_conntrack_man ,
	60	char, unsigned int *);
	61	static int try_rfc1123(const char , size_t, struct nf_conntrack_man ,
	62	char, unsigned int *);
	63	static int try_eprt(const char , size_t, struct nf_conntrack_man ,
	64	char, unsigned int *);
9fb9cbb1	65	static int try_epsv_response(const char , size_t, struct nf_conntrack_man ,
4e7dba99	66	char, unsigned int *);
9fb9cbb1 YK	67
9fb9cbb1 YK	68	static struct ftp_search {
9fb9cbb1 YK	69	const char *pattern;
	70	size_t plen;
	71	char skip;
	72	char term;
55a73324	73	enum nf_ct_ftp_type ftptype;
4e7dba99	74	int (getnum)(const char , size_t, struct nf_conntrack_man , char, unsigned int );
7d8c5018 PM	75	} search[IP_CT_DIR_MAX][2] = {
	76	[IP_CT_DIR_ORIGINAL] = {
	77	{
	78	.pattern = "PORT",
	79	.plen = sizeof("PORT") - 1,
	80	.skip = ' ',
	81	.term = '\r',
55a73324	82	.ftptype = NF_CT_FTP_PORT,
7d8c5018 PM	83	.getnum = try_rfc959,
	84	},
	85	{
	86	.pattern = "EPRT",
	87	.plen = sizeof("EPRT") - 1,
	88	.skip = ' ',
	89	.term = '\r',
55a73324	90	.ftptype = NF_CT_FTP_EPRT,
7d8c5018 PM	91	.getnum = try_eprt,
7d8c5018 PM	92	},
9fb9cbb1	93	},
7d8c5018 PM	94	[IP_CT_DIR_REPLY] = {
	95	{
	96	.pattern = "227 ",
	97	.plen = sizeof("227 ") - 1,
55a73324	98	.ftptype = NF_CT_FTP_PASV,
4e7dba99	99	.getnum = try_rfc1123,
7d8c5018 PM	100	},
	101	{
	102	.pattern = "229 ",
	103	.plen = sizeof("229 ") - 1,
	104	.skip = '(',
	105	.term = ')',
55a73324	106	.ftptype = NF_CT_FTP_EPSV,
7d8c5018 PM	107	.getnum = try_epsv_response,
7d8c5018 PM	108	},
9fb9cbb1 YK	109	},
	110	};
	111
9fb9cbb1 YK	112	static int
	113	get_ipv6_addr(const char src, size_t dlen, struct in6_addr dst, u_int8_t term)
	114	{
6a28ec8c DM	115	const char *end;
6a28ec8c DM	116	int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
1884f78c YH	117	if (ret > 0)
	118	return (int)(end - src);
	119	return 0;
9fb9cbb1 YK	120	}
	121
	122	static int try_number(const char *data, size_t dlen, u_int32_t array[],
601e68e1	123	int array_size, char sep, char term)
9fb9cbb1 YK	124	{
	125	u_int32_t i, len;
	126
	127	memset(array, 0, sizeof(array[0])*array_size);
	128
	129	/* Keep data pointing at next char. */
	130	for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
	131	if (data >= '0' && data <= '9') {
	132	array[i] = array[i]10 + data - '0';
	133	}
	134	else if (*data == sep)
	135	i++;
	136	else {
	137	/* Unexpected character; true if it's the
4e7dba99 JM	138	terminator (or we don't care about one)
	139	and we're finished. */
	140	if ((*data == term \|\| !term) && i == array_size - 1)
9fb9cbb1 YK	141	return len;
9fb9cbb1 YK	142
0d53778e PM	143	pr_debug("Char %u (got %u nums) `%u' unexpected\n",
0d53778e PM	144	len, i, *data);
9fb9cbb1 YK	145	return 0;
	146	}
	147	}
0d53778e PM	148	pr_debug("Failed to fill %u numbers separated by %c\n",
0d53778e PM	149	array_size, sep);
9fb9cbb1 YK	150	return 0;
	151	}
	152
	153	/* Returns 0, or length of numbers: 192,168,1,1,5,6 */
	154	static int try_rfc959(const char *data, size_t dlen,
4e7dba99 JM	155	struct nf_conntrack_man *cmd, char term,
4e7dba99 JM	156	unsigned int *offset)
9fb9cbb1 YK	157	{
	158	int length;
	159	u_int32_t array[6];
	160
	161	length = try_number(data, dlen, array, 6, ',', term);
	162	if (length == 0)
	163	return 0;
	164
	165	cmd->u3.ip = htonl((array[0] << 24) \| (array[1] << 16) \|
	166	(array[2] << 8) \| array[3]);
	167	cmd->u.tcp.port = htons((array[4] << 8) \| array[5]);
	168	return length;
	169	}
	170
4e7dba99 JM	171	/*
	172	* From RFC 1123:
	173	* The format of the 227 reply to a PASV command is not
	174	* well standardized. In particular, an FTP client cannot
	175	* assume that the parentheses shown on page 40 of RFC-959
	176	* will be present (and in fact, Figure 3 on page 43 omits
	177	* them). Therefore, a User-FTP program that interprets
	178	* the PASV reply must scan the reply for the first digit
	179	* of the host and port numbers.
	180	*/
	181	static int try_rfc1123(const char *data, size_t dlen,
	182	struct nf_conntrack_man *cmd, char term,
	183	unsigned int *offset)
	184	{
	185	int i;
	186	for (i = 0; i < dlen; i++)
	187	if (isdigit(data[i]))
	188	break;
	189
	190	if (i == dlen)
	191	return 0;
	192
	193	*offset += i;
	194
	195	return try_rfc959(data + i, dlen - i, cmd, 0, offset);
	196	}
	197
9fb9cbb1 YK	198	/* Grab port: number up to delimiter */
9fb9cbb1 YK	199	static int get_port(const char *data, int start, size_t dlen, char delim,
bff9a89b	200	__be16 *port)
9fb9cbb1 YK	201	{
	202	u_int16_t tmp_port = 0;
	203	int i;
	204
	205	for (i = start; i < dlen; i++) {
	206	/* Finished? */
	207	if (data[i] == delim) {
	208	if (tmp_port == 0)
	209	break;
	210	*port = htons(tmp_port);
0d53778e	211	pr_debug("get_port: return %d\n", tmp_port);
9fb9cbb1 YK	212	return i + 1;
	213	}
	214	else if (data[i] >= '0' && data[i] <= '9')
	215	tmp_port = tmp_port*10 + data[i] - '0';
	216	else { /* Some other crap */
0d53778e	217	pr_debug("get_port: invalid char.\n");
9fb9cbb1 YK	218	break;
	219	}
	220	}
	221	return 0;
	222	}
	223
	224	/* Returns 0, or length of numbers: \|1\|132.235.1.2\|6275\| or \|2\|3ffe::1\|6275\| */
	225	static int try_eprt(const char data, size_t dlen, struct nf_conntrack_man cmd,
4e7dba99	226	char term, unsigned int *offset)
9fb9cbb1 YK	227	{
	228	char delim;
	229	int length;
	230
	231	/* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
	232	then delimiter again. */
	233	if (dlen <= 3) {
0d53778e	234	pr_debug("EPRT: too short\n");
9fb9cbb1 YK	235	return 0;
	236	}
	237	delim = data[0];
	238	if (isdigit(delim) \|\| delim < 33 \|\| delim > 126 \|\| data[2] != delim) {
8d6c0eaa	239	pr_debug("try_eprt: invalid delimiter.\n");
9fb9cbb1 YK	240	return 0;
	241	}
	242
	243	if ((cmd->l3num == PF_INET && data[1] != '1') \|\|
	244	(cmd->l3num == PF_INET6 && data[1] != '2')) {
0d53778e	245	pr_debug("EPRT: invalid protocol number.\n");
9fb9cbb1 YK	246	return 0;
	247	}
	248
0d53778e	249	pr_debug("EPRT: Got %c%c%c\n", delim, data[1], delim);
9fb9cbb1 YK	250
	251	if (data[1] == '1') {
	252	u_int32_t array[4];
	253
	254	/* Now we have IP address. */
	255	length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
	256	if (length != 0)
	257	cmd->u3.ip = htonl((array[0] << 24) \| (array[1] << 16)
	258	\| (array[2] << 8) \| array[3]);
	259	} else {
	260	/* Now we have IPv6 address. */
	261	length = get_ipv6_addr(data + 3, dlen - 3,
	262	(struct in6_addr *)cmd->u3.ip6, delim);
	263	}
	264
	265	if (length == 0)
	266	return 0;
0d53778e	267	pr_debug("EPRT: Got IP address!\n");
9fb9cbb1 YK	268	/* Start offset includes initial "\|1\|", and trailing delimiter */
	269	return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
	270	}
	271
	272	/* Returns 0, or length of numbers: \|\|\|6446\| */
	273	static int try_epsv_response(const char *data, size_t dlen,
4e7dba99 JM	274	struct nf_conntrack_man *cmd, char term,
4e7dba99 JM	275	unsigned int *offset)
9fb9cbb1 YK	276	{
	277	char delim;
	278
	279	/* Three delimiters. */
	280	if (dlen <= 3) return 0;
	281	delim = data[0];
f64f9e71 JP	282	if (isdigit(delim) \|\| delim < 33 \|\| delim > 126 \|\|
f64f9e71 JP	283	data[1] != delim \|\| data[2] != delim)
9fb9cbb1 YK	284	return 0;
	285
	286	return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
	287	}
	288
	289	/* Return 1 for match, 0 for accept, -1 for partial. */
	290	static int find_pattern(const char *data, size_t dlen,
	291	const char *pattern, size_t plen,
	292	char skip, char term,
	293	unsigned int *numoff,
	294	unsigned int *numlen,
	295	struct nf_conntrack_man *cmd,
	296	int (getnum)(const char , size_t,
4e7dba99 JM	297	struct nf_conntrack_man *, char,
4e7dba99 JM	298	unsigned int *))
9fb9cbb1	299	{
4e7dba99	300	size_t i = plen;
9fb9cbb1	301
5b5e0928	302	pr_debug("find_pattern `%s': dlen = %zu\n", pattern, dlen);
9fb9cbb1 YK	303
	304	if (dlen <= plen) {
	305	/* Short packet: try for partial? */
18082746	306	if (strncasecmp(data, pattern, dlen) == 0)
9fb9cbb1 YK	307	return -1;
	308	else return 0;
	309	}
	310
ddb075b0	311	if (strncasecmp(data, pattern, plen) != 0)
9fb9cbb1	312	return 0;
9fb9cbb1	313
0d53778e	314	pr_debug("Pattern matches!\n");
9fb9cbb1 YK	315	/* Now we've found the constant string, try to skip
9fb9cbb1 YK	316	to the 'skip' character */
4e7dba99 JM	317	if (skip) {
	318	for (i = plen; data[i] != skip; i++)
	319	if (i == dlen - 1) return -1;
9fb9cbb1	320
4e7dba99 JM	321	/* Skip over the last character */
	322	i++;
	323	}
9fb9cbb1	324
0d53778e	325	pr_debug("Skipped up to `%c'!\n", skip);
9fb9cbb1 YK	326
9fb9cbb1 YK	327	*numoff = i;
4e7dba99	328	*numlen = getnum(data + i, dlen - i, cmd, term, numoff);
9fb9cbb1 YK	329	if (!*numlen)
	330	return -1;
	331
0d53778e	332	pr_debug("Match succeeded!\n");
9fb9cbb1 YK	333	return 1;
	334	}
	335
	336	/* Look up to see if we're just after a \n. */
55a73324	337	static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir)
9fb9cbb1 YK	338	{
	339	unsigned int i;
	340
	341	for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
	342	if (info->seq_aft_nl[dir][i] == seq)
	343	return 1;
	344	return 0;
	345	}
	346
	347	/* We don't update if it's older than what we have. */
a71996fc AD	348	static void update_nl_seq(struct nf_conn *ct, u32 nl_seq,
a71996fc AD	349	struct nf_ct_ftp_master *info, int dir,
9fb9cbb1 YK	350	struct sk_buff *skb)
9fb9cbb1 YK	351	{
aaff23a9	352	unsigned int i, oldest;
9fb9cbb1 YK	353
	354	/* Look for oldest: if we find exact match, we're done. */
	355	for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
	356	if (info->seq_aft_nl[dir][i] == nl_seq)
	357	return;
9fb9cbb1 YK	358	}
	359
	360	if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
	361	info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
aaff23a9 PM	362	} else {
	363	if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1]))
	364	oldest = 0;
	365	else
	366	oldest = 1;
	367
	368	if (after(nl_seq, info->seq_aft_nl[dir][oldest]))
	369	info->seq_aft_nl[dir][oldest] = nl_seq;
9fb9cbb1 YK	370	}
	371	}
	372
3db05fea	373	static int help(struct sk_buff *skb,
9fb9cbb1 YK	374	unsigned int protoff,
	375	struct nf_conn *ct,
	376	enum ip_conntrack_info ctinfo)
	377	{
	378	unsigned int dataoff, datalen;
58c0fb0d JE	379	const struct tcphdr *th;
	380	struct tcphdr _tcph;
	381	const char *fb_ptr;
9fb9cbb1 YK	382	int ret;
	383	u32 seq;
	384	int dir = CTINFO2DIR(ctinfo);
d6e8cc6c	385	unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff);
1afc5679	386	struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct);
9fb9cbb1	387	struct nf_conntrack_expect *exp;
643a2c15	388	union nf_inet_addr *daddr;
9fb9cbb1	389	struct nf_conntrack_man cmd = {};
9fb9cbb1 YK	390	unsigned int i;
9fb9cbb1 YK	391	int found = 0, ends_in_nl;
337fbc41	392	typeof(nf_nat_ftp_hook) nf_nat_ftp;
9fb9cbb1 YK	393
9fb9cbb1 YK	394	/* Until there's been traffic both ways, don't look in packets. */
f64f9e71	395	if (ctinfo != IP_CT_ESTABLISHED &&
fb048833	396	ctinfo != IP_CT_ESTABLISHED_REPLY) {
0d53778e	397	pr_debug("ftp: Conntrackinfo = %u\n", ctinfo);
9fb9cbb1 YK	398	return NF_ACCEPT;
	399	}
	400
3db05fea	401	th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
9fb9cbb1 YK	402	if (th == NULL)
	403	return NF_ACCEPT;
	404
	405	dataoff = protoff + th->doff * 4;
	406	/* No data? */
3db05fea	407	if (dataoff >= skb->len) {
0d53778e	408	pr_debug("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
3db05fea	409	skb->len);
9fb9cbb1 YK	410	return NF_ACCEPT;
9fb9cbb1 YK	411	}
3db05fea	412	datalen = skb->len - dataoff;
9fb9cbb1 YK	413
9fb9cbb1 YK	414	spin_lock_bh(&nf_ftp_lock);
3db05fea	415	fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer);
9fb9cbb1 YK	416	BUG_ON(fb_ptr == NULL);
	417
	418	ends_in_nl = (fb_ptr[datalen - 1] == '\n');
	419	seq = ntohl(th->seq) + datalen;
	420
	421	/* Look up to see if we're just after a \n. */
	422	if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
7be54ca4 PNA	423	/* We're picking up this, clear flags and let it continue */
	424	if (unlikely(ct_ftp_info->flags[dir] & NF_CT_FTP_SEQ_PICKUP)) {
	425	ct_ftp_info->flags[dir] ^= NF_CT_FTP_SEQ_PICKUP;
	426	goto skip_nl_seq;
	427	}
	428
9fb9cbb1	429	/* Now if this ends in \n, update ftp info. */
0d53778e PM	430	pr_debug("nf_conntrack_ftp: wrong seq pos %s(%u) or %s(%u)\n",
	431	ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
	432	ct_ftp_info->seq_aft_nl[dir][0],
	433	ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
	434	ct_ftp_info->seq_aft_nl[dir][1]);
9fb9cbb1 YK	435	ret = NF_ACCEPT;
	436	goto out_update_nl;
	437	}
	438
7be54ca4	439	skip_nl_seq:
601e68e1 YH	440	/* Initialize IP/IPv6 addr to expected address (it's not mentioned
601e68e1 YH	441	in EPSV responses) */
5e8fbe2a	442	cmd.l3num = nf_ct_l3num(ct);
9fb9cbb1 YK	443	memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
	444	sizeof(cmd.u3.all));
	445
7d8c5018	446	for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
9fb9cbb1	447	found = find_pattern(fb_ptr, datalen,
7d8c5018 PM	448	search[dir][i].pattern,
	449	search[dir][i].plen,
	450	search[dir][i].skip,
	451	search[dir][i].term,
9fb9cbb1 YK	452	&matchoff, &matchlen,
9fb9cbb1 YK	453	&cmd,
7d8c5018	454	search[dir][i].getnum);
9fb9cbb1 YK	455	if (found) break;
	456	}
	457	if (found == -1) {
	458	/* We don't usually drop packets. After all, this is
	459	connection tracking, not packet filtering.
	460	However, it is necessary for accurate tracking in
	461	this case. */
b20ab9cc PNA	462	nf_ct_helper_log(skb, ct, "partial matching of `%s'",
b20ab9cc PNA	463	search[dir][i].pattern);
9fb9cbb1 YK	464	ret = NF_DROP;
	465	goto out;
	466	} else if (found == 0) { /* No match */
	467	ret = NF_ACCEPT;
	468	goto out_update_nl;
	469	}
	470
0d53778e PM	471	pr_debug("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
	472	matchlen, fb_ptr + matchoff,
	473	matchlen, ntohl(th->seq) + matchoff);
9fb9cbb1	474
6823645d	475	exp = nf_ct_expect_alloc(ct);
9fb9cbb1	476	if (exp == NULL) {
b20ab9cc	477	nf_ct_helper_log(skb, ct, "cannot alloc expectation");
9fb9cbb1 YK	478	ret = NF_DROP;
	479	goto out;
	480	}
	481
	482	/* We refer to the reverse direction ("!dir") tuples here,
	483	* because we're expecting something in the other direction.
	484	* Doesn't matter unless NAT is happening. */
df43b4e7	485	daddr = &ct->tuplehash[!dir].tuple.dst.u3;
9fb9cbb1 YK	486
9fb9cbb1 YK	487	/* Update the ftp info */
5e8fbe2a	488	if ((cmd.l3num == nf_ct_l3num(ct)) &&
9fb9cbb1 YK	489	memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
	490	sizeof(cmd.u3.all))) {
	491	/* Enrico Scholz's passive FTP to partially RNAT'd ftp
601e68e1 YH	492	server: it really wants us to connect to a
	493	different IP address. Simply don't record it for
	494	NAT. */
9fb9cbb1	495	if (cmd.l3num == PF_INET) {
ad6d9503	496	pr_debug("NOT RECORDING: %pI4 != %pI4\n",
14d5e834 HH	497	&cmd.u3.ip,
14d5e834 HH	498	&ct->tuplehash[dir].tuple.src.u3.ip);
9fb9cbb1	499	} else {
ad6d9503	500	pr_debug("NOT RECORDING: %pI6 != %pI6\n",
38ff4fa4 HH	501	cmd.u3.ip6,
38ff4fa4 HH	502	ct->tuplehash[dir].tuple.src.u3.ip6);
9fb9cbb1 YK	503	}
	504
	505	/* Thanks to Cristiano Lincoln Mattos
	506	<lincoln@cesar.org.br> for reporting this potential
	507	problem (DMZ machines opening holes to internal
	508	networks, or the packet filter itself). */
	509	if (!loose) {
	510	ret = NF_ACCEPT;
	511	goto out_put_expect;
	512	}
df43b4e7	513	daddr = &cmd.u3;
9fb9cbb1 YK	514	}
9fb9cbb1 YK	515
6002f266	516	nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, cmd.l3num,
df43b4e7 PM	517	&ct->tuplehash[!dir].tuple.src.u3, daddr,
df43b4e7 PM	518	IPPROTO_TCP, NULL, &cmd.u.tcp.port);
9fb9cbb1 YK	519
	520	/* Now, NAT might want to mangle the packet, and register the
	521	* (possibly changed) expectation itself. */
337fbc41	522	nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook);
d33cbeeb	523	if (nf_nat_ftp && ct->status & IPS_NAT_MASK)
3db05fea	524	ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype,
051966c0	525	protoff, matchoff, matchlen, exp);
9fb9cbb1 YK	526	else {
9fb9cbb1 YK	527	/* Can't expect this? Best to drop packet now. */
3c00fb0b	528	if (nf_ct_expect_related(exp, 0) != 0) {
b20ab9cc	529	nf_ct_helper_log(skb, ct, "cannot add expectation");
9fb9cbb1	530	ret = NF_DROP;
b20ab9cc	531	} else
9fb9cbb1 YK	532	ret = NF_ACCEPT;
	533	}
	534
	535	out_put_expect:
6823645d	536	nf_ct_expect_put(exp);
9fb9cbb1 YK	537
	538	out_update_nl:
	539	/* Now if this ends in \n, update ftp info. Seq may have been
	540	* adjusted by NAT code. */
	541	if (ends_in_nl)
a71996fc	542	update_nl_seq(ct, seq, ct_ftp_info, dir, skb);
9fb9cbb1 YK	543	out:
	544	spin_unlock_bh(&nf_ftp_lock);
	545	return ret;
	546	}
	547
7be54ca4 PNA	548	static int nf_ct_ftp_from_nlattr(struct nlattr attr, struct nf_conn ct)
	549	{
	550	struct nf_ct_ftp_master *ftp = nfct_help_data(ct);
	551
	552	/* This conntrack has been injected from user-space, always pick up
	553	* sequence tracking. Otherwise, the first FTP command after the
	554	* failover breaks.
	555	*/
	556	ftp->flags[IP_CT_DIR_ORIGINAL] \|= NF_CT_FTP_SEQ_PICKUP;
	557	ftp->flags[IP_CT_DIR_REPLY] \|= NF_CT_FTP_SEQ_PICKUP;
	558	return 0;
	559	}
	560
82de0be6	561	static struct nf_conntrack_helper ftp[MAX_PORTS * 2] __read_mostly;
9fb9cbb1	562
6002f266 PM	563	static const struct nf_conntrack_expect_policy ftp_exp_policy = {
	564	.max_expected = 1,
	565	.timeout = 5 * 60,
	566	};
	567
35341a61	568	static void __exit nf_conntrack_ftp_fini(void)
9fb9cbb1	569	{
82de0be6	570	nf_conntrack_helpers_unregister(ftp, ports_c * 2);
9fb9cbb1 YK	571	kfree(ftp_buffer);
	572	}
	573
65b4b4e8	574	static int __init nf_conntrack_ftp_init(void)
9fb9cbb1	575	{
82de0be6	576	int i, ret = 0;
9fb9cbb1	577
dcf67740 FW	578	NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_ftp_master));
dcf67740 FW	579
9fb9cbb1 YK	580	ftp_buffer = kmalloc(65536, GFP_KERNEL);
	581	if (!ftp_buffer)
	582	return -ENOMEM;
	583
	584	if (ports_c == 0)
	585	ports[ports_c++] = FTP_PORT;
	586
	587	/* FIXME should be configurable whether IPv4 and IPv6 FTP connections
	588	are tracked or not - YK */
	589	for (i = 0; i < ports_c; i++) {
08010a21 FL	590	nf_ct_helper_init(&ftp[2 * i], AF_INET, IPPROTO_TCP,
	591	HELPER_NAME, FTP_PORT, ports[i], ports[i],
	592	&ftp_exp_policy, 0, help,
	593	nf_ct_ftp_from_nlattr, THIS_MODULE);
	594	nf_ct_helper_init(&ftp[2 * i + 1], AF_INET6, IPPROTO_TCP,
	595	HELPER_NAME, FTP_PORT, ports[i], ports[i],
	596	&ftp_exp_policy, 0, help,
	597	nf_ct_ftp_from_nlattr, THIS_MODULE);
82de0be6 GF	598	}
	599
	600	ret = nf_conntrack_helpers_register(ftp, ports_c * 2);
	601	if (ret < 0) {
	602	pr_err("failed to register helpers\n");
	603	kfree(ftp_buffer);
	604	return ret;
9fb9cbb1 YK	605	}
	606
	607	return 0;
	608	}
	609
65b4b4e8 AM	610	module_init(nf_conntrack_ftp_init);
65b4b4e8 AM	611	module_exit(nf_conntrack_ftp_fini);