Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 501 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/ip_conntrack_ftp.c b/net/ipv4/netfilter/ip_conntrack_ftp.c
new file mode 100644
index 00000000000..12b88cbb11d
--- /dev/null
+++ b/net/ipv4/netfilter/ip_conntrack_ftp.c
@@ -0,0 +1,501 @@
+/* FTP extension for IP connection tracking. */
+
+/* (C) 1999-2001 Paul `Rusty' Russell  
+ * (C) 2002-2004 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/config.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/ip.h>
+#include <linux/ctype.h>
+#include <net/checksum.h>
+#include <net/tcp.h>
+
+#include <linux/netfilter_ipv4/lockhelp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
+#include <linux/netfilter_ipv4/ip_conntrack_ftp.h>
+#include <linux/moduleparam.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
+MODULE_DESCRIPTION("ftp connection tracking helper");
+
+/* This is slow, but it's simple. --RR */
+static char ftp_buffer[65536];
+
+static DECLARE_LOCK(ip_ftp_lock);
+
+#define MAX_PORTS 8
+static int ports[MAX_PORTS];
+static int ports_c;
+module_param_array(ports, int, &ports_c, 0400);
+
+static int loose;
+module_param(loose, int, 0600);
+
+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);
+EXPORT_SYMBOL_GPL(ip_nat_ftp_hook);
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static int try_rfc959(const char *, size_t, u_int32_t [], char);
+static int try_eprt(const char *, size_t, u_int32_t [], char);
+static int try_epsv_response(const char *, size_t, u_int32_t [], char);
+
+static struct ftp_search {
+	enum ip_conntrack_dir dir;
+	const char *pattern;
+	size_t plen;
+	char skip;
+	char term;
+	enum ip_ct_ftp_type ftptype;
+	int (*getnum)(const char *, size_t, u_int32_t[], char);
+} search[] = {
+	{
+		IP_CT_DIR_ORIGINAL,
+		"PORT",	sizeof("PORT") - 1, ' ', '\r',
+		IP_CT_FTP_PORT,
+		try_rfc959,
+	},
+	{
+		IP_CT_DIR_REPLY,
+		"227 ",	sizeof("227 ") - 1, '(', ')',
+		IP_CT_FTP_PASV,
+		try_rfc959,
+	},
+	{
+		IP_CT_DIR_ORIGINAL,
+		"EPRT", sizeof("EPRT") - 1, ' ', '\r',
+		IP_CT_FTP_EPRT,
+		try_eprt,
+	},
+	{
+		IP_CT_DIR_REPLY,
+		"229 ", sizeof("229 ") - 1, '(', ')',
+		IP_CT_FTP_EPSV,
+		try_epsv_response,
+	},
+};
+
+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 and we're finished. */
+			if (*data == term && i == array_size - 1)
+				return len;
+
+			DEBUGP("Char %u (got %u nums) `%u' unexpected\n",
+			       len, i, *data);
+			return 0;
+		}
+	}
+	DEBUGP("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, u_int32_t array[6],
+		       char term)
+{
+	return try_number(data, dlen, array, 6, ',', term);
+}
+
+/* Grab port: number up to delimiter */
+static int get_port(const char *data, int start, size_t dlen, char delim,
+		    u_int32_t array[2])
+{
+	u_int16_t port = 0;
+	int i;
+
+	for (i = start; i < dlen; i++) {
+		/* Finished? */
+		if (data[i] == delim) {
+			if (port == 0)
+				break;
+			array[0] = port >> 8;
+			array[1] = port;
+			return i + 1;
+		}
+		else if (data[i] >= '0' && data[i] <= '9')
+			port = port*10 + data[i] - '0';
+		else /* Some other crap */
+			break;
+	}
+	return 0;
+}
+
+/* Returns 0, or length of numbers: |1|132.235.1.2|6275| */
+static int try_eprt(const char *data, size_t dlen, u_int32_t array[6],
+		    char term)
+{
+	char delim;
+	int length;
+
+	/* First character is delimiter, then "1" for IPv4, then
+           delimiter again. */
+	if (dlen <= 3) return 0;
+	delim = data[0];
+	if (isdigit(delim) || delim < 33 || delim > 126
+	    || data[1] != '1' || data[2] != delim)
+		return 0;
+
+	DEBUGP("EPRT: Got |1|!\n");
+	/* Now we have IP address. */
+	length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
+	if (length == 0)
+		return 0;
+
+	DEBUGP("EPRT: Got IP address!\n");
+	/* Start offset includes initial "|1|", and trailing delimiter */
+	return get_port(data, 3 + length + 1, dlen, delim, array+4);
+}
+
+/* Returns 0, or length of numbers: |||6446| */
+static int try_epsv_response(const char *data, size_t dlen, u_int32_t array[6],
+			     char term)
+{
+	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, array+4);
+}
+
+/* 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,
+			u_int32_t array[6],
+			int (*getnum)(const char *, size_t, u_int32_t[], char))
+{
+	size_t i;
+
+	DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen);
+	if (dlen == 0)
+		return 0;
+
+	if (dlen <= plen) {
+		/* Short packet: try for partial? */
+		if (strnicmp(data, pattern, dlen) == 0)
+			return -1;
+		else return 0;
+	}
+
+	if (strnicmp(data, pattern, plen) != 0) {
+#if 0
+		size_t i;
+
+		DEBUGP("ftp: string mismatch\n");
+		for (i = 0; i < plen; i++) {
+			DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
+				i, data[i], data[i],
+				pattern[i], pattern[i]);
+		}
+#endif
+		return 0;
+	}
+
+	DEBUGP("Pattern matches!\n");
+	/* Now we've found the constant string, try to skip
+	   to the 'skip' character */
+	for (i = plen; data[i] != skip; i++)
+		if (i == dlen - 1) return -1;
+
+	/* Skip over the last character */
+	i++;
+
+	DEBUGP("Skipped up to `%c'!\n", skip);
+
+	*numoff = i;
+	*numlen = getnum(data + i, dlen - i, array, term);
+	if (!*numlen)
+		return -1;
+
+	DEBUGP("Match succeeded!\n");
+	return 1;
+}
+
+/* Look up to see if we're just after a \n. */
+static int find_nl_seq(u16 seq, const struct ip_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(u16 nl_seq, struct ip_ct_ftp_master *info, int dir)
+{
+	unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
+
+	/* 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 (oldest == info->seq_aft_nl_num[dir]
+		    || before(info->seq_aft_nl[dir][i], oldest))
+			oldest = i;
+	}
+
+	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 (oldest != NUM_SEQ_TO_REMEMBER)
+		info->seq_aft_nl[dir][oldest] = nl_seq;
+}
+
+static int help(struct sk_buff **pskb,
+		struct ip_conntrack *ct,
+		enum ip_conntrack_info ctinfo)
+{
+	unsigned int dataoff, datalen;
+	struct tcphdr _tcph, *th;
+	char *fb_ptr;
+	int ret;
+	u32 seq, array[6] = { 0 };
+	int dir = CTINFO2DIR(ctinfo);
+	unsigned int matchlen, matchoff;
+	struct ip_ct_ftp_master *ct_ftp_info = &ct->help.ct_ftp_info;
+	struct ip_conntrack_expect *exp;
+	unsigned int i;
+	int found = 0, ends_in_nl;
+
+	/* Until there's been traffic both ways, don't look in packets. */
+	if (ctinfo != IP_CT_ESTABLISHED
+	    && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
+		DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo);
+		return NF_ACCEPT;
+	}
+
+	th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl*4,
+				sizeof(_tcph), &_tcph);
+	if (th == NULL)
+		return NF_ACCEPT;
+
+	dataoff = (*pskb)->nh.iph->ihl*4 + th->doff*4;
+	/* No data? */
+	if (dataoff >= (*pskb)->len) {
+		DEBUGP("ftp: pskblen = %u\n", (*pskb)->len);
+		return NF_ACCEPT;
+	}
+	datalen = (*pskb)->len - dataoff;
+
+	LOCK_BH(&ip_ftp_lock);
+	fb_ptr = skb_header_pointer(*pskb, dataoff,
+				    (*pskb)->len - dataoff, 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)) {
+		/* Now if this ends in \n, update ftp info. */
+		DEBUGP("ip_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n",
+		       ct_ftp_info->seq_aft_nl[0][dir] 
+		       old_seq_aft_nl_set ? "":"(UNSET) ", old_seq_aft_nl);
+		ret = NF_ACCEPT;
+		goto out_update_nl;
+	}
+
+	/* Initialize IP array to expected address (it's not mentioned
+           in EPSV responses) */
+	array[0] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 24) & 0xFF;
+	array[1] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 16) & 0xFF;
+	array[2] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 8) & 0xFF;
+	array[3] = ntohl(ct->tuplehash[dir].tuple.src.ip) & 0xFF;
+
+	for (i = 0; i < ARRAY_SIZE(search); i++) {
+		if (search[i].dir != dir) continue;
+
+		found = find_pattern(fb_ptr, (*pskb)->len - dataoff,
+				     search[i].pattern,
+				     search[i].plen,
+				     search[i].skip,
+				     search[i].term,
+				     &matchoff, &matchlen,
+				     array,
+				     search[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. */
+		if (net_ratelimit())
+			printk("conntrack_ftp: partial %s %u+%u\n",
+			       search[i].pattern,
+			       ntohl(th->seq), datalen);
+		ret = NF_DROP;
+		goto out;
+	} else if (found == 0) { /* No match */
+		ret = NF_ACCEPT;
+		goto out_update_nl;
+	}
+
+	DEBUGP("conntrack_ftp: match `%s' (%u bytes at %u)\n",
+	       fb_ptr + matchoff, matchlen, ntohl(th->seq) + matchoff);
+			 
+	/* Allocate expectation which will be inserted */
+	exp = ip_conntrack_expect_alloc();
+	if (exp == NULL) {
+		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.  */
+	exp->tuple.dst.ip = ct->tuplehash[!dir].tuple.dst.ip;
+
+	if (htonl((array[0] << 24) | (array[1] << 16) | (array[2] << 8) | array[3])
+	    != ct->tuplehash[dir].tuple.src.ip) {
+		/* 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. */
+		DEBUGP("conntrack_ftp: NOT RECORDING: %u,%u,%u,%u != %u.%u.%u.%u\n",
+		       array[0], array[1], array[2], array[3],
+		       NIPQUAD(ct->tuplehash[dir].tuple.src.ip));
+
+		/* 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;
+			ip_conntrack_expect_free(exp);
+			goto out_update_nl;
+		}
+		exp->tuple.dst.ip = htonl((array[0] << 24) | (array[1] << 16)
+					 | (array[2] << 8) | array[3]);
+	}
+
+	exp->tuple.src.ip = ct->tuplehash[!dir].tuple.src.ip;
+	exp->tuple.dst.u.tcp.port = htons(array[4] << 8 | array[5]);
+	exp->tuple.src.u.tcp.port = 0; /* Don't care. */
+	exp->tuple.dst.protonum = IPPROTO_TCP;
+	exp->mask = ((struct ip_conntrack_tuple)
+		{ { 0xFFFFFFFF, { 0 } },
+		  { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFF }});
+
+	exp->expectfn = NULL;
+	exp->master = ct;
+
+	/* Now, NAT might want to mangle the packet, and register the
+	 * (possibly changed) expectation itself. */
+	if (ip_nat_ftp_hook)
+		ret = ip_nat_ftp_hook(pskb, ctinfo, search[i].ftptype,
+				      matchoff, matchlen, exp, &seq);
+	else {
+		/* Can't expect this?  Best to drop packet now. */
+		if (ip_conntrack_expect_related(exp) != 0) {
+			ip_conntrack_expect_free(exp);
+			ret = NF_DROP;
+		} else
+			ret = NF_ACCEPT;
+	}
+
+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(seq, ct_ftp_info,dir);
+ out:
+	UNLOCK_BH(&ip_ftp_lock);
+	return ret;
+}
+
+static struct ip_conntrack_helper ftp[MAX_PORTS];
+static char ftp_names[MAX_PORTS][10];
+
+/* Not __exit: called from init() */
+static void fini(void)
+{
+	int i;
+	for (i = 0; i < ports_c; i++) {
+		DEBUGP("ip_ct_ftp: unregistering helper for port %d\n",
+				ports[i]);
+		ip_conntrack_helper_unregister(&ftp[i]);
+	}
+}
+
+static int __init init(void)
+{
+	int i, ret;
+	char *tmpname;
+
+	if (ports_c == 0)
+		ports[ports_c++] = FTP_PORT;
+
+	for (i = 0; i < ports_c; i++) {
+		ftp[i].tuple.src.u.tcp.port = htons(ports[i]);
+		ftp[i].tuple.dst.protonum = IPPROTO_TCP;
+		ftp[i].mask.src.u.tcp.port = 0xFFFF;
+		ftp[i].mask.dst.protonum = 0xFF;
+		ftp[i].max_expected = 1;
+		ftp[i].timeout = 5 * 60; /* 5 minutes */
+		ftp[i].me = THIS_MODULE;
+		ftp[i].help = help;
+
+		tmpname = &ftp_names[i][0];
+		if (ports[i] == FTP_PORT)
+			sprintf(tmpname, "ftp");
+		else
+			sprintf(tmpname, "ftp-%d", ports[i]);
+		ftp[i].name = tmpname;
+
+		DEBUGP("ip_ct_ftp: registering helper for port %d\n", 
+				ports[i]);
+		ret = ip_conntrack_helper_register(&ftp[i]);
+
+		if (ret) {
+			fini();
+			return ret;
+		}
+	}
+	return 0;
+}
+
+module_init(init);
+module_exit(fini);