Add kernel parts of revived ipfilter (3.3.3.)

1 files changed, 460 insertions, 0 deletions

diff --git a/sys/netinet/ip_ftp_pxy.c b/sys/netinet/ip_ftp_pxy.c
new file mode 100644
index 0000000..0600617
--- /dev/null
+++ b/sys/netinet/ip_ftp_pxy.c
@@ -0,0 +1,460 @@
+/*
+ * Simple FTP transparent proxy for in-kernel use.  For use with the NAT
+ * code.
+ *
+ * $Id$
+ * $FreeBSD$
+ */
+#if SOLARIS && defined(_KERNEL)
+extern	kmutex_t	ipf_rw;
+#endif
+
+#define	isdigit(x)	((x) >= '0' && (x) <= '9')
+
+#define	IPF_FTP_PROXY
+
+#define	IPF_MINPORTLEN	18
+#define	IPF_MAXPORTLEN	30
+#define	IPF_MIN227LEN	39
+#define	IPF_MAX227LEN	51
+
+
+int ippr_ftp_init __P((void));
+int ippr_ftp_out __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
+int ippr_ftp_in __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
+int ippr_ftp_portmsg __P((fr_info_t *, ip_t *, nat_t *));
+int ippr_ftp_pasvmsg __P((fr_info_t *, ip_t *, nat_t *));
+
+u_short ipf_ftp_atoi __P((char **));
+
+static	frentry_t	natfr;
+
+
+/*
+ * Initialize local structures.
+ */
+int ippr_ftp_init()
+{
+	bzero((char *)&natfr, sizeof(natfr));
+	natfr.fr_ref = 1;
+	natfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
+	return 0;
+}
+
+
+/*
+ * ipf_ftp_atoi - implement a version of atoi which processes numbers in
+ * pairs separated by commas (which are expected to be in the range 0 - 255),
+ * returning a 16 bit number combining either side of the , as the MSB and
+ * LSB.
+ */
+u_short ipf_ftp_atoi(ptr)
+char **ptr;
+{
+	register char *s = *ptr, c;
+	register u_char i = 0, j = 0;
+
+	while ((c = *s++) && isdigit(c)) {
+		i *= 10;
+		i += c - '0';
+	}
+	if (c != ',') {
+		*ptr = NULL;
+		return 0;
+	}
+	while ((c = *s++) && isdigit(c)) {
+		j *= 10;
+		j += c - '0';
+	}
+	*ptr = s;
+	return (i << 8) | j;
+}
+
+
+int ippr_ftp_portmsg(fin, ip, nat)
+fr_info_t *fin;
+ip_t *ip;
+nat_t *nat;
+{
+	char portbuf[IPF_MAXPORTLEN + 1], newbuf[IPF_MAXPORTLEN + 1], *s;
+	tcphdr_t *tcp, tcph, *tcp2 = &tcph;
+	size_t nlen = 0, dlen, olen;
+	u_short a5, a6, sp, dp;
+	u_int a1, a2, a3, a4;
+	struct in_addr swip;
+	int off, inc = 0;
+	fr_info_t fi;
+	nat_t *ipn;
+	mb_t *m;
+#if	SOLARIS
+	mb_t *m1;
+#endif
+
+	tcp = (tcphdr_t *)fin->fin_dp;
+	bzero(portbuf, sizeof(portbuf));
+	off = (ip->ip_hl << 2) + (tcp->th_off << 2);
+
+#if	SOLARIS
+	m = fin->fin_qfm;
+
+	dlen = msgdsize(m) - off;
+	if (dlen > 0)
+		copyout_mblk(m, off, MIN(sizeof(portbuf), dlen), portbuf);
+#else
+	m = *(mb_t **)fin->fin_mp;
+
+	dlen = mbufchainlen(m) - off;
+	if (dlen > 0)
+		m_copydata(m, off, MIN(sizeof(portbuf), dlen), portbuf);
+#endif
+	if (dlen == 0)
+		return 0;
+	portbuf[sizeof(portbuf) - 1] = '\0';
+	*newbuf = '\0';
+	if (!strncmp(portbuf, "PORT ", 5)) { 
+		if (dlen < IPF_MINPORTLEN)
+			return 0;
+	} else
+		return 0;
+
+	/*
+	 * Skip the PORT command + space
+	 */
+	s = portbuf + 5;
+	/*
+	 * Pick out the address components, two at a time.
+	 */
+	a1 = ipf_ftp_atoi(&s);
+	if (!s)
+		return 0;
+	a2 = ipf_ftp_atoi(&s);
+	if (!s)
+		return 0;
+
+	/*
+	 * check that IP address in the PORT/PASV reply is the same as the
+	 * sender of the command - prevents using PORT for port scanning.
+	 */
+	a1 <<= 16;
+	a1 |= a2;
+	if (a1 != ntohl(nat->nat_inip.s_addr))
+		return 0;
+
+	a5 = ipf_ftp_atoi(&s);
+	if (!s)
+		return 0;
+	if (*s == ')')
+		s++;
+
+	/*
+	 * check for CR-LF at the end.
+	 */
+	if (*s == '\n')
+		s--;
+	if ((*s == '\r') && (*(s + 1) == '\n')) {
+		s += 2;
+		a6 = a5 & 0xff;
+	} else
+		return 0;
+	a5 >>= 8;
+	/*
+	 * Calculate new address parts for PORT command
+	 */
+	a1 = ntohl(ip->ip_src.s_addr);
+	a2 = (a1 >> 16) & 0xff;
+	a3 = (a1 >> 8) & 0xff;
+	a4 = a1 & 0xff;
+	a1 >>= 24;
+	olen = s - portbuf;
+	(void) snprintf(newbuf, sizeof(newbuf), "%s %u,%u,%u,%u,%u,%u\r\n",
+		       "PORT", a1, a2, a3, a4, a5, a6);
+
+	nlen = strlen(newbuf);
+	inc = nlen - olen;
+#if SOLARIS
+	for (m1 = m; m1->b_cont; m1 = m1->b_cont)
+		;
+	if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
+		mblk_t *nm;
+
+		/* alloc enough to keep same trailer space for lower driver */
+		nm = allocb(nlen, BPRI_MED);
+		PANIC((!nm),("ippr_ftp_out: allocb failed"));
+
+		nm->b_band = m1->b_band;
+		nm->b_wptr += nlen;
+
+		m1->b_wptr -= olen;
+		PANIC((m1->b_wptr < m1->b_rptr),
+		      ("ippr_ftp_out: cannot handle fragmented data block"));
+
+		linkb(m1, nm);
+	} else {
+		if (m1->b_datap->db_struiolim == m1->b_wptr)
+			m1->b_datap->db_struiolim += inc;
+		m1->b_datap->db_struioflag &= ~STRUIO_IP;
+		m1->b_wptr += inc;
+	}
+	copyin_mblk(m, off, nlen, newbuf);
+#else
+	if (inc < 0)
+		m_adj(m, inc);
+	/* the mbuf chain will be extended if necessary by m_copyback() */
+	m_copyback(m, off, nlen, newbuf);
+#endif
+	if (inc != 0) {
+#if SOLARIS || defined(__sgi)
+		register u_32_t	sum1, sum2;
+
+		sum1 = ip->ip_len;
+		sum2 = ip->ip_len + inc;
+
+		/* Because ~1 == -2, We really need ~1 == -1 */
+		if (sum1 > sum2)
+			sum2--;
+		sum2 -= sum1;
+		sum2 = (sum2 & 0xffff) + (sum2 >> 16);
+
+		fix_outcksum(&ip->ip_sum, sum2);
+#endif
+		ip->ip_len += inc;
+	}
+
+	/*
+	 * Add skeleton NAT entry for connection which will come back the
+	 * other way.
+	 */
+	sp = htons(a5 << 8 | a6);
+	/*
+	 * The server may not make the connection back from port 20, but
+	 * it is the most likely so use it here to check for a conflicting
+	 * mapping.
+	 */
+	dp = htons(fin->fin_data[1] - 1);
+	ipn = nat_outlookup(fin->fin_ifp, IPN_TCP, nat->nat_p, nat->nat_inip,
+			    ip->ip_dst, (dp << 16) | sp);
+	if (ipn == NULL) {
+		bcopy((char *)fin, (char *)&fi, sizeof(fi));
+		bzero((char *)tcp2, sizeof(*tcp2));
+		tcp2->th_win = htons(8192);
+		tcp2->th_sport = sp;
+		tcp2->th_dport = 0; /* XXX - don't specify remote port */
+		fi.fin_data[0] = ntohs(sp);
+		fi.fin_data[1] = 0;
+		fi.fin_dp = (char *)tcp2;
+		swip = ip->ip_src;
+		ip->ip_src = nat->nat_inip;
+		ipn = nat_new(nat->nat_ptr, ip, &fi, IPN_TCP|FI_W_DPORT,
+			      NAT_OUTBOUND);
+		if (ipn != NULL) {
+			ipn->nat_age = fr_defnatage;
+			(void) fr_addstate(ip, &fi, FI_W_DPORT);
+		}
+		ip->ip_src = swip;
+	}
+	return inc;
+}
+
+
+int ippr_ftp_out(fin, ip, aps, nat)
+fr_info_t *fin;
+ip_t *ip;
+ap_session_t *aps;
+nat_t *nat;
+{
+	return ippr_ftp_portmsg(fin, ip, nat);
+}
+
+
+int ippr_ftp_pasvmsg(fin, ip, nat)
+fr_info_t *fin;
+ip_t *ip;
+nat_t *nat;
+{
+	char portbuf[IPF_MAX227LEN + 1], newbuf[IPF_MAX227LEN + 1], *s;
+	int off, olen, dlen, nlen = 0, inc = 0;
+	tcphdr_t tcph, *tcp2 = &tcph;
+	struct in_addr swip, swip2;
+	u_short a5, a6, dp, sp;
+	u_int a1, a2, a3, a4;
+	tcphdr_t *tcp;
+	fr_info_t fi;
+	nat_t *ipn;
+	mb_t *m;
+#if	SOLARIS
+	mb_t *m1;
+#endif
+
+	tcp = (tcphdr_t *)fin->fin_dp;
+	off = (ip->ip_hl << 2) + (tcp->th_off << 2);
+	m = *(mb_t **)fin->fin_mp;
+	bzero(portbuf, sizeof(portbuf));
+
+#if	SOLARIS
+	m = fin->fin_qfm;
+
+	dlen = msgdsize(m) - off;
+	if (dlen > 0)
+		copyout_mblk(m, off, MIN(sizeof(portbuf), dlen), portbuf);
+#else
+	dlen = mbufchainlen(m) - off;
+	if (dlen > 0)
+		m_copydata(m, off, MIN(sizeof(portbuf), dlen), portbuf);
+#endif
+	if (dlen == 0)
+		return 0;
+	portbuf[sizeof(portbuf) - 1] = '\0';
+	*newbuf = '\0';
+
+	if (!strncmp(portbuf, "227 ", 4)) {
+		if (dlen < IPF_MIN227LEN)
+			return 0;
+		else if (strncmp(portbuf, "227 Entering Passive Mode", 25))
+			return 0;
+	} else
+		return 0;
+	/*
+	 * Skip the PORT command + space
+	 */
+	s = portbuf + 25;
+	while (*s && !isdigit(*s))
+		s++;
+	/*
+	 * Pick out the address components, two at a time.
+	 */
+	a1 = ipf_ftp_atoi(&s);
+	if (!s)
+		return 0;
+	a2 = ipf_ftp_atoi(&s);
+	if (!s)
+		return 0;
+
+	/*
+	 * check that IP address in the PORT/PASV reply is the same as the
+	 * sender of the command - prevents using PORT for port scanning.
+	 */
+	a1 <<= 16;
+	a1 |= a2;
+	if (a1 != ntohl(nat->nat_oip.s_addr))
+		return 0;
+
+	a5 = ipf_ftp_atoi(&s);
+	if (!s)
+		return 0;
+
+	if (*s == ')')
+		s++;
+	if (*s == '\n')
+		s--;
+	/*
+	 * check for CR-LF at the end.
+	 */
+	if ((*s == '\r') && (*(s + 1) == '\n')) {
+		s += 2;
+		a6 = a5 & 0xff;
+	} else
+		return 0;
+	a5 >>= 8;
+	/*
+	 * Calculate new address parts for 227 reply
+	 */
+	a1 = ntohl(ip->ip_src.s_addr);
+	a2 = (a1 >> 16) & 0xff;
+	a3 = (a1 >> 8) & 0xff;
+	a4 = a1 & 0xff;
+	a1 >>= 24;
+	olen = s - portbuf;
+	(void) sprintf(newbuf, "%s %u,%u,%u,%u,%u,%u\r\n",
+		       "227 Entering Passive Mode", a1, a2, a3, a4, a5, a6);
+
+	nlen = strlen(newbuf);
+	inc = nlen - olen;
+#if SOLARIS
+	for (m1 = m; m1->b_cont; m1 = m1->b_cont)
+		;
+	if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
+		mblk_t *nm;
+
+		/* alloc enough to keep same trailer space for lower driver */
+		nm = allocb(nlen, BPRI_MED);
+		PANIC((!nm),("ippr_ftp_out: allocb failed"));
+
+		nm->b_band = m1->b_band;
+		nm->b_wptr += nlen;
+
+		m1->b_wptr -= olen;
+		PANIC((m1->b_wptr < m1->b_rptr),
+		      ("ippr_ftp_out: cannot handle fragmented data block"));
+
+		linkb(m1, nm);
+	} else {
+		m1->b_wptr += inc;
+	}
+	copyin_mblk(m, off, nlen, newbuf);
+#else
+	if (inc < 0)
+		m_adj(m, inc);
+	/* the mbuf chain will be extended if necessary by m_copyback() */
+	m_copyback(m, off, nlen, newbuf);
+#endif
+	if (inc != 0) {
+#if SOLARIS || defined(__sgi)
+		register u_32_t	sum1, sum2;
+
+		sum1 = ip->ip_len;
+		sum2 = ip->ip_len + inc;
+
+		/* Because ~1 == -2, We really need ~1 == -1 */
+		if (sum1 > sum2)
+			sum2--;
+		sum2 -= sum1;
+		sum2 = (sum2 & 0xffff) + (sum2 >> 16);
+
+		fix_outcksum(&ip->ip_sum, sum2);
+#endif
+		ip->ip_len += inc;
+	}
+
+	/*
+	 * Add skeleton NAT entry for connection which will come back the
+	 * other way.
+	 */
+	sp = 0;
+	dp = htons(fin->fin_data[1] - 1);
+	ipn = nat_outlookup(fin->fin_ifp, IPN_TCP, nat->nat_p, nat->nat_inip,
+			    ip->ip_dst, (dp << 16) | sp);
+	if (ipn == NULL) {
+		bcopy((char *)fin, (char *)&fi, sizeof(fi));
+		bzero((char *)tcp2, sizeof(*tcp2));
+		tcp2->th_win = htons(8192);
+		tcp2->th_sport = 0;		/* XXX - fake it for nat_new */
+		fi.fin_data[0] = a5 << 8 | a6;
+		tcp2->th_dport = htons(fi.fin_data[0]);
+		fi.fin_data[1] = 0;
+		fi.fin_dp = (char *)tcp2;
+		swip = ip->ip_src;
+		swip2 = ip->ip_dst;
+		ip->ip_dst = ip->ip_src;
+		ip->ip_src = nat->nat_inip;
+		ipn = nat_new(nat->nat_ptr, ip, &fi, IPN_TCP|FI_W_SPORT,
+			      NAT_OUTBOUND);
+		if (ipn != NULL) {
+			ipn->nat_age = fr_defnatage;
+			(void) fr_addstate(ip, &fi, FI_W_SPORT);
+		}
+		ip->ip_src = swip;
+		ip->ip_dst = swip2;
+	}
+	return inc;
+}
+
+
+int ippr_ftp_in(fin, ip, aps, nat)
+fr_info_t *fin;
+ip_t *ip;
+ap_session_t *aps;
+nat_t *nat;
+{
+
+	return ippr_ftp_pasvmsg(fin, ip, nat);
+}