461 lines
9.6 KiB
C
461 lines
9.6 KiB
C
|
/*
|
||
|
|
* 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);
|
||
|
|
}
|