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NetBSD/sys/dist/ipf/netinet/ip_rpcb_pxy.c

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/* $NetBSD: ip_rpcb_pxy.c,v 1.12 2007/12/11 04:55:04 lukem Exp $ */
/*
* Copyright (C) 2002-2003 by Ryan Beasley <ryanb@goddamnbastard.org>
*
* See the IPFILTER.LICENCE file for details on licencing.
*/
/*
* Overview:
* This is an in-kernel application proxy for Sun's RPCBIND (nee portmap)
* protocol as defined in RFC1833. It is far from complete, mostly
* lacking in less-likely corner cases, but it's definitely functional.
*
* Invocation:
* rdr <int> <e_ip>/32 port <e_p> -> <i_ip> port <i_p> udp proxy rpcbu
*
* If the host running IP Filter is the same as the RPC server, it's
* perfectly legal for both the internal and external addresses and ports
* to match.
*
* When triggered by appropriate IP NAT rules, this proxy works by
* examining data contained in received packets. Requests and replies are
* modified, NAT and state table entries created, etc., as necessary.
*/
/*
* TODO / NOTES
*
* o Must implement locking to protect proxy session data.
* o Fragmentation isn't supported.
* o Only supports UDP.
* o Doesn't support multiple RPC records in a single request.
* o Errors should be more fine-grained. (e.g., malloc failure vs.
* illegal RPCB request / reply)
* o Even with the limit on the total amount of recorded transactions,
* should there be a timeout on transaction removal?
* o There is a potential collision between cloning, wildcard NAT and
* state entries. There should be an appr_getport routine for
* to avoid this.
* o The enclosed hack of STREAMS support is pretty sick and most likely
* broken.
*
* Id: ip_rpcb_pxy.c,v 2.25.2.6 2007/01/17 11:34:54 darrenr Exp
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(1, "$NetBSD: ip_rpcb_pxy.c,v 1.12 2007/12/11 04:55:04 lukem Exp $");
#define IPF_RPCB_PROXY
/*
* Function prototypes
*/
int ippr_rpcb_init __P((void));
void ippr_rpcb_fini __P((void));
int ippr_rpcb_new __P((fr_info_t *, ap_session_t *, nat_t *));
void ippr_rpcb_del __P((ap_session_t *));
int ippr_rpcb_in __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_rpcb_out __P((fr_info_t *, ap_session_t *, nat_t *));
static void ippr_rpcb_flush __P((rpcb_session_t *));
static int ippr_rpcb_decodereq __P((fr_info_t *, nat_t *,
rpcb_session_t *, rpc_msg_t *));
static int ippr_rpcb_skipauth __P((rpc_msg_t *, xdr_auth_t *, u_32_t **));
static int ippr_rpcb_insert __P((rpcb_session_t *, rpcb_xact_t *));
static int ippr_rpcb_xdrrpcb __P((rpc_msg_t *, u_32_t *, rpcb_args_t *));
static int ippr_rpcb_getuaddr __P((rpc_msg_t *, xdr_uaddr_t *,
u_32_t **));
static u_int ippr_rpcb_atoi __P((char *));
static int ippr_rpcb_modreq __P((fr_info_t *, nat_t *, rpc_msg_t *,
mb_t *, u_int));
static int ippr_rpcb_decoderep __P((fr_info_t *, nat_t *,
rpcb_session_t *, rpc_msg_t *, rpcb_xact_t **));
static rpcb_xact_t * ippr_rpcb_lookup __P((rpcb_session_t *, u_32_t));
static void ippr_rpcb_deref __P((rpcb_session_t *, rpcb_xact_t *));
static int ippr_rpcb_getproto __P((rpc_msg_t *, xdr_proto_t *,
u_32_t **));
static int ippr_rpcb_getnat __P((fr_info_t *, nat_t *, u_int, u_int));
static int ippr_rpcb_modv3 __P((fr_info_t *, nat_t *, rpc_msg_t *,
mb_t *, u_int));
static int ippr_rpcb_modv4 __P((fr_info_t *, nat_t *, rpc_msg_t *,
mb_t *, u_int));
static void ippr_rpcb_fixlen __P((fr_info_t *, int));
/*
* Global variables
*/
static frentry_t rpcbfr; /* Skeleton rule for reference by entities
this proxy creates. */
static int rpcbcnt; /* Upper bound of allocated RPCB sessions. */
/* XXX rpcbcnt still requires locking. */
int rpcb_proxy_init = 0;
/*
* Since rpc_msg contains only pointers, one should use this macro as a
* handy way to get to the goods. (In case you're wondering about the name,
* this started as BYTEREF -> BREF -> B.)
*/
#define B(r) (u_32_t)ntohl(*(r))
/*
* Public subroutines
*/
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_init */
/* Returns: int - 0 == success */
/* Parameters: (void) */
/* */
/* Initialize the filter rule entry and session limiter. */
/* -------------------------------------------------------------------- */
int
ippr_rpcb_init()
{
rpcbcnt = 0;
bzero((char *)&rpcbfr, sizeof(rpcbfr));
rpcbfr.fr_ref = 1;
rpcbfr.fr_flags = FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&rpcbfr.fr_lock, "ipf Sun RPCB proxy rule lock");
rpcb_proxy_init = 1;
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_fini */
/* Returns: void */
/* Parameters: (void) */
/* */
/* Destroy rpcbfr's mutex to avoid a lock leak. */
/* -------------------------------------------------------------------- */
void
ippr_rpcb_fini()
{
if (rpcb_proxy_init == 1) {
MUTEX_DESTROY(&rpcbfr.fr_lock);
rpcb_proxy_init = 0;
}
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_new */
/* Returns: int - -1 == failure, 0 == success */
/* Parameters: fin(I) - pointer to packet information */
/* aps(I) - pointer to proxy session structure */
/* nat(I) - pointer to NAT session structure */
/* */
/* Allocate resources for per-session proxy structures. */
/* -------------------------------------------------------------------- */
int
ippr_rpcb_new(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
rpcb_session_t *rs;
fin = fin; /* LINT */
nat = nat; /* LINT */
KMALLOC(rs, rpcb_session_t *);
if (rs == NULL)
return(-1);
bzero((char *)rs, sizeof(*rs));
MUTEX_INIT(&rs->rs_rxlock, "ipf Sun RPCB proxy session lock");
aps->aps_data = rs;
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_del */
/* Returns: void */
/* Parameters: aps(I) - pointer to proxy session structure */
/* */
/* Free up a session's list of RPCB requests. */
/* -------------------------------------------------------------------- */
void
ippr_rpcb_del(aps)
ap_session_t *aps;
{
rpcb_session_t *rs;
rs = (rpcb_session_t *)aps->aps_data;
MUTEX_ENTER(&rs->rs_rxlock);
ippr_rpcb_flush(rs);
MUTEX_EXIT(&rs->rs_rxlock);
MUTEX_DESTROY(&rs->rs_rxlock);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_in */
/* Returns: int - APR_ERR(1) == drop the packet, */
/* APR_ERR(2) == kill the proxy session, */
/* else change in packet length (in bytes) */
/* Parameters: fin(I) - pointer to packet information */
/* ip(I) - pointer to packet header */
/* aps(I) - pointer to proxy session structure */
/* nat(I) - pointer to NAT session structure */
/* */
/* Given a presumed RPCB request, perform some minor tests and pass off */
/* for decoding. Also pass packet off for a rewrite if necessary. */
/* -------------------------------------------------------------------- */
int
ippr_rpcb_in(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
rpc_msg_t rpcmsg, *rm;
rpcb_session_t *rs;
u_int off, dlen;
mb_t *m;
int rv;
/* Disallow fragmented or illegally short packets. */
if ((fin->fin_flx & (FI_FRAG|FI_SHORT)) != 0)
return(APR_ERR(1));
/* Perform basic variable initialization. */
rs = (rpcb_session_t *)aps->aps_data;
m = fin->fin_m;
off = (char *)fin->fin_dp - (char *)fin->fin_ip;
off += sizeof(udphdr_t) + fin->fin_ipoff;
dlen = fin->fin_dlen - sizeof(udphdr_t);
/* Disallow packets outside legal range for supported requests. */
if ((dlen < RPCB_REQMIN) || (dlen > RPCB_REQMAX))
return(APR_ERR(1));
/* Copy packet over to convenience buffer. */
rm = &rpcmsg;
bzero((char *)rm, sizeof(*rm));
COPYDATA(m, off, dlen, (void *)&rm->rm_msgbuf);
rm->rm_buflen = dlen;
/* Send off to decode request. */
rv = ippr_rpcb_decodereq(fin, nat, rs, rm);
switch(rv)
{
case -1:
return(APR_ERR(1));
/*NOTREACHED*/
break;
case 0:
break;
case 1:
rv = ippr_rpcb_modreq(fin, nat, rm, m, off);
break;
default:
/*CONSTANTCONDITION*/
IPF_PANIC(1, ("illegal rv %d (ippr_rpcb_req)", rv));
}
return(rv);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_out */
/* Returns: int - APR_ERR(1) == drop the packet, */
/* APR_ERR(2) == kill the proxy session, */
/* else change in packet length (in bytes) */
/* Parameters: fin(I) - pointer to packet information */
/* ip(I) - pointer to packet header */
/* aps(I) - pointer to proxy session structure */
/* nat(I) - pointer to NAT session structure */
/* */
/* Given a presumed RPCB reply, perform some minor tests and pass off */
/* for decoding. If the message indicates a successful request with */
/* valid addressing information, create NAT and state structures to */
/* allow direct communication between RPC client and server. */
/* -------------------------------------------------------------------- */
int
ippr_rpcb_out(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
rpc_msg_t rpcmsg, *rm;
rpcb_session_t *rs;
rpcb_xact_t *rx;
u_int off, dlen;
int rv, diff;
mb_t *m;
rx = NULL; /* XXX gcc */
/* Disallow fragmented or illegally short packets. */
if ((fin->fin_flx & (FI_FRAG|FI_SHORT)) != 0)
return(APR_ERR(1));
/* Perform basic variable initialization. */
rs = (rpcb_session_t *)aps->aps_data;
m = fin->fin_m;
off = (char *)fin->fin_dp - (char *)fin->fin_ip;
off += sizeof(udphdr_t) + fin->fin_ipoff;
dlen = fin->fin_dlen - sizeof(udphdr_t);
diff = 0;
/* Disallow packets outside legal range for supported requests. */
if ((dlen < RPCB_REPMIN) || (dlen > RPCB_REPMAX))
return(APR_ERR(1));
/* Copy packet over to convenience buffer. */
rm = &rpcmsg;
bzero((char *)rm, sizeof(*rm));
COPYDATA(m, off, dlen, (void *)&rm->rm_msgbuf);
rm->rm_buflen = dlen;
rx = NULL; /* XXX gcc */
/* Send off to decode reply. */
rv = ippr_rpcb_decoderep(fin, nat, rs, rm, &rx);
switch(rv)
{
case -1: /* Bad packet */
if (rx != NULL) {
MUTEX_ENTER(&rs->rs_rxlock);
ippr_rpcb_deref(rs, rx);
MUTEX_EXIT(&rs->rs_rxlock);
}
return(APR_ERR(1));
/*NOTREACHED*/
break;
case 0: /* Negative reply / request rejected */
break;
case 1: /* Positive reply */
/*
* With the IP address embedded in a GETADDR(LIST) reply,
* we'll need to rewrite the packet in the very possible
* event that the internal & external addresses aren't the
* same. (i.e., this box is either a router or rpcbind
* only listens on loopback.)
*/
if (nat->nat_inip.s_addr != nat->nat_outip.s_addr) {
if (rx->rx_type == RPCB_RES_STRING)
diff = ippr_rpcb_modv3(fin, nat, rm, m, off);
else if (rx->rx_type == RPCB_RES_LIST)
diff = ippr_rpcb_modv4(fin, nat, rm, m, off);
}
break;
default:
/*CONSTANTCONDITION*/
IPF_PANIC(1, ("illegal rv %d (ippr_rpcb_decoderep)", rv));
}
if (rx != NULL) {
MUTEX_ENTER(&rs->rs_rxlock);
/* XXX Gross hack - I'm overloading the reference
* counter to deal with both threads and retransmitted
* requests. One deref signals that this thread is
* finished with rx, and the other signals that we've
* processed its reply.
*/
ippr_rpcb_deref(rs, rx);
ippr_rpcb_deref(rs, rx);
MUTEX_EXIT(&rs->rs_rxlock);
}
return(diff);
}
/*
* Private support subroutines
*/
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_flush */
/* Returns: void */
/* Parameters: rs(I) - pointer to RPCB session structure */
/* */
/* Simply flushes the list of outstanding transactions, if any. */
/* -------------------------------------------------------------------- */
static void
ippr_rpcb_flush(rs)
rpcb_session_t *rs;
{
rpcb_xact_t *r1, *r2;
r1 = rs->rs_rxlist;
if (r1 == NULL)
return;
while (r1 != NULL) {
r2 = r1;
r1 = r1->rx_next;
KFREE(r2);
}
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_decodereq */
/* Returns: int - -1 == bad request or critical failure, */
/* 0 == request successfully decoded, */
/* 1 == request successfully decoded; requires */
/* address rewrite/modification */
/* Parameters: fin(I) - pointer to packet information */
/* nat(I) - pointer to NAT session structure */
/* rs(I) - pointer to RPCB session structure */
/* rm(I) - pointer to RPC message structure */
/* */
/* Take a presumed RPCB request, decode it, and store the results in */
/* the transaction list. If the internal target address needs to be */
/* modified, store its location in ptr. */
/* WARNING: It's the responsibility of the caller to make sure there */
/* is enough room in rs_buf for the basic RPC message "preamble". */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_decodereq(fin, nat, rs, rm)
fr_info_t *fin;
nat_t *nat;
rpcb_session_t *rs;
rpc_msg_t *rm;
{
rpcb_args_t *ra;
u_32_t xdr, *p;
rpc_call_t *rc;
rpcb_xact_t rx;
int mod;
p = (u_32_t *)rm->rm_msgbuf;
mod = 0;
bzero((char *)&rx, sizeof(rx));
rc = &rm->rm_call;
rm->rm_xid = p;
rx.rx_xid = B(p++); /* Record this message's XID. */
/* Parse out and test the RPC header. */
if ((B(p++) != RPCB_CALL) ||
(B(p++) != RPCB_MSG_VERSION) ||
(B(p++) != RPCB_PROG))
return(-1);
/* Record the RPCB version and procedure. */
rc->rc_vers = p++;
rc->rc_proc = p++;
/* Bypass RPC authentication stuff. */
if (ippr_rpcb_skipauth(rm, &rc->rc_authcred, &p) != 0)
return(-1);
if (ippr_rpcb_skipauth(rm, &rc->rc_authverf, &p) != 0)
return(-1);
/* Compare RPCB version and procedure numbers. */
switch(B(rc->rc_vers))
{
case 2:
/* This proxy only supports PMAP_GETPORT. */
if (B(rc->rc_proc) != RPCB_GETPORT)
return(-1);
/* Portmap requests contain four 4 byte parameters. */
if (RPCB_BUF_EQ(rm, p, 16) == 0)
return(-1);
p += 2; /* Skip requested program and version numbers. */
/* Sanity check the requested protocol. */
xdr = B(p);
if (!(xdr == IPPROTO_UDP || xdr == IPPROTO_TCP))
return(-1);
rx.rx_type = RPCB_RES_PMAP;
rx.rx_proto = xdr;
break;
case 3:
case 4:
/* GETADDRLIST is exclusive to v4; GETADDR for v3 & v4 */
switch(B(rc->rc_proc))
{
case RPCB_GETADDR:
rx.rx_type = RPCB_RES_STRING;
rx.rx_proto = (u_int)fin->fin_p;
break;
case RPCB_GETADDRLIST:
if (B(rc->rc_vers) != 4)
return(-1);
rx.rx_type = RPCB_RES_LIST;
break;
default:
return(-1);
}
ra = &rc->rc_rpcbargs;
/* Decode the 'struct rpcb' request. */
if (ippr_rpcb_xdrrpcb(rm, p, ra) != 0)
return(-1);
/* Are the target address & port valid? */
if ((ra->ra_maddr.xu_ip != nat->nat_outip.s_addr) ||
(ra->ra_maddr.xu_port != nat->nat_outport))
return(-1);
/* Do we need to rewrite this packet? */
if ((nat->nat_outip.s_addr != nat->nat_inip.s_addr) ||
(nat->nat_outport != nat->nat_inport))
mod = 1;
break;
default:
return(-1);
}
MUTEX_ENTER(&rs->rs_rxlock);
if (ippr_rpcb_insert(rs, &rx) != 0) {
MUTEX_EXIT(&rs->rs_rxlock);
return(-1);
}
MUTEX_EXIT(&rs->rs_rxlock);
return(mod);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_skipauth */
/* Returns: int -- -1 == illegal auth parameters (lengths) */
/* 0 == valid parameters, pointer advanced */
/* Parameters: rm(I) - pointer to RPC message structure */
/* auth(I) - pointer to RPC auth structure */
/* buf(IO) - pointer to location within convenience buffer */
/* */
/* Record auth data length & location of auth data, then advance past */
/* it. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_skipauth(rm, auth, buf)
rpc_msg_t *rm;
xdr_auth_t *auth;
u_32_t **buf;
{
u_32_t *p, xdr;
p = *buf;
/* Make sure we have enough space for expected fixed auth parms. */
if (RPCB_BUF_GEQ(rm, p, 8) == 0)
return(-1);
p++; /* We don't care about auth_flavor. */
auth->xa_string.xs_len = p;
xdr = B(p++); /* Length of auth_data */
/* Test for absurdity / illegality of auth_data length. */
if ((XDRALIGN(xdr) < xdr) || (RPCB_BUF_GEQ(rm, p, XDRALIGN(xdr)) == 0))
return(-1);
auth->xa_string.xs_str = (char *)p;
p += XDRALIGN(xdr); /* Advance our location. */
*buf = (u_32_t *)p;
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_insert */
/* Returns: int -- -1 == list insertion failed, */
/* 0 == item successfully added */
/* Parameters: rs(I) - pointer to RPCB session structure */
/* rx(I) - pointer to RPCB transaction structure */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_insert(rs, rx)
rpcb_session_t *rs;
rpcb_xact_t *rx;
{
rpcb_xact_t *rxp;
rxp = ippr_rpcb_lookup(rs, rx->rx_xid);
if (rxp != NULL) {
++rxp->rx_ref;
return(0);
}
if (rpcbcnt == RPCB_MAXREQS)
return(-1);
KMALLOC(rxp, rpcb_xact_t *);
if (rxp == NULL)
return(-1);
bcopy((char *)rx, (char *)rxp, sizeof(*rx));
if (rs->rs_rxlist != NULL)
rs->rs_rxlist->rx_pnext = &rxp->rx_next;
rxp->rx_pnext = &rs->rs_rxlist;
rxp->rx_next = rs->rs_rxlist;
rs->rs_rxlist = rxp;
rxp->rx_ref = 1;
++rpcbcnt;
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_xdrrpcb */
/* Returns: int -- -1 == failure to properly decode the request */
/* 0 == rpcb successfully decoded */
/* Parameters: rs(I) - pointer to RPCB session structure */
/* p(I) - pointer to location within session buffer */
/* rpcb(O) - pointer to rpcb (xdr type) structure */
/* */
/* Decode a XDR encoded rpcb structure and record its contents in rpcb */
/* within only the context of TCP/UDP over IP networks. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_xdrrpcb(rm, p, ra)
rpc_msg_t *rm;
u_32_t *p;
rpcb_args_t *ra;
{
if (!RPCB_BUF_GEQ(rm, p, 20))
return(-1);
/* Bypass target program & version. */
p += 2;
/* Decode r_netid. Must be "tcp" or "udp". */
if (ippr_rpcb_getproto(rm, &ra->ra_netid, &p) != 0)
return(-1);
/* Decode r_maddr. */
if (ippr_rpcb_getuaddr(rm, &ra->ra_maddr, &p) != 0)
return(-1);
/* Advance to r_owner and make sure it's empty. */
if (!RPCB_BUF_EQ(rm, p, 4) || (B(p) != 0))
return(-1);
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_getuaddr */
/* Returns: int -- -1 == illegal string, */
/* 0 == string parsed; contents recorded */
/* Parameters: rm(I) - pointer to RPC message structure */
/* xu(I) - pointer to universal address structure */
/* p(IO) - pointer to location within message buffer */
/* */
/* Decode the IP address / port at p and record them in xu. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_getuaddr(rm, xu, p)
rpc_msg_t *rm;
xdr_uaddr_t *xu;
u_32_t **p;
{
char *c, *i, *b, *pp;
u_int d, dd, l, t;
char uastr[24];
/* Test for string length. */
if (!RPCB_BUF_GEQ(rm, *p, 4))
return(-1);
xu->xu_xslen = (*p)++;
xu->xu_xsstr = (char *)*p;
/* Length check */
l = B(xu->xu_xslen);
if (l < 11 || l > 23 || !RPCB_BUF_GEQ(rm, *p, XDRALIGN(l)))
return(-1);
/* Advance p */
*(char **)p += XDRALIGN(l);
/* Copy string to local buffer & terminate C style */
bcopy(xu->xu_xsstr, uastr, l);
uastr[l] = '\0';
i = (char *)&xu->xu_ip;
pp = (char *)&xu->xu_port;
/*
* Expected format: a.b.c.d.e.f where [a-d] correspond to bytes of
* an IP address and [ef] are the bytes of a L4 port.
*/
if (!(ISDIGIT(uastr[0]) && ISDIGIT(uastr[l-1])))
return(-1);
b = uastr;
for (c = &uastr[1], d = 0, dd = 0; c < &uastr[l-1]; c++) {
if (ISDIGIT(*c)) {
dd = 0;
continue;
}
if (*c == '.') {
if (dd != 0)
return(-1);
/* Check for ASCII byte. */
*c = '\0';
t = ippr_rpcb_atoi(b);
if (t > 255)
return(-1);
/* Aim b at beginning of the next byte. */
b = c + 1;
/* Switch off IP addr vs port parsing. */
if (d < 4)
i[d++] = t & 0xff;
else
pp[d++ - 4] = t & 0xff;
dd = 1;
continue;
}
return(-1);
}
if (d != 5) /* String must contain exactly 5 periods. */
return(-1);
/* Handle the last byte (port low byte) */
t = ippr_rpcb_atoi(b);
if (t > 255)
return(-1);
pp[d - 4] = t & 0xff;
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_atoi (XXX should be generic for all proxies) */
/* Returns: int -- integer representation of supplied string */
/* Parameters: ptr(I) - input string */
/* */
/* Simple version of atoi(3) ripped from ip_rcmd_pxy.c. */
/* -------------------------------------------------------------------- */
static u_int
ippr_rpcb_atoi(ptr)
char *ptr;
{
register char *s = ptr, c;
register u_int i = 0;
while (((c = *s++) != '\0') && ISDIGIT(c)) {
i *= 10;
i += c - '0';
}
return i;
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_modreq */
/* Returns: int -- change in datagram length */
/* APR_ERR(2) - critical failure */
/* Parameters: fin(I) - pointer to packet information */
/* nat(I) - pointer to NAT session */
/* rm(I) - pointer to RPC message structure */
/* m(I) - pointer to mbuf chain */
/* off(I) - current offset within mbuf chain */
/* */
/* When external and internal addresses differ, we rewrite the former */
/* with the latter. (This is exclusive to protocol versions 3 & 4). */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_modreq(fin, nat, rm, m, off)
fr_info_t *fin;
nat_t *nat;
rpc_msg_t *rm;
mb_t *m;
u_int off;
{
u_int len, xlen, pos, bogo;
rpcb_args_t *ra;
char uaddr[24];
udphdr_t *udp;
char *i, *p;
int diff;
ra = &rm->rm_call.rc_rpcbargs;
i = (char *)&nat->nat_inip.s_addr;
p = (char *)&nat->nat_inport;
/* Form new string. */
bzero(uaddr, sizeof(uaddr)); /* Just in case we need padding. */
#if defined(SNPRINTF) && defined(_KERNEL)
SNPRINTF(uaddr, sizeof(uaddr),
#else
(void) sprintf(uaddr,
#endif
"%u.%u.%u.%u.%u.%u", i[0] & 0xff, i[1] & 0xff,
i[2] & 0xff, i[3] & 0xff, p[0] & 0xff, p[1] & 0xff);
len = strlen(uaddr);
xlen = XDRALIGN(len);
/* Determine mbuf offset to start writing to. */
pos = (char *)ra->ra_maddr.xu_xslen - rm->rm_msgbuf;
off += pos;
/* Write new string length. */
bogo = htonl(len);
COPYBACK(m, off, 4, (void *)&bogo);
off += 4;
/* Write new string. */
COPYBACK(m, off, xlen, uaddr);
off += xlen;
/* Write in zero r_owner. */
bogo = 0;
COPYBACK(m, off, 4, (void *)&bogo);
/* Determine difference in data lengths. */
diff = xlen - XDRALIGN(B(ra->ra_maddr.xu_xslen));
/*
* If our new string has a different length, make necessary
* adjustments.
*/
if (diff != 0) {
udp = fin->fin_dp;
udp->uh_ulen = htons(ntohs(udp->uh_ulen) + diff);
fin->fin_ip->ip_len += diff;
fin->fin_dlen += diff;
fin->fin_plen += diff;
/* XXX Storage lengths. */
}
return(diff);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_decoderep */
/* Returns: int - -1 == bad request or critical failure, */
/* 0 == valid, negative reply */
/* 1 == vaddlid, positive reply; needs no changes */
/* Parameters: fin(I) - pointer to packet information */
/* nat(I) - pointer to NAT session structure */
/* rs(I) - pointer to RPCB session structure */
/* rm(I) - pointer to RPC message structure */
/* rxp(O) - pointer to RPCB transaction structure */
/* */
/* Take a presumed RPCB reply, extract the XID, search for the original */
/* request information, and determine whether the request was accepted */
/* or rejected. With a valid accepted reply, go ahead and create NAT */
/* and state entries, and finish up by rewriting the packet as */
/* required. */
/* */
/* WARNING: It's the responsibility of the caller to make sure there */
/* is enough room in rs_buf for the basic RPC message "preamble". */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_decoderep(fin, nat, rs, rm, rxp)
fr_info_t *fin;
nat_t *nat;
rpcb_session_t *rs;
rpc_msg_t *rm;
rpcb_xact_t **rxp;
{
rpcb_listp_t *rl;
rpcb_entry_t *re;
rpcb_xact_t *rx;
u_32_t xdr, *p;
rpc_resp_t *rr;
int rv, cnt;
p = (u_32_t *)rm->rm_msgbuf;
bzero((char *)&rx, sizeof(rx));
rr = &rm->rm_resp;
rm->rm_xid = p;
xdr = B(p++); /* Record this message's XID. */
/* Lookup XID */
MUTEX_ENTER(&rs->rs_rxlock);
if ((rx = ippr_rpcb_lookup(rs, xdr)) == NULL) {
MUTEX_EXIT(&rs->rs_rxlock);
return(-1);
}
++rx->rx_ref; /* per thread reference */
MUTEX_EXIT(&rs->rs_rxlock);
*rxp = rx;
/* Test call vs reply */
if (B(p++) != RPCB_REPLY)
return(-1);
/* Test reply_stat */
switch(B(p++))
{
case RPCB_MSG_DENIED:
return(0);
case RPCB_MSG_ACCEPTED:
break;
default:
return(-1);
}
/* Bypass RPC authentication stuff. */
if (ippr_rpcb_skipauth(rm, &rr->rr_authverf, &p) != 0)
return(-1);
/* Test accept status */
if (!RPCB_BUF_GEQ(rm, p, 4))
return(-1);
if (B(p++) != 0)
return(0);
/* Parse out the expected reply */
switch(rx->rx_type)
{
case RPCB_RES_PMAP:
/* There must be only one 4 byte argument. */
if (!RPCB_BUF_EQ(rm, p, 4))
return(-1);
rr->rr_v2 = p;
xdr = B(rr->rr_v2);
/* Reply w/ a 0 port indicates service isn't registered */
if (xdr == 0)
return(0);
/* Is the value sane? */
if (xdr > 65535)
return(-1);
/* Create NAT & state table entries. */
if (ippr_rpcb_getnat(fin, nat, rx->rx_proto, (u_int)xdr) != 0)
return(-1);
break;
case RPCB_RES_STRING:
/* Expecting a XDR string; need 4 bytes for length */
if (!RPCB_BUF_GEQ(rm, p, 4))
return(-1);
rr->rr_v3.xu_str.xs_len = p++;
rr->rr_v3.xu_str.xs_str = (char *)p;
xdr = B(rr->rr_v3.xu_xslen);
/* A null string indicates an unregistered service */
if ((xdr == 0) && RPCB_BUF_EQ(rm, p, 0))
return(0);
/* Decode the target IP address / port. */
if (ippr_rpcb_getuaddr(rm, &rr->rr_v3, &p) != 0)
return(-1);
/* Validate the IP address and port contained. */
if (nat->nat_inip.s_addr != rr->rr_v3.xu_ip)
return(-1);
/* Create NAT & state table entries. */
if (ippr_rpcb_getnat(fin, nat, rx->rx_proto,
(u_int)rr->rr_v3.xu_port) != 0)
return(-1);
break;
case RPCB_RES_LIST:
if (!RPCB_BUF_GEQ(rm, p, 4))
return(-1);
/* rpcb_entry_list_ptr */
switch(B(p))
{
case 0:
return(0);
/*NOTREACHED*/
break;
case 1:
break;
default:
return(-1);
}
rl = &rr->rr_v4;
rl->rl_list = p++;
cnt = 0;
for(;;) {
re = &rl->rl_entries[rl->rl_cnt];
if (ippr_rpcb_getuaddr(rm, &re->re_maddr, &p) != 0)
return(-1);
if (ippr_rpcb_getproto(rm, &re->re_netid, &p) != 0)
return(-1);
/* re_semantics & re_pfamily length */
if (!RPCB_BUF_GEQ(rm, p, 12))
return(-1);
p++; /* Skipping re_semantics. */
xdr = B(p++);
if ((xdr != 4) || strncmp((char *)p, "inet", 4))
return(-1);
p++;
if (ippr_rpcb_getproto(rm, &re->re_proto, &p) != 0)
return(-1);
if (!RPCB_BUF_GEQ(rm, p, 4))
return(-1);
re->re_more = p;
if (B(re->re_more) > 1) /* 0,1 only legal values */
return(-1);
++rl->rl_cnt;
++cnt;
if (B(re->re_more) == 0)
break;
/* Replies in max out at 2; TCP and/or UDP */
if (cnt > 2)
return(-1);
p++;
}
for(rl->rl_cnt = 0; rl->rl_cnt < cnt; rl->rl_cnt++) {
re = &rl->rl_entries[rl->rl_cnt];
rv = ippr_rpcb_getnat(fin, nat,
re->re_proto.xp_proto,
(u_int)re->re_maddr.xu_port);
if (rv != 0)
return(-1);
}
break;
default:
/*CONSTANTCONDITION*/
IPF_PANIC(1, ("illegal rx_type %d", rx->rx_type));
}
return(1);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_lookup */
/* Returns: rpcb_xact_t * - NULL == no matching record, */
/* else pointer to relevant entry */
/* Parameters: rs(I) - pointer to RPCB session */
/* xid(I) - XID to look for */
/* -------------------------------------------------------------------- */
static rpcb_xact_t *
ippr_rpcb_lookup(rs, xid)
rpcb_session_t *rs;
u_32_t xid;
{
rpcb_xact_t *rx;
if (rs->rs_rxlist == NULL)
return(NULL);
for (rx = rs->rs_rxlist; rx != NULL; rx = rx->rx_next)
if (rx->rx_xid == xid)
break;
return(rx);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_deref */
/* Returns: (void) */
/* Parameters: rs(I) - pointer to RPCB session */
/* rx(I) - pointer to RPC transaction struct to remove */
/* force(I) - indicates to delete entry regardless of */
/* reference count */
/* Locking: rs->rs_rxlock must be held write only */
/* */
/* Free the RPCB transaction record rx from the chain of entries. */
/* -------------------------------------------------------------------- */
static void
ippr_rpcb_deref(rs, rx)
rpcb_session_t *rs;
rpcb_xact_t *rx;
{
rs = rs; /* LINT */
if (rx == NULL)
return;
if (--rx->rx_ref != 0)
return;
if (rx->rx_next != NULL)
rx->rx_next->rx_pnext = rx->rx_pnext;
*rx->rx_pnext = rx->rx_next;
KFREE(rx);
--rpcbcnt;
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_getproto */
/* Returns: int - -1 == illegal protocol/netid, */
/* 0 == legal protocol/netid */
/* Parameters: rm(I) - pointer to RPC message structure */
/* xp(I) - pointer to netid structure */
/* p(IO) - pointer to location within packet buffer */
/* */
/* Decode netid/proto stored at p and record its numeric value. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_getproto(rm, xp, p)
rpc_msg_t *rm;
xdr_proto_t *xp;
u_32_t **p;
{
u_int len;
/* Must have 4 bytes for length & 4 bytes for "tcp" or "udp". */
if (!RPCB_BUF_GEQ(rm, p, 8))
return(-1);
xp->xp_xslen = (*p)++;
xp->xp_xsstr = (char *)*p;
/* Test the string length. */
len = B(xp->xp_xslen);
if (len != 3)
return(-1);
/* Test the actual string & record the protocol accordingly. */
if (!strncmp((char *)xp->xp_xsstr, "tcp\0", 4))
xp->xp_proto = IPPROTO_TCP;
else if (!strncmp((char *)xp->xp_xsstr, "udp\0", 4))
xp->xp_proto = IPPROTO_UDP;
else {
return(-1);
}
/* Advance past the string. */
(*p)++;
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_getnat */
/* Returns: int -- -1 == failed to create table entries, */
/* 0 == success */
/* Parameters: fin(I) - pointer to packet information */
/* nat(I) - pointer to NAT table entry */
/* proto(I) - transport protocol for new entries */
/* port(I) - new port to use w/ wildcard table entries */
/* */
/* Create state and NAT entries to handle an anticipated connection */
/* attempt between RPC client and server. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_getnat(fin, nat, proto, port)
fr_info_t *fin;
nat_t *nat;
u_int proto;
u_int port;
{
ipnat_t *ipn, ipnat;
tcphdr_t tcp;
ipstate_t *is;
fr_info_t fi;
nat_t *natl;
int nflags;
ipn = nat->nat_ptr;
/* Generate dummy fr_info */
bcopy((char *)fin, (char *)&fi, sizeof(fi));
fi.fin_state = NULL;
fi.fin_nat = NULL;
fi.fin_out = 0;
fi.fin_src = fin->fin_dst;
fi.fin_dst = nat->nat_outip;
fi.fin_p = proto;
fi.fin_sport = 0;
fi.fin_dport = port & 0xffff;
fi.fin_flx |= FI_IGNORE;
bzero((char *)&tcp, sizeof(tcp));
tcp.th_dport = htons(port);
if (proto == IPPROTO_TCP) {
tcp.th_win = htons(8192);
TCP_OFF_A(&tcp, sizeof(tcphdr_t) >> 2);
fi.fin_dlen = sizeof(tcphdr_t);
tcp.th_flags = TH_SYN;
nflags = NAT_TCP;
} else {
fi.fin_dlen = sizeof(udphdr_t);
nflags = NAT_UDP;
}
nflags |= SI_W_SPORT|NAT_SEARCH;
fi.fin_dp = &tcp;
fi.fin_plen = fi.fin_hlen + fi.fin_dlen;
/*
* Search for existing NAT & state entries. Pay close attention to
* mutexes / locks grabbed from lookup routines, as not doing so could
* lead to bad things.
*
* If successful, fr_stlookup returns with ipf_state locked. We have
* no use for this lock, so simply unlock it if necessary.
*/
is = fr_stlookup(&fi, &tcp, NULL);
if (is != NULL) {
RWLOCK_EXIT(&ipf_state);
}
RWLOCK_EXIT(&ipf_nat);
WRITE_ENTER(&ipf_nat);
natl = nat_inlookup(&fi, nflags, proto, fi.fin_src, fi.fin_dst);
if ((natl != NULL) && (is != NULL)) {
MUTEX_DOWNGRADE(&ipf_nat);
return(0);
}
/* Slightly modify the following structures for actual use in creating
* NAT and/or state entries. We're primarily concerned with stripping
* flags that may be detrimental to the creation process or simply
* shouldn't be associated with a table entry.
*/
fi.fin_fr = &rpcbfr;
fi.fin_flx &= ~FI_IGNORE;
nflags &= ~NAT_SEARCH;
if (natl == NULL) {
/* XXX Since we're just copying the original ipn contents
* back, would we be better off just sending a pointer to
* the 'temp' copy off to nat_new instead?
*/
/* Generate template/bogus NAT rule. */
bcopy((char *)ipn, (char *)&ipnat, sizeof(ipnat));
ipn->in_flags = nflags & IPN_TCPUDP;
ipn->in_apr = NULL;
ipn->in_p = proto;
ipn->in_pmin = htons(fi.fin_dport);
ipn->in_pmax = htons(fi.fin_dport);
ipn->in_pnext = htons(fi.fin_dport);
ipn->in_space = 1;
ipn->in_ippip = 1;
if (ipn->in_flags & IPN_FILTER) {
ipn->in_scmp = 0;
ipn->in_dcmp = 0;
}
*ipn->in_plabel = '\0';
/* Create NAT entry. return NULL if this fails. */
natl = nat_new(&fi, ipn, NULL, nflags|SI_CLONE|NAT_SLAVE,
NAT_INBOUND);
bcopy((char *)&ipnat, (char *)ipn, sizeof(ipnat));
if (natl == NULL) {
MUTEX_DOWNGRADE(&ipf_nat);
return(-1);
}
ipn->in_use++;
(void) nat_proto(&fi, natl, nflags);
nat_update(&fi, natl, natl->nat_ptr);
}
MUTEX_DOWNGRADE(&ipf_nat);
if (is == NULL) {
/* Create state entry. Return NULL if this fails. */
fi.fin_dst = nat->nat_inip;
fi.fin_nat = (void *)natl;
fi.fin_flx |= FI_NATED;
fi.fin_flx &= ~FI_STATE;
nflags &= NAT_TCPUDP;
nflags |= SI_W_SPORT|SI_CLONE;
is = fr_addstate(&fi, NULL, nflags);
if (is == NULL) {
/*
* XXX nat_delete is private to ip_nat.c. Should
* check w/ Darren about this one.
*
* nat_delete(natl, NL_EXPIRE);
*/
return(-1);
}
if (fi.fin_state != NULL)
fr_statederef((ipstate_t **)&fi.fin_state);
}
return(0);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_modv3 */
/* Returns: int -- change in packet length */
/* Parameters: fin(I) - pointer to packet information */
/* nat(I) - pointer to NAT session */
/* rm(I) - pointer to RPC message structure */
/* m(I) - pointer to mbuf chain */
/* off(I) - offset within mbuf chain */
/* */
/* Write a new universal address string to this packet, adjusting */
/* lengths as necessary. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_modv3(fin, nat, rm, m, off)
fr_info_t *fin;
nat_t *nat;
rpc_msg_t *rm;
mb_t *m;
u_int off;
{
u_int len, xlen, pos, bogo;
rpc_resp_t *rr;
char uaddr[24];
char *i, *p;
int diff;
rr = &rm->rm_resp;
i = (char *)&nat->nat_outip.s_addr;
p = (char *)&rr->rr_v3.xu_port;
/* Form new string. */
bzero(uaddr, sizeof(uaddr)); /* Just in case we need padding. */
#if defined(SNPRINTF) && defined(_KERNEL)
SNPRINTF(uaddr, sizeof(uaddr),
#else
(void) sprintf(uaddr,
#endif
"%u.%u.%u.%u.%u.%u", i[0] & 0xff, i[1] & 0xff,
i[2] & 0xff, i[3] & 0xff, p[0] & 0xff, p[1] & 0xff);
len = strlen(uaddr);
xlen = XDRALIGN(len);
/* Determine mbuf offset to write to. */
pos = (char *)rr->rr_v3.xu_xslen - rm->rm_msgbuf;
off += pos;
/* Write new string length. */
bogo = htonl(len);
COPYBACK(m, off, 4, (void *)&bogo);
off += 4;
/* Write new string. */
COPYBACK(m, off, xlen, uaddr);
/* Determine difference in data lengths. */
diff = xlen - XDRALIGN(B(rr->rr_v3.xu_xslen));
/*
* If our new string has a different length, make necessary
* adjustments.
*/
if (diff != 0)
ippr_rpcb_fixlen(fin, diff);
return(diff);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_modv4 */
/* Returns: int -- change in packet length */
/* Parameters: fin(I) - pointer to packet information */
/* nat(I) - pointer to NAT session */
/* rm(I) - pointer to RPC message structure */
/* m(I) - pointer to mbuf chain */
/* off(I) - offset within mbuf chain */
/* */
/* Write new rpcb_entry list, adjusting lengths as necessary. */
/* -------------------------------------------------------------------- */
static int
ippr_rpcb_modv4(fin, nat, rm, m, off)
fr_info_t *fin;
nat_t *nat;
rpc_msg_t *rm;
mb_t *m;
u_int off;
{
u_int len, xlen, pos, bogo;
rpcb_listp_t *rl;
rpcb_entry_t *re;
rpc_resp_t *rr;
char uaddr[24];
int diff, cnt;
char *i, *p;
diff = 0;
rr = &rm->rm_resp;
rl = &rr->rr_v4;
i = (char *)&nat->nat_outip.s_addr;
/* Determine mbuf offset to write to. */
re = &rl->rl_entries[0];
pos = (char *)re->re_maddr.xu_xslen - rm->rm_msgbuf;
off += pos;
for (cnt = 0; cnt < rl->rl_cnt; cnt++) {
re = &rl->rl_entries[cnt];
p = (char *)&re->re_maddr.xu_port;
/* Form new string. */
bzero(uaddr, sizeof(uaddr)); /* Just in case we need
padding. */
#if defined(SNPRINTF) && defined(_KERNEL)
SNPRINTF(uaddr, sizeof(uaddr),
#else
(void) sprintf(uaddr,
#endif
"%u.%u.%u.%u.%u.%u", i[0] & 0xff,
i[1] & 0xff, i[2] & 0xff, i[3] & 0xff,
p[0] & 0xff, p[1] & 0xff);
len = strlen(uaddr);
xlen = XDRALIGN(len);
/* Write new string length. */
bogo = htonl(len);
COPYBACK(m, off, 4, (void *)&bogo);
off += 4;
/* Write new string. */
COPYBACK(m, off, xlen, uaddr);
off += xlen;
/* Record any change in length. */
diff += xlen - XDRALIGN(B(re->re_maddr.xu_xslen));
/* If the length changed, copy back the rest of this entry. */
len = ((char *)re->re_more + 4) -
(char *)re->re_netid.xp_xslen;
if (diff != 0) {
COPYBACK(m, off, len, (void *)re->re_netid.xp_xslen);
}
off += len;
}
/*
* If our new string has a different length, make necessary
* adjustments.
*/
if (diff != 0)
ippr_rpcb_fixlen(fin, diff);
return(diff);
}
/* -------------------------------------------------------------------- */
/* Function: ippr_rpcb_fixlen */
/* Returns: (void) */
/* Parameters: fin(I) - pointer to packet information */
/* len(I) - change in packet length */
/* */
/* Adjust various packet related lengths held in structure and packet */
/* header fields. */
/* -------------------------------------------------------------------- */
static void
ippr_rpcb_fixlen(fin, len)
fr_info_t *fin;
int len;
{
udphdr_t *udp;
udp = fin->fin_dp;
udp->uh_ulen = htons(ntohs(udp->uh_ulen) + len);
fin->fin_ip->ip_len += len;
fin->fin_dlen += len;
fin->fin_plen += len;
}
#undef B
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