freebsd-dev/sys/netinet/ip_divert.c
Archie Cobbs 2127f26023 Examine all occurrences of sprintf(), strcat(), and str[n]cpy()
for possible buffer overflow problems. Replaced most sprintf()'s
with snprintf(); for others cases, added terminating NUL bytes where
appropriate, replaced constants like "16" with sizeof(), etc.

These changes include several bug fixes, but most changes are for
maintainability's sake. Any instance where it wasn't "immediately
obvious" that a buffer overflow could not occur was made safer.

Reviewed by:	Bruce Evans <bde@zeta.org.au>
Reviewed by:	Matthew Dillon <dillon@apollo.backplane.com>
Reviewed by:	Mike Spengler <mks@networkcs.com>
1998-12-04 22:54:57 +00:00

438 lines
12 KiB
C

/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: ip_divert.c,v 1.34 1998/07/06 09:06:58 julian Exp $
*/
#include "opt_inet.h"
#include "opt_ipfw.h"
#include "opt_ipdivert.h"
#ifndef INET
#error "IPDIVERT requires INET."
#endif
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <vm/vm_zone.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
/*
* Divert sockets
*/
/*
* Allocate enough space to hold a full IP packet
*/
#define DIVSNDQ (65536 + 100)
#define DIVRCVQ (65536 + 100)
/* Global variables */
/*
* ip_input() and ip_output() set this secret value before calling us to
* let us know which divert port to divert a packet to; this is done so
* we can use the existing prototype for struct protosw's pr_input().
* This is stored in host order.
*/
u_short ip_divert_port;
/*
* A 16 bit cookie is passed to the user process.
* The user process can send it back to help the caller know something
* about where the packet came from.
*
* If IPFW is the caller then the cookie is the rule that sent
* us here. On reinjection is is the rule after which processing
* should continue. Leaving it the same will make processing start
* at the rule number after that which sent it here. Setting it to
* 0 will restart processing at the beginning.
*/
u_int16_t ip_divert_cookie;
/* Internal variables */
static struct inpcbhead divcb;
static struct inpcbinfo divcbinfo;
static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
/* Optimization: have this preinitialized */
static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET };
/* Internal functions */
static int div_output(struct socket *so,
struct mbuf *m, struct sockaddr *addr, struct mbuf *control);
/*
* Initialize divert connection block queue.
*/
void
div_init(void)
{
LIST_INIT(&divcb);
divcbinfo.listhead = &divcb;
/*
* XXX We don't use the hash list for divert IP, but it's easier
* to allocate a one entry hash list than it is to check all
* over the place for hashbase == NULL.
*/
divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb),
maxsockets, ZONE_INTERRUPT, 0);
}
/*
* Setup generic address and protocol structures
* for div_input routine, then pass them along with
* mbuf chain. ip->ip_len is assumed to have had
* the header length (hlen) subtracted out already.
* We tell whether the packet was incoming or outgoing
* by seeing if hlen == 0, which is a hack.
*/
void
div_input(struct mbuf *m, int hlen)
{
struct ip *ip;
struct inpcb *inp;
struct socket *sa;
/* Sanity check */
if (ip_divert_port == 0)
panic("div_input: port is 0");
/* Assure header */
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == 0) {
return;
}
ip = mtod(m, struct ip *);
/* Record divert cookie */
divsrc.sin_port = ip_divert_cookie;
ip_divert_cookie = 0;
/* Restore packet header fields */
ip->ip_len += hlen;
HTONS(ip->ip_len);
HTONS(ip->ip_off);
/*
* Record receive interface address, if any
* But only for incoming packets.
*/
divsrc.sin_addr.s_addr = 0;
if (hlen) {
struct ifaddr *ifa;
#ifdef DIAGNOSTIC
/* Sanity check */
if (!(m->m_flags & M_PKTHDR))
panic("div_input: no pkt hdr");
#endif
/* More fields affected by ip_input() */
HTONS(ip->ip_id);
/* Find IP address for receive interface */
for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first;
ifa != NULL; ifa = ifa->ifa_link.tqe_next) {
if (ifa->ifa_addr == NULL)
continue;
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
divsrc.sin_addr =
((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
break;
}
}
/*
* Record the incoming interface name whenever we have one.
*/
bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero));
if (m->m_pkthdr.rcvif) {
/*
* Hide the actual interface name in there in the
* sin_zero array. XXX This needs to be moved to a
* different sockaddr type for divert, e.g.
* sockaddr_div with multiple fields like
* sockaddr_dl. Presently we have only 7 bytes
* but that will do for now as most interfaces
* are 4 or less + 2 or less bytes for unit.
* There is probably a faster way of doing this,
* possibly taking it from the sockaddr_dl on the iface.
* This solves the problem of a P2P link and a LAN interface
* having the same address, which can result in the wrong
* interface being assigned to the packet when fed back
* into the divert socket. Theoretically if the daemon saves
* and re-uses the sockaddr_in as suggested in the man pages,
* this iface name will come along for the ride.
* (see div_output for the other half of this.)
*/
snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero),
"%s%d", m->m_pkthdr.rcvif->if_name,
m->m_pkthdr.rcvif->if_unit);
}
/* Put packet on socket queue, if any */
sa = NULL;
for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
if (inp->inp_lport == htons(ip_divert_port))
sa = inp->inp_socket;
}
ip_divert_port = 0;
if (sa) {
if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc,
m, (struct mbuf *)0) == 0)
m_freem(m);
else
sorwakeup(sa);
} else {
m_freem(m);
ipstat.ips_noproto++;
ipstat.ips_delivered--;
}
}
/*
* Deliver packet back into the IP processing machinery.
*
* If no address specified, or address is 0.0.0.0, send to ip_output();
* otherwise, send to ip_input() and mark as having been received on
* the interface with that address.
*/
static int
div_output(so, m, addr, control)
struct socket *so;
register struct mbuf *m;
struct sockaddr *addr;
struct mbuf *control;
{
register struct inpcb *const inp = sotoinpcb(so);
register struct ip *const ip = mtod(m, struct ip *);
struct sockaddr_in *sin = (struct sockaddr_in *)addr;
int error = 0;
if (control)
m_freem(control); /* XXX */
/* Loopback avoidance and state recovery */
if (sin) {
int len = 0;
char *c = sin->sin_zero;
ip_divert_cookie = sin->sin_port;
/*
* Find receive interface with the given name or IP address.
* The name is user supplied data so don't trust it's size or
* that it is zero terminated. The name has priority.
* We are presently assuming that the sockaddr_in
* has not been replaced by a sockaddr_div, so we limit it
* to 16 bytes in total. the name is stuffed (if it exists)
* in the sin_zero[] field.
*/
while (*c++ && (len++ < sizeof(sin->sin_zero)));
if ((len > 0) && (len < sizeof(sin->sin_zero)))
m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
} else {
ip_divert_cookie = 0;
}
/* Reinject packet into the system as incoming or outgoing */
if (!sin || sin->sin_addr.s_addr == 0) {
/*
* Don't allow both user specified and setsockopt options,
* and don't allow packet length sizes that will crash
*/
if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
error = EINVAL;
goto cantsend;
}
/* Convert fields to host order for ip_output() */
NTOHS(ip->ip_len);
NTOHS(ip->ip_off);
/* Send packet to output processing */
ipstat.ips_rawout++; /* XXX */
error = ip_output(m, inp->inp_options, &inp->inp_route,
(so->so_options & SO_DONTROUTE) |
IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions);
} else {
struct ifaddr *ifa;
/* If no luck with the name above. check by IP address. */
if (m->m_pkthdr.rcvif == NULL) {
if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) {
error = EADDRNOTAVAIL;
goto cantsend;
}
m->m_pkthdr.rcvif = ifa->ifa_ifp;
}
/* Send packet to input processing */
ip_input(m);
}
/* paranoid: Reset for next time (and other packets) */
/* almost definitly already done in the ipfw filter but.. */
ip_divert_cookie = 0;
return error;
cantsend:
ip_divert_cookie = 0;
m_freem(m);
return error;
}
static int
div_attach(struct socket *so, int proto, struct proc *p)
{
struct inpcb *inp;
int error, s;
inp = sotoinpcb(so);
if (inp)
panic("div_attach");
if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0)
return error;
s = splnet();
error = in_pcballoc(so, &divcbinfo, p);
splx(s);
if (error)
return error;
error = soreserve(so, div_sendspace, div_recvspace);
if (error)
return error;
inp = (struct inpcb *)so->so_pcb;
inp->inp_ip_p = proto;
inp->inp_flags |= INP_HDRINCL;
/* The socket is always "connected" because
we always know "where" to send the packet */
so->so_state |= SS_ISCONNECTED;
return 0;
}
static int
div_detach(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
if (inp == 0)
panic("div_detach");
in_pcbdetach(inp);
return 0;
}
static int
div_abort(struct socket *so)
{
soisdisconnected(so);
return div_detach(so);
}
static int
div_disconnect(struct socket *so)
{
if ((so->so_state & SS_ISCONNECTED) == 0)
return ENOTCONN;
return div_abort(so);
}
static int
div_bind(struct socket *so, struct sockaddr *nam, struct proc *p)
{
struct inpcb *inp;
int s;
int error;
s = splnet();
inp = sotoinpcb(so);
error = in_pcbbind(inp, nam, p);
splx(s);
return 0;
}
static int
div_shutdown(struct socket *so)
{
socantsendmore(so);
return 0;
}
static int
div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
struct mbuf *control, struct proc *p)
{
/* Packet must have a header (but that's about it) */
if (m->m_len < sizeof (struct ip) ||
(m = m_pullup(m, sizeof (struct ip))) == 0) {
ipstat.ips_toosmall++;
m_freem(m);
return EINVAL;
}
/* Send packet */
return div_output(so, m, nam, control);
}
struct pr_usrreqs div_usrreqs = {
div_abort, pru_accept_notsupp, div_attach, div_bind,
pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach,
div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp,
pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown,
in_setsockaddr, sosend, soreceive, sopoll
};