freebsd-dev/sys/net/radix_mpath.c
Conrad Meyer dcbee68850 radix_mpath: Don't derefence a NULL pointer in for loop iteration
It seems rn_dupedkey may be NULL, because of the NULL check inside the loop.
(Also, the rt gets assigned from rn_dupedkey and NULL checked at top of loop.)
However, the for-loop update condition happens before the top-of-loop check and
dereferences 'rt' unconditionally.

Instead, NULL-check before dereferencing.

If rn_dupedkey cannot in fact be NULL, or something else protects this, feel
free to revert this and add an ASSERT of some kind instead.

This was introduced in r191080 (2009) and moved around slightly in r293657.

Reported by:	Coverity
CID:		1348482
Sponsored by:	EMC / Isilon Storage Division
2016-04-26 20:27:17 +00:00

323 lines
8.1 KiB
C

/* $KAME: radix_mpath.c,v 1.17 2004/11/08 10:29:39 itojun Exp $ */
/*
* Copyright (C) 2001 WIDE Project.
* 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
* THE AUTHORS DO NOT GUARANTEE THAT THIS SOFTWARE DOES NOT INFRINGE
* ANY OTHERS' INTELLECTUAL PROPERTIES. IN NO EVENT SHALL THE AUTHORS
* BE LIABLE FOR ANY INFRINGEMENT OF ANY OTHERS' INTELLECTUAL
* PROPERTIES.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/domain.h>
#include <sys/syslog.h>
#include <net/radix.h>
#include <net/radix_mpath.h>
#include <net/route.h>
#include <net/route_var.h>
#include <net/if.h>
#include <net/if_var.h>
/*
* give some jitter to hash, to avoid synchronization between routers
*/
static uint32_t hashjitter;
int
rt_mpath_capable(struct rib_head *rnh)
{
return rnh->rnh_multipath;
}
int
rn_mpath_capable(struct radix_head *rh)
{
return (rt_mpath_capable((struct rib_head *)rh));
}
struct radix_node *
rn_mpath_next(struct radix_node *rn)
{
struct radix_node *next;
if (!rn->rn_dupedkey)
return NULL;
next = rn->rn_dupedkey;
if (rn->rn_mask == next->rn_mask)
return next;
else
return NULL;
}
uint32_t
rn_mpath_count(struct radix_node *rn)
{
uint32_t i = 0;
struct rtentry *rt;
while (rn != NULL) {
rt = (struct rtentry *)rn;
i += rt->rt_weight;
rn = rn_mpath_next(rn);
}
return (i);
}
struct rtentry *
rt_mpath_matchgate(struct rtentry *rt, struct sockaddr *gate)
{
struct radix_node *rn;
if (!gate || !rt->rt_gateway)
return NULL;
/* beyond here, we use rn as the master copy */
rn = (struct radix_node *)rt;
do {
rt = (struct rtentry *)rn;
/*
* we are removing an address alias that has
* the same prefix as another address
* we need to compare the interface address because
* rt_gateway is a special sockadd_dl structure
*/
if (rt->rt_gateway->sa_family == AF_LINK) {
if (!memcmp(rt->rt_ifa->ifa_addr, gate, gate->sa_len))
break;
}
/*
* Check for other options:
* 1) Routes with 'real' IPv4/IPv6 gateway
* 2) Loopback host routes (another AF_LINK/sockadd_dl check)
* */
if (rt->rt_gateway->sa_len == gate->sa_len &&
!memcmp(rt->rt_gateway, gate, gate->sa_len))
break;
} while ((rn = rn_mpath_next(rn)) != NULL);
return (struct rtentry *)rn;
}
/*
* go through the chain and unlink "rt" from the list
* the caller will free "rt"
*/
int
rt_mpath_deldup(struct rtentry *headrt, struct rtentry *rt)
{
struct radix_node *t, *tt;
if (!headrt || !rt)
return (0);
t = (struct radix_node *)headrt;
tt = rn_mpath_next(t);
while (tt) {
if (tt == (struct radix_node *)rt) {
t->rn_dupedkey = tt->rn_dupedkey;
tt->rn_dupedkey = NULL;
tt->rn_flags &= ~RNF_ACTIVE;
tt[1].rn_flags &= ~RNF_ACTIVE;
return (1);
}
t = tt;
tt = rn_mpath_next((struct radix_node *)t);
}
return (0);
}
/*
* check if we have the same key/mask/gateway on the table already.
* Assume @rt rt_key host bits are cleared according to @netmask
*/
int
rt_mpath_conflict(struct rib_head *rnh, struct rtentry *rt,
struct sockaddr *netmask)
{
struct radix_node *rn, *rn1;
struct rtentry *rt1;
rn = (struct radix_node *)rt;
rn1 = rnh->rnh_lookup(rt_key(rt), netmask, &rnh->head);
if (!rn1 || rn1->rn_flags & RNF_ROOT)
return (0);
/* key/mask are the same. compare gateway for all multipaths */
do {
rt1 = (struct rtentry *)rn1;
/* sanity: no use in comparing the same thing */
if (rn1 == rn)
continue;
if (rt1->rt_gateway->sa_family == AF_LINK) {
if (rt1->rt_ifa->ifa_addr->sa_len != rt->rt_ifa->ifa_addr->sa_len ||
bcmp(rt1->rt_ifa->ifa_addr, rt->rt_ifa->ifa_addr,
rt1->rt_ifa->ifa_addr->sa_len))
continue;
} else {
if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len ||
bcmp(rt1->rt_gateway, rt->rt_gateway,
rt1->rt_gateway->sa_len))
continue;
}
/* all key/mask/gateway are the same. conflicting entry. */
return (EEXIST);
} while ((rn1 = rn_mpath_next(rn1)) != NULL);
return (0);
}
static struct rtentry *
rt_mpath_selectrte(struct rtentry *rte, uint32_t hash)
{
struct radix_node *rn0, *rn;
uint32_t total_weight;
struct rtentry *rt;
int64_t weight;
/* beyond here, we use rn as the master copy */
rn0 = rn = (struct radix_node *)rte;
rt = rte;
/* gw selection by Modulo-N Hash (RFC2991) XXX need improvement? */
total_weight = rn_mpath_count(rn0);
hash += hashjitter;
hash %= total_weight;
for (weight = abs((int32_t)hash);
rt != NULL && weight >= rt->rt_weight;
weight -= (rt == NULL) ? 0 : rt->rt_weight) {
/* stay within the multipath routes */
if (rn->rn_dupedkey && rn->rn_mask != rn->rn_dupedkey->rn_mask)
break;
rn = rn->rn_dupedkey;
rt = (struct rtentry *)rn;
}
return (rt);
}
struct rtentry *
rt_mpath_select(struct rtentry *rte, uint32_t hash)
{
if (rn_mpath_next((struct radix_node *)rte) == NULL)
return (rte);
return (rt_mpath_selectrte(rte, hash));
}
void
rtalloc_mpath_fib(struct route *ro, uint32_t hash, u_int fibnum)
{
struct rtentry *rt;
/*
* XXX we don't attempt to lookup cached route again; what should
* be done for sendto(3) case?
*/
if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP)
&& RT_LINK_IS_UP(ro->ro_rt->rt_ifp))
return;
ro->ro_rt = rtalloc1_fib(&ro->ro_dst, 1, 0, fibnum);
/* if the route does not exist or it is not multipath, don't care */
if (ro->ro_rt == NULL)
return;
if (rn_mpath_next((struct radix_node *)ro->ro_rt) == NULL) {
RT_UNLOCK(ro->ro_rt);
return;
}
rt = rt_mpath_selectrte(ro->ro_rt, hash);
/* XXX try filling rt_gwroute and avoid unreachable gw */
/* gw selection has failed - there must be only zero weight routes */
if (!rt) {
RT_UNLOCK(ro->ro_rt);
ro->ro_rt = NULL;
return;
}
if (ro->ro_rt != rt) {
RTFREE_LOCKED(ro->ro_rt);
ro->ro_rt = rt;
RT_LOCK(ro->ro_rt);
RT_ADDREF(ro->ro_rt);
}
RT_UNLOCK(ro->ro_rt);
}
extern int in6_inithead(void **head, int off);
extern int in_inithead(void **head, int off);
#ifdef INET
int
rn4_mpath_inithead(void **head, int off)
{
struct rib_head *rnh;
hashjitter = arc4random();
if (in_inithead(head, off) == 1) {
rnh = (struct rib_head *)*head;
rnh->rnh_multipath = 1;
return 1;
} else
return 0;
}
#endif
#ifdef INET6
int
rn6_mpath_inithead(void **head, int off)
{
struct rib_head *rnh;
hashjitter = arc4random();
if (in6_inithead(head, off) == 1) {
rnh = (struct rib_head *)*head;
rnh->rnh_multipath = 1;
return 1;
} else
return 0;
}
#endif