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Fixes a nasty bug in OSPF.

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Sending malformed network prefixes in LSAs causes OSPF to crash
just after the LSA is propagated to the other routers.
This commit is contained in:
Ondrej Zajicek 2011-03-29 01:41:46 +02:00
parent 52a43ae3b7
commit ab16497189
4 changed files with 45 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
nest/rt-table.c
View File

@ -374,7 +374,7 @@ rte_validate(rte *e)
if ((n->n.pxlen > BITS_PER_IP_ADDRESS) || !ip_is_prefix(n->n.prefix,n->n.pxlen)) if ((n->n.pxlen > BITS_PER_IP_ADDRESS) || !ip_is_prefix(n->n.prefix,n->n.pxlen))
{ {
log(L_BUG "Ignoring bogus prefix %I/%d received via %s", log(L_WARN "Ignoring bogus prefix %I/%d received via %s",
n->n.prefix, n->n.pxlen, e->sender->name); n->n.prefix, n->n.pxlen, e->sender->name);
return 0; return 0;
} }

4
proto/ospf/ospf.h
View File

@ -587,6 +587,10 @@ lsa_get_ipv6_prefix(u32 *buf, ip_addr *addr, int *pxlen, u8 *pxopts, u16 *rest)
if (pxl > 96) if (pxl > 96)
_I3(*addr) = *buf++; _I3(*addr) = *buf++;
/* Clean up remaining bits */
if (pxl < 128)
addr->addr[pxl / 32] &= u32_mkmask(pxl % 32);
return buf; return buf;
} }

7
proto/ospf/packet.c
View File

@ -269,9 +269,10 @@ ospf_rx_hook(sock *sk, int size)
struct proto_ospf *po = ifa->oa->po; struct proto_ospf *po = ifa->oa->po;
// struct proto *p = &po->proto; // struct proto *p = &po->proto;
int src_local = ipa_in_net(sk->faddr, ifa->addr->prefix, ifa->addr->pxlen); int src_local, dst_local UNUSED, dst_mcast;
int dst_local = ipa_equal(sk->laddr, ifa->addr->ip); src_local = ipa_in_net(sk->faddr, ifa->addr->prefix, ifa->addr->pxlen);
int dst_mcast = ipa_equal(sk->laddr, AllSPFRouters) || ipa_equal(sk->laddr, AllDRouters); dst_local = ipa_equal(sk->laddr, ifa->addr->ip);
dst_mcast = ipa_equal(sk->laddr, AllSPFRouters) || ipa_equal(sk->laddr, AllDRouters);
#ifdef OSPFv2 #ifdef OSPFv2
/* First, we eliminate packets with strange address combinations. /* First, we eliminate packets with strange address combinations.

49
proto/ospf/rt.c
View File

@ -245,6 +245,13 @@ add_network(struct ospf_area *oa, ip_addr px, int pxlen, int metric, struct top_
.nhs = en->nhs .nhs = en->nhs
}; };
if (pxlen < 0 || pxlen > MAX_PREFIX_LENGTH)
{
log(L_WARN "%s: Invalid prefix in LSA (Type: %04x, Id: %R, Rt: %R)",
oa->po->proto.name, en->lsa.type, en->lsa.id, en->lsa.rt);
return;
}
if (en == oa->rt) if (en == oa->rt)
{ {
/* /*
@ -336,7 +343,8 @@ ospf_rt_spfa_rtlinks(struct ospf_area *oa, struct top_hash_entry *act, struct to
{ {
// struct proto *p = &oa->po->proto; // struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po; struct proto_ospf *po = oa->po;
int i; ip_addr prefix UNUSED;
int pxlen UNUSED, i;
struct ospf_lsa_rt *rt = en->lsa_body; struct ospf_lsa_rt *rt = en->lsa_body;
struct ospf_lsa_rt_link *rr = (struct ospf_lsa_rt_link *) (rt + 1); struct ospf_lsa_rt_link *rr = (struct ospf_lsa_rt_link *) (rt + 1);
@ -357,9 +365,9 @@ ospf_rt_spfa_rtlinks(struct ospf_area *oa, struct top_hash_entry *act, struct to
* the same result by handing them here because add_network() * the same result by handing them here because add_network()
* will keep the best (not the first) found route. * will keep the best (not the first) found route.
*/ */
add_network(oa, ipa_from_u32(rtl->id), prefix = ipa_from_u32(rtl->id & rtl->data);
ipa_mklen(ipa_from_u32(rtl->data)), pxlen = ipa_mklen(ipa_from_u32(rtl->data));
act->dist + rtl->metric, act, i); add_network(oa, prefix, pxlen, act->dist + rtl->metric, act, i);
break; break;
#endif #endif
@ -398,6 +406,8 @@ ospf_rt_spfa(struct ospf_area *oa)
struct ospf_lsa_rt *rt; struct ospf_lsa_rt *rt;
struct ospf_lsa_net *ln; struct ospf_lsa_net *ln;
struct top_hash_entry *act, *tmp; struct top_hash_entry *act, *tmp;
ip_addr prefix UNUSED;
int pxlen UNUSED;
u32 i, *rts; u32 i, *rts;
node *n; node *n;
@ -470,8 +480,9 @@ ospf_rt_spfa(struct ospf_area *oa)
ln = act->lsa_body; ln = act->lsa_body;
#ifdef OSPFv2 #ifdef OSPFv2
add_network(oa, ipa_and(ipa_from_u32(act->lsa.id), ln->netmask), prefix = ipa_and(ipa_from_u32(act->lsa.id), ln->netmask);
ipa_mklen(ln->netmask), act->dist, act, -1); pxlen = ipa_mklen(ln->netmask);
add_network(oa, prefix, pxlen, act->dist, act, -1);
#endif #endif
rts = (u32 *) (ln + 1); rts = (u32 *) (ln + 1);
@ -618,8 +629,8 @@ ospf_rt_sum(struct ospf_area *oa)
{ {
#ifdef OSPFv2 #ifdef OSPFv2
struct ospf_lsa_sum *ls = en->lsa_body; struct ospf_lsa_sum *ls = en->lsa_body;
pxlen = ipa_mklen(ls->netmask);
ip = ipa_and(ipa_from_u32(en->lsa.id), ls->netmask); ip = ipa_and(ipa_from_u32(en->lsa.id), ls->netmask);
pxlen = ipa_mklen(ls->netmask);
#else /* OSPFv3 */ #else /* OSPFv3 */
u8 pxopts; u8 pxopts;
u16 rest; u16 rest;
@ -630,6 +641,13 @@ ospf_rt_sum(struct ospf_area *oa)
continue; continue;
#endif #endif
if (pxlen < 0 || pxlen > MAX_PREFIX_LENGTH)
{
log(L_WARN "%s: Invalid prefix in LSA (Type: %04x, Id: %R, Rt: %R)",
p->name, en->lsa.type, en->lsa.id, en->lsa.rt);
continue;
}
metric = ls->metric & METRIC_MASK; metric = ls->metric & METRIC_MASK;
options = 0; options = 0;
type = ORT_NET; type = ORT_NET;
@ -695,7 +713,7 @@ ospf_rt_sum(struct ospf_area *oa)
static void static void
ospf_rt_sum_tr(struct ospf_area *oa) ospf_rt_sum_tr(struct ospf_area *oa)
{ {
// struct proto *p = &oa->po->proto; struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po; struct proto_ospf *po = oa->po;
struct ospf_area *bb = po->backbone; struct ospf_area *bb = po->backbone;
ip_addr abrip; ip_addr abrip;
@ -728,8 +746,8 @@ ospf_rt_sum_tr(struct ospf_area *oa)
int pxlen; int pxlen;
#ifdef OSPFv2 #ifdef OSPFv2
struct ospf_lsa_sum *ls = en->lsa_body; struct ospf_lsa_sum *ls = en->lsa_body;
pxlen = ipa_mklen(ls->netmask);
ip = ipa_and(ipa_from_u32(en->lsa.id), ls->netmask); ip = ipa_and(ipa_from_u32(en->lsa.id), ls->netmask);
pxlen = ipa_mklen(ls->netmask);
#else /* OSPFv3 */ #else /* OSPFv3 */
u8 pxopts; u8 pxopts;
u16 rest; u16 rest;
@ -740,6 +758,13 @@ ospf_rt_sum_tr(struct ospf_area *oa)
continue; continue;
#endif #endif
if (pxlen < 0 || pxlen > MAX_PREFIX_LENGTH)
{
log(L_WARN "%s: Invalid prefix in LSA (Type: %04x, Id: %R, Rt: %R)",
p->name, en->lsa.type, en->lsa.id, en->lsa.rt);
continue;
}
metric = ls->metric & METRIC_MASK; metric = ls->metric & METRIC_MASK;
re = fib_find(&po->rtf, &ip, pxlen); re = fib_find(&po->rtf, &ip, pxlen);
} }
@ -1139,9 +1164,9 @@ ospf_ext_spf(struct proto_ospf *po)
rt_tag = 0; rt_tag = 0;
#endif #endif
if (pxlen < 0) if (pxlen < 0 || pxlen > MAX_PREFIX_LENGTH)
{ {
log(L_WARN "%s: Invalid mask in LSA (Type: %04x, Id: %R, Rt: %R)", log(L_WARN "%s: Invalid prefix in LSA (Type: %04x, Id: %R, Rt: %R)",
p->name, en->lsa.type, en->lsa.id, en->lsa.rt); p->name, en->lsa.type, en->lsa.id, en->lsa.rt);
continue; continue;
} }
@ -1703,8 +1728,6 @@ again1:
e->net = ne; e->net = ne;
e->pref = p->preference; e->pref = p->preference;
DBG("Mod rte type %d - %I/%d via %I on iface %s, met %d\n", DBG("Mod rte type %d - %I/%d via %I on iface %s, met %d\n",
a0.source, nf->fn.prefix, nf->fn.pxlen, a0.gw, a0.iface ? a0.iface->name : "(none)", nf->n.metric1); a0.source, nf->fn.prefix, nf->fn.pxlen, a0.gw, a0.iface ? a0.iface->name : "(none)", nf->n.metric1);
rte_update(p->table, ne, p, p, e); rte_update(p->table, ne, p, p, e);