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ospf6d: CVE-2011-3323 (fortify packet reception)

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This vulnerability (CERT-FI #514840) was reported by CROSS project.

ospf6d processes IPv6 prefix structures in incoming packets without
verifying that the declared prefix length is valid. This leads to a
crash
caused by out of bounds memory access.

* ospf6_abr.h: new macros for size/alignment validation
* ospf6_asbr.h: idem
* ospf6_intra.h: idem
* ospf6_lsa.h: idem
* ospf6_message.h: idem
* ospf6_proto.h: idem
* ospf6_message.c
  * ospf6_packet_minlen: helper array for ospf6_packet_examin()
  * ospf6_lsa_minlen: helper array for ospf6_lsa_examin()
  * ospf6_hello_recv(): do not call ospf6_header_examin(), let upper
    layer verify the input data
  * ospf6_dbdesc_recv(): idem
  * ospf6_lsreq_recv(): idem
  * ospf6_lsupdate_recv(): idem
  * ospf6_lsack_recv(): idem
  * ospf6_prefixes_examin(): new function, implements A.4.1
  * ospf6_lsa_examin(): new function, implements A.4
  * ospf6_lsaseq_examin(): new function, an interface to above
  * ospf6_packet_examin(): new function, implements A.3
  * ospf6_rxpacket_examin(): new function, replaces
    ospf6_header_examin()
  * ospf6_header_examin(): sayonara
  * ospf6_receive(): perform passive interface check earliest possible,
    employ ospf6_rxpacket_examin()
This commit is contained in:
Denis Ovsienko 2011-09-26 13:18:51 +04:00
parent 308687b7d7
commit 552563a1c4
7 changed files with 492 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
ospf6d/ospf6_abr.h
View File

@ -35,6 +35,7 @@ extern unsigned char conf_debug_ospf6_abr;
(conf_debug_ospf6_abr)
/* Inter-Area-Prefix-LSA */
#define OSPF6_INTER_PREFIX_LSA_MIN_SIZE 4U /* w/o IPv6 prefix */
struct ospf6_inter_prefix_lsa
{
u_int32_t metric;
@ -42,6 +43,7 @@ struct ospf6_inter_prefix_lsa
};
/* Inter-Area-Router-LSA */
#define OSPF6_INTER_ROUTER_LSA_FIX_SIZE 12U
struct ospf6_inter_router_lsa
{
u_char mbz;

1
ospf6d/ospf6_asbr.h
View File

@ -51,6 +51,7 @@ struct ospf6_external_info
};
/* AS-External-LSA */
#define OSPF6_AS_EXTERNAL_LSA_MIN_SIZE 4U /* w/o IPv6 prefix */
struct ospf6_as_external_lsa
{
u_int32_t bits_metric;

6
ospf6d/ospf6_intra.h
View File

@ -69,6 +69,7 @@ extern u_int32_t conf_debug_ospf6_brouter_specific_area_id;
conf_debug_ospf6_brouter_specific_area_id == (area_id))
/* Router-LSA */
#define OSPF6_ROUTER_LSA_MIN_SIZE 4U
struct ospf6_router_lsa
{
u_char bits;
@ -77,6 +78,7 @@ struct ospf6_router_lsa
};
/* Link State Description in Router-LSA */
#define OSPF6_ROUTER_LSDESC_FIX_SIZE 16U
struct ospf6_router_lsdesc
{
u_char type;
@ -105,6 +107,7 @@ struct ospf6_router_lsdesc
(((struct ospf6_router_lsdesc *)(x))->neighbor_router_id)
/* Network-LSA */
#define OSPF6_NETWORK_LSA_MIN_SIZE 4U
struct ospf6_network_lsa
{
u_char reserved;
@ -113,6 +116,7 @@ struct ospf6_network_lsa
};
/* Link State Description in Router-LSA */
#define OSPF6_NETWORK_LSDESC_FIX_SIZE 4U
struct ospf6_network_lsdesc
{
u_int32_t router_id;
@ -121,6 +125,7 @@ struct ospf6_network_lsdesc
(((struct ospf6_network_lsdesc *)(x))->router_id)
/* Link-LSA */
#define OSPF6_LINK_LSA_MIN_SIZE 24U /* w/o 1st IPv6 prefix */
struct ospf6_link_lsa
{
u_char priority;
@ -131,6 +136,7 @@ struct ospf6_link_lsa
};
/* Intra-Area-Prefix-LSA */
#define OSPF6_INTRA_PREFIX_LSA_MIN_SIZE 12U /* w/o 1st IPv6 prefix */
struct ospf6_intra_prefix_lsa
{
u_int16_t prefix_num;

1
ospf6d/ospf6_lsa.h
View File

@ -79,6 +79,7 @@
(ntohs (type) & OSPF6_LSTYPE_SCOPE_MASK)
/* LSA Header */
#define OSPF6_LSA_HEADER_SIZE 20U
struct ospf6_lsa_header
{
u_int16_t age; /* LS age */

547
ospf6d/ospf6_message.c
View File

@ -39,6 +39,11 @@
#include "ospf6_neighbor.h"
#include "ospf6_interface.h"
/* for structures and macros ospf6_lsa_examin() needs */
#include "ospf6_abr.h"
#include "ospf6_asbr.h"
#include "ospf6_intra.h"
#include "ospf6_flood.h"
#include "ospf6d.h"
@ -48,6 +53,34 @@ unsigned char conf_debug_ospf6_message[6] = {0x03, 0, 0, 0, 0, 0};
const char *ospf6_message_type_str[] =
{ "Unknown", "Hello", "DbDesc", "LSReq", "LSUpdate", "LSAck" };
/* Minimum (besides the standard OSPF packet header) lengths for OSPF
packets of particular types, offset is the "type" field. */
const u_int16_t ospf6_packet_minlen[OSPF6_MESSAGE_TYPE_ALL] =
{
0,
OSPF6_HELLO_MIN_SIZE,
OSPF6_DB_DESC_MIN_SIZE,
OSPF6_LS_REQ_MIN_SIZE,
OSPF6_LS_UPD_MIN_SIZE,
OSPF6_LS_ACK_MIN_SIZE
};
/* Minimum (besides the standard LSA header) lengths for LSAs of particular
types, offset is the "LSA function code" portion of "LSA type" field. */
const u_int16_t ospf6_lsa_minlen[OSPF6_LSTYPE_SIZE] =
{
0,
/* 0x2001 */ OSPF6_ROUTER_LSA_MIN_SIZE,
/* 0x2002 */ OSPF6_NETWORK_LSA_MIN_SIZE,
/* 0x2003 */ OSPF6_INTER_PREFIX_LSA_MIN_SIZE,
/* 0x2004 */ OSPF6_INTER_ROUTER_LSA_FIX_SIZE,
/* 0x4005 */ OSPF6_AS_EXTERNAL_LSA_MIN_SIZE,
/* 0x2006 */ 0,
/* 0x2007 */ OSPF6_AS_EXTERNAL_LSA_MIN_SIZE,
/* 0x0008 */ OSPF6_LINK_LSA_MIN_SIZE,
/* 0x2009 */ OSPF6_INTRA_PREFIX_LSA_MIN_SIZE
};
/* print functions */
static void
@ -226,52 +259,6 @@ ospf6_lsack_print (struct ospf6_header *oh)
zlog_debug ("Trailing garbage exists");
}
/* Receive function */
static int
ospf6_header_examin (struct in6_addr *src, struct in6_addr *dst,
struct ospf6_interface *oi, struct ospf6_header *oh)
{
u_char type;
type = OSPF6_MESSAGE_TYPE_CANONICAL (oh->type);
/* version check */
if (oh->version != OSPFV3_VERSION)
{
if (IS_OSPF6_DEBUG_MESSAGE (type, RECV))
zlog_debug ("Message with unknown version");
return MSG_NG;
}
/* Area-ID check */
if (oh->area_id != oi->area->area_id)
{
if (oh->area_id == BACKBONE_AREA_ID)
{
if (IS_OSPF6_DEBUG_MESSAGE (type, RECV))
zlog_debug ("Message may be via Virtual Link: not supported");
return MSG_NG;
}
if (IS_OSPF6_DEBUG_MESSAGE (type, RECV))
zlog_debug ("Area-ID mismatch");
return MSG_NG;
}
/* Instance-ID check */
if (oh->instance_id != oi->instance_id)
{
if (IS_OSPF6_DEBUG_MESSAGE (type, RECV))
zlog_debug ("Instance-ID mismatch");
return MSG_NG;
}
/* Router-ID check */
if (oh->router_id == oi->area->ospf6->router_id)
zlog_warn ("Detect duplicate Router-ID");
return MSG_OK;
}
static void
ospf6_hello_recv (struct in6_addr *src, struct in6_addr *dst,
struct ospf6_interface *oi, struct ospf6_header *oh)
@ -283,9 +270,6 @@ ospf6_hello_recv (struct in6_addr *src, struct in6_addr *dst,
int neighborchange = 0;
int backupseen = 0;
if (ospf6_header_examin (src, dst, oi, oh) != MSG_OK)
return;
hello = (struct ospf6_hello *)
((caddr_t) oh + sizeof (struct ospf6_header));
@ -817,9 +801,6 @@ ospf6_dbdesc_recv (struct in6_addr *src, struct in6_addr *dst,
struct ospf6_neighbor *on;
struct ospf6_dbdesc *dbdesc;
if (ospf6_header_examin (src, dst, oi, oh) != MSG_OK)
return;
on = ospf6_neighbor_lookup (oh->router_id, oi);
if (on == NULL)
{
@ -869,9 +850,6 @@ ospf6_lsreq_recv (struct in6_addr *src, struct in6_addr *dst,
struct ospf6_lsdb *lsdb = NULL;
struct ospf6_lsa *lsa;
if (ospf6_header_examin (src, dst, oi, oh) != MSG_OK)
return;
on = ospf6_neighbor_lookup (oh->router_id, oi);
if (on == NULL)
{
@ -946,6 +924,433 @@ ospf6_lsreq_recv (struct in6_addr *src, struct in6_addr *dst,
thread_add_event (master, ospf6_lsupdate_send_neighbor, on, 0);
}
/* Verify, that the specified memory area contains exactly N valid IPv6
prefixes as specified by RFC5340, A.4.1. */
static unsigned
ospf6_prefixes_examin
(
struct ospf6_prefix *current, /* start of buffer */
unsigned length,
const u_int32_t req_num_pfxs /* always compared with the actual number of prefixes */
)
{
u_char requested_pfx_bytes;
u_int32_t real_num_pfxs = 0;
while (length)
{
if (length < OSPF6_PREFIX_MIN_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized IPv6 prefix header", __func__);
return MSG_NG;
}
/* safe to look deeper */
if (current->prefix_length > IPV6_MAX_BITLEN)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: invalid PrefixLength (%u bits)", __func__, current->prefix_length);
return MSG_NG;
}
/* covers both fixed- and variable-sized fields */
requested_pfx_bytes = OSPF6_PREFIX_MIN_SIZE + OSPF6_PREFIX_SPACE (current->prefix_length);
if (requested_pfx_bytes > length)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized IPv6 prefix", __func__);
return MSG_NG;
}
/* next prefix */
length -= requested_pfx_bytes;
current = (struct ospf6_prefix *) ((caddr_t) current + requested_pfx_bytes);
real_num_pfxs++;
}
if (real_num_pfxs != req_num_pfxs)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: IPv6 prefix number mismatch (%u required, %u real)",
__func__, req_num_pfxs, real_num_pfxs);
return MSG_NG;
}
return MSG_OK;
}
/* Verify an LSA to have a valid length and dispatch further (where
appropriate) to check if the contents, including nested IPv6 prefixes,
is properly sized/aligned within the LSA. Note that this function gets
LSA type in network byte order, uses in host byte order and passes to
ospf6_lstype_name() in network byte order again. */
static unsigned
ospf6_lsa_examin (struct ospf6_lsa_header *lsah, const u_int16_t lsalen, const u_char headeronly)
{
struct ospf6_intra_prefix_lsa *intra_prefix_lsa;
struct ospf6_as_external_lsa *as_external_lsa;
struct ospf6_link_lsa *link_lsa;
unsigned exp_length;
u_int8_t ltindex;
u_int16_t lsatype;
/* In case an additional minimum length constraint is defined for current
LSA type, make sure that this constraint is met. */
lsatype = ntohs (lsah->type);
ltindex = lsatype & OSPF6_LSTYPE_FCODE_MASK;
if
(
ltindex < OSPF6_LSTYPE_SIZE &&
ospf6_lsa_minlen[ltindex] &&
lsalen < ospf6_lsa_minlen[ltindex] + OSPF6_LSA_HEADER_SIZE
)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized (%u B) LSA", __func__, lsalen);
return MSG_NG;
}
switch (lsatype)
{
case OSPF6_LSTYPE_ROUTER:
/* RFC5340 A.4.3, LSA header + OSPF6_ROUTER_LSA_MIN_SIZE bytes followed
by N>=0 interface descriptions. */
if ((lsalen - OSPF6_LSA_HEADER_SIZE - OSPF6_ROUTER_LSA_MIN_SIZE) % OSPF6_ROUTER_LSDESC_FIX_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: interface description alignment error", __func__);
return MSG_NG;
}
break;
case OSPF6_LSTYPE_NETWORK:
/* RFC5340 A.4.4, LSA header + OSPF6_NETWORK_LSA_MIN_SIZE bytes
followed by N>=0 attached router descriptions. */
if ((lsalen - OSPF6_LSA_HEADER_SIZE - OSPF6_NETWORK_LSA_MIN_SIZE) % OSPF6_NETWORK_LSDESC_FIX_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: router description alignment error", __func__);
return MSG_NG;
}
break;
case OSPF6_LSTYPE_INTER_PREFIX:
/* RFC5340 A.4.5, LSA header + OSPF6_INTER_PREFIX_LSA_MIN_SIZE bytes
followed by 3-4 fields of a single IPv6 prefix. */
if (headeronly)
break;
return ospf6_prefixes_examin
(
(struct ospf6_prefix *) ((caddr_t) lsah + OSPF6_LSA_HEADER_SIZE + OSPF6_INTER_PREFIX_LSA_MIN_SIZE),
lsalen - OSPF6_LSA_HEADER_SIZE - OSPF6_INTER_PREFIX_LSA_MIN_SIZE,
1
);
case OSPF6_LSTYPE_INTER_ROUTER:
/* RFC5340 A.4.6, fixed-size LSA. */
if (lsalen > OSPF6_LSA_HEADER_SIZE + OSPF6_INTER_ROUTER_LSA_FIX_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: oversized (%u B) LSA", __func__, lsalen);
return MSG_NG;
}
break;
case OSPF6_LSTYPE_AS_EXTERNAL: /* RFC5340 A.4.7, same as A.4.8. */
case OSPF6_LSTYPE_TYPE_7:
/* RFC5340 A.4.8, LSA header + OSPF6_AS_EXTERNAL_LSA_MIN_SIZE bytes
followed by 3-4 fields of IPv6 prefix and 3 conditional LSA fields:
16 bytes of forwarding address, 4 bytes of external route tag,
4 bytes of referenced link state ID. */
if (headeronly)
break;
as_external_lsa = (struct ospf6_as_external_lsa *) ((caddr_t) lsah + OSPF6_LSA_HEADER_SIZE);
exp_length = OSPF6_LSA_HEADER_SIZE + OSPF6_AS_EXTERNAL_LSA_MIN_SIZE;
/* To find out if the last optional field (Referenced Link State ID) is
assumed in this LSA, we need to access fixed fields of the IPv6
prefix before ospf6_prefix_examin() confirms its sizing. */
if (exp_length + OSPF6_PREFIX_MIN_SIZE > lsalen)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized (%u B) LSA header", __func__, lsalen);
return MSG_NG;
}
/* forwarding address */
if (CHECK_FLAG (as_external_lsa->bits_metric, OSPF6_ASBR_BIT_F))
exp_length += 16;
/* external route tag */
if (CHECK_FLAG (as_external_lsa->bits_metric, OSPF6_ASBR_BIT_T))
exp_length += 4;
/* referenced link state ID */
if (as_external_lsa->prefix.u._prefix_referenced_lstype)
exp_length += 4;
/* All the fixed-size fields (mandatory and optional) must fit. I.e.,
this check does not include any IPv6 prefix fields. */
if (exp_length > lsalen)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized (%u B) LSA header", __func__, lsalen);
return MSG_NG;
}
/* The last call completely covers the remainder (IPv6 prefix). */
return ospf6_prefixes_examin
(
(struct ospf6_prefix *) ((caddr_t) as_external_lsa + OSPF6_AS_EXTERNAL_LSA_MIN_SIZE),
lsalen - exp_length,
1
);
case OSPF6_LSTYPE_LINK:
/* RFC5340 A.4.9, LSA header + OSPF6_LINK_LSA_MIN_SIZE bytes followed
by N>=0 IPv6 prefix blocks (with N declared beforehand). */
if (headeronly)
break;
link_lsa = (struct ospf6_link_lsa *) ((caddr_t) lsah + OSPF6_LSA_HEADER_SIZE);
return ospf6_prefixes_examin
(
(struct ospf6_prefix *) ((caddr_t) link_lsa + OSPF6_LINK_LSA_MIN_SIZE),
lsalen - OSPF6_LSA_HEADER_SIZE - OSPF6_LINK_LSA_MIN_SIZE,
ntohl (link_lsa->prefix_num) /* 32 bits */
);
case OSPF6_LSTYPE_INTRA_PREFIX:
/* RFC5340 A.4.10, LSA header + OSPF6_INTRA_PREFIX_LSA_MIN_SIZE bytes
followed by N>=0 IPv6 prefixes (with N declared beforehand). */
if (headeronly)
break;
intra_prefix_lsa = (struct ospf6_intra_prefix_lsa *) ((caddr_t) lsah + OSPF6_LSA_HEADER_SIZE);
return ospf6_prefixes_examin
(
(struct ospf6_prefix *) ((caddr_t) intra_prefix_lsa + OSPF6_INTRA_PREFIX_LSA_MIN_SIZE),
lsalen - OSPF6_LSA_HEADER_SIZE - OSPF6_INTRA_PREFIX_LSA_MIN_SIZE,
ntohs (intra_prefix_lsa->prefix_num) /* 16 bits */
);
}
/* No additional validation is possible for unknown LSA types, which are
themselves valid in OPSFv3, hence the default decision is to accept. */
return MSG_OK;
}
/* Verify if the provided input buffer is a valid sequence of LSAs. This
includes verification of LSA blocks length/alignment and dispatching
of deeper-level checks. */
static unsigned
ospf6_lsaseq_examin
(
struct ospf6_lsa_header *lsah, /* start of buffered data */
size_t length,
const u_char headeronly,
/* When declared_num_lsas is not 0, compare it to the real number of LSAs
and treat the difference as an error. */
const u_int32_t declared_num_lsas
)
{
u_int32_t counted_lsas = 0;
while (length)
{
u_int16_t lsalen;
if (length < OSPF6_LSA_HEADER_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized (%u B) trailing (#%u) LSA header",
__func__, length, counted_lsas);
return MSG_NG;
}
/* save on ntohs() calls here and in the LSA validator */
lsalen = OSPF6_LSA_SIZE (lsah);
if (lsalen < OSPF6_LSA_HEADER_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: malformed LSA header #%u, declared length is %u B",
__func__, counted_lsas, lsalen);
return MSG_NG;
}
if (headeronly)
{
/* less checks here and in ospf6_lsa_examin() */
if (MSG_OK != ospf6_lsa_examin (lsah, lsalen, 1))
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: anomaly in header-only %s LSA #%u", __func__,
ospf6_lstype_name (lsah->type), counted_lsas);
return MSG_NG;
}
lsah = (struct ospf6_lsa_header *) ((caddr_t) lsah + OSPF6_LSA_HEADER_SIZE);
length -= OSPF6_LSA_HEADER_SIZE;
}
else
{
/* make sure the input buffer is deep enough before further checks */
if (lsalen > length)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: anomaly in %s LSA #%u: declared length is %u B, buffered length is %u B",
__func__, ospf6_lstype_name (lsah->type), counted_lsas, lsalen, length);
return MSG_NG;
}
if (MSG_OK != ospf6_lsa_examin (lsah, lsalen, 0))
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: anomaly in %s LSA #%u", __func__,
ospf6_lstype_name (lsah->type), counted_lsas);
return MSG_NG;
}
lsah = (struct ospf6_lsa_header *) ((caddr_t) lsah + lsalen);
length -= lsalen;
}
counted_lsas++;
}
if (declared_num_lsas && counted_lsas != declared_num_lsas)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: #LSAs declared (%u) does not match actual (%u)",
__func__, declared_num_lsas, counted_lsas);
return MSG_NG;
}
return MSG_OK;
}
/* Verify a complete OSPF packet for proper sizing/alignment. */
static unsigned
ospf6_packet_examin (struct ospf6_header *oh, const unsigned bytesonwire)
{
struct ospf6_lsupdate *lsupd;
unsigned test;
/* length, 1st approximation */
if (bytesonwire < OSPF6_HEADER_SIZE)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized (%u B) packet", __func__, bytesonwire);
return MSG_NG;
}
/* Now it is safe to access header fields. */
if (bytesonwire != ntohs (oh->length))
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: packet length error (%u real, %u declared)",
__func__, bytesonwire, ntohs (oh->length));
return MSG_NG;
}
/* version check */
if (oh->version != OSPFV3_VERSION)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: invalid (%u) protocol version", __func__, oh->version);
return MSG_NG;
}
/* length, 2nd approximation */
if
(
oh->type < OSPF6_MESSAGE_TYPE_ALL &&
ospf6_packet_minlen[oh->type] &&
bytesonwire < OSPF6_HEADER_SIZE + ospf6_packet_minlen[oh->type]
)
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: undersized (%u B) %s packet", __func__,
bytesonwire, ospf6_message_type_str[oh->type]);
return MSG_NG;
}
/* type-specific deeper validation */
switch (oh->type)
{
case OSPF6_MESSAGE_TYPE_HELLO:
/* RFC5340 A.3.2, packet header + OSPF6_HELLO_MIN_SIZE bytes followed
by N>=0 router-IDs. */
if (0 == (bytesonwire - OSPF6_HEADER_SIZE - OSPF6_HELLO_MIN_SIZE) % 4)
return MSG_OK;
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: alignment error in %s packet",
__func__, ospf6_message_type_str[oh->type]);
return MSG_NG;
case OSPF6_MESSAGE_TYPE_DBDESC:
/* RFC5340 A.3.3, packet header + OSPF6_DB_DESC_MIN_SIZE bytes followed
by N>=0 header-only LSAs. */
test = ospf6_lsaseq_examin
(
(struct ospf6_lsa_header *) ((caddr_t) oh + OSPF6_HEADER_SIZE + OSPF6_DB_DESC_MIN_SIZE),
bytesonwire - OSPF6_HEADER_SIZE - OSPF6_DB_DESC_MIN_SIZE,
1,
0
);
break;
case OSPF6_MESSAGE_TYPE_LSREQ:
/* RFC5340 A.3.4, packet header + N>=0 LS description blocks. */
if (0 == (bytesonwire - OSPF6_HEADER_SIZE - OSPF6_LS_REQ_MIN_SIZE) % OSPF6_LSREQ_LSDESC_FIX_SIZE)
return MSG_OK;
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: alignment error in %s packet",
__func__, ospf6_message_type_str[oh->type]);
return MSG_NG;
case OSPF6_MESSAGE_TYPE_LSUPDATE:
/* RFC5340 A.3.5, packet header + OSPF6_LS_UPD_MIN_SIZE bytes followed
by N>=0 full LSAs (with N declared beforehand). */
lsupd = (struct ospf6_lsupdate *) ((caddr_t) oh + OSPF6_HEADER_SIZE);
test = ospf6_lsaseq_examin
(
(struct ospf6_lsa_header *) ((caddr_t) lsupd + OSPF6_LS_UPD_MIN_SIZE),
bytesonwire - OSPF6_HEADER_SIZE - OSPF6_LS_UPD_MIN_SIZE,
0,
ntohl (lsupd->lsa_number) /* 32 bits */
);
break;
case OSPF6_MESSAGE_TYPE_LSACK:
/* RFC5340 A.3.6, packet header + N>=0 header-only LSAs. */
test = ospf6_lsaseq_examin
(
(struct ospf6_lsa_header *) ((caddr_t) oh + OSPF6_HEADER_SIZE + OSPF6_LS_ACK_MIN_SIZE),
bytesonwire - OSPF6_HEADER_SIZE - OSPF6_LS_ACK_MIN_SIZE,
1,
0
);
break;
default:
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: invalid (%u) message type", __func__, oh->type);
return MSG_NG;
}
if (test != MSG_OK && IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: anomaly in %s packet", __func__, ospf6_message_type_str[oh->type]);
return test;
}
/* Verify particular fields of otherwise correct received OSPF packet to
meet the requirements of RFC. */
static int
ospf6_rxpacket_examin (struct ospf6_interface *oi, struct ospf6_header *oh, const unsigned bytesonwire)
{
char buf[2][INET_ADDRSTRLEN];
if (MSG_OK != ospf6_packet_examin (oh, bytesonwire))
return MSG_NG;
/* Area-ID check */
if (oh->area_id != oi->area->area_id)
{
if (IS_OSPF6_DEBUG_MESSAGE (oh->type, RECV))
{
if (oh->area_id == BACKBONE_AREA_ID)
zlog_debug ("%s: Message may be via Virtual Link: not supported", __func__);
else
zlog_debug
(
"%s: Area-ID mismatch (my %s, rcvd %s)", __func__,
inet_ntop (AF_INET, &oi->area->area_id, buf[0], INET_ADDRSTRLEN),
inet_ntop (AF_INET, &oh->area_id, buf[1], INET_ADDRSTRLEN)
);
}
return MSG_NG;
}
/* Instance-ID check */
if (oh->instance_id != oi->instance_id)
{
if (IS_OSPF6_DEBUG_MESSAGE (oh->type, RECV))
zlog_debug ("%s: Instance-ID mismatch (my %u, rcvd %u)", __func__, oi->instance_id, oh->instance_id);
return MSG_NG;
}
/* Router-ID check */
if (oh->router_id == oi->area->ospf6->router_id)
{
zlog_warn ("%s: Duplicate Router-ID (%s)", __func__, inet_ntop (AF_INET, &oh->router_id, buf[0], INET_ADDRSTRLEN));
return MSG_NG;
}
return MSG_OK;
}
static void
ospf6_lsupdate_recv (struct in6_addr *src, struct in6_addr *dst,
struct ospf6_interface *oi, struct ospf6_header *oh)
@ -955,9 +1360,6 @@ ospf6_lsupdate_recv (struct in6_addr *src, struct in6_addr *dst,
unsigned long num;
char *p;
if (ospf6_header_examin (src, dst, oi, oh) != MSG_OK)
return;
on = ospf6_neighbor_lookup (oh->router_id, oi);
if (on == NULL)
{
@ -1035,8 +1437,6 @@ ospf6_lsack_recv (struct in6_addr *src, struct in6_addr *dst,
struct ospf6_lsdb *lsdb = NULL;
assert (oh->type == OSPF6_MESSAGE_TYPE_LSACK);
if (ospf6_header_examin (src, dst, oi, oh) != MSG_OK)
return;
on = ospf6_neighbor_lookup (oh->router_id, oi);
if (on == NULL)
@ -1201,11 +1601,6 @@ ospf6_receive (struct thread *thread)
zlog_err ("Excess message read");
return 0;
}
else if (len < sizeof (struct ospf6_header))
{
zlog_err ("Deficient message read");
return 0;
}
oi = ospf6_interface_lookup_by_ifindex (ifindex);
if (oi == NULL || oi->area == NULL)
@ -1213,8 +1608,22 @@ ospf6_receive (struct thread *thread)
zlog_debug ("Message received on disabled interface");
return 0;
}
if (CHECK_FLAG (oi->flag, OSPF6_INTERFACE_PASSIVE))
{
if (IS_OSPF6_DEBUG_MESSAGE (OSPF6_MESSAGE_TYPE_UNKNOWN, RECV))
zlog_debug ("%s: Ignore message on passive interface %s",
__func__, oi->interface->name);
return 0;
}
oh = (struct ospf6_header *) recvbuf;
if (ospf6_rxpacket_examin (oi, oh, len) != MSG_OK)
return 0;
/* Being here means, that no sizing/alignment issues were detected in
the input packet. This renders the additional checks performed below
and also in the type-specific dispatching functions a dead code,
which can be dismissed in a cleanup-focused review round later. */
/* Log */
if (IS_OSPF6_DEBUG_MESSAGE (oh->type, RECV))
@ -1251,14 +1660,6 @@ ospf6_receive (struct thread *thread)
}
}
if (CHECK_FLAG (oi->flag, OSPF6_INTERFACE_PASSIVE))
{
if (IS_OSPF6_DEBUG_MESSAGE (oh->type, RECV))
zlog_debug ("Ignore message on passive interface %s",
oi->interface->name);
return 0;
}
switch (oh->type)
{
case OSPF6_MESSAGE_TYPE_HELLO:

7
ospf6d/ospf6_message.h
View File

@ -52,6 +52,7 @@ extern const char *ospf6_message_type_str[];
(ospf6_message_type_str[ OSPF6_MESSAGE_TYPE_CANONICAL (T) ])
/* OSPFv3 packet header */
#define OSPF6_HEADER_SIZE 16U
struct ospf6_header
{
u_char version;
@ -67,6 +68,7 @@ struct ospf6_header
#define OSPF6_MESSAGE_END(H) ((caddr_t) (H) + ntohs ((H)->length))
/* Hello */
#define OSPF6_HELLO_MIN_SIZE 20U
struct ospf6_hello
{
u_int32_t interface_id;
@ -80,6 +82,7 @@ struct ospf6_hello
};
/* Database Description */
#define OSPF6_DB_DESC_MIN_SIZE 12U
struct ospf6_dbdesc
{
u_char reserved1;
@ -96,7 +99,9 @@ struct ospf6_dbdesc
#define OSPF6_DBDESC_IBIT (0x04) /* initial bit */
/* Link State Request */
#define OSPF6_LS_REQ_MIN_SIZE 0U
/* It is just a sequence of entries below */
#define OSPF6_LSREQ_LSDESC_FIX_SIZE 12U
struct ospf6_lsreq_entry
{
u_int16_t reserved; /* Must Be Zero */
@ -106,6 +111,7 @@ struct ospf6_lsreq_entry
};
/* Link State Update */
#define OSPF6_LS_UPD_MIN_SIZE 4U
struct ospf6_lsupdate
{
u_int32_t lsa_number;
@ -113,6 +119,7 @@ struct ospf6_lsupdate
};
/* Link State Acknowledgement */
#define OSPF6_LS_ACK_MIN_SIZE 0U
/* It is just a sequence of LSA Headers */
/* Function definition */

1
ospf6d/ospf6_proto.h
View File

@ -73,6 +73,7 @@
#define OSPF6_OPT_V6 (1 << 0) /* IPv6 forwarding Capability */
/* OSPF6 Prefix */
#define OSPF6_PREFIX_MIN_SIZE 4U /* .length == 0 */
struct ospf6_prefix
{
u_int8_t prefix_length;