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OSPF: Use message authentication interface

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Based on former commit from Pavel Tvrdik
This commit is contained in:
Ondrej Zajicek (work) 2016-10-27 20:58:21 +02:00
parent 390601f038
commit 29239ba2bb
4 changed files with 94 additions and 73 deletions
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14
proto/ospf/config.Y
View file

@ -42,6 +42,20 @@ ospf_iface_finish(void)
if ((ip->autype == OSPF_AUTH_NONE) && (ip->passwords != NULL)) if ((ip->autype == OSPF_AUTH_NONE) && (ip->passwords != NULL))
log(L_WARN "Password option without authentication option does not make sense"); log(L_WARN "Password option without authentication option does not make sense");
if (ip->passwords)
{
struct password_item *pass;
WALK_LIST(pass, *ip->passwords)
{
if (pass->alg && (ip->autype != OSPF_AUTH_CRYPT))
cf_error("Password algorithm option requires cryptographic authentication");
/* Set default OSPF crypto algorithms */
if (!pass->alg && (ip->autype == OSPF_AUTH_CRYPT))
pass->alg = ospf_cfg_is_v2() ? ALG_MD5 : ALG_HMAC_SHA256;
}
}
} }
static void static void

24
proto/ospf/iface.c
View file

@ -9,6 +9,7 @@
*/ */
#include "ospf.h" #include "ospf.h"
#include "nest/password.h"
const char *ospf_is_names[] = { const char *ospf_is_names[] = {
@ -51,6 +52,18 @@ ifa_tx_length(struct ospf_iface *ifa)
return ifa->cf->tx_length ?: ifa->iface->mtu; return ifa->cf->tx_length ?: ifa->iface->mtu;
} }
static inline uint
ifa_tx_hdrlen(struct ospf_iface *ifa)
{
uint hlen = SIZE_OF_IP_HEADER;
/* Relevant just for OSPFv2 */
if (ifa->autype == OSPF_AUTH_CRYPT)
hlen += max_mac_length(ifa->passwords);
return hlen;
}
static inline uint static inline uint
ifa_bufsize(struct ospf_iface *ifa) ifa_bufsize(struct ospf_iface *ifa)
{ {
@ -67,11 +80,7 @@ ifa_flood_queue_size(struct ospf_iface *ifa)
int int
ospf_iface_assure_bufsize(struct ospf_iface *ifa, uint plen) ospf_iface_assure_bufsize(struct ospf_iface *ifa, uint plen)
{ {
plen += SIZE_OF_IP_HEADER; plen += ifa->tx_hdrlen;
/* This is relevant just for OSPFv2 */
if (ifa->autype == OSPF_AUTH_CRYPT)
plen += OSPF_AUTH_CRYPT_SIZE;
if (plen <= ifa->sk->tbsize) if (plen <= ifa->sk->tbsize)
return 0; return 0;
@ -574,6 +583,7 @@ ospf_iface_new(struct ospf_area *oa, struct ifa *addr, struct ospf_iface_patt *i
ifa->stub = ospf_iface_stubby(ip, addr); ifa->stub = ospf_iface_stubby(ip, addr);
ifa->ioprob = OSPF_I_OK; ifa->ioprob = OSPF_I_OK;
ifa->tx_length = ifa_tx_length(ifa); ifa->tx_length = ifa_tx_length(ifa);
ifa->tx_hdrlen = ifa_tx_hdrlen(ifa);
ifa->check_link = ip->check_link; ifa->check_link = ip->check_link;
ifa->ecmp_weight = ip->ecmp_weight; ifa->ecmp_weight = ip->ecmp_weight;
ifa->check_ttl = (ip->ttl_security == 1); ifa->check_ttl = (ip->ttl_security == 1);
@ -684,6 +694,7 @@ ospf_iface_new_vlink(struct ospf_proto *p, struct ospf_iface_patt *ip)
ifa->deadint = ip->deadint; ifa->deadint = ip->deadint;
ifa->inftransdelay = ip->inftransdelay; ifa->inftransdelay = ip->inftransdelay;
ifa->tx_length = ospf_is_v2(p) ? IP4_MIN_MTU : IP6_MIN_MTU; ifa->tx_length = ospf_is_v2(p) ? IP4_MIN_MTU : IP6_MIN_MTU;
ifa->tx_hdrlen = ifa_tx_hdrlen(ifa);
ifa->autype = ip->autype; ifa->autype = ip->autype;
ifa->passwords = ip->passwords; ifa->passwords = ip->passwords;
ifa->instance_id = ip->instance_id; ifa->instance_id = ip->instance_id;
@ -824,6 +835,9 @@ ospf_iface_reconfigure(struct ospf_iface *ifa, struct ospf_iface_patt *new)
/* Update passwords */ /* Update passwords */
ifa->passwords = new->passwords; ifa->passwords = new->passwords;
/* Update header length */
ifa->tx_hdrlen = ifa_tx_hdrlen(ifa);
/* Remaining options are just for proper interfaces */ /* Remaining options are just for proper interfaces */
if (ifa->type == OSPF_IT_VLINK) if (ifa->type == OSPF_IT_VLINK)
return 1; return 1;

21
proto/ospf/ospf.h
View file

@ -180,11 +180,7 @@ struct ospf_iface_patt
#define OSPF_RXBUF_MINSIZE 256 /* Minimal allowed size */ #define OSPF_RXBUF_MINSIZE 256 /* Minimal allowed size */
u8 instance_id; u8 instance_id;
u8 autype; /* Not really used in OSPFv3 */ u8 autype; /* OSPF_AUTH_*, not really used in OSPFv3 */
#define OSPF_AUTH_NONE 0
#define OSPF_AUTH_SIMPLE 1
#define OSPF_AUTH_CRYPT 2
#define OSPF_AUTH_CRYPT_SIZE 16
u8 strictnbma; u8 strictnbma;
u8 check_link; u8 check_link;
u8 ecmp_weight; u8 ecmp_weight;
@ -334,6 +330,7 @@ struct ospf_iface
u8 marked; /* Used in OSPF reconfigure, 2 for force restart */ u8 marked; /* Used in OSPF reconfigure, 2 for force restart */
u16 rxbuf; /* Buffer size */ u16 rxbuf; /* Buffer size */
u16 tx_length; /* Soft TX packet length limit, usually MTU */ u16 tx_length; /* Soft TX packet length limit, usually MTU */
u16 tx_hdrlen; /* Expected packet header length, less than tx_length */
u8 check_link; /* Whether iface link change is used */ u8 check_link; /* Whether iface link change is used */
u8 ecmp_weight; /* Weight used for ECMP */ u8 ecmp_weight; /* Weight used for ECMP */
u8 link_lsa_suppression; /* Suppression of Link-LSA origination */ u8 link_lsa_suppression; /* Suppression of Link-LSA origination */
@ -424,6 +421,11 @@ struct ospf_neighbor
#define ISM_UNLOOP 5 /* Link up */ #define ISM_UNLOOP 5 /* Link up */
#define ISM_DOWN 6 /* Interface down */ #define ISM_DOWN 6 /* Interface down */
/* OSPF authentication types */
#define OSPF_AUTH_NONE 0
#define OSPF_AUTH_SIMPLE 1
#define OSPF_AUTH_CRYPT 2
/* OSPF neighbor states */ /* OSPF neighbor states */
#define NEIGHBOR_DOWN 0 #define NEIGHBOR_DOWN 0
@ -455,7 +457,6 @@ struct ospf_neighbor
#define TRANS_WAIT 2 /* Waiting before the end of translation */ #define TRANS_WAIT 2 /* Waiting before the end of translation */
/* Generic option flags */ /* Generic option flags */
#define OPT_V6 0x01 /* OSPFv3, LSA relevant for IPv6 routing calculation */ #define OPT_V6 0x01 /* OSPFv3, LSA relevant for IPv6 routing calculation */
#define OPT_E 0x02 /* Related to AS-external LSAs */ #define OPT_E 0x02 /* Related to AS-external LSAs */
@ -491,7 +492,7 @@ struct ospf_packet
u8 autype; /* Undefined for OSPFv3 */ u8 autype; /* Undefined for OSPFv3 */
}; };
struct ospf_md5 struct ospf_auth_crypto
{ {
u16 zero; u16 zero;
u8 keyid; u8 keyid;
@ -502,7 +503,7 @@ struct ospf_md5
union ospf_auth union ospf_auth
{ {
u8 password[8]; u8 password[8];
struct ospf_md5 md5; struct ospf_auth_crypto c32;
}; };
/* Packet types */ /* Packet types */
@ -896,7 +897,6 @@ void ospf_sh_neigh_info(struct ospf_neighbor *n);
/* packet.c */ /* packet.c */
void ospf_pkt_fill_hdr(struct ospf_iface *ifa, void *buf, u8 h_type); void ospf_pkt_fill_hdr(struct ospf_iface *ifa, void *buf, u8 h_type);
uint ospf_pkt_maxsize(struct ospf_iface *ifa);
int ospf_rx_hook(sock * sk, uint size); int ospf_rx_hook(sock * sk, uint size);
// void ospf_tx_hook(sock * sk); // void ospf_tx_hook(sock * sk);
void ospf_err_hook(sock * sk, int err); void ospf_err_hook(sock * sk, int err);
@ -905,6 +905,9 @@ void ospf_send_to(struct ospf_iface *ifa, ip_addr ip);
void ospf_send_to_agt(struct ospf_iface *ifa, u8 state); void ospf_send_to_agt(struct ospf_iface *ifa, u8 state);
void ospf_send_to_bdr(struct ospf_iface *ifa); void ospf_send_to_bdr(struct ospf_iface *ifa);
static inline uint ospf_pkt_maxsize(struct ospf_iface *ifa)
{ return ifa->tx_length - ifa->tx_hdrlen; }
static inline void ospf_send_to_all(struct ospf_iface *ifa) static inline void ospf_send_to_all(struct ospf_iface *ifa)
{ ospf_send_to(ifa, ifa->all_routers); } { ospf_send_to(ifa, ifa->all_routers); }

108
proto/ospf/packet.c
View file

@ -32,25 +32,12 @@ ospf_pkt_fill_hdr(struct ospf_iface *ifa, void *buf, u8 h_type)
pkt->autype = ifa->autype; pkt->autype = ifa->autype;
} }
uint
ospf_pkt_maxsize(struct ospf_iface *ifa)
{
uint headers = SIZE_OF_IP_HEADER;
/* Relevant just for OSPFv2 */
if (ifa->autype == OSPF_AUTH_CRYPT)
headers += OSPF_AUTH_CRYPT_SIZE;
return ifa->tx_length - headers;
}
/* We assume OSPFv2 in ospf_pkt_finalize() */ /* We assume OSPFv2 in ospf_pkt_finalize() */
static void static void
ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt) ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt, uint *plen)
{ {
struct password_item *passwd = NULL; struct password_item *pass = NULL;
union ospf_auth *auth = (void *) (pkt + 1); union ospf_auth *auth = (void *) (pkt + 1);
uint plen = ntohs(pkt->length);
pkt->checksum = 0; pkt->checksum = 0;
pkt->autype = ifa->autype; pkt->autype = ifa->autype;
@ -62,25 +49,25 @@ ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt)
switch (ifa->autype) switch (ifa->autype)
{ {
case OSPF_AUTH_SIMPLE: case OSPF_AUTH_SIMPLE:
passwd = password_find(ifa->passwords, 1); pass = password_find(ifa->passwords, 1);
if (!passwd) if (!pass)
{ {
log(L_ERR "No suitable password found for authentication"); log(L_ERR "No suitable password found for authentication");
return; return;
} }
strncpy(auth->password, passwd->password, sizeof(auth->password)); strncpy(auth->password, pass->password, sizeof(auth->password));
case OSPF_AUTH_NONE: case OSPF_AUTH_NONE:
{ {
void *body = (void *) (auth + 1); void *body = (void *) (auth + 1);
uint blen = plen - sizeof(struct ospf_packet) - sizeof(union ospf_auth); uint blen = *plen - sizeof(struct ospf_packet) - sizeof(union ospf_auth);
pkt->checksum = ipsum_calculate(pkt, sizeof(struct ospf_packet), body, blen, NULL); pkt->checksum = ipsum_calculate(pkt, sizeof(struct ospf_packet), body, blen, NULL);
} }
break; break;
case OSPF_AUTH_CRYPT: case OSPF_AUTH_CRYPT:
passwd = password_find(ifa->passwords, 0); pass = password_find(ifa->passwords, 0);
if (!passwd) if (!pass)
{ {
log(L_ERR "No suitable password found for authentication"); log(L_ERR "No suitable password found for authentication");
return; return;
@ -101,20 +88,25 @@ ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt)
ifa->csn_use = now; ifa->csn_use = now;
auth->md5.zero = 0; uint auth_len = mac_type_length(pass->alg);
auth->md5.keyid = passwd->id; byte *auth_tail = ((byte *) pkt + *plen);
auth->md5.len = OSPF_AUTH_CRYPT_SIZE; *plen += auth_len;
auth->md5.csn = htonl(ifa->csn);
void *tail = ((void *) pkt) + plen; ASSERT(*plen < ifa->sk->tbsize);
char password[OSPF_AUTH_CRYPT_SIZE];
strncpy(password, passwd->password, sizeof(password));
struct hash_context ctx; auth->c32.zero = 0;
md5_init(&ctx); auth->c32.keyid = pass->id;
md5_update(&ctx, (char *) pkt, plen); auth->c32.len = auth_len;
md5_update(&ctx, password, OSPF_AUTH_CRYPT_SIZE); auth->c32.csn = htonl(ifa->csn);
memcpy((byte *) tail, md5_final(&ctx), MD5_SIZE);
/* Append key for keyed hash, append padding for HMAC (RFC 5709 3.3) */
if (pass->alg < ALG_HMAC)
strncpy(auth_tail, pass->password, auth_len);
else
memset32(auth_tail, HMAC_MAGIC, auth_len / 4);
mac_fill(pass->alg, pass->password, pass->length,
(byte *) pkt, *plen, auth_tail);
break; break;
default: default:
@ -155,13 +147,19 @@ ospf_pkt_checkauth(struct ospf_neighbor *n, struct ospf_iface *ifa, struct ospf_
return 1; return 1;
case OSPF_AUTH_CRYPT: case OSPF_AUTH_CRYPT:
if (auth->md5.len != OSPF_AUTH_CRYPT_SIZE) pass = password_find_by_id(ifa->passwords, auth->c32.keyid);
DROP("invalid MD5 digest length", auth->md5.len); if (!pass)
DROP("no suitable password found", auth->c32.keyid);
if (plen + OSPF_AUTH_CRYPT_SIZE > len) uint auth_len = mac_type_length(pass->alg);
DROP("length mismatch", len);
u32 rcv_csn = ntohl(auth->md5.csn); if (plen + auth->c32.len > len)
DROP("packet length mismatch", len);
if (auth->c32.len != auth_len)
DROP("wrong authentication length", auth->c32.len);
u32 rcv_csn = ntohl(auth->c32.csn);
if (n && (rcv_csn < n->csn)) if (n && (rcv_csn < n->csn))
// DROP("lower sequence number", rcv_csn); // DROP("lower sequence number", rcv_csn);
{ {
@ -172,22 +170,19 @@ ospf_pkt_checkauth(struct ospf_neighbor *n, struct ospf_iface *ifa, struct ospf_
return 0; return 0;
} }
pass = password_find_by_id(ifa->passwords, auth->md5.keyid); byte *auth_tail = ((byte *) pkt) + plen;
if (!pass) byte *auth_data = alloca(auth_len);
DROP("no suitable password found", auth->md5.keyid); memcpy(auth_data, auth_tail, auth_len);
byte *tail = ((byte *) pkt) + plen; /* Append key for keyed hash, append padding for HMAC (RFC 5709 3.3) */
char received[OSPF_AUTH_CRYPT_SIZE]; if (pass->alg < ALG_HMAC)
memcpy(received, tail, OSPF_AUTH_CRYPT_SIZE); strncpy(auth_tail, pass->password, auth_len);
strncpy(tail, pass->password, OSPF_AUTH_CRYPT_SIZE); else
memset32(auth_tail, HMAC_MAGIC, auth_len / 4);
struct hash_context ctx; if (!mac_verify(pass->alg, pass->password, pass->length,
md5_init(&ctx); (byte *) pkt, plen + auth_len, auth_data))
md5_update(&ctx, (byte *) pkt, plen + OSPF_AUTH_CRYPT_SIZE); DROP("wrong authentication code", pass->id);
char *computed = md5_final(&ctx);
if (memcmp(received, computed, OSPF_AUTH_CRYPT_SIZE))
DROP("wrong MD5 digest", pass->id);
if (n) if (n)
n->csn = rcv_csn; n->csn = rcv_csn;
@ -473,15 +468,10 @@ ospf_send_to(struct ospf_iface *ifa, ip_addr dst)
{ {
sock *sk = ifa->sk; sock *sk = ifa->sk;
struct ospf_packet *pkt = (struct ospf_packet *) sk->tbuf; struct ospf_packet *pkt = (struct ospf_packet *) sk->tbuf;
int plen = ntohs(pkt->length); uint plen = ntohs(pkt->length);
if (ospf_is_v2(ifa->oa->po)) if (ospf_is_v2(ifa->oa->po))
{ ospf_pkt_finalize(ifa, pkt, &plen);
if (ifa->autype == OSPF_AUTH_CRYPT)
plen += OSPF_AUTH_CRYPT_SIZE;
ospf_pkt_finalize(ifa, pkt);
}
int done = sk_send_to(sk, plen, dst, 0); int done = sk_send_to(sk, plen, dst, 0);
if (!done) if (!done)