0
0
mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-12-23 02:01:55 +00:00
bird/proto/rip/auth.c
Ondrej Zajicek b21f68b4cd Fix bugs in OSPF MD5 authentication. First bug is that default
values for MD5 password ID changed during reconfigure, Second
bug is that BIRD chooses password in first-fit manner, but RFC
says that it should use the one with the latest generate-from.

It also modifies the syntax for multiple passwords.
Now it is possible to just add more 'password' statements
to the interface section and it is not needed to use
'passwords' section. Old syntax can be used too.
2008-11-08 17:24:23 +01:00

169 lines
4.8 KiB
C

/*
* Rest in pieces - RIP protocol
*
* Copyright (c) 1999 Pavel Machek <pavel@ucw.cz>
* Copyright (c) 2004 Ondrej Filip <feela@network.cz>
*
* Bug fixes by Eric Leblond <eleblond@init-sys.com>, April 2003
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "lib/socket.h"
#include "lib/resource.h"
#include "lib/lists.h"
#include "lib/timer.h"
#include "lib/md5.h"
#include "lib/string.h"
#include "rip.h"
#define P ((struct rip_proto *) p)
#define P_CF ((struct rip_proto_config *)p->cf)
#define PACKETLEN(num) (num * sizeof(struct rip_block) + sizeof(struct rip_packet_heading))
/*
* rip_incoming_authentication - check authentication of incomming packet and return 1 if there's problem.
*/
int
rip_incoming_authentication( struct proto *p, struct rip_block_auth *block, struct rip_packet *packet, int num, ip_addr whotoldme )
{
DBG( "Incoming authentication: " );
switch (ntohs(block->authtype)) { /* Authentication type */
case AT_PLAINTEXT:
{
struct password_item *passwd = password_find(P_CF->passwords, 1);
DBG( "Plaintext passwd" );
if (!passwd) {
log( L_AUTH "No passwords set and password authentication came" );
return 1;
}
if (strncmp( (char *) (&block->packetlen), passwd->password, 16)) {
log( L_AUTH "Passwd authentication failed!" );
DBG( "Expected %s, got %.16s\n", passwd->password, &block->packetlen );
return 1;
}
}
break;
case AT_MD5:
DBG( "md5 password" );
{
struct password_item *pass = NULL, *ptmp;
struct rip_md5_tail *tail;
struct MD5Context ctxt;
char md5sum_packet[16];
char md5sum_computed[16];
struct neighbor *neigh = neigh_find(p, &whotoldme, 0);
list *l = P_CF->passwords;
if (ntohs(block->packetlen) != PACKETLEN(num) - sizeof(struct rip_md5_tail) ) {
log( L_ERR "Packet length in MD5 does not match computed value" );
return 1;
}
tail = (struct rip_md5_tail *) ((char *) packet + (ntohs(block->packetlen) ));
if ((tail->mustbeFFFF != 0xffff) || (tail->mustbe0001 != 0x0100)) {
log( L_ERR "MD5 tail signature is not there" );
return 1;
}
WALK_LIST(ptmp, *l)
{
if (block->keyid != ptmp->id) continue;
if ((ptmp->genfrom > now_real) || (ptmp->gento < now_real)) continue;
pass = ptmp;
break;
}
if(!pass) return 1;
if (!neigh) {
log( L_AUTH "Non-neighbour MD5 checksummed packet?" );
} else {
if (neigh->aux > block->seq) {
log( L_AUTH "MD5 protected packet with lower numbers" );
return 1;
}
neigh->aux = block->seq;
}
memcpy(md5sum_packet, tail->md5, 16);
password_cpy(tail->md5, pass->password, 16);
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) packet, ntohs(block->packetlen) + sizeof(struct rip_block_auth) );
MD5Final(md5sum_computed, &ctxt);
if (memcmp(md5sum_packet, md5sum_computed, 16))
return 1;
}
}
return 0;
}
/*
* rip_outgoing_authentication - append authentication information to the packet.
* %num: number of rip_blocks already in packets. This function returns size of packet to send.
*/
int
rip_outgoing_authentication( struct proto *p, struct rip_block_auth *block, struct rip_packet *packet, int num )
{
struct password_item *passwd = password_find(P_CF->passwords, 1);
if (!P_CF->authtype)
return PACKETLEN(num);
DBG( "Outgoing authentication: " );
if (!passwd) {
log( L_ERR "No suitable password found for authentication" );
return PACKETLEN(num);
}
block->authtype = htons(P_CF->authtype);
block->mustbeFFFF = 0xffff;
switch (P_CF->authtype) {
case AT_PLAINTEXT:
password_cpy( (char *) (&block->packetlen), passwd->password, 16);
return PACKETLEN(num);
case AT_MD5:
{
struct rip_md5_tail *tail;
struct MD5Context ctxt;
static u32 sequence = 0;
if (num > PACKET_MD5_MAX)
bug( "We can not add MD5 authentication to this long packet" );
/* need to preset the sequence number to a sane value */
if (!sequence)
sequence = (u32) time(NULL);
block->keyid = passwd->id;
block->authlen = sizeof(struct rip_block_auth);
block->seq = sequence++;
block->zero0 = 0;
block->zero1 = 0;
block->packetlen = htons(PACKETLEN(num));
tail = (struct rip_md5_tail *) ((char *) packet + PACKETLEN(num) );
tail->mustbeFFFF = 0xffff;
tail->mustbe0001 = 0x0100;
password_cpy(tail->md5, passwd->password, 16);
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) packet, PACKETLEN(num) + sizeof(struct rip_md5_tail));
MD5Final(tail->md5, &ctxt);
return PACKETLEN(num) + block->authlen;
}
default:
bug( "Unknown authtype in outgoing authentication?" );
}
}