1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/*
* Rest in pieces - RIP protocol
*
* Copyright (c) 1999 Pavel Machek <pavel@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#define 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 (block->authtype) { /* Authentication type */
case AT_PLAINTEXT:
{
struct password_item *passwd = get_best_password( P_CF->passwords, 0 );
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 %s\n", passwd->password, &block->packetlen );
return 1;
}
}
return 0;
case AT_MD5:
DBG( "md5 password" );
{
struct password_item *head;
struct rip_md5_tail *tail;
if (block->packetlen != PACKETLEN(num)) {
log( L_ERR "Packet length in MD5 does not match computed value" );
return 1;
}
tail = (struct rip_md5_tail *) ((char *) packet + (block->packetlen - sizeof(struct rip_block_auth)));
if ((tail->mustbeFFFF != 0xffff) || (tail->mustbe0001 != 0x0001)) {
log( L_ERR "MD5 tail signature is not there" );
return 1;
}
head = P_CF->passwords;
while (head) {
DBG( "time, " );
if ((head->from > now) || (head->to < now))
goto skip;
if (block->seq) {
struct neighbor *neigh = neigh_find(p, &whotoldme, 0);
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 0;
}
neigh->aux = block->seq;
}
}
DBG( "check, " );
if (head->id == block->keyid) {
struct MD5Context ctxt;
char md5sum_packet[16];
char md5sum_computed[16];
memcpy(md5sum_packet, tail->md5, 16);
password_strncpy(tail->md5, head->password, 16);
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) packet, block->packetlen );
MD5Final(md5sum_computed, &ctxt);
if (memcmp(md5sum_packet, md5sum_computed, 16))
return 1;
return 0;
}
skip:
head = head->next;
}
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 = get_best_password( P_CF->passwords, 0 );
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 = P_CF->authtype;
block->mustbeFFFF = 0xffff;
switch (P_CF->authtype) {
case AT_PLAINTEXT:
password_strncpy( (char *) (&block->packetlen), passwd->password, 16);
return PACKETLEN(num);
case AT_MD5:
{
struct rip_md5_tail *tail;
struct MD5Context ctxt;
static int sequence = 0;
if (num > PACKET_MD5_MAX)
bug( "We can not add MD5 authentication to this long packet" );
block->keyid = passwd->id;
block->authlen = 20;
block->seq = sequence++;
block->zero0 = 0;
block->zero1 = 0;
block->packetlen = PACKETLEN(num) + block->authlen;
tail = (struct rip_md5_tail *) ((char *) packet + (block->packetlen - sizeof(struct rip_block_auth)));
tail->mustbeFFFF = 0xffff;
tail->mustbe0001 = 0x0001;
password_strncpy( (char *) (&tail->md5), passwd->password, 16 );
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) packet, block->packetlen );
MD5Final((char *) (&tail->md5), &ctxt);
return PACKETLEN(num) + block->authlen;
}
default:
bug( "Unknown authtype in outgoing authentication?" );
}
}
|
