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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/* authen_r.c - Read authentication reply from server.
*
* Copyright (C) 2010, Pawel Krawczyk <pawel.krawczyk@hush.com> and
* Jeroen Nijhof <jeroen@jeroennijhof.nl>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program - see the file COPYING.
*
* See `CHANGES' file for revision history.
*/
#include "xalloc.h"
#include "libtac.h"
#include "messages.h"
/* reads packet from TACACS+ server; returns:
* TAC_PLUS_AUTHEN_STATUS_PASS if the authentication succeded
* an other integer if failed. Check tacplus.h for all possible values
*
* return value:
* < 0 : error status code, see LIBTAC_STATUS_...
* LIBTAC_STATUS_READ_TIMEOUT
* LIBTAC_STATUS_SHORT_HDR
* LIBTAC_STATUS_SHORT_BODY
* LIBTAC_STATUS_PROTOCOL_ERR
* >= 0 : server response, see TAC_PLUS_AUTHEN_STATUS_...
*/
int tac_authen_read(int fd, struct areply *re) {
HDR th;
struct authen_reply *tb = NULL;
int r;
unsigned int len_from_header, len_from_body;
ssize_t packet_read;
char *msg = NULL;
int timeleft;
memset(re, 0, sizeof(struct areply));
/* read the reply header */
if (tac_readtimeout_enable &&
tac_read_wait(fd,tac_timeout*1000,TAC_PLUS_HDR_SIZE,&timeleft) < 0 ) {
if (timeleft > 0) {
TACSYSLOG((LOG_ERR,\
"%s: reply error, connection closed", __func__))
re->status = LIBTAC_STATUS_CONN_CLOSED;
}
else {
TACSYSLOG((LOG_ERR,\
"%s: reply timeout after %d secs", __func__, tac_timeout))
re->status=LIBTAC_STATUS_READ_TIMEOUT;
}
free(tb);
return re->status;
}
packet_read = read(fd, &th, TAC_PLUS_HDR_SIZE);
if (packet_read < TAC_PLUS_HDR_SIZE) {
if (packet_read < 0)
TACSYSLOG((LOG_ERR,\
"%s: reply header read error: %m", __func__))
else
TACSYSLOG((LOG_ERR,\
"%s: short reply header, read %d of %d",\
__func__, r, TAC_PLUS_HDR_SIZE))
re->status=LIBTAC_STATUS_READ_TIMEOUT;
free(tb);
return re->status;
}
/* check the reply fields in header */
msg = _tac_check_header(&th, TAC_PLUS_AUTHEN);
if(msg != NULL) {
re->msg = tac_xstrdup(msg);
re->status = LIBTAC_STATUS_PROTOCOL_ERR;
free(tb);
return re->status;
}
re->seq_no = th.seq_no;
len_from_header = ntohl(th.datalength);
if (len_from_header > TAC_PLUS_MAX_PACKET_SIZE) {
TACSYSLOG((LOG_ERR,\
"%s: length declared in the packet %d exceeds max packet size %d",\
__func__,\
len_from_header, TAC_PLUS_MAX_PACKET_SIZE))
re->status = LIBTAC_STATUS_PROTOCOL_ERR;
free(tb);
return re->status;
}
tb = (struct authen_reply *) tac_xcalloc(1, len_from_header);
/* read reply packet body */
if (tac_readtimeout_enable &&
tac_read_wait(fd,timeleft,len_from_header,&timeleft) < 0 ) {
if (timeleft > 0) {
TACSYSLOG((LOG_ERR,\
"%s: reply error, connection closed", __func__))
re->status = LIBTAC_STATUS_CONN_CLOSED;
}
else {
TACSYSLOG((LOG_ERR,\
"%s: reply timeout after %d secs", __func__, tac_timeout))
re->status=LIBTAC_STATUS_READ_TIMEOUT;
}
re->msg = tac_xstrdup(authen_syserr_msg);
free(tb);
return re->status;
}
r = read(fd, tb, len_from_header);
if (r < len_from_header) {
if (r < 0)
TACSYSLOG((LOG_ERR,\
"%s: reply body read failed: %m", __func__))
else
TACSYSLOG((LOG_ERR,\
"%s: short reply body, read %d of %d",\
__func__, r, len_from_header))
re->msg = tac_xstrdup(authen_syserr_msg);
re->status = LIBTAC_STATUS_SHORT_BODY;
free(tb);
return re->status;
}
/* decrypt the body */
_tac_crypt((u_char *) tb, &th, len_from_header);
/* Convert network byte order to host byte order */
tb->msg_len = ntohs(tb->msg_len);
tb->data_len = ntohs(tb->data_len);
/* check the length fields */
len_from_body = sizeof(tb->status) + sizeof(tb->flags) +
sizeof(tb->msg_len) + sizeof(tb->data_len) +
tb->msg_len + tb->data_len;
if(len_from_header != len_from_body) {
TACSYSLOG((LOG_ERR,\
"%s: inconsistent reply body, incorrect key?",\
__func__))
re->msg = tac_xstrdup(protocol_err_msg);
re->status = LIBTAC_STATUS_PROTOCOL_ERR;
free(tb);
return re->status;
}
/* save status and clean up */
re->status = r = tb->status;
if (0 < tb->msg_len) {
msg = tac_xcalloc(tb->msg_len + 1, sizeof(char));
memset(msg, 0, (tb->msg_len + 1));
memcpy(msg, (char*)tb + sizeof(struct authen_reply), tb->msg_len);
re->msg = msg;
}
/* server authenticated username and password successfully */
if (r == TAC_PLUS_AUTHEN_STATUS_PASS) {
TACDEBUG((LOG_DEBUG, "%s: authentication ok", __func__))
free(tb);
return re->status;
}
/* server ask for continue packet with password */
if (r == TAC_PLUS_AUTHEN_STATUS_GETPASS) {
TACDEBUG((LOG_DEBUG, "%s: continue packet with password needed", __func__))
free(tb);
return re->status;
}
/* server wants to prompt user for more data */
if (r == TAC_PLUS_AUTHEN_STATUS_GETDATA) {
re->flags = tb->flags;
TACDEBUG((LOG_DEBUG, "%s: continue packet with data request: msg=%.*s",
__func__, tb->msg_len, (char*)tb + sizeof(struct authen_reply)))
free(tb);
return re->status;
}
TACDEBUG((LOG_DEBUG, "%s: authentication failed, server reply status=%d",
__func__, r))
free(tb);
return re->status;
} /* tac_authen_read */
|
