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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/* Copyright (C) 2017-2021 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* 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
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*/
/**
* \file
*
* \author Clément Galland <clement.galland@epita.fr>
*
* Parser for NTP application layer running on UDP port 69.
*/
#include "suricata-common.h"
#include "suricata.h"
#include "stream.h"
#include "conf.h"
#include "util-unittest.h"
#include "app-layer.h"
#include "app-layer-detect-proto.h"
#include "app-layer-parser.h"
#include "app-layer-tftp.h"
#include "rust.h"
/* The default port to probe if not provided in the configuration file. */
#define TFTP_DEFAULT_PORT "69"
/* The minimum size for an message. For some protocols this might
* be the size of a header. */
#define TFTP_MIN_FRAME_LEN 4
static void *TFTPStateAlloc(void *orig_state, AppProto proto_orig)
{
return rs_tftp_state_alloc();
}
static void TFTPStateFree(void *state)
{
rs_tftp_state_free(state);
}
/**
* \brief Callback from the application layer to have a transaction freed.
*
* \param state a void pointer to the TFTPState object.
* \param tx_id the transaction ID to free.
*/
static void TFTPStateTxFree(void *state, uint64_t tx_id)
{
rs_tftp_state_tx_free(state, tx_id);
}
static int TFTPStateGetEventInfo(const char *event_name, int *event_id,
AppLayerEventType *event_type)
{
return -1;
}
/**
* \brief Probe the input to see if it looks like tftp.
*
* \retval ALPROTO_TFTP if it looks like tftp, otherwise
* ALPROTO_UNKNOWN.
*/
static AppProto TFTPProbingParser(Flow *f, uint8_t direction,
const uint8_t *input, uint32_t input_len, uint8_t *rdir)
{
/* Very simple test - if there is input, this is tftp.
* Also check if it's starting by a zero */
if (input_len >= TFTP_MIN_FRAME_LEN && *input == 0) {
SCLogDebug("Detected as ALPROTO_TFTP.");
return ALPROTO_TFTP;
}
SCLogDebug("Protocol not detected as ALPROTO_TFTP.");
return ALPROTO_UNKNOWN;
}
static AppLayerResult TFTPParseRequest(Flow *f, void *state, AppLayerParserState *pstate,
StreamSlice stream_slice, void *local_data)
{
const uint8_t *input = StreamSliceGetData(&stream_slice);
uint32_t input_len = StreamSliceGetDataLen(&stream_slice);
SCLogDebug("Parsing tftp request: len=%" PRIu32, input_len);
/* Likely connection closed, we can just return here. */
if ((input == NULL || input_len == 0) &&
AppLayerParserStateIssetFlag(pstate, APP_LAYER_PARSER_EOF_TS)) {
SCReturnStruct(APP_LAYER_OK);
}
/* Probably don't want to create a transaction in this case
* either. */
if (input == NULL || input_len == 0) {
SCReturnStruct(APP_LAYER_OK);
}
int res = rs_tftp_request(state, input, input_len);
if (res < 0) {
SCReturnStruct(APP_LAYER_ERROR);
}
SCReturnStruct(APP_LAYER_OK);
}
/**
* \brief Response parsing is not implemented
*/
static AppLayerResult TFTPParseResponse(Flow *f, void *state, AppLayerParserState *pstate,
StreamSlice stream_slice, void *local_data)
{
SCReturnStruct(APP_LAYER_OK);
}
static uint64_t TFTPGetTxCnt(void *state)
{
return rs_tftp_get_tx_cnt(state);
}
static void *TFTPGetTx(void *state, uint64_t tx_id)
{
return rs_tftp_get_tx(state, tx_id);
}
/**
* \brief Return the state of a transaction in a given direction.
*
* In the case of the tftp protocol, the existence of a transaction
* means that the request is done. However, some protocols that may
* need multiple chunks of data to complete the request may need more
* than just the existence of a transaction for the request to be
* considered complete.
*
* For the response to be considered done, the response for a request
* needs to be seen. The response_done flag is set on response for
* checking here.
*/
static int TFTPGetStateProgress(void *tx, uint8_t direction)
{
return 1;
}
void RegisterTFTPParsers(void)
{
const char *proto_name = "tftp";
/* Check if TFTP UDP detection is enabled. If it does not exist in
* the configuration file then it will be enabled by default. */
if (AppLayerProtoDetectConfProtoDetectionEnabled("udp", proto_name)) {
SCLogDebug("TFTP UDP protocol detection enabled.");
AppLayerProtoDetectRegisterProtocol(ALPROTO_TFTP, proto_name);
if (RunmodeIsUnittests()) {
SCLogDebug("Unittest mode, registering default configuration.");
AppLayerProtoDetectPPRegister(IPPROTO_UDP, TFTP_DEFAULT_PORT,
ALPROTO_TFTP, 0, TFTP_MIN_FRAME_LEN,
STREAM_TOSERVER, TFTPProbingParser,
TFTPProbingParser);
} else {
if (!AppLayerProtoDetectPPParseConfPorts("udp", IPPROTO_UDP,
proto_name, ALPROTO_TFTP,
0, TFTP_MIN_FRAME_LEN,
TFTPProbingParser, TFTPProbingParser)) {
SCLogDebug("No tftp app-layer configuration, enabling tftp"
" detection UDP detection on port %s.",
TFTP_DEFAULT_PORT);
AppLayerProtoDetectPPRegister(IPPROTO_UDP,
TFTP_DEFAULT_PORT, ALPROTO_TFTP,
0, TFTP_MIN_FRAME_LEN,
STREAM_TOSERVER,TFTPProbingParser,
TFTPProbingParser);
}
}
} else {
SCLogDebug("Protocol detector and parser disabled for TFTP.");
return;
}
if (AppLayerParserConfParserEnabled("udp", proto_name)) {
SCLogDebug("Registering TFTP protocol parser.");
/* Register functions for state allocation and freeing. A
* state is allocated for every new TFTP flow. */
AppLayerParserRegisterStateFuncs(IPPROTO_UDP, ALPROTO_TFTP,
TFTPStateAlloc, TFTPStateFree);
/* Register request parser for parsing frame from server to client. */
AppLayerParserRegisterParser(IPPROTO_UDP, ALPROTO_TFTP,
STREAM_TOSERVER, TFTPParseRequest);
/* Register response parser for parsing frames from server to client. */
AppLayerParserRegisterParser(IPPROTO_UDP, ALPROTO_TFTP,
STREAM_TOCLIENT, TFTPParseResponse);
/* Register a function to be called by the application layer
* when a transaction is to be freed. */
AppLayerParserRegisterTxFreeFunc(IPPROTO_UDP, ALPROTO_TFTP,
TFTPStateTxFree);
/* Register a function to return the current transaction count. */
AppLayerParserRegisterGetTxCnt(IPPROTO_UDP, ALPROTO_TFTP,
TFTPGetTxCnt);
/* Transaction handling. */
AppLayerParserRegisterStateProgressCompletionStatus(ALPROTO_TFTP, 1, 1);
AppLayerParserRegisterGetStateProgressFunc(IPPROTO_UDP,
ALPROTO_TFTP,
TFTPGetStateProgress);
AppLayerParserRegisterGetTx(IPPROTO_UDP, ALPROTO_TFTP,
TFTPGetTx);
AppLayerParserRegisterGetEventInfo(IPPROTO_UDP, ALPROTO_TFTP,
TFTPStateGetEventInfo);
AppLayerParserRegisterTxDataFunc(IPPROTO_UDP, ALPROTO_TFTP,
rs_tftp_get_tx_data);
AppLayerParserRegisterStateDataFunc(IPPROTO_UDP, ALPROTO_TFTP, rs_tftp_get_state_data);
}
else {
SCLogDebug("TFTP protocol parsing disabled.");
}
}
|
