suricata
detect-http-ua.c
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1 /* Copyright (C) 2007-2018 Open Information Security Foundation
2  *
3  * You can copy, redistribute or modify this Program under the terms of
4  * the GNU General Public License version 2 as published by the Free
5  * Software Foundation.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * version 2 along with this program; if not, write to the Free Software
14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15  * 02110-1301, USA.
16  */
17 
18 /**
19  * \ingroup httplayer
20  *
21  * @{
22  */
23 
24 
25 /**
26  * \file
27  *
28  * \author Anoop Saldanha <anoopsaldanha@gmail.com>
29  *
30  * Implements support for the http_user_agent keyword.
31  */
32 
33 #include "suricata-common.h"
34 #include "threads.h"
35 #include "decode.h"
36 
37 #include "detect.h"
38 #include "detect-parse.h"
39 #include "detect-engine.h"
40 #include "detect-engine-buffer.h"
41 #include "detect-engine-mpm.h"
42 #include "detect-engine-state.h"
44 #include "detect-content.h"
45 #include "detect-pcre.h"
46 
47 #include "flow.h"
48 #include "flow-var.h"
49 #include "flow-util.h"
50 
51 #include "util-debug.h"
52 #include "util-unittest.h"
53 #include "util-unittest-helper.h"
54 #include "util-spm.h"
55 
56 #include "app-layer.h"
57 #include "app-layer-parser.h"
58 
59 #include "app-layer-htp.h"
60 #include "stream-tcp.h"
61 #include "detect-http-ua.h"
62 
63 static int DetectHttpUASetup(DetectEngineCtx *, Signature *, const char *);
64 #ifdef UNITTESTS
65 static void DetectHttpUARegisterTests(void);
66 #endif
67 static int g_http_ua_buffer_id = 0;
68 static int DetectHttpUserAgentSetup(DetectEngineCtx *, Signature *, const char *);
69 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
70  const DetectEngineTransforms *transforms,
71  Flow *_f, const uint8_t _flow_flags,
72  void *txv, const int list_id);
73 static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
74  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
75  const int list_id);
76 
77 /**
78  * \brief Registers the keyword handlers for the "http_user_agent" keyword.
79  */
81 {
82  /* http_user_agent content modifier */
83  sigmatch_table[DETECT_HTTP_USER_AGENT].name = "http_user_agent";
85  "content modifier to match only on the HTTP User-Agent header";
86  sigmatch_table[DETECT_HTTP_USER_AGENT].url = "/rules/http-keywords.html#http-user-agent";
87  sigmatch_table[DETECT_HTTP_USER_AGENT].Setup = DetectHttpUASetup;
88 #ifdef UNITTESTS
89  sigmatch_table[DETECT_HTTP_USER_AGENT].RegisterTests = DetectHttpUARegisterTests;
90 #endif
94 
95  /* http.user_agent sticky buffer */
96  sigmatch_table[DETECT_HTTP_UA].name = "http.user_agent";
97  sigmatch_table[DETECT_HTTP_UA].desc = "sticky buffer to match specifically and only on the HTTP User Agent buffer";
98  sigmatch_table[DETECT_HTTP_UA].url = "/rules/http-keywords.html#http-user-agent";
99  sigmatch_table[DETECT_HTTP_UA].Setup = DetectHttpUserAgentSetup;
102 
104  HTP_REQUEST_PROGRESS_HEADERS, DetectEngineInspectBufferGeneric, GetData);
105 
107  GetData, ALPROTO_HTTP1, HTP_REQUEST_PROGRESS_HEADERS);
108 
110  HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetData2);
111 
113  GetData2, ALPROTO_HTTP2, HTTP2StateDataClient);
114 
115  DetectBufferTypeSetDescriptionByName("http_user_agent",
116  "http user agent");
117 
118  g_http_ua_buffer_id = DetectBufferTypeGetByName("http_user_agent");
119 }
120 
121 /**
122  * \brief The setup function for the http_user_agent keyword for a signature.
123  *
124  * \param de_ctx Pointer to the detection engine context.
125  * \param s Pointer to the signature for the current Signature being
126  * parsed from the rules.
127  * \param m Pointer to the head of the SigMatch for the current rule
128  * being parsed.
129  * \param arg Pointer to the string holding the keyword value.
130  *
131  * \retval 0 On success
132  * \retval -1 On failure
133  */
134 int DetectHttpUASetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
135 {
137  de_ctx, s, arg, DETECT_HTTP_USER_AGENT, g_http_ua_buffer_id, ALPROTO_HTTP1);
138 }
139 
140 /**
141  * \brief this function setup the http.user_agent keyword used in the rule
142  *
143  * \param de_ctx Pointer to the Detection Engine Context
144  * \param s Pointer to the Signature to which the current keyword belongs
145  * \param str Should hold an empty string always
146  *
147  * \retval 0 On success
148  */
149 static int DetectHttpUserAgentSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
150 {
151  if (SCDetectBufferSetActiveList(de_ctx, s, g_http_ua_buffer_id) < 0)
152  return -1;
154  return -1;
155  return 0;
156 }
157 
158 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
159  const DetectEngineTransforms *transforms, Flow *_f,
160  const uint8_t _flow_flags, void *txv, const int list_id)
161 {
162  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
163  if (buffer->inspect == NULL) {
164  htp_tx_t *tx = (htp_tx_t *)txv;
165 
166  if (htp_tx_request_headers(tx) == NULL)
167  return NULL;
168 
169  const htp_header_t *h = htp_tx_request_header(tx, "User-Agent");
170  if (h == NULL || htp_header_value(h) == NULL) {
171  SCLogDebug("HTTP UA header not present in this request");
172  return NULL;
173  }
174 
175  const uint32_t data_len = (uint32_t)htp_header_value_len(h);
176  const uint8_t *data = htp_header_value_ptr(h);
177 
179  det_ctx, list_id, buffer, data, data_len, transforms);
180  }
181 
182  return buffer;
183 }
184 
185 static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
186  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
187  const int list_id)
188 {
189  SCEnter();
190 
191  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
192  if (buffer->inspect == NULL) {
193  uint32_t b_len = 0;
194  const uint8_t *b = NULL;
195 
196  if (SCHttp2TxGetUserAgent(txv, &b, &b_len) != 1)
197  return NULL;
198  if (b == NULL || b_len == 0)
199  return NULL;
200 
201  InspectionBufferSetupAndApplyTransforms(det_ctx, list_id, buffer, b, b_len, transforms);
202  }
203 
204  return buffer;
205 }
206 
207 #ifdef UNITTESTS
209 #endif /* UNITTESTS */
210 
211 /**
212  * @}
213  */
SigTableElmt_::url
const char * url
Definition: detect.h:1431
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:2313
detect-content.h
detect-engine.h
SIGMATCH_INFO_STICKY_BUFFER
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1645
SigTableElmt_::desc
const char * desc
Definition: detect.h:1430
sigmatch_table
SigTableElmt * sigmatch_table
Definition: detect-parse.c:155
DetectEngineInspectBufferGeneric
uint8_t DetectEngineInspectBufferGeneric(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
Do the content inspection & validation for a signature.
Definition: detect-engine.c:2103
flow-util.h
SIGMATCH_INFO_CONTENT_MODIFIER
#define SIGMATCH_INFO_CONTENT_MODIFIER
Definition: detect.h:1643
SigTableElmt_::name
const char * name
Definition: detect.h:1428
InspectionBufferSetupAndApplyTransforms
void InspectionBufferSetupAndApplyTransforms(DetectEngineThreadCtx *det_ctx, const int list_id, InspectionBuffer *buffer, const uint8_t *data, const uint32_t data_len, const DetectEngineTransforms *transforms)
setup the buffer with our initial data
Definition: detect-engine.c:1570
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:415
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:269
InspectionBuffer
Definition: detect.h:380
threads.h
Flow_
Flow data structure.
Definition: flow.h:356
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1422
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:931
SCDetectBufferSetActiveList
int SCDetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine-buffer.c:29
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1413
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1429
util-unittest-helper.h
detect-http-ua.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1157
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:270
app-layer-htp.h
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:18
DetectEngineThreadCtx_
Definition: detect.h:1223
SCEnter
#define SCEnter(...)
Definition: util-debug.h:271
detect-engine-mpm.h
detect.h
DetectHttpUARegister
void DetectHttpUARegister(void)
Registers the keyword handlers for the "http_user_agent" keyword.
Definition: detect-http-ua.c:80
PrefilterGenericMpmRegister
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:1547
SigTableElmt_::alternative
uint16_t alternative
Definition: detect.h:1426
DetectAppLayerMpmRegister
void DetectAppLayerMpmRegister(const char *name, int direction, int priority, PrefilterRegisterFunc PrefilterRegister, InspectionBufferGetDataPtr GetData, AppProto alproto, int tx_min_progress)
register an app layer keyword for mpm
Definition: detect-engine-mpm.c:151
app-layer-parser.h
DetectEngineContentModifierBufferSetup
int DetectEngineContentModifierBufferSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg, int sm_type, int sm_list, AppProto alproto)
Definition: detect-parse.c:222
detect-engine-state.h
Data structures and function prototypes for keeping state for the detection engine.
ALPROTO_HTTP2
@ ALPROTO_HTTP2
Definition: app-layer-protos.h:69
DETECT_HTTP_UA
@ DETECT_HTTP_UA
Definition: detect-engine-register.h:183
suricata-common.h
ALPROTO_HTTP1
@ ALPROTO_HTTP1
Definition: app-layer-protos.h:36
util-spm.h
detect-engine-buffer.h
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:381
str
#define str(s)
Definition: suricata-common.h:308
DETECT_HTTP_USER_AGENT
@ DETECT_HTTP_USER_AGENT
Definition: detect-engine-register.h:182
detect-parse.h
Signature_
Signature container.
Definition: detect.h:670
ALPROTO_HTTP
@ ALPROTO_HTTP
Definition: app-layer-protos.h:75
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1620
DetectAppLayerInspectEngineRegister
void DetectAppLayerInspectEngineRegister(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr Callback, InspectionBufferGetDataPtr GetData)
Registers an app inspection engine.
Definition: detect-engine.c:245
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1254
flow.h
detect-http-user-agent.c
Handle HTTP user agent match.
flow-var.h
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1420
app-layer.h