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-mpm.h"
41 #include "detect-engine-state.h"
43 #include "detect-content.h"
44 #include "detect-pcre.h"
45 
46 #include "flow.h"
47 #include "flow-var.h"
48 #include "flow-util.h"
49 
50 #include "util-debug.h"
51 #include "util-unittest.h"
52 #include "util-unittest-helper.h"
53 #include "util-spm.h"
54 
55 #include "app-layer.h"
56 #include "app-layer-parser.h"
57 
58 #include "app-layer-htp.h"
59 #include "stream-tcp.h"
60 #include "detect-http-ua.h"
61 
62 static int DetectHttpUASetup(DetectEngineCtx *, Signature *, const char *);
63 #ifdef UNITTESTS
64 static void DetectHttpUARegisterTests(void);
65 #endif
66 static int g_http_ua_buffer_id = 0;
67 static int DetectHttpUserAgentSetup(DetectEngineCtx *, Signature *, const char *);
68 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
69  const DetectEngineTransforms *transforms,
70  Flow *_f, const uint8_t _flow_flags,
71  void *txv, const int list_id);
72 static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
73  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
74  const int list_id);
75 
76 /**
77  * \brief Registers the keyword handlers for the "http_user_agent" keyword.
78  */
80 {
81  /* http_user_agent content modifier */
82  sigmatch_table[DETECT_HTTP_USER_AGENT].name = "http_user_agent";
84  "content modifier to match only on the HTTP User-Agent header";
85  sigmatch_table[DETECT_HTTP_USER_AGENT].url = "/rules/http-keywords.html#http-user-agent";
86  sigmatch_table[DETECT_HTTP_USER_AGENT].Setup = DetectHttpUASetup;
87 #ifdef UNITTESTS
88  sigmatch_table[DETECT_HTTP_USER_AGENT].RegisterTests = DetectHttpUARegisterTests;
89 #endif
93 
94  /* http.user_agent sticky buffer */
95  sigmatch_table[DETECT_HTTP_UA].name = "http.user_agent";
96  sigmatch_table[DETECT_HTTP_UA].desc = "sticky buffer to match specifically and only on the HTTP User Agent buffer";
97  sigmatch_table[DETECT_HTTP_UA].url = "/rules/http-keywords.html#http-user-agent";
98  sigmatch_table[DETECT_HTTP_UA].Setup = DetectHttpUserAgentSetup;
101 
104 
107 
109  HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetData2);
110 
112  GetData2, ALPROTO_HTTP2, HTTP2StateDataClient);
113 
114  DetectBufferTypeSetDescriptionByName("http_user_agent",
115  "http user agent");
116 
117  g_http_ua_buffer_id = DetectBufferTypeGetByName("http_user_agent");
118 }
119 
120 /**
121  * \brief The setup function for the http_user_agent keyword for a signature.
122  *
123  * \param de_ctx Pointer to the detection engine context.
124  * \param s Pointer to the signature for the current Signature being
125  * parsed from the rules.
126  * \param m Pointer to the head of the SigMatch for the current rule
127  * being parsed.
128  * \param arg Pointer to the string holding the keyword value.
129  *
130  * \retval 0 On success
131  * \retval -1 On failure
132  */
133 int DetectHttpUASetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
134 {
136  de_ctx, s, arg, DETECT_HTTP_USER_AGENT, g_http_ua_buffer_id, ALPROTO_HTTP1);
137 }
138 
139 /**
140  * \brief this function setup the http.user_agent keyword used in the rule
141  *
142  * \param de_ctx Pointer to the Detection Engine Context
143  * \param s Pointer to the Signature to which the current keyword belongs
144  * \param str Should hold an empty string always
145  *
146  * \retval 0 On success
147  */
148 static int DetectHttpUserAgentSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
149 {
150  if (DetectBufferSetActiveList(de_ctx, s, g_http_ua_buffer_id) < 0)
151  return -1;
153  return -1;
154  return 0;
155 }
156 
157 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
158  const DetectEngineTransforms *transforms, Flow *_f,
159  const uint8_t _flow_flags, void *txv, const int list_id)
160 {
161  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
162  if (buffer->inspect == NULL) {
163  htp_tx_t *tx = (htp_tx_t *)txv;
164 
165  if (htp_tx_request_headers(tx) == NULL)
166  return NULL;
167 
168  const htp_header_t *h = htp_tx_request_header(tx, "User-Agent");
169  if (h == NULL || htp_header_value(h) == NULL) {
170  SCLogDebug("HTTP UA header not present in this request");
171  return NULL;
172  }
173 
174  const uint32_t data_len = htp_header_value_len(h);
175  const uint8_t *data = htp_header_value_ptr(h);
176 
178  det_ctx, list_id, buffer, data, data_len, transforms);
179  }
180 
181  return buffer;
182 }
183 
184 static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
185  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
186  const int list_id)
187 {
188  SCEnter();
189 
190  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
191  if (buffer->inspect == NULL) {
192  uint32_t b_len = 0;
193  const uint8_t *b = NULL;
194 
195  if (rs_http2_tx_get_useragent(txv, &b, &b_len) != 1)
196  return NULL;
197  if (b == NULL || b_len == 0)
198  return NULL;
199 
200  InspectionBufferSetupAndApplyTransforms(det_ctx, list_id, buffer, b, b_len, transforms);
201  }
202 
203  return buffer;
204 }
205 
206 #ifdef UNITTESTS
208 #endif /* UNITTESTS */
209 
210 /**
211  * @}
212  */
htp_header_value_len
#define htp_header_value_len(h)
Definition: app-layer-htp-libhtp.h:191
SigTableElmt_::url
const char * url
Definition: detect.h:1329
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1870
detect-content.h
detect-engine.h
SIGMATCH_INFO_STICKY_BUFFER
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1534
SigTableElmt_::desc
const char * desc
Definition: detect.h:1328
sigmatch_table
SigTableElmt * sigmatch_table
Definition: detect-parse.c:153
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:2195
flow-util.h
SIGMATCH_INFO_CONTENT_MODIFIER
#define SIGMATCH_INFO_CONTENT_MODIFIER
Definition: detect.h:1532
SigTableElmt_::name
const char * name
Definition: detect.h:1326
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:1662
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:409
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:269
DetectBufferSetActiveList
int DetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine.c:1377
InspectionBuffer
Definition: detect.h:374
threads.h
Flow_
Flow data structure.
Definition: flow.h:354
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1320
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:860
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1311
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1521
util-unittest-helper.h
htp_header_value
#define htp_header_value(h)
Definition: app-layer-htp-libhtp.h:193
detect-http-ua.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1114
htp_tx_request_headers
#define htp_tx_request_headers(tx)
Definition: app-layer-htp-libhtp.h:173
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:269
app-layer-htp.h
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:18
DetectEngineThreadCtx_
Definition: detect.h:1116
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:79
PrefilterGenericMpmRegister
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:761
SigTableElmt_::alternative
uint16_t alternative
Definition: detect.h:1324
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:220
htp_header_value_ptr
#define htp_header_value_ptr(h)
Definition: app-layer-htp-libhtp.h:192
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:70
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
HTP_REQUEST_PROGRESS_HEADERS
#define HTP_REQUEST_PROGRESS_HEADERS
Definition: app-layer-htp-libhtp.h:89
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:375
str
#define str(s)
Definition: suricata-common.h:300
DETECT_HTTP_USER_AGENT
@ DETECT_HTTP_USER_AGENT
Definition: detect-engine-register.h:182
detect-parse.h
Signature_
Signature container.
Definition: detect.h:618
ALPROTO_HTTP
@ ALPROTO_HTTP
Definition: app-layer-protos.h:76
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1510
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:1211
flow.h
detect-http-user-agent.c
Handle HTTP user agent match.
flow-var.h
htp_tx_request_header
#define htp_tx_request_header(tx, header)
Definition: app-layer-htp-libhtp.h:184
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1318
app-layer.h