suricata
detect-ftpdata.c
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1 /* Copyright (C) 2017-2020 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  * \file
20  *
21  * \author Eric Leblond <eric@regit.org>
22  *
23  * Match on ftp command used to trigger a ftp data transfer
24  */
25 
26 #include "suricata-common.h"
27 #include "util-unittest.h"
28 
29 #include "detect-parse.h"
30 #include "detect-engine.h"
31 #include "detect-engine-state.h"
32 
33 #include "app-layer-ftp.h"
34 
35 #include "detect-ftpdata.h"
36 
37 /**
38  * \brief Regex for parsing our keyword options
39  */
40 #define PARSE_REGEX "^\\s*(stor|retr)\\s*$"
41 static DetectParseRegex parse_regex;
42 
43 /* Prototypes of functions registered in DetectFtpdataRegister below */
44 static int DetectFtpdataMatch(DetectEngineThreadCtx *,
45  Flow *, uint8_t, void *, void *,
46  const Signature *, const SigMatchCtx *);
47 static int DetectFtpdataSetup (DetectEngineCtx *, Signature *, const char *);
48 static void DetectFtpdataFree (DetectEngineCtx *, void *);
49 #ifdef UNITTESTS
50 static void DetectFtpdataRegisterTests (void);
51 #endif
52 static int DetectEngineInspectFtpdataGeneric(DetectEngineCtx *de_ctx,
53  DetectEngineThreadCtx *det_ctx, const struct DetectEngineAppInspectionEngine_ *engine,
54  const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id);
55 static int g_ftpdata_buffer_id = 0;
56 
57 /**
58  * \brief Registration function for ftpcommand: keyword
59  *
60  * This function is called once in the 'lifetime' of the engine.
61  */
63  /* keyword name: this is how the keyword is used in a rule */
64  sigmatch_table[DETECT_FTPDATA].name = "ftpdata_command";
65  /* description: listed in "suricata --list-keywords=all" */
66  sigmatch_table[DETECT_FTPDATA].desc = "match FTP command triggering a FTP data channel";
67  sigmatch_table[DETECT_FTPDATA].url = "/rules/ftp-keywords.html#ftpdata-command";
68  sigmatch_table[DETECT_FTPDATA].AppLayerTxMatch = DetectFtpdataMatch;
69  /* setup function is called during signature parsing, when the ftpcommand
70  * keyword is encountered in the rule */
71  sigmatch_table[DETECT_FTPDATA].Setup = DetectFtpdataSetup;
72  /* free function is called when the detect engine is freed. Normally at
73  * shutdown, but also during rule reloads. */
74  sigmatch_table[DETECT_FTPDATA].Free = DetectFtpdataFree;
75  /* registers unittests into the system */
76 #ifdef UNITTESTS
77  sigmatch_table[DETECT_FTPDATA].RegisterTests = DetectFtpdataRegisterTests;
78 #endif
80  DetectEngineInspectFtpdataGeneric, NULL);
81 
83  DetectEngineInspectFtpdataGeneric, NULL);
84  g_ftpdata_buffer_id = DetectBufferTypeGetByName("ftpdata_command");
85 
86  /* set up the PCRE for keyword parsing */
87  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
88 }
89 
90 static int DetectEngineInspectFtpdataGeneric(DetectEngineCtx *de_ctx,
91  DetectEngineThreadCtx *det_ctx, const struct DetectEngineAppInspectionEngine_ *engine,
92  const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
93 {
95  de_ctx, det_ctx, s, engine->smd, f, flags, alstate, txv, tx_id);
96 }
97 
98 /**
99  * \brief This function is used to check matches from the FTP App Layer Parser
100  *
101  * \param t pointer to thread vars
102  * \param det_ctx pointer to the pattern matcher thread
103  * \param p pointer to the current packet
104  * \param m pointer to the sigmatch
105  * \retval 0 no match
106  * \retval 1 match
107  */
108 static int DetectFtpdataMatch(DetectEngineThreadCtx *det_ctx,
109  Flow *f, uint8_t flags,
110  void *state, void *txv,
111  const Signature *s, const SigMatchCtx *m)
112 {
113  const DetectFtpdataData *ftpcommandd = (const DetectFtpdataData *) m;
114  const FtpDataState *ftp_state = (const FtpDataState *)state;
115 
116  if (ftp_state == NULL)
117  return 0;
118 
119  if (ftpcommandd->command == ftp_state->command) {
120  /* Only match if the flow is in the good direction */
121  if ((flags & STREAM_TOSERVER) && (ftpcommandd->command == FTP_COMMAND_RETR)) {
122  return 0;
123  } else if ((flags & STREAM_TOCLIENT) && (ftpcommandd->command == FTP_COMMAND_STOR)) {
124  return 0;
125  }
126  return 1;
127  }
128 
129  return 0;
130 }
131 
132 /**
133  * \brief This function is used to parse ftpcommand options passed via ftpcommand: keyword
134  *
135  * \param ftpcommandstr Pointer to the user provided ftpcommand options
136  *
137  * \retval ftpcommandd pointer to DetectFtpdataData on success
138  * \retval NULL on failure
139  */
140 static DetectFtpdataData *DetectFtpdataParse(const char *ftpcommandstr)
141 {
142  DetectFtpdataData *ftpcommandd = NULL;
143  char arg1[5] = "";
144  size_t pcre2len;
145 
146  int ret = DetectParsePcreExec(&parse_regex, ftpcommandstr, 0, 0);
147  if (ret != 2) {
148  SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret);
149  goto error;
150  }
151 
152  pcre2len = sizeof(arg1);
153  int res = pcre2_substring_copy_bynumber(parse_regex.match, 1, (PCRE2_UCHAR8 *)arg1, &pcre2len);
154  if (res < 0) {
155  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre2_substring_copy_bynumber failed");
156  goto error;
157  }
158  SCLogDebug("Arg1 \"%s\"", arg1);
159 
160  ftpcommandd = SCMalloc(sizeof (DetectFtpdataData));
161  if (unlikely(ftpcommandd == NULL))
162  goto error;
163  if (!strcmp(arg1, "stor")) {
164  ftpcommandd->command = FTP_COMMAND_STOR;
165  } else if (!strcmp(arg1, "retr")) {
166  ftpcommandd->command = FTP_COMMAND_RETR;
167  } else {
168  SCLogError(SC_ERR_NOT_SUPPORTED, "Invalid command value");
169  goto error;
170  }
171 
172  return ftpcommandd;
173 
174 error:
175  if (ftpcommandd)
176  SCFree(ftpcommandd);
177  return NULL;
178 }
179 
180 /**
181  * \brief parse the options from the 'ftpcommand' keyword in the rule into
182  * the Signature data structure.
183  *
184  * \param de_ctx pointer to the Detection Engine Context
185  * \param s pointer to the Current Signature
186  * \param str pointer to the user provided ftpcommand options
187  *
188  * \retval 0 on Success
189  * \retval -1 on Failure
190  */
191 static int DetectFtpdataSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
192 {
194  return -1;
195 
196  DetectFtpdataData *ftpcommandd = DetectFtpdataParse(str);
197  if (ftpcommandd == NULL)
198  return -1;
199 
200  SigMatch *sm = SigMatchAlloc();
201  if (sm == NULL) {
202  DetectFtpdataFree(de_ctx, ftpcommandd);
203  return -1;
204  }
205  sm->type = DETECT_FTPDATA;
206  sm->ctx = (void *)ftpcommandd;
207 
208  SigMatchAppendSMToList(s, sm, g_ftpdata_buffer_id);
209  return 0;
210 }
211 
212 /**
213  * \brief this function will free memory associated with DetectFtpdataData
214  *
215  * \param ptr pointer to DetectFtpdataData
216  */
217 static void DetectFtpdataFree(DetectEngineCtx *de_ctx, void *ptr) {
218  DetectFtpdataData *ftpcommandd = (DetectFtpdataData *)ptr;
219 
220  /* do more specific cleanup here, if needed */
221 
222  SCFree(ftpcommandd);
223 }
224 
225 #ifdef UNITTESTS
226 
227 static int DetectFtpdataParseTest01(void)
228 {
229  DetectFtpdataData *ftpcommandd = DetectFtpdataParse("stor");
230  FAIL_IF_NULL(ftpcommandd);
231  FAIL_IF(!(ftpcommandd->command == FTP_COMMAND_STOR));
232  DetectFtpdataFree(NULL, ftpcommandd);
233  PASS;
234 }
235 
236 static int DetectFtpdataSignatureTest01(void)
237 {
240 
241  Signature *sig = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any (ftpdata_command:stor; sid:1; rev:1;)");
242  FAIL_IF_NULL(sig);
243  sig = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any (ftpdata_command:retr; sid:2; rev:1;)");
244  FAIL_IF_NULL(sig);
245  sig = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any (ftpdata_command:xxx; sid:3; rev:1;)");
246  FAIL_IF_NOT_NULL(sig);
247 
249  PASS;
250 }
251 
252 /**
253  * \brief this function registers unit tests for DetectFtpdata
254  */
255 static void DetectFtpdataRegisterTests(void)
256 {
257  UtRegisterTest("DetectFtpdataParseTest01", DetectFtpdataParseTest01);
258  UtRegisterTest("DetectFtpdataSignatureTest01",
259  DetectFtpdataSignatureTest01);
260 }
261 #endif /* UNITTESTS */
DetectParseRegex::match
pcre2_match_data * match
Definition: detect-parse.h:45
DetectEngineAppInspectionEngine_
Definition: detect.h:398
SigTableElmt_::url
const char * url
Definition: detect.h:1270
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1490
detect-engine.h
FAIL_IF_NULL
#define FAIL_IF_NULL(expr)
Fail a test if expression evaluates to NULL.
Definition: util-unittest.h:89
DETECT_FTPDATA
@ DETECT_FTPDATA
Definition: detect-engine-register.h:267
SigTableElmt_::desc
const char * desc
Definition: detect.h:1269
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, const char *str, int start_offset, int options)
Definition: detect-parse.c:2474
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing our keyword options.
Definition: detect-ftpdata.c:40
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1257
DetectEngineInspectGenericList
int DetectEngineInspectGenericList(const DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const Signature *s, const SigMatchData *smd, Flow *f, const uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
Do the content inspection & validation for a signature.
Definition: detect-engine.c:1941
DetectParseRegex
Definition: detect-parse.h:42
SigTableElmt_::name
const char * name
Definition: detect.h:1267
unlikely
#define unlikely(expr)
Definition: util-optimize.h:35
UtRegisterTest
void UtRegisterTest(const char *name, int(*TestFn)(void))
Register unit test.
Definition: util-unittest.c:103
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:298
DetectFtpdataData_::command
FtpRequestCommand command
Definition: detect-ftpdata.h:36
SC_ERR_NOT_SUPPORTED
@ SC_ERR_NOT_SUPPORTED
Definition: util-error.h:257
Flow_
Flow data structure.
Definition: flow.h:353
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:811
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2433
FtpDataState_::command
FtpRequestCommand command
Definition: app-layer-ftp.h:207
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1238
m
SCMutex m
Definition: flow-hash.h:6
SC_ERR_PCRE_GET_SUBSTRING
@ SC_ERR_PCRE_GET_SUBSTRING
Definition: util-error.h:34
app-layer-ftp.h
detect-ftpdata.h
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:237
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1252
util-unittest.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1077
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:236
FAIL_IF_NOT_NULL
#define FAIL_IF_NOT_NULL(expr)
Fail a test if expression evaluates to non-NULL.
Definition: util-unittest.h:96
SC_ERR_PCRE_MATCH
@ SC_ERR_PCRE_MATCH
Definition: util-error.h:32
PASS
#define PASS
Pass the test.
Definition: util-unittest.h:105
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1060
res
PoolThreadReserved res
Definition: stream-tcp-private.h:0
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2597
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:324
DetectAppLayerInspectEngineRegister2
void DetectAppLayerInspectEngineRegister2(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr2 Callback2, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
Definition: detect-engine.c:225
detect-engine-state.h
Data structures and function prototypes for keeping state for the detection engine.
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:235
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:316
DetectEngineAppInspectionEngine_::smd
SigMatchData * smd
Definition: detect.h:415
DetectEngineAppendSig
Signature * DetectEngineAppendSig(DetectEngineCtx *de_ctx, const char *sigstr)
Parse and append a Signature into the Detection Engine Context signature list.
Definition: detect-parse.c:2420
FAIL_IF
#define FAIL_IF(expr)
Fail a test if expression evaluates to true.
Definition: util-unittest.h:71
flags
uint8_t flags
Definition: decode-gre.h:0
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:322
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:73
SCLogError
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:257
ALPROTO_FTPDATA
@ ALPROTO_FTPDATA
Definition: app-layer-protos.h:47
FtpDataState_
Definition: app-layer-ftp.h:201
SCMalloc
#define SCMalloc(sz)
Definition: util-mem.h:47
str
#define str(s)
Definition: suricata-common.h:272
SCFree
#define SCFree(p)
Definition: util-mem.h:61
DetectFtpdataData_
Definition: detect-ftpdata.h:35
detect-parse.h
Signature_
Signature container.
Definition: detect.h:548
SigMatch_
a single match condition for a signature
Definition: detect.h:321
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2394
FTP_COMMAND_RETR
@ FTP_COMMAND_RETR
Definition: app-layer-ftp.h:70
FTP_COMMAND_STOR
@ FTP_COMMAND_STOR
Definition: app-layer-ftp.h:78
DetectFtpdataRegister
void DetectFtpdataRegister(void)
Registration function for ftpcommand: keyword.
Definition: detect-ftpdata.c:62
SigMatchAppendSMToList
void SigMatchAppendSMToList(Signature *s, SigMatch *new, int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:349
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1259