You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
suricata/src/detect-parse.c

767 lines
20 KiB
C

/* signature parser */
#include "eidps-common.h"
#include "debug.h"
#include "detect.h"
#include "detect-engine.h"
#include "detect-engine-address.h"
#include "detect-engine-port.h"
#include "flow.h"
#include "util-unittest.h"
static pcre *config_pcre = NULL;
static pcre *option_pcre = NULL;
static pcre_extra *config_pcre_extra = NULL;
static pcre_extra *option_pcre_extra = NULL;
/* XXX this should be part of the DE */
//static uint32_t signum = 0;
static uint32_t dbg_srcportany_cnt = 0;
static uint32_t dbg_dstportany_cnt = 0;
#define CONFIG_PARTS 8
#define CONFIG_ACTION 0
#define CONFIG_PROTO 1
#define CONFIG_SRC 2
#define CONFIG_SP 3
#define CONFIG_DIREC 4
#define CONFIG_DST 5
#define CONFIG_DP 6
#define CONFIG_OPTS 7
// action protocol src sp dir dst dp options
#define CONFIG_PCRE "^([A-z]+)\\s+([A-z0-9]+)\\s+([\\[\\]A-z0-9\\.\\:_\\$\\!\\-,\\/]+)\\s+([\\:A-z0-9_\\$\\!,]+)\\s+(\\<-|-\\>|\\<\\>)\\s+([\\[\\]A-z0-9\\.\\:_\\$\\!\\-,/]+)\\s+([\\:A-z0-9_\\$\\!,]+)(?:\\s+\\((.*)?(?:\\s*)\\))?(?:(?:\\s*)\\n)?$"
16 years ago
#define OPTION_PARTS 3
#define OPTION_PCRE "^\\s*([A-z_0-9-]+)(?:\\s*\\:\\s*(.*)(?<!\\\\))?\\s*;\\s*(?:\\s*(.*))?\\s*$"
uint32_t DbgGetSrcPortAnyCnt(void) {
return dbg_srcportany_cnt;
}
uint32_t DbgGetDstPortAnyCnt(void) {
return dbg_dstportany_cnt;
}
SigMatch *SigMatchAlloc(void) {
SigMatch *sm = malloc(sizeof(SigMatch));
if (sm == NULL)
return NULL;
memset(sm, 0, sizeof(SigMatch));
return sm;
}
/** \brief free a SigMatch
* \param sm SigMatch to free.
*/
void SigMatchFree(SigMatch *sm) {
if (sm == NULL)
return;
/** free the ctx, for that we call the Free func */
if (sm->ctx != NULL) {
if (sigmatch_table[sm->type].Free != NULL) {
sigmatch_table[sm->type].Free(sm->ctx);
}
}
free(sm);
}
/* Get the detection module by name */
SigTableElmt *SigTableGet(char *name) {
SigTableElmt *st = NULL;
int i = 0;
for (i = 0; i < DETECT_TBLSIZE; i++) {
st = &sigmatch_table[i];
if (st->name != NULL) {
if (strcasecmp(name,st->name) == 0)
return st;
}
}
return NULL;
}
/* Append 'new' SigMatch to the current Signature. If present
* append it to Sigmatch 'm', otherwise place it in the root.
*/
void SigMatchAppend(Signature *s, SigMatch *m, SigMatch *new) {
//printf("s:%p,m:%p,new:%p\n", s,m,new);
if (m == NULL)
m = s->match;
if (s->match == NULL)
s->match = new;
else {
m->next = new;
new->prev = m;
}
}
void SigParsePrepare(void) {
char *regexstr = CONFIG_PCRE;
const char *eb;
int eo;
int opts = 0;
opts |= PCRE_UNGREEDY;
config_pcre = pcre_compile(regexstr, opts, &eb, &eo, NULL);
if(config_pcre == NULL)
{
printf("pcre compile of \"%s\" failed at offset %" PRId32 ": %s\n", regexstr, eo, eb);
exit(1);
}
config_pcre_extra = pcre_study(config_pcre, 0, &eb);
if(eb != NULL)
{
printf("pcre study failed: %s\n", eb);
exit(1);
}
regexstr = OPTION_PCRE;
opts |= PCRE_UNGREEDY;
option_pcre = pcre_compile(regexstr, opts, &eb, &eo, NULL);
if(option_pcre == NULL)
{
printf("pcre compile of \"%s\" failed at offset %" PRId32 ": %s\n", regexstr, eo, eb);
exit(1);
}
option_pcre_extra = pcre_study(option_pcre, 0, &eb);
if(eb != NULL)
{
printf("pcre study failed: %s\n", eb);
exit(1);
}
}
int SigParseOptions(DetectEngineCtx *de_ctx, Signature *s, SigMatch *m, char *optstr) {
#define MAX_SUBSTRINGS 30
int ov[MAX_SUBSTRINGS];
int ret = 0, i = 0;
SigTableElmt *st = NULL;
char *optname = NULL, *optvalue = NULL, *optmore = NULL;
const char **arr = calloc(OPTION_PARTS+1, sizeof(char *));
if (arr == NULL)
return -1;
ret = pcre_exec(option_pcre, option_pcre_extra, optstr, strlen(optstr), 0, 0, ov, MAX_SUBSTRINGS);
/* if successful, we either have:
* 2: keyword w/o value
* 3: keyword w value, final opt OR keyword w/o value, more options coming
* 4: keyword w value, more options coming
*/
if (ret != 2 && ret != 3 && ret != 4) {
printf("pcre_exec failed: ret %" PRId32 ", optstr \"%s\"\n", ret, optstr);
goto error;
}
/* extract the substrings */
for (i = 1; i <= ret-1; i++) {
pcre_get_substring(optstr, ov, MAX_SUBSTRINGS, i, &arr[i-1]);
//printf("SigParseOptions: arr[%" PRId32 "] = \"%s\"\n", i-1, arr[i-1]);
}
arr[i-1]=NULL;
/* Call option parsing */
st = SigTableGet((char *)arr[0]);
if (st == NULL) {
printf("Unknown rule keyword '%s'.\n", (char *)arr[0]);
goto error;
}
if (st->flags & SIGMATCH_NOOPT) {
optname = (char *)arr[0];
optvalue = NULL;
if (ret == 3) optmore = (char *)arr[1];
else if (ret == 4) optmore = (char *)arr[2];
else optmore = NULL;
} else {
optname = (char *)arr[0];
optvalue = (char *)arr[1];
if (ret == 4) optmore = (char *)arr[2];
else optmore = NULL;
}
/* setup may or may not add a new SigMatch to the list */
if (st->Setup(de_ctx, s, m, optvalue) < 0)
goto error;
/* thats why we check for that here */
if (m != NULL && m->next != NULL)
m = m->next;
else if (m == NULL && s->match != NULL)
m = s->match;
if (ret == 4 && optmore != NULL) {
//printf("SigParseOptions: recursive call for more options... (s:%p,m:%p)\n", s, m);
if (optname) pcre_free_substring(optname);
if (optvalue) pcre_free_substring(optvalue);
if (optstr) free(optstr);
//if (optmore) pcre_free_substring(optmore);
if (arr != NULL) free(arr);
return SigParseOptions(de_ctx, s, m, optmore);
}
if (optname) pcre_free_substring(optname);
if (optvalue) pcre_free_substring(optvalue);
if (optmore) pcre_free_substring(optmore);
if (optstr) free(optstr);
if (arr != NULL) free(arr);
return 0;
error:
if (optname) pcre_free_substring(optname);
if (optvalue) pcre_free_substring(optvalue);
if (optmore) pcre_free_substring(optmore);
if (optstr) free(optstr);
if (arr != NULL) free(arr);
return -1;
}
/* XXX implement this for real
*
*/
int SigParseAddress(Signature *s, const char *addrstr, char flag) {
char *addr = NULL;
if (strcmp(addrstr,"$HOME_NET") == 0) {
addr = "[192.168.0.0/16,10.8.0.0/16,127.0.0.1,2001:888:13c5:5AFE::/64,2001:888:13c5:CAFE::/64]";
// addr = "[192.168.0.0/16,10.8.0.0/16,2001:888:13c5:5AFE::/64,2001:888:13c5:CAFE::/64]";
} else if (strcmp(addrstr,"$EXTERNAL_NET") == 0) {
addr = "[!192.168.0.0/16,2000::/3]";
} else if (strcmp(addrstr,"$HTTP_SERVERS") == 0) {
addr = "!192.168.0.0/16";
} else if (strcmp(addrstr,"$SMTP_SERVERS") == 0) {
addr = "!192.168.0.0/16";
} else if (strcmp(addrstr,"$SQL_SERVERS") == 0) {
addr = "!192.168.0.0/16";
} else if (strcmp(addrstr,"$DNS_SERVERS") == 0) {
addr = "any";
} else if (strcmp(addrstr,"$TELNET_SERVERS") == 0) {
addr = "any";
} else if (strcmp(addrstr,"$AIM_SERVERS") == 0) {
addr = "any";
} else if (strcmp(addrstr,"any") == 0) {
addr = "any";
} else {
addr = (char *)addrstr;
//printf("SigParseAddress: addr \"%s\"\n", addrstr);
}
/* pass on to the address(list) parser */
if (flag == 0) {
if (strcasecmp(addrstr,"any") == 0)
s->flags |= SIG_FLAG_SRC_ANY;
if (DetectAddressGroupParse(&s->src,addr) < 0) {
goto error;
}
} else {
if (strcasecmp(addrstr,"any") == 0)
s->flags |= SIG_FLAG_DST_ANY;
if (DetectAddressGroupParse(&s->dst,addr) < 0) {
goto error;
}
}
return 0;
error:
return -1;
}
/* http://www.iana.org/assignments/protocol-numbers
*
*/
int SigParseProto(Signature *s, const char *protostr) {
int r = DetectProtoParse(&s->proto,(char *)protostr);
if (r < 0) {
return -1;
}
return 0;
}
/* src: flag = 0, dst: flag = 1
*
*/
int SigParsePort(Signature *s, const char *portstr, char flag) {
int r = 0;
char *port;
char negate = 0;
/* XXX VJ exclude handling this for none UDP/TCP proto's */
17 years ago
/* XXX hack, fix this */
if (portstr[0] == '!' && portstr[1] == '$') {
portstr++;
negate = 1;
}
if (strcmp(portstr,"$HTTP_PORTS") == 0) {
if (negate) port = "![80:81,88]";
else port = "80:81,88";
} else if (strcmp(portstr,"$SHELLCODE_PORTS") == 0) {
port = "!80";
} else if (strcmp(portstr,"$ORACLE_PORTS") == 0) {
if (negate) port = "!1521";
else port = "1521";
} else if (strcmp(portstr,"$SSH_PORTS") == 0) {
if (negate) port = "!22";
else port = "22";
} else {
port = (char *)portstr;
}
if (flag == 0) {
if (strcasecmp(port,"any") == 0) {
s->flags |= SIG_FLAG_SP_ANY;
}
r = DetectPortParse(&s->sp,(char *)port);
} else if (flag == 1) {
if (strcasecmp(port,"any") == 0)
s->flags |= SIG_FLAG_DP_ANY;
r = DetectPortParse(&s->dp,(char *)port);
//DetectPortPrint(s->dp);
}
if (r < 0) {
return -1;
}
return 0;
}
int SigParseAction(Signature *s, const char *action) {
if (strcasecmp(action, "alert") == 0) {
s->action = ACTION_ALERT;
return 0;
} else if(strcasecmp(action, "drop") == 0) {
s->action = ACTION_DROP;
return 0;
} else if(strcasecmp(action, "pass") == 0) {
s->action = ACTION_PASS;
return 0;
} else if(strcasecmp(action, "reject") == 0) {
s->action = ACTION_REJECT;
return 0;
} else if(strcasecmp(action, "rejectsrc") == 0) {
s->action = ACTION_REJECT;
return 0;
} else if(strcasecmp(action, "rejectdst") == 0) {
s->action = ACTION_REJECT_DST;
return 0;
} else if(strcasecmp(action, "rejectboth") == 0) {
s->action = ACTION_REJECT_BOTH;
return 0;
} else {
return -1;
}
}
int SigParseBasics(Signature *s, char *sigstr, char ***result) {
#define MAX_SUBSTRINGS 30
int ov[MAX_SUBSTRINGS];
int ret = 0, i = 0;
const char **arr = calloc(CONFIG_PARTS+1, sizeof(char *));
if (arr == NULL)
return -1;
ret = pcre_exec(config_pcre, config_pcre_extra, sigstr, strlen(sigstr), 0, 0, ov, MAX_SUBSTRINGS);
if (ret != 8 && ret != 9) {
printf("SigParseBasics: pcre_exec failed: ret %" PRId32 ", sigstr \"%s\"\n", ret, sigstr);
goto error;
}
DEBUGPRINT("SigParseBasics: pcre_exec returned %" PRId32, ret);
for (i = 1; i <= ret-1; i++) {
pcre_get_substring(sigstr, ov, MAX_SUBSTRINGS, i, &arr[i-1]);
//printf("SigParseBasics: arr[%" PRId32 "] = \"%s\"\n", i-1, arr[i-1]);
}
arr[i-1]=NULL;
/* Parse Action */
if (SigParseAction(s, arr[CONFIG_ACTION]) < 0)
goto error;
/* Parse Proto */
if (SigParseProto(s, arr[CONFIG_PROTO]) < 0)
goto error;
/* Parse Address & Ports */
if (SigParseAddress(s, arr[CONFIG_SRC], 0) < 0)
goto error;
/* For "ip" we parse the ports as well, even though they will
be just "any". We do this for later sgh building for the
tcp and udp protocols. */
if (strcasecmp(arr[CONFIG_PROTO],"tcp") == 0 ||
strcasecmp(arr[CONFIG_PROTO],"udp") == 0 ||
strcasecmp(arr[CONFIG_PROTO],"ip") == 0) {
if (SigParsePort(s, arr[CONFIG_SP], 0) < 0)
goto error;
if (SigParsePort(s, arr[CONFIG_DP], 1) < 0)
goto error;
}
if (SigParseAddress(s, arr[CONFIG_DST], 1) < 0)
goto error;
*result = (char **)arr;
DEBUGPRINT("SigParseBasics: %p %p", arr, *result);
return 0;
error:
if (arr) free(arr);
*result = NULL;
return -1;
}
int SigParse(DetectEngineCtx *de_ctx, Signature *s, char *sigstr) {
char **basics;
int ret = SigParseBasics(s, sigstr, &basics);
if (ret < 0) {
//printf("SigParseBasics failed\n");
return -1;
}
#ifdef DEBUG
DEBUGPRINT("SigParse: %p", basics);
int i;
for (i = 0; basics[i] != NULL; i++) {
DEBUGPRINT("SigParse: basics[%" PRId32 "]: %p, %s", i, basics[i], basics[i]);
}
#endif /* DEBUG */
/* we can have no options, so make sure we have them */
if (basics[CONFIG_OPTS] != NULL) {
ret = SigParseOptions(de_ctx, s, NULL, strdup(basics[CONFIG_OPTS]));
}
/* cleanup */
if (basics) {
int i = 0;
while (basics[i] != NULL) {
free(basics[i]);
i++;
}
free(basics);
}
return ret;
}
Signature *SigAlloc (void) {
Signature *sig = malloc(sizeof(Signature));
if (sig == NULL)
return NULL;
memset(sig, 0, sizeof(Signature));
return sig;
}
void SigFree(Signature *s) {
if (s == NULL)
return;
SigMatch *sm = s->match, *nsm;
while (sm != NULL) {
nsm = sm->next;
SigMatchFree(sm);
sm = nsm;
}
DetectAddressGroupsHeadCleanup(&s->src);
DetectAddressGroupsHeadCleanup(&s->dst);
if (s->msg != NULL) free(s->msg);
free(s);
}
Signature *SigInit(DetectEngineCtx *de_ctx, char *sigstr) {
Signature *sig = SigAlloc();
if (sig == NULL)
goto error;
/* XXX one day we will support this the way Snort does,
* through classifications.config */
sig->prio = 3;
if (SigParse(de_ctx, sig, sigstr) < 0)
goto error;
sig->num = de_ctx->signum;
de_ctx->signum++;
return sig;
error:
SigFree(sig);
return NULL;
}
/*
* TESTS
*/
int SigParseTest01 (void) {
int result = 1;
Signature *sig = NULL;
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
sig = SigInit(de_ctx, "alert tcp 1.2.3.4 any -> !1.2.3.4 any (msg:\"SigParseTest01\"; sid:1;)");
if (sig == NULL) {
result = 0;
goto end;
}
SigFree(sig);
DetectEngineCtxFree(de_ctx);
end:
return result;
}
17 years ago
int SigParseTest02 (void) {
int result = 0;
Signature *sig = NULL;
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
sig = SigInit(de_ctx, "alert tcp any !21:902 -> any any (msg:\"ET MALWARE Suspicious 220 Banner on Local Port\"; content:\"220\"; offset:0; depth:4; pcre:\"/220[- ]/\"; classtype:non-standard-protocol; sid:2003055; rev:4;)");
17 years ago
if (sig == NULL) {
goto end;
}
DetectPort *port = NULL;
int r = DetectPortParse(&port, "0:20");
if (r < 0)
goto end;
17 years ago
if (DetectPortCmp(sig->sp, port) == PORT_EQ) {
result = 1;
} else {
DetectPortPrint(port); printf(" != "); DetectPortPrint(sig->sp); printf(": ");
}
SigFree(sig);
DetectEngineCtxFree(de_ctx);
17 years ago
end:
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation01 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp !any any -> any any (msg:\"SigTest41-01 src address is !any \"; classtype:misc-activity; sid:410001; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation02 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp any !any -> any any (msg:\"SigTest41-02 src ip is !any \"; classtype:misc-activity; sid:410002; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation03 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp any any -> any [80:!80] (msg:\"SigTest41-03 dst port [80:!80] \"; classtype:misc-activity; sid:410003; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation04 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp any any -> any [80,!80] (msg:\"SigTest41-03 dst port [80:!80] \"; classtype:misc-activity; sid:410003; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation05 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp any any -> [192.168.0.2,!192.168.0.2] any (msg:\"SigTest41-04 dst ip [192.168.0.2,!192.168.0.2] \"; classtype:misc-activity; sid:410004; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation06 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp any any -> any [100:1000,!1:20000] (msg:\"SigTest41-05 dst port [100:1000,!1:20000] \"; classtype:misc-activity; sid:410005; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test check that we don't allow invalid negation options
*/
static int SigParseTestNegation07 (void) {
int result = 0;
DetectEngineCtx *de_ctx;
Signature *s=NULL;
de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
de_ctx->flags |= DE_QUIET;
s = SigInit(de_ctx,"alert tcp any any -> [192.168.0.2,!192.168.0.0/24] any (msg:\"SigTest41-06 dst ip [192.168.0.2,!192.168.0.0/24] \"; classtype:misc-activity; sid:410006; rev:1;)");
if (s != NULL) {
SigFree(s);
goto end;
}
result = 1;
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
//printf("%s\n", result?"ok":"fail");
//exit(1);
return result;
}
void SigParseRegisterTests(void) {
UtRegisterTest("SigParseTest01", SigParseTest01, 1);
17 years ago
UtRegisterTest("SigParseTest02", SigParseTest02, 1);
UtRegisterTest("SigParseTestNegation01", SigParseTestNegation01, 1);
UtRegisterTest("SigParseTestNegation02", SigParseTestNegation02, 1);
UtRegisterTest("SigParseTestNegation03", SigParseTestNegation03, 1);
UtRegisterTest("SigParseTestNegation04", SigParseTestNegation04, 1);
UtRegisterTest("SigParseTestNegation05", SigParseTestNegation05, 1);
UtRegisterTest("SigParseTestNegation06", SigParseTestNegation06, 1);
UtRegisterTest("SigParseTestNegation07", SigParseTestNegation07, 1);
}