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suricata/src/util-reference-config.c

795 lines
22 KiB
C

/* Copyright (C) 2007-2010 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 Anoop Saldanha <anoopsaldanha@gmail.com>
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-engine.h"
#include "util-hash.h"
#include "util-reference-config.h"
#include "conf.h"
#include "util-unittest.h"
#include "util-error.h"
#include "util-debug.h"
#include "util-fmemopen.h"
/* Regex to parse each line from reference.config file. The first substring
* is for the system name and the second for the url */
/*-----------------------------------------------------------system-------------------url----*/
#define SC_RCONF_REGEX "^\\s*config\\s+reference\\s*:\\s*([a-zA-Z][a-zA-Z0-9-_]*)\\s+(.+)\\s*$"
/* Default path for the reference.conf file */
#define SC_RCONF_DEFAULT_FILE_PATH "reference.config"
/* Holds a pointer to the default path for the reference.config file */
static const char *file_path = SC_RCONF_DEFAULT_FILE_PATH;
static FILE *fd = NULL;
static pcre *regex = NULL;
static pcre_extra *regex_study = NULL;
/* the hash functions */
uint32_t SCRConfReferenceHashFunc(HashTable *ht, void *data, uint16_t datalen);
char SCRConfReferenceHashCompareFunc(void *data1, uint16_t datalen1,
void *data2, uint16_t datalen2);
void SCRConfReferenceHashFree(void *ch);
/* used to get the reference.config file path */
static char *SCRConfGetConfFilename(void);
/**
* \brief Inits the context to be used by the Reference Config parsing API.
*
* This function initializes the hash table to be used by the Detection
* Engine Context to hold the data from reference.config file,
* obtains the file descriptor to parse the reference.config file, and
* inits the regex used to parse the lines from reference.config file.
*
* \param de_ctx Pointer to the Detection Engine Context.
*
* \retval 0 On success.
* \retval -1 On failure.
*/
static int SCRConfInitContext(DetectEngineCtx *de_ctx)
{
char *filename = NULL;
const char *eb = NULL;
int eo;
int opts = 0;
/* init the hash table to be used by the reference config references */
de_ctx->reference_conf_ht = HashTableInit(128, SCRConfReferenceHashFunc,
SCRConfReferenceHashCompareFunc,
SCRConfReferenceHashFree);
if (de_ctx->reference_conf_ht == NULL) {
SCLogError(SC_ERR_HASH_TABLE_INIT, "Error initializing the hash "
"table");
return -1;
}
/* if it is not NULL, use the file descriptor. The hack so that we can
* avoid using a dummy reference file for testing purposes and
* instead use an input stream against a buffer containing the
* reference strings */
if (fd == NULL) {
filename = SCRConfGetConfFilename();
if ((fd = fopen(filename, "r")) == NULL) {
SCLogError(SC_ERR_FOPEN, "Error opening file: \"%s\": %s", filename,
strerror(errno));
goto error;
}
}
regex = pcre_compile(SC_RCONF_REGEX, opts, &eb, &eo, NULL);
if (regex == NULL) {
SCLogDebug("Compile of \"%s\" failed at offset %" PRId32 ": %s",
SC_RCONF_REGEX, eo, eb);
goto error;
}
regex_study = pcre_study(regex, 0, &eb);
if (eb != NULL) {
SCLogDebug("pcre study failed: %s", eb);
goto error;
}
return 0;
error:
if (de_ctx->reference_conf_ht != NULL) {
HashTableFree(de_ctx->reference_conf_ht);
de_ctx->reference_conf_ht = NULL;
}
if (fd != NULL) {
fclose(fd);
fd = NULL;
}
return -1;
}
/**
* \brief Returns the path for the Reference Config file. We check if we
* can retrieve the path from the yaml conf file. If it is not present,
* return the default path for the reference.config file which is
* "./reference.config".
*
* \retval log_filename Pointer to a string containing the path for the
* reference.config file.
*/
static char *SCRConfGetConfFilename(void)
{
char *path = (char *)file_path;
ConfGet("reference-config-file", &path);
return path;
}
/**
* \brief Releases resources used by the Reference Config API.
*/
static void SCRConfDeInitContext(DetectEngineCtx *de_ctx)
{
if (fd != NULL)
fclose(fd);
file_path = SC_RCONF_DEFAULT_FILE_PATH;
fd = NULL;
return;
}
/**
* \brief Converts a string to lowercase.
*
* \param str Pointer to the string to be converted.
*/
static char *SCRConfStringToLowercase(const char *str)
{
char *new_str = NULL;
char *temp_str = NULL;
if ((new_str = SCStrdup(str)) == NULL) {
return NULL;
}
temp_str = new_str;
while (*temp_str != '\0') {
*temp_str = tolower(*temp_str);
temp_str++;
}
return new_str;
}
/**
* \brief Parses a line from the reference config file and adds it to Reference
* Config hash table DetectEngineCtx->reference_conf_ht.
*
* \param rawstr Pointer to the string to be parsed.
* \param de_ctx Pointer to the Detection Engine Context.
*
* \retval 0 On success.
* \retval -1 On failure.
*/
static int SCRConfAddReference(char *rawstr, DetectEngineCtx *de_ctx)
{
const char *system = NULL;
const char *url = NULL;
SCRConfReference *ref_new = NULL;
SCRConfReference *ref_lookup = NULL;
#define MAX_SUBSTRINGS 30
int ret = 0;
int ov[MAX_SUBSTRINGS];
ret = pcre_exec(regex, regex_study, rawstr, strlen(rawstr), 0, 0, ov, 30);
if (ret < 0) {
SCLogError(SC_ERR_REFERENCE_CONFIG, "Invalid Reference Config in "
"reference.config file");
goto error;
}
/* retrieve the reference system */
ret = pcre_get_substring((char *)rawstr, ov, 30, 1, &system);
if (ret < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring() failed");
goto error;
}
/* retrieve the reference url */
ret = pcre_get_substring((char *)rawstr, ov, 30, 2, &url);
if (ret < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring() failed");
goto error;
}
/* Create a new instance of the parsed Reference string */
ref_new = SCRConfAllocSCRConfReference(system, url);
/* Check if the Reference is present in the HashTable. In case it's present
* ignore it, as it's a duplicate. If not present, add it to the table */
ref_lookup = HashTableLookup(de_ctx->reference_conf_ht, ref_new, 0);
if (ref_lookup == NULL) {
if (HashTableAdd(de_ctx->reference_conf_ht, ref_new, 0) < 0) {
SCLogDebug("HashTable Add failed");
}
} else {
SCLogDebug("Duplicate reference found inside reference.config");
SCRConfDeAllocSCRConfReference(ref_new);
}
/* free the substrings */
pcre_free_substring(system);
pcre_free_substring(url);
return 0;
error:
if (system)
pcre_free_substring(system);
if (url)
pcre_free_substring(url);
return -1;
}
/**
* \brief Checks if a string is a comment or a blank line.
*
* Comments lines are lines of the following format -
* "# This is a comment string" or
* " # This is a comment string".
*
* \param line String that has to be checked.
*
* \retval 1 On the argument string being a comment or blank line.
* \retval 0 Otherwise.
*/
static int SCRConfIsLineBlankOrComment(char *line)
{
while (*line != '\0') {
/* we have a comment */
if (*line == '#')
return 1;
/* this line is neither a comment line, nor a blank line */
if (!isspace(*line))
return 0;
line++;
}
/* we have a blank line */
return 1;
}
/**
* \brief Parses the Reference Config file and updates the
* DetectionEngineCtx->reference_conf_ht with the Reference information.
*
* \param de_ctx Pointer to the Detection Engine Context.
*/
static void SCRConfParseFile(DetectEngineCtx *de_ctx)
{
char line[1024];
uint8_t i = 1;
while (fgets(line, sizeof(line), fd) != NULL) {
if (SCRConfIsLineBlankOrComment(line))
continue;
SCRConfAddReference(line, de_ctx);
i++;
}
#ifdef UNITTESTS
SCLogInfo("Added \"%d\" reference types from the reference.config file",
de_ctx->reference_conf_ht->count);
#endif /* UNITTESTS */
return;
}
/**
* \brief Returns a new SCRConfReference instance. The reference string
* is converted into lowercase, before being assigned to the instance.
*
* \param system Pointer to the system.
* \param url Pointer to the reference url.
*
* \retval ref Pointer to the new instance of SCRConfReference.
*/
SCRConfReference *SCRConfAllocSCRConfReference(const char *system,
const char *url)
{
SCRConfReference *ref = NULL;
if (system == NULL) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid arguments. system NULL");
return NULL;
}
if ((ref = SCMalloc(sizeof(SCRConfReference))) == NULL) {
return NULL;
}
memset(ref, 0, sizeof(SCRConfReference));
if ((ref->system = SCRConfStringToLowercase(system)) == NULL) {
SCFree(ref);
return NULL;
}
if (url != NULL && (ref->url = SCStrdup(url)) == NULL) {
SCFree(ref->system);
SCFree(ref);
return NULL;
}
return ref;
}
/**
* \brief Frees a SCRConfReference instance.
*
* \param Pointer to the SCRConfReference instance that has to be freed.
*/
void SCRConfDeAllocSCRConfReference(SCRConfReference *ref)
{
if (ref != NULL) {
if (ref->system != NULL)
SCFree(ref->system);
if (ref->url != NULL)
SCFree(ref->url);
SCFree(ref);
}
return;
}
/**
* \brief Hashing function to be used to hash the Reference name. Would be
* supplied as an argument to the HashTableInit function for
* DetectEngineCtx->reference_conf_ht.
*
* \param ht Pointer to the HashTable.
* \param data Pointer to the data to be hashed. In this case, the data
* would be a pointer to a SCRConfReference instance.
* \param datalen Not used by this function.
*/
uint32_t SCRConfReferenceHashFunc(HashTable *ht, void *data, uint16_t datalen)
{
SCRConfReference *ref = (SCRConfReference *)data;
uint32_t hash = 0;
int i = 0;
int len = strlen(ref->system);
for (i = 0; i < len; i++)
hash += tolower(ref->system[i]);
hash = hash % ht->array_size;
return hash;
}
/**
* \brief Used to compare two References that have been stored in the HashTable.
* This function is supplied as an argument to the HashTableInit function
* for DetectionEngineCtx->reference_conf_ct.
*
* \param data1 Pointer to the first SCRConfReference to be compared.
* \param len1 Not used by this function.
* \param data2 Pointer to the second SCRConfReference to be compared.
* \param len2 Not used by this function.
*
* \retval 1 On data1 and data2 being equal.
* \retval 0 On data1 and data2 not being equal.
*/
char SCRConfReferenceHashCompareFunc(void *data1, uint16_t datalen1,
void *data2, uint16_t datalen2)
{
SCRConfReference *ref1 = (SCRConfReference *)data1;
SCRConfReference *ref2 = (SCRConfReference *)data2;
int len1 = 0;
int len2 = 0;
if (ref1 == NULL || ref2 == NULL)
return 0;
if (ref1->system == NULL || ref2->system == NULL)
return 0;
len1 = strlen(ref1->system);
len2 = strlen(ref2->system);
if (len1 == len2 && memcmp(ref1->system, ref2->system, len1) == 0) {
SCLogDebug("Match found inside Reference-Config hash function");
return 1;
}
return 0;
}
/**
* \brief Used to free the Reference Config Hash Data that was stored in
* DetectEngineCtx->reference_conf_ht Hashtable.
*
* \param data Pointer to the data that has to be freed.
*/
void SCRConfReferenceHashFree(void *data)
{
SCRConfDeAllocSCRConfReference(data);
return;
}
/**
* \brief Loads the Reference info from the reference.config file.
*
* The reference.config file contains references that can be used in
* Signatures. Each line of the file should have the following format -
* config reference: system_name, reference_url.
*
* \param de_ctx Pointer to the Detection Engine Context that should be updated
* with reference information.
*
* \retval 0 On success.
* \retval -1 On failure.
*/
int SCRConfLoadReferenceConfigFile(DetectEngineCtx *de_ctx)
{
if (SCRConfInitContext(de_ctx) == -1) {
printf("\nPlease check the \"reference-config-file\" option in your suricata.yaml file.\n");
exit(EXIT_FAILURE);
return -1;
}
SCRConfParseFile(de_ctx);
SCRConfDeInitContext(de_ctx);
return 0;
}
/*----------------------------------Unittests---------------------------------*/
#ifdef UNITTESTS
/**
* \brief Creates a dummy reference config, with all valid references, for
* testing purposes.
*/
void SCRConfGenerateValidDummyReferenceConfigFD01(void)
{
const char *buffer =
"config reference: one http://www.one.com\n"
"config reference: two http://www.two.com\n"
"config reference: three http://www.three.com\n"
"config reference: one http://www.one.com\n"
"config reference: three http://www.three.com\n";
fd = SCFmemopen((void *)buffer, strlen(buffer), "r");
if (fd == NULL)
SCLogDebug("Error with SCFmemopen() called by Reference Config test code");
return;
}
/**
* \brief Creates a dummy reference config, with some valid references and a
* couple of invalid references, for testing purposes.
*/
void SCRConfGenerateInValidDummyReferenceConfigFD02(void)
{
const char *buffer =
"config reference: one http://www.one.com\n"
"config_ reference: two http://www.two.com\n"
"config reference_: three http://www.three.com\n"
"config reference: four\n"
"config reference five http://www.five.com\n";
fd = SCFmemopen((void *)buffer, strlen(buffer), "r");
if (fd == NULL)
SCLogDebug("Error with SCFmemopen() called by Reference Config test code");
return;
}
/**
* \brief Creates a dummy reference config, with all invalid references, for
* testing purposes.
*/
void SCRConfGenerateInValidDummyReferenceConfigFD03(void)
{
const char *buffer =
"config reference one http://www.one.com\n"
"config_ reference: two http://www.two.com\n"
"config reference_: three http://www.three.com\n"
"config reference: four\n";
fd = SCFmemopen((void *)buffer, strlen(buffer), "r");
if (fd == NULL)
SCLogDebug("Error with SCFmemopen() called by Reference Config test code");
return;
}
/**
* \brief Deletes the FD, if set by the other testing functions.
*/
void SCRConfDeleteDummyReferenceConfigFD(void)
{
if (fd != NULL) {
fclose(fd);
fd = NULL;
}
return;
}
/**
* \test Check that the reference file is loaded and the detection engine
* content reference_conf_ht loaded with the reference data.
*/
int SCRConfTest01(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
int result = 0;
if (de_ctx == NULL)
return result;
SCRConfGenerateValidDummyReferenceConfigFD01();
SCRConfLoadReferenceConfigFile(de_ctx);
SCRConfDeleteDummyReferenceConfigFD();
if (de_ctx->reference_conf_ht == NULL)
goto end;
result = (de_ctx->reference_conf_ht->count == 3);
if (result == 0)
printf("FAILED: de_ctx->reference_conf_ht->count %u: ", de_ctx->reference_conf_ht->count);
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test Check that invalid references present in the reference.config file
* aren't loaded.
*/
int SCRConfTest02(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
int result = 0;
if (de_ctx == NULL)
return result;
SCRConfGenerateInValidDummyReferenceConfigFD03();
SCRConfLoadReferenceConfigFile(de_ctx);
SCRConfDeleteDummyReferenceConfigFD();
if (de_ctx->reference_conf_ht == NULL)
goto end;
result = (de_ctx->reference_conf_ht->count == 0);
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test Check that only valid references are loaded into the hash table from
* the reference.config file.
*/
int SCRConfTest03(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
int result = 0;
if (de_ctx == NULL)
return result;
SCRConfGenerateInValidDummyReferenceConfigFD02();
SCRConfLoadReferenceConfigFile(de_ctx);
SCRConfDeleteDummyReferenceConfigFD();
if (de_ctx->reference_conf_ht == NULL)
goto end;
result = (de_ctx->reference_conf_ht->count == 1);
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test Check if the reference info from the reference.config file have
* been loaded into the hash table.
*/
int SCRConfTest04(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
SCRConfReference *ref = NULL;
int result = 1;
if (de_ctx == NULL)
return 0;
SCRConfGenerateValidDummyReferenceConfigFD01();
SCRConfLoadReferenceConfigFile(de_ctx);
SCRConfDeleteDummyReferenceConfigFD();
if (de_ctx->reference_conf_ht == NULL)
goto end;
result = (de_ctx->reference_conf_ht->count == 3);
ref = SCRConfAllocSCRConfReference("one", "http://www.one.com");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) != NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("two", "http://www.two.com");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) != NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("three", "http://www.three.com");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) != NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("four", "http://www.four.com");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test Check if the reference info from the invalid reference.config file
* have not been loaded into the hash table, and cross verify to check
* that the hash table contains no reference data.
*/
int SCRConfTest05(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
SCRConfReference *ref = NULL;
int result = 1;
if (de_ctx == NULL)
return 0;
SCRConfGenerateInValidDummyReferenceConfigFD03();
SCRConfLoadReferenceConfigFile(de_ctx);
SCRConfDeleteDummyReferenceConfigFD();
if (de_ctx->reference_conf_ht == NULL)
goto end;
result = (de_ctx->reference_conf_ht->count == 0);
ref = SCRConfAllocSCRConfReference("one", "one");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("two", "two");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("three", "three");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("four", "four");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("five", "five");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
/**
* \test Check if the reference info from the reference.config file have
* been loaded into the hash table.
*/
int SCRConfTest06(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
SCRConfReference *ref = NULL;
int result = 1;
if (de_ctx == NULL)
return 0;
SCRConfGenerateInValidDummyReferenceConfigFD02();
SCRConfLoadReferenceConfigFile(de_ctx);
SCRConfDeleteDummyReferenceConfigFD();
if (de_ctx->reference_conf_ht == NULL)
goto end;
result = (de_ctx->reference_conf_ht->count == 1);
ref = SCRConfAllocSCRConfReference("one", "one");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) != NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("two", "two");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("three", "three");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("four", "four");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
ref = SCRConfAllocSCRConfReference("five", "five");
result &= (HashTableLookup(de_ctx->reference_conf_ht, ref, 0) == NULL);
SCRConfDeAllocSCRConfReference(ref);
end:
if (de_ctx != NULL)
DetectEngineCtxFree(de_ctx);
return result;
}
#endif /* UNITTESTS */
/**
* \brief This function registers unit tests for Reference Config API.
*/
void SCRConfRegisterTests(void)
{
#ifdef UNITTESTS
UtRegisterTest("SCRConfTest01", SCRConfTest01, 1);
UtRegisterTest("SCRConfTest02", SCRConfTest02, 1);
UtRegisterTest("SCRConfTest03", SCRConfTest03, 1);
UtRegisterTest("SCRConfTest04", SCRConfTest04, 1);
UtRegisterTest("SCRConfTest05", SCRConfTest05, 1);
UtRegisterTest("SCRConfTest06", SCRConfTest06, 1);
#endif /* UNITTESTS */
return;
}