text: /* 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 Breno Silva <breno.silva@gmail.com>
   * \author Anoop Saldanha <anoopsaldanha@gmail.com>
   *
   * Implements the reference keyword support
   */
  
  #include "suricata-common.h"
  #include "suricata.h"
  #include "detect.h"
  #include "detect-parse.h"
  #include "detect-engine.h"
  #include "detect-engine-mpm.h"
  
  #include "decode.h"
  #include "flow-var.h"
  #include "decode-events.h"
  #include "stream-tcp.h"
  
  #include "util-reference-config.h"
  #include "detect-reference.h"
  
  #include "util-unittest.h"
  #include "util-byte.h"
  #include "util-debug.h"
  
  #define PARSE_REGEX "^\\s*([A-Za-z0-9]+)\\s*,\"?\\s*\"?\\s*([a-zA-Z0-9\\-_\\.\\/\\?\\=]+)\"?\\s*\"?"
  
  static pcre *parse_regex;
  static pcre_extra *parse_regex_study;
  
  static int DetectReferenceSetup(DetectEngineCtx *, Signature *s, char *str);
  
  /**
   * \brief Registration function for the reference: keyword
   */
  void DetectReferenceRegister(void)
  {
      sigmatch_table[DETECT_REFERENCE].name = "reference";
      sigmatch_table[DETECT_REFERENCE].desc = "direct to places where information about the rule can be found";
      sigmatch_table[DETECT_REFERENCE].url = DOC_URL DOC_VERSION "/rules/meta.html#reference";
      sigmatch_table[DETECT_REFERENCE].Match = NULL;
      sigmatch_table[DETECT_REFERENCE].Setup = DetectReferenceSetup;
      sigmatch_table[DETECT_REFERENCE].Free  = NULL;
      sigmatch_table[DETECT_REFERENCE].RegisterTests = ReferenceRegisterTests;
  
      DetectSetupParseRegexes(PARSE_REGEX, &parse_regex, &parse_regex_study);
  }
  
  /**
   *  \brief Free a Reference object
   */
  void DetectReferenceFree(DetectReference *ref)
  {
      SCEnter();
  
      if (ref->reference != NULL) {
          SCFree(ref->reference);
      }
      SCFree(ref);
  
      SCReturn;
  }
  
  /**
   * \internal
   * \brief This function is used to parse reference options passed via reference: keyword
   *
   * \param rawstr Pointer to the user provided reference options.
   *
   * \retval ref  Pointer to signature reference on success.
   * \retval NULL On failure.
   */
  static DetectReference *DetectReferenceParse(char *rawstr, DetectEngineCtx *de_ctx)
  {
      SCEnter();
  
      DetectReference *ref = NULL;
  #define MAX_SUBSTRINGS 30
      int ret = 0, res = 0;
      int ov[MAX_SUBSTRINGS];
      char key[64] = "";
      char content[1024] = "";
  
      ret = pcre_exec(parse_regex, parse_regex_study, rawstr, strlen(rawstr),
                      0, 0, ov, MAX_SUBSTRINGS);
      if (ret < 2) {
          SCLogError(SC_ERR_INVALID_SIGNATURE, "Unable to parse \"reference\" "
                     "keyword argument - \"%s\".   Invalid argument.", rawstr);
          goto error;
      }
  
      ref = SCMalloc(sizeof(DetectReference));
      if (unlikely(ref == NULL)) {
          goto error;
      }
      memset(ref, 0, sizeof(DetectReference));
  
      res = pcre_copy_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 1, key, sizeof(key));
      if (res < 0) {
          SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
          goto error;
      }
  
      res = pcre_copy_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 2, content, sizeof(content));
      if (res < 0) {
          SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring failed");
          goto error;
      }
  
      if (strlen(key) == 0 || strlen(content) == 0)
          goto error;
  
      SCRConfReference *lookup_ref_conf = SCRConfGetReference(key, de_ctx);
      if (lookup_ref_conf != NULL) {
          ref->key = lookup_ref_conf->url;
      } else {
          SCLogError(SC_ERR_REFERENCE_UNKNOWN, "unknown reference key \"%s\". "
                     "Supported keys are defined in reference.config file.  Please "
                     "have a look at the conf param \"reference-config-file\"", key);
          goto error;
      }
  
      /* make a copy so we can free pcre's substring */
      ref->reference = SCStrdup((char *)content);
      if (ref->reference == NULL) {
          SCLogError(SC_ERR_MEM_ALLOC, "strdup failed: %s", strerror(errno));
          goto error;
      }
  
      /* free the substrings */
      SCReturnPtr(ref, "Reference");
  
  error:
      if (ref != NULL)
          DetectReferenceFree(ref);
  
      SCReturnPtr(NULL, "Reference");
  }
  
  /**
   * \internal
   * \brief Used to add the parsed reference into the current signature.
   *
   * \param de_ctx Pointer to the Detection Engine Context.
   * \param s      Pointer to the Current Signature.
   * \param m      Pointer to the Current SigMatch.
   * \param rawstr Pointer to the user provided reference options.
   *
   * \retval  0 On Success.
   * \retval -1 On Failure.
   */
  static int DetectReferenceSetup(DetectEngineCtx *de_ctx, Signature *s,
                                  char *rawstr)
  {
      SCEnter();
  
      DetectReference *ref = NULL;
      DetectReference *sig_refs = NULL;
  
      ref = DetectReferenceParse(rawstr, de_ctx);
      if (ref == NULL)
          goto error;
  
      SCLogDebug("ref %s %s", ref->key, ref->reference);
  
      if (s->references == NULL)  {
          s->references = ref;
      } else {
          sig_refs = s->references;
          while (sig_refs->next != NULL) {
              sig_refs = sig_refs->next;
          }
          sig_refs->next = ref;
          ref->next = NULL;
      }
  
      SCReturnInt(0);
  
  error:
      SCReturnInt(-1);
  }
  
  /***************************************Unittests******************************/
  
  #ifdef UNITTESTS
  
  /**
   * \test one valid reference.
   *
   *  \retval 1 on succces.
   *  \retval 0 on failure.
   */
  static int DetectReferenceParseTest01(void)
  {
      int result = 0;
      Signature *s = NULL;
      DetectReference *ref = NULL;
  
      DetectEngineCtx *de_ctx = DetectEngineCtxInit();
      if (de_ctx == NULL) {
          goto cleanup;
      }
      de_ctx->flags |= DE_QUIET;
  
      FILE *fd = SCRConfGenerateValidDummyReferenceConfigFD01();
      SCRConfLoadReferenceConfigFile(de_ctx, fd);
  
      s = de_ctx->sig_list = SigInit(de_ctx, "alert icmp any any -> any any "
                                     "(msg:\"One reference\"; reference:one,001-2010; sid:2;)");
      if (s == NULL) {
          goto cleanup;
      }
  
      if (s->references == NULL)  {
          goto cleanup;
      }
  
      ref = s->references;
      if (strcmp(ref->key, "http://www.one.com") != 0 ||
          strcmp(ref->reference, "001-2010") != 0) {
          goto cleanup;
      }
  
      result = 1;
  
  cleanup:
      if (de_ctx != NULL) {
          DetectEngineCtxFree(de_ctx);
      }
      return result;
  
  }
  
  /**
   * \test for two valid references.
   *
   *  \retval 1 on succces.
   *  \retval 0 on failure.
   */
  static int DetectReferenceParseTest02(void)
  {
      int result = 0;
      Signature *s = NULL;
  
      DetectEngineCtx *de_ctx = DetectEngineCtxInit();
      if (de_ctx == NULL) {
          goto cleanup;
      }
      de_ctx->flags |= DE_QUIET;
  
      FILE *fd = SCRConfGenerateValidDummyReferenceConfigFD01();
      SCRConfLoadReferenceConfigFile(de_ctx, fd);
  
      s = de_ctx->sig_list = SigInit(de_ctx, "alert icmp any any -> any any "
                                     "(msg:\"Two references\"; "
                                     "reference:one,openinfosecdoundation.txt; "
                                     "reference:two,001-2010; sid:2;)");
      if (s == NULL) {
          printf("sig parse failed: ");
          goto cleanup;
      }
  
      if (s->references == NULL || s->references->next == NULL)  {
          printf("no ref or not enough refs: ");
          goto cleanup;
      }
  
      if (strcmp(s->references->key, "http://www.one.com") != 0 ||
          strcmp(s->references->reference, "openinfosecdoundation.txt") != 0) {
          printf("first ref failed: ");
          goto cleanup;
      }
  
      if (strcmp(s->references->next->key, "http://www.two.com") != 0 ||
          strcmp(s->references->next->reference, "001-2010") != 0) {
          printf("second ref failed: ");
          goto cleanup;
      }
  
      result = 1;
  
  cleanup:
      if (de_ctx != NULL) {
          DetectEngineCtxFree(de_ctx);
      }
      return result;
  }
  
  /**
   * \test parsing: invalid reference.
   *
   *  \retval 1 on succces.
   *  \retval 0 on failure.
   */
  static int DetectReferenceParseTest03(void)
  {
      int result = 0;
      Signature *s = NULL;
      DetectEngineCtx *de_ctx = DetectEngineCtxInit();
      if (de_ctx == NULL) {
          goto cleanup;
      }
      de_ctx->flags |= DE_QUIET;
  
      FILE *fd =SCRConfGenerateValidDummyReferenceConfigFD01();
      SCRConfLoadReferenceConfigFile(de_ctx, fd);
  
      s = de_ctx->sig_list = SigInit(de_ctx, "alert icmp any any -> any any "
                                     "(msg:\"invalid ref\"; "
                                     "reference:unknownkey,001-2010; sid:2;)");
      if (s != NULL) {
          printf("sig parsed even though it's invalid: ");
          goto cleanup;
      }
  
      result = 1;
  
  cleanup:
      if (de_ctx != NULL) {
          DetectEngineCtxFree(de_ctx);
      }
      return result;
  }
  
  #endif /* UNITTESTS */
  
  void ReferenceRegisterTests(void)
  {
  #ifdef UNITTESTS
      UtRegisterTest("DetectReferenceParseTest01", DetectReferenceParseTest01);
      UtRegisterTest("DetectReferenceParseTest02", DetectReferenceParseTest02);
      UtRegisterTest("DetectReferenceParseTest03", DetectReferenceParseTest03);
  #endif /* UNITTESTS */
  
      return;
  }
  