/**
* \brief This function is used to parse fileet
*
* \param str Pointer to the fileext value string
*
* \retval pointer to DetectFileextData on success
* \retval NULL on failure
*/
static DetectFileextData *DetectFileextParse (const char *str, bool negate)
{
DetectFileextData *fileext = NULL;
/* We have a correct filename option */
fileext = SCMalloc(sizeof(DetectFileextData));
if (unlikely(fileext == NULL))
goto error;
memset(fileext, 0x00, sizeof(DetectFileextData));
if (DetectContentDataParse("fileext", str, &fileext->ext, &fileext->len) == -1) {
goto error;
}
uint16_t u;
for (u = 0; u < fileext->len; u++)
fileext->ext[u] = tolower(fileext->ext[u]);
if (negate) {
fileext->flags |= DETECT_CONTENT_NEGATED;
}
SCLogDebug("flags %02X", fileext->flags);
if (fileext->flags & DETECT_CONTENT_NEGATED) {
SCLogDebug("negated fileext");
}
#ifdef DEBUG
if (SCLogDebugEnabled()) {
char *ext = SCMalloc(fileext->len + 1);
if (ext != NULL) {
memcpy(ext, fileext->ext, fileext->len);
ext[fileext->len] = '\0';
SCLogDebug("will look for fileext %s", ext);
}
}
#endif
return fileext;
error:
if (fileext != NULL)
DetectFileextFree(fileext);
return NULL;
}
/**
* \brief Parse the filename keyword
*
* \param idstr Pointer to the user provided option
*
* \retval filename pointer to DetectFilenameData on success
* \retval NULL on failure
*/
static DetectFilenameData *DetectFilenameParse (char *str)
{
DetectFilenameData *filename = NULL;
/* We have a correct filename option */
filename = SCMalloc(sizeof(DetectFilenameData));
if (unlikely(filename == NULL))
goto error;
memset(filename, 0x00, sizeof(DetectFilenameData));
if (DetectContentDataParse ("filename", str, &filename->name, &filename->len, &filename->flags) == -1) {
goto error;
}
filename->bm_ctx = BoyerMooreCtxInit(filename->name, filename->len);
if (filename->bm_ctx == NULL) {
goto error;
}
SCLogDebug("flags %02X", filename->flags);
if (filename->flags & DETECT_CONTENT_NEGATED) {
SCLogDebug("negated filename");
}
BoyerMooreCtxToNocase(filename->bm_ctx, filename->name, filename->len);
#ifdef DEBUG
if (SCLogDebugEnabled()) {
char *name = SCMalloc(filename->len + 1);
if (name != NULL) {
memcpy(name, filename->name, filename->len);
name[filename->len] = '\0';
SCLogDebug("will look for filename %s", name);
}
}
#endif
return filename;
error:
if (filename != NULL)
DetectFilenameFree(filename);
return NULL;
}
int DetectReplaceSetup(DetectEngineCtx *de_ctx, Signature *s, char *replacestr)
{
uint8_t *content = NULL;
uint16_t len = 0;
uint32_t flags = 0;
SigMatch *pm = NULL;
DetectContentData *ud = NULL;
int ret = DetectContentDataParse("replace", replacestr, &content, &len, &flags);
if (ret == -1)
goto error;
if (flags & DETECT_CONTENT_NEGATED) {
SCLogError(SC_ERR_INVALID_VALUE, "Can't negate replacement string: %s",
replacestr);
goto error;
}
switch (run_mode) {
case RUNMODE_NFQ:
case RUNMODE_IPFW:
break;
default:
SCLogWarning(SC_ERR_RUNMODE,
"Can't use 'replace' keyword in non IPS mode: %s",
s->sig_str);
/* this is a success, having the alert is interesting */
return 0;
}
/* add to the latest "content" keyword from either dmatch or pmatch */
pm = SigMatchGetLastSMFromLists(s, 2,
DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_PMATCH]);
if (pm == NULL) {
SCLogError(SC_ERR_WITHIN_MISSING_CONTENT, "replace needs"
"preceding content option for raw sig");
SCFree(content);
return -1;
}
/* we can remove this switch now with the unified structure */
ud = (DetectContentData *)pm->ctx;
if (ud == NULL) {
SCLogError(SC_ERR_INVALID_ARGUMENT, "invalid argument");
SCFree(content);
return -1;
}
if (ud->flags & DETECT_CONTENT_NEGATED) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "can't have a relative "
"negated keyword set along with a replacement");
goto error;
}
if (ud->content_len != len) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "can't have a content "
"length different from replace length");
goto error;
}
ud->replace = SCMalloc(len);
if (ud->replace == NULL) {
goto error;
}
memcpy(ud->replace, content, len);
ud->replace_len = len;
ud->flags |= DETECT_CONTENT_REPLACE;
/* want packet matching only won't be able to replace data with
* a flow.
*/
s->flags |= SIG_FLAG_REQUIRE_PACKET;
SCFree(content);
return 0;
error:
SCFree(content);
return -1;
}
static int DetectFlowvarSetup (DetectEngineCtx *de_ctx, Signature *s, char *rawstr)
{
DetectFlowvarData *fd = NULL;
SigMatch *sm = NULL;
char *varname = NULL, *varcontent = NULL;
#define MAX_SUBSTRINGS 30
int ret = 0, res = 0;
int ov[MAX_SUBSTRINGS];
const char *str_ptr;
uint8_t *content = NULL;
uint16_t contentlen = 0;
uint32_t contentflags = 0;
ret = pcre_exec(parse_regex, parse_regex_study, rawstr, strlen(rawstr), 0, 0, ov, MAX_SUBSTRINGS);
if (ret != 3) {
SCLogError(SC_ERR_PCRE_MATCH, "\"%s\" is not a valid setting for flowvar.", rawstr);
return -1;
}
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 1, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring failed");
return -1;
}
varname = (char *)str_ptr;
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 2, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring failed");
return -1;
}
varcontent = (char *)str_ptr;
res = DetectContentDataParse("flowvar", varcontent, &content, &contentlen, &contentflags);
if (res == -1)
goto error;
fd = SCMalloc(sizeof(DetectFlowvarData));
if (unlikely(fd == NULL))
goto error;
memset(fd, 0x00, sizeof(*fd));
fd->content = SCMalloc(contentlen);
if (unlikely(fd->content == NULL))
goto error;
memcpy(fd->content, content, contentlen);
fd->content_len = contentlen;
fd->flags = contentflags;
fd->name = SCStrdup(varname);
if (unlikely(fd->name == NULL))
goto error;
fd->idx = VariableNameGetIdx(de_ctx, varname, VAR_TYPE_FLOW_VAR);
/* Okay so far so good, lets get this into a SigMatch
* and put it in the Signature. */
sm = SigMatchAlloc();
if (unlikely(sm == NULL))
goto error;
sm->type = DETECT_FLOWVAR;
sm->ctx = (SigMatchCtx *)fd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
SCFree(content);
return 0;
error:
if (fd != NULL)
DetectFlowvarDataFree(fd);
if (sm != NULL)
SCFree(sm);
if (content != NULL)
SCFree(content);
return -1;
}
static int DetectPktvarSetup (DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
{
char *varname = NULL, *varcontent = NULL;
#define MAX_SUBSTRINGS 30
int ret = 0, res = 0;
int ov[MAX_SUBSTRINGS];
uint8_t *content = NULL;
uint16_t len = 0;
ret = pcre_exec(parse_regex, parse_regex_study, rawstr, strlen(rawstr), 0, 0, ov, MAX_SUBSTRINGS);
if (ret != 3) {
SCLogError(SC_ERR_PCRE_MATCH, "\"%s\" is not a valid setting for pktvar.", rawstr);
return -1;
}
const char *str_ptr;
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 1, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring failed");
return -1;
}
varname = (char *)str_ptr;
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 2, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_get_substring failed");
return -1;
}
varcontent = (char *)str_ptr;
SCLogDebug("varname '%s', varcontent '%s'", varname, varcontent);
char *parse_content;
if (strlen(varcontent) >= 2 && varcontent[0] == '"' &&
varcontent[strlen(varcontent) - 1] == '"')
{
parse_content = varcontent + 1;
varcontent[strlen(varcontent) - 1] = '\0';
} else {
parse_content = varcontent;
}
ret = DetectContentDataParse("pktvar", parse_content, &content, &len);
if (ret == -1 || content == NULL) {
pcre_free(varname);
pcre_free(varcontent);
return -1;
}
DetectPktvarData *cd = SCCalloc(1, sizeof(DetectPktvarData));
if (unlikely(cd == NULL)) {
pcre_free(varname);
pcre_free(varcontent);
SCFree(content);
return -1;
}
cd->content = content;
cd->content_len = len;
cd->id = VarNameStoreSetupAdd(varname, VAR_TYPE_PKT_VAR);
pcre_free(varname);
pcre_free(varcontent);
/* Okay so far so good, lets get this into a SigMatch
* and put it in the Signature. */
SigMatch *sm = SigMatchAlloc();
if (unlikely(sm == NULL)) {
SCFree(cd->content);
SCFree(cd);
return -1;
}
sm->type = DETECT_PKTVAR;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
}