/**
* \brief match the specified filemagic
*
* \param t thread local vars
* \param det_ctx pattern matcher thread local data
* \param f *LOCKED* flow
* \param flags direction flags
* \param file file being inspected
* \param s signature being inspected
* \param m sigmatch that we will cast into DetectFilemagicData
*
* \retval 0 no match
* \retval 1 match
*/
static int DetectFilemagicMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx,
Flow *f, uint8_t flags, File *file, Signature *s, SigMatch *m)
{
SCEnter();
int ret = 0;
DetectFilemagicData *filemagic = (DetectFilemagicData *)m->ctx;
if (file->txid < det_ctx->tx_id)
SCReturnInt(0);
if (file->txid > det_ctx->tx_id)
SCReturnInt(0);
DetectFilemagicThreadData *tfilemagic = (DetectFilemagicThreadData *)DetectThreadCtxGetKeywordThreadCtx(det_ctx, filemagic->thread_ctx_id);
if (tfilemagic == NULL) {
SCReturnInt(0);
}
if (file->magic == NULL) {
FilemagicThreadLookup(&tfilemagic->ctx, file);
}
if (file->magic != NULL) {
SCLogDebug("magic %s", file->magic);
/* we include the \0 in the inspection, so patterns can match on the
* end of the string. */
if (BoyerMooreNocase(filemagic->name, filemagic->len, (uint8_t *)file->magic,
strlen(file->magic) + 1, filemagic->bm_ctx) != NULL)
{
#ifdef DEBUG
if (SCLogDebugEnabled()) {
char *name = SCMalloc(filemagic->len + 1);
if (name != NULL) {
memcpy(name, filemagic->name, filemagic->len);
name[filemagic->len] = '\0';
SCLogDebug("will look for filemagic %s", name);
}
}
#endif
if (!(filemagic->flags & DETECT_CONTENT_NEGATED)) {
ret = 1;
}
} else if (filemagic->flags & DETECT_CONTENT_NEGATED) {
SCLogDebug("negated match");
ret = 1;
}
}
SCReturnInt(ret);
}
/**
* \brief match the specified filename
*
* \param t thread local vars
* \param det_ctx pattern matcher thread local data
* \param f *LOCKED* flow
* \param flags direction flags
* \param file file being inspected
* \param s signature being inspected
* \param m sigmatch that we will cast into DetectFilenameData
*
* \retval 0 no match
* \retval 1 match
*/
static int DetectFilenameMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx,
Flow *f, uint8_t flags, File *file, Signature *s, SigMatch *m)
{
SCEnter();
int ret = 0;
DetectFilenameData *filename = m->ctx;
if (file->name == NULL)
SCReturnInt(0);
if (file->txid < det_ctx->tx_id)
SCReturnInt(0);
if (file->txid > det_ctx->tx_id)
SCReturnInt(0);
if (BoyerMooreNocase(filename->name, filename->len, file->name,
file->name_len, filename->bm_ctx->bmGs,
filename->bm_ctx->bmBc) != NULL)
{
#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
if (!(filename->flags & DETECT_CONTENT_NEGATED)) {
ret = 1;
}
}
if (ret == 0 && (filename->flags & DETECT_CONTENT_NEGATED)) {
SCLogDebug("negated match");
ret = 1;
}
SCReturnInt(ret);
}
/**
* \brief Run the actual payload match functions
*
* The following keywords are inspected:
* - content, including all the http and dce modified contents
* - isdaatat
* - pcre
* - bytejump
* - bytetest
* - byte_extract
* - urilen
* -
*
* All keywords are evaluated against the buffer with buffer_len.
*
* For accounting the last match in relative matching the
* det_ctx->buffer_offset int is used.
*
* \param de_ctx Detection engine context
* \param det_ctx Detection engine thread context
* \param s Signature to inspect
* \param sm SigMatch to inspect
* \param f Flow (for pcre flowvar storage)
* \param buffer Ptr to the buffer to inspect
* \param buffer_len Length of the payload
* \param stream_start_offset Indicates the start of the current buffer in
* the whole buffer stream inspected. This
* applies if the current buffer is inspected
* in chunks.
* \param inspection_mode Refers to the engine inspection mode we are currently
* inspecting. Can be payload, stream, one of the http
* buffer inspection modes or dce inspection mode.
* \param data Used to send some custom data. For example in
* payload inspection mode, data contains packet ptr,
* and under dce inspection mode, contains dce state.
*
* \retval 0 no match
* \retval 1 match
*/
int DetectEngineContentInspection(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
Signature *s, SigMatch *sm,
Flow *f,
uint8_t *buffer, uint32_t buffer_len,
uint32_t stream_start_offset,
uint8_t inspection_mode, void *data)
{
SCEnter();
KEYWORD_PROFILING_START;
det_ctx->inspection_recursion_counter++;
if (det_ctx->inspection_recursion_counter == de_ctx->inspection_recursion_limit) {
det_ctx->discontinue_matching = 1;
KEYWORD_PROFILING_END(det_ctx, sm->type, 0);
SCReturnInt(0);
}
if (sm == NULL || buffer_len == 0) {
KEYWORD_PROFILING_END(det_ctx, sm->type, 0);
SCReturnInt(0);
}
/* \todo unify this which is phase 2 of payload inspection unification */
if (sm->type == DETECT_CONTENT) {
DetectContentData *cd = (DetectContentData *)sm->ctx;
SCLogDebug("inspecting content %"PRIu32" buffer_len %"PRIu32, cd->id, buffer_len);
/* we might have already have this content matched by the mpm.
* (if there is any other reason why we'd want to avoid checking
* it here, please fill it in) */
//if (cd->flags & DETECT_CONTENT_NO_DOUBLE_INSPECTION_REQUIRED) {
// goto match;
//}
/* rule parsers should take care of this */
#ifdef DEBUG
BUG_ON(cd->depth != 0 && cd->depth <= cd->offset);
#endif
/* search for our pattern, checking the matches recursively.
* if we match we look for the next SigMatch as well */
uint8_t *found = NULL;
uint32_t offset = 0;
uint32_t depth = buffer_len;
uint32_t prev_offset = 0; /**< used in recursive searching */
uint32_t prev_buffer_offset = det_ctx->buffer_offset;
do {
if ((cd->flags & DETECT_CONTENT_DISTANCE) ||
(cd->flags & DETECT_CONTENT_WITHIN)) {
SCLogDebug("det_ctx->buffer_offset %"PRIu32, det_ctx->buffer_offset);
offset = prev_buffer_offset;
depth = buffer_len;
int distance = cd->distance;
if (cd->flags & DETECT_CONTENT_DISTANCE) {
if (cd->flags & DETECT_CONTENT_DISTANCE_BE) {
distance = det_ctx->bj_values[cd->distance];
}
if (distance < 0 && (uint32_t)(abs(distance)) > offset)
offset = 0;
else
offset += distance;
SCLogDebug("cd->distance %"PRIi32", offset %"PRIu32", depth %"PRIu32,
distance, offset, depth);
}
if (cd->flags & DETECT_CONTENT_WITHIN) {
if (cd->flags & DETECT_CONTENT_WITHIN_BE) {
if ((int32_t)depth > (int32_t)(prev_buffer_offset + det_ctx->bj_values[cd->within] + distance)) {
depth = prev_buffer_offset + det_ctx->bj_values[cd->within] + distance;
}
} else {
if ((int32_t)depth > (int32_t)(prev_buffer_offset + cd->within + distance)) {
depth = prev_buffer_offset + cd->within + distance;
}
SCLogDebug("cd->within %"PRIi32", det_ctx->buffer_offset %"PRIu32", depth %"PRIu32,
cd->within, prev_buffer_offset, depth);
}
if (stream_start_offset != 0 && prev_buffer_offset == 0) {
if (depth <= stream_start_offset) {
goto no_match;
} else if (depth >= (stream_start_offset + buffer_len)) {
;
} else {
depth = depth - stream_start_offset;
}
}
}
if (cd->flags & DETECT_CONTENT_DEPTH_BE) {
if ((det_ctx->bj_values[cd->depth] + prev_buffer_offset) < depth) {
depth = prev_buffer_offset + det_ctx->bj_values[cd->depth];
}
} else {
if (cd->depth != 0) {
if ((cd->depth + prev_buffer_offset) < depth) {
depth = prev_buffer_offset + cd->depth;
}
SCLogDebug("cd->depth %"PRIu32", depth %"PRIu32, cd->depth, depth);
}
}
if (cd->flags & DETECT_CONTENT_OFFSET_BE) {
if (det_ctx->bj_values[cd->offset] > offset)
offset = det_ctx->bj_values[cd->offset];
} else {
if (cd->offset > offset) {
offset = cd->offset;
SCLogDebug("setting offset %"PRIu32, offset);
}
}
} else { /* implied no relative matches */
/* set depth */
if (cd->flags & DETECT_CONTENT_DEPTH_BE) {
depth = det_ctx->bj_values[cd->depth];
} else {
if (cd->depth != 0) {
depth = cd->depth;
}
}
if (stream_start_offset != 0 && cd->flags & DETECT_CONTENT_DEPTH) {
if (depth <= stream_start_offset) {
goto no_match;
} else if (depth >= (stream_start_offset + buffer_len)) {
;
} else {
depth = depth - stream_start_offset;
}
}
/* set offset */
if (cd->flags & DETECT_CONTENT_OFFSET_BE)
offset = det_ctx->bj_values[cd->offset];
else
offset = cd->offset;
prev_buffer_offset = 0;
}
/* update offset with prev_offset if we're searching for
* matches after the first occurence. */
SCLogDebug("offset %"PRIu32", prev_offset %"PRIu32, offset, prev_offset);
if (prev_offset != 0)
offset = prev_offset;
SCLogDebug("offset %"PRIu32", depth %"PRIu32, offset, depth);
if (depth > buffer_len)
depth = buffer_len;
/* if offset is bigger than depth we can never match on a pattern.
* We can however, "match" on a negated pattern. */
if (offset > depth || depth == 0) {
if (cd->flags & DETECT_CONTENT_NEGATED) {
goto match;
} else {
goto no_match;
}
}
uint8_t *sbuffer = buffer + offset;
uint32_t sbuffer_len = depth - offset;
uint32_t match_offset = 0;
SCLogDebug("sbuffer_len %"PRIu32, sbuffer_len);
#ifdef DEBUG
BUG_ON(sbuffer_len > buffer_len);
#endif
/* \todo Add another optimization here. If cd->content_len is
* greater than sbuffer_len found is anyways NULL */
/* do the actual search */
if (cd->flags & DETECT_CONTENT_NOCASE)
found = BoyerMooreNocase(cd->content, cd->content_len, sbuffer, sbuffer_len, cd->bm_ctx->bmGs, cd->bm_ctx->bmBc);
else
found = BoyerMoore(cd->content, cd->content_len, sbuffer, sbuffer_len, cd->bm_ctx->bmGs, cd->bm_ctx->bmBc);
/* next we evaluate the result in combination with the
* negation flag. */
SCLogDebug("found %p cd negated %s", found, cd->flags & DETECT_CONTENT_NEGATED ? "true" : "false");
if (found == NULL && !(cd->flags & DETECT_CONTENT_NEGATED)) {
goto no_match;
} else if (found == NULL && (cd->flags & DETECT_CONTENT_NEGATED)) {
goto match;
} else if (found != NULL && (cd->flags & DETECT_CONTENT_NEGATED)) {
SCLogDebug("content %"PRIu32" matched at offset %"PRIu32", but negated so no match", cd->id, match_offset);
/* don't bother carrying recursive matches now, for preceding
* relative keywords */
if (DETECT_CONTENT_IS_SINGLE(cd))
det_ctx->discontinue_matching = 1;
goto no_match;
} else {
match_offset = (uint32_t)((found - buffer) + cd->content_len);
SCLogDebug("content %"PRIu32" matched at offset %"PRIu32"", cd->id, match_offset);
det_ctx->buffer_offset = match_offset;
/* Match branch, add replace to the list if needed */
if (cd->flags & DETECT_CONTENT_REPLACE) {
if (inspection_mode == DETECT_ENGINE_CONTENT_INSPECTION_MODE_PAYLOAD) {
/* we will need to replace content if match is confirmed */
det_ctx->replist = DetectReplaceAddToList(det_ctx->replist, found, cd);
} else {
SCLogWarning(SC_ERR_INVALID_VALUE, "Can't modify payload without packet");
}
}
if (!(cd->flags & DETECT_CONTENT_RELATIVE_NEXT)) {
SCLogDebug("no relative match coming up, so this is a match");
goto match;
}
/* bail out if we have no next match. Technically this is an
* error, as the current cd has the DETECT_CONTENT_RELATIVE_NEXT
* flag set. */
if (sm->next == NULL) {
goto no_match;
}
SCLogDebug("content %"PRIu32, cd->id);
KEYWORD_PROFILING_END(det_ctx, sm->type, 1);
/* see if the next buffer keywords match. If not, we will
* search for another occurence of this content and see
* if the others match then until we run out of matches */
int r = DetectEngineContentInspection(de_ctx, det_ctx, s, sm->next, f, buffer, buffer_len, stream_start_offset, inspection_mode, data);
if (r == 1) {
SCReturnInt(1);
}
if (det_ctx->discontinue_matching)
goto no_match;
/* set the previous match offset to the start of this match + 1 */
prev_offset = (match_offset - (cd->content_len - 1));
SCLogDebug("trying to see if there is another match after prev_offset %"PRIu32, prev_offset);
}
} while(1);
} else if (sm->type == DETECT_ISDATAAT) {
SCLogDebug("inspecting isdataat");
DetectIsdataatData *id = (DetectIsdataatData *)sm->ctx;
if (id->flags & ISDATAAT_RELATIVE) {
if (det_ctx->buffer_offset + id->dataat > buffer_len) {
SCLogDebug("det_ctx->buffer_offset + id->dataat %"PRIu32" > %"PRIu32, det_ctx->buffer_offset + id->dataat, buffer_len);
if (id->flags & ISDATAAT_NEGATED)
goto match;
goto no_match;
} else {
SCLogDebug("relative isdataat match");
if (id->flags & ISDATAAT_NEGATED)
goto no_match;
goto match;
}
} else {
if (id->dataat < buffer_len) {
SCLogDebug("absolute isdataat match");
if (id->flags & ISDATAAT_NEGATED)
goto no_match;
goto match;
} else {
SCLogDebug("absolute isdataat mismatch, id->isdataat %"PRIu32", buffer_len %"PRIu32"", id->dataat, buffer_len);
if (id->flags & ISDATAAT_NEGATED)
goto match;
goto no_match;
}
}
} else if (sm->type == DETECT_PCRE) {
SCLogDebug("inspecting pcre");
DetectPcreData *pe = (DetectPcreData *)sm->ctx;
uint32_t prev_buffer_offset = det_ctx->buffer_offset;
uint32_t prev_offset = 0;
int r = 0;
det_ctx->pcre_match_start_offset = 0;
do {
Packet *p = NULL;
if (inspection_mode == DETECT_ENGINE_CONTENT_INSPECTION_MODE_PAYLOAD)
p = (Packet *)data;
r = DetectPcrePayloadMatch(det_ctx, s, sm, p, f,
buffer, buffer_len);
if (r == 0) {
goto no_match;
}
if (!(pe->flags & DETECT_PCRE_RELATIVE_NEXT)) {
SCLogDebug("no relative match coming up, so this is a match");
goto match;
}
KEYWORD_PROFILING_END(det_ctx, sm->type, 1);
/* save it, in case we need to do a pcre match once again */
prev_offset = det_ctx->pcre_match_start_offset;
/* see if the next payload keywords match. If not, we will
* search for another occurence of this pcre and see
* if the others match, until we run out of matches */
r = DetectEngineContentInspection(de_ctx, det_ctx, s, sm->next,
f, buffer, buffer_len, stream_start_offset, inspection_mode, data);
if (r == 1) {
SCReturnInt(1);
}
if (det_ctx->discontinue_matching)
goto no_match;
det_ctx->buffer_offset = prev_buffer_offset;
det_ctx->pcre_match_start_offset = prev_offset;
} while (1);
} else if (sm->type == DETECT_BYTETEST) {
DetectBytetestData *btd = (DetectBytetestData *)sm->ctx;
uint8_t flags = btd->flags;
int32_t offset = btd->offset;
uint64_t value = btd->value;
if (flags & DETECT_BYTETEST_OFFSET_BE) {
offset = det_ctx->bj_values[offset];
}
if (flags & DETECT_BYTETEST_VALUE_BE) {
value = det_ctx->bj_values[value];
}
/* if we have dce enabled we will have to use the endianness
* specified by the dce header */
if (flags & DETECT_BYTETEST_DCE) {
DCERPCState *dcerpc_state = (DCERPCState *)data;
/* enable the endianness flag temporarily. once we are done
* processing we reset the flags to the original value*/
flags |= ((dcerpc_state->dcerpc.dcerpchdr.packed_drep[0] & 0x10) ?
DETECT_BYTETEST_LITTLE: 0);
}
if (DetectBytetestDoMatch(det_ctx, s, sm, buffer, buffer_len, flags,
offset, value) != 1) {
goto no_match;
}
goto match;
} else if (sm->type == DETECT_BYTEJUMP) {
DetectBytejumpData *bjd = (DetectBytejumpData *)sm->ctx;
uint8_t flags = bjd->flags;
int32_t offset = bjd->offset;
if (flags & DETECT_BYTEJUMP_OFFSET_BE) {
offset = det_ctx->bj_values[offset];
}
/* if we have dce enabled we will have to use the endianness
* specified by the dce header */
if (flags & DETECT_BYTEJUMP_DCE) {
DCERPCState *dcerpc_state = (DCERPCState *)data;
/* enable the endianness flag temporarily. once we are done
* processing we reset the flags to the original value*/
flags |= ((dcerpc_state->dcerpc.dcerpchdr.packed_drep[0] & 0x10) ?
DETECT_BYTEJUMP_LITTLE: 0);
}
if (DetectBytejumpDoMatch(det_ctx, s, sm, buffer, buffer_len,
flags, offset) != 1) {
goto no_match;
}
goto match;
} else if (sm->type == DETECT_BYTE_EXTRACT) {
DetectByteExtractData *bed = (DetectByteExtractData *)sm->ctx;
uint8_t endian = bed->endian;
/* if we have dce enabled we will have to use the endianness
* specified by the dce header */
if ((bed->flags & DETECT_BYTE_EXTRACT_FLAG_ENDIAN) &&
endian == DETECT_BYTE_EXTRACT_ENDIAN_DCE) {
DCERPCState *dcerpc_state = (DCERPCState *)data;
/* enable the endianness flag temporarily. once we are done
* processing we reset the flags to the original value*/
endian |= ((dcerpc_state->dcerpc.dcerpchdr.packed_drep[0] == 0x10) ?
DETECT_BYTE_EXTRACT_ENDIAN_LITTLE : DETECT_BYTE_EXTRACT_ENDIAN_BIG);
}
if (DetectByteExtractDoMatch(det_ctx, sm, s, buffer,
buffer_len,
&det_ctx->bj_values[bed->local_id],
endian) != 1) {
goto no_match;
}
goto match;
/* we should never get here, but bail out just in case */
} else if (sm->type == DETECT_AL_URILEN) {
SCLogDebug("inspecting uri len");
int r = 0;
DetectUrilenData *urilend = (DetectUrilenData *) sm->ctx;
switch (urilend->mode) {
case DETECT_URILEN_EQ:
if (buffer_len == urilend->urilen1)
r = 1;
break;
case DETECT_URILEN_LT:
if (buffer_len < urilend->urilen1)
r = 1;
break;
case DETECT_URILEN_GT:
if (buffer_len > urilend->urilen1)
r = 1;
break;
case DETECT_URILEN_RA:
if (buffer_len > urilend->urilen1 &&
buffer_len < urilend->urilen2) {
r = 1;
}
break;
}
if (r == 1) {
goto match;
}
det_ctx->discontinue_matching = 0;
goto no_match;
#ifdef HAVE_LUAJIT
}
else if (sm->type == DETECT_LUAJIT) {
/* for flowvar gets and sets we need to know the flow's lock status */
int need_flow_lock = 0;
if (inspection_mode <= DETECT_ENGINE_CONTENT_INSPECTION_MODE_STREAM)
need_flow_lock = 1;
if (DetectLuajitMatchBuffer(det_ctx, s, sm, buffer, buffer_len,
det_ctx->buffer_offset, f, need_flow_lock) != 1)
{
goto no_match;
}
goto match;
#endif
} else {
SCLogDebug("sm->type %u", sm->type);
#ifdef DEBUG
BUG_ON(1);
#endif
}
no_match:
KEYWORD_PROFILING_END(det_ctx, sm->type, 0);
SCReturnInt(0);
match:
/* this sigmatch matched, inspect the next one. If it was the last,
* the buffer portion of the signature matched. */
if (sm->next != NULL) {
KEYWORD_PROFILING_END(det_ctx, sm->type, 1);
int r = DetectEngineContentInspection(de_ctx, det_ctx, s, sm->next, f, buffer, buffer_len, stream_start_offset, inspection_mode, data);
SCReturnInt(r);
} else {
KEYWORD_PROFILING_END(det_ctx, sm->type, 1);
SCReturnInt(1);
}
}
