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Initial implementation of filemagic keyword.

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remotes/origin/master-1.2.x
Victor Julien 15 years ago
parent f4a6f4b293
commit 5945e652d6
8 changed files with 414 additions and 1 deletions
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1
src/Makefile.am
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@ -154,6 +154,7 @@ detect-asn1.c detect-asn1.h \
detect-filename.c detect-filename.h \
detect-fileext.c detect-fileext.h \
detect-filestore.c detect-filestore.h \
detect-filemagic.c detect-filemagic.h \
detect-http-stat-code.c detect-http-stat-code.h \
detect-ssl-version.c detect-ssl-version.h \
detect-ssl-state.c detect-ssl-state.h \

6
src/detect-engine-file.c
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@ -104,6 +104,12 @@ static int DetectFileInspect(ThreadVars *tv, DetectEngineThreadCtx *det_ctx, Flo
break;
}
if (s->file_flags & FILE_SIG_NEED_FILECONTENT && file->chunks_head == NULL) {
SCLogDebug("sig needs file content, but we don't have any");
r = 0;
break;
}
/* run the file match functions. */
for (sm = s->sm_lists[DETECT_SM_LIST_FILEMATCH]; sm != NULL; sm = sm->next) {
SCLogDebug("sm %p, sm->next %p", sm, sm->next);

363
src/detect-filemagic.c
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@ -0,0 +1,363 @@
/* Copyright (C) 2007-2011 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 Victor Julien <victor@inliniac.net>
*
*/
#include "suricata-common.h"
#include "threads.h"
#include "debug.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-state.h"
#include "flow.h"
#include "flow-var.h"
#include "flow-util.h"
#include "util-debug.h"
#include "util-spm-bm.h"
#include "util-magic.h"
#include "util-unittest.h"
#include "util-unittest-helper.h"
#include "app-layer.h"
#include "stream-tcp.h"
#include "detect-filemagic.h"
int DetectFilemagicMatch (ThreadVars *, DetectEngineThreadCtx *, Flow *, uint8_t, void *, Signature *, SigMatch *);
static int DetectFilemagicSetup (DetectEngineCtx *, Signature *, char *);
void DetectFilemagicRegisterTests(void);
void DetectFilemagicFree(void *);
/**
* \brief Registration function for keyword: filemagic
*/
void DetectFilemagicRegister(void) {
sigmatch_table[DETECT_FILEMAGIC].name = "filemagic";
sigmatch_table[DETECT_FILEMAGIC].Match = NULL;
sigmatch_table[DETECT_FILEMAGIC].AppLayerMatch = DetectFilemagicMatch;
sigmatch_table[DETECT_FILEMAGIC].alproto = ALPROTO_HTTP;
sigmatch_table[DETECT_FILEMAGIC].Setup = DetectFilemagicSetup;
sigmatch_table[DETECT_FILEMAGIC].Free = DetectFilemagicFree;
sigmatch_table[DETECT_FILEMAGIC].RegisterTests = DetectFilemagicRegisterTests;
SCLogDebug("registering filemagic rule option");
return;
}
#define FILEMAGIC_MIN_SIZE 512
/**
* \brief run the magic check
*
* \param file the file
*
* \retval -1 error
* \retval 0 ok
*/
static int FilemagicLookup(FlowFile *file) {
if (file == NULL || file->chunks_head == NULL) {
SCReturnInt(-1);
}
if (file->chunks_head->len >= FILEMAGIC_MIN_SIZE) {
file->magic = MagicLookup(file->chunks_head->data, FILEMAGIC_MIN_SIZE);
} else {
uint8_t *buf = SCMalloc(FILEMAGIC_MIN_SIZE);
uint32_t size = 0;
if (buf != NULL) {
FlowFileData *ffd = file->chunks_head;
for ( ; ffd != NULL; ffd = ffd->next) {
uint32_t copy_len = ffd->len;
if (size + ffd->len > FILEMAGIC_MIN_SIZE)
copy_len = FILEMAGIC_MIN_SIZE - size;
memcpy(buf + size, ffd->data, copy_len);
size += copy_len;
if (size >= FILEMAGIC_MIN_SIZE) {
file->magic = MagicLookup(buf, size);
break;
}
/* file is done but smaller than FILEMAGIC_MIN_SIZE */
if (ffd->next == NULL && file->state >= FLOWFILE_STATE_CLOSED) {
file->magic = MagicLookup(buf, size);
break;
}
}
SCFree(buf);
}
}
SCReturnInt(0);
}
/**
* \brief match the specified filemagic
*
* \param t pointer to thread vars
* \param det_ctx pointer to the pattern matcher thread
* \param p pointer to the current packet
* \param m pointer to the sigmatch that we will cast into DetectFilemagicData
*
* \retval 0 no match
* \retval 1 match
*/
int DetectFilemagicMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags, void *state, Signature *s, SigMatch *m)
{
SCEnter();
int ret = 0;
DetectFilemagicData *filemagic = m->ctx;
FlowFile *file = (FlowFile *)state;
if (file->txid < det_ctx->tx_id)
SCReturnInt(0);
if (file->txid > det_ctx->tx_id)
SCReturnInt(0);
if (file->magic == NULL) {
FilemagicLookup(file);
}
if (file->magic != NULL) {
SCLogDebug("magic %s", file->magic);
if (BoyerMooreNocase(filemagic->name, filemagic->len, (uint8_t *)file->magic,
strlen(file->magic), filemagic->bm_ctx->bmGs,
filemagic->bm_ctx->bmBc) != NULL)
{
#ifdef DEBUG
if (SCLogDebugEnabled()) {
char *name = SCMalloc(filemagic->len + 1);
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;
}
}
if (ret == 0 && filemagic->flags & DETECT_CONTENT_NEGATED) {
SCLogDebug("negated match");
ret = 1;
}
}
SCReturnInt(ret);
}
/**
* \brief Parse the filemagic keyword
*
* \param idstr Pointer to the user provided option
*
* \retval filemagic pointer to DetectFilemagicData on success
* \retval NULL on failure
*/
DetectFilemagicData *DetectFilemagicParse (char *str)
{
DetectFilemagicData *filemagic = NULL;
/* We have a correct filemagic option */
filemagic = SCMalloc(sizeof(DetectFilemagicData));
if (filemagic == NULL)
goto error;
memset(filemagic, 0x00, sizeof(DetectFilemagicData));
if (DetectParseContentString (str, &filemagic->name, &filemagic->len, &filemagic->flags) == -1) {
goto error;
}
filemagic->bm_ctx = BoyerMooreCtxInit(filemagic->name, filemagic->len);
if (filemagic->bm_ctx == NULL) {
goto error;
}
SCLogDebug("flags %02X", filemagic->flags);
if (filemagic->flags & DETECT_CONTENT_NEGATED) {
SCLogDebug("negated filemagic");
}
BoyerMooreCtxToNocase(filemagic->bm_ctx, filemagic->name, filemagic->len);
#ifdef DEBUG
if (SCLogDebugEnabled()) {
char *name = SCMalloc(filemagic->len + 1);
memcpy(name, filemagic->name, filemagic->len);
name[filemagic->len] = '\0';
SCLogDebug("will look for filemagic %s", name);
}
#endif
return filemagic;
error:
if (filemagic != NULL)
DetectFilemagicFree(filemagic);
return NULL;
}
/**
* \brief this function is used to parse filemagic options
* \brief into the current signature
*
* \param de_ctx pointer to the Detection Engine Context
* \param s pointer to the Current Signature
* \param str pointer to the user provided "filemagic" option
*
* \retval 0 on Success
* \retval -1 on Failure
*/
static int DetectFilemagicSetup (DetectEngineCtx *de_ctx, Signature *s, char *str)
{
DetectFilemagicData *filemagic = NULL;
SigMatch *sm = NULL;
filemagic = DetectFilemagicParse(str);
if (filemagic == NULL)
goto error;
/* Okay so far so good, lets get this into a SigMatch
* and put it in the Signature. */
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_FILEMAGIC;
sm->ctx = (void *)filemagic;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_FILEMATCH);
if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_HTTP) {
SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains conflicting keywords.");
goto error;
}
AppLayerHtpNeedFileInspection();
s->alproto = ALPROTO_HTTP;
s->file_flags |= (FILE_SIG_NEED_FILE|FILE_SIG_NEED_FILECONTENT);
return 0;
error:
if (filemagic != NULL)
DetectFilemagicFree(filemagic);
if (sm != NULL)
SCFree(sm);
return -1;
}
/**
* \brief this function will free memory associated with DetectFilemagicData
*
* \param filemagic pointer to DetectFilemagicData
*/
void DetectFilemagicFree(void *ptr) {
if (ptr != NULL) {
DetectFilemagicData *filemagic = (DetectFilemagicData *)ptr;
if (filemagic->bm_ctx != NULL) {
BoyerMooreCtxDeInit(filemagic->bm_ctx);
}
SCFree(filemagic);
}
}
#ifdef UNITTESTS /* UNITTESTS */
/**
* \test DetectFilemagicTestParse01
*/
int DetectFilemagicTestParse01 (void) {
DetectFilemagicData *dnd = DetectFilemagicParse("secret.pdf");
if (dnd != NULL) {
DetectFilemagicFree(dnd);
return 1;
}
return 0;
}
/**
* \test DetectFilemagicTestParse02
*/
int DetectFilemagicTestParse02 (void) {
int result = 0;
DetectFilemagicData *dnd = DetectFilemagicParse("\"backup.tar.gz\"");
if (dnd != NULL) {
if (dnd->len == 13 && memcmp(dnd->name, "backup.tar.gz", 13) == 0) {
result = 1;
}
DetectFilemagicFree(dnd);
return result;
}
return 0;
}
/**
* \test DetectFilemagicTestParse03
*/
int DetectFilemagicTestParse03 (void) {
int result = 0;
DetectFilemagicData *dnd = DetectFilemagicParse("cmd.exe");
if (dnd != NULL) {
if (dnd->len == 7 && memcmp(dnd->name, "cmd.exe", 7) == 0) {
result = 1;
}
DetectFilemagicFree(dnd);
return result;
}
return 0;
}
#endif /* UNITTESTS */
/**
* \brief this function registers unit tests for DetectFilemagic
*/
void DetectFilemagicRegisterTests(void) {
#ifdef UNITTESTS /* UNITTESTS */
UtRegisterTest("DetectFilemagicTestParse01", DetectFilemagicTestParse01, 1);
UtRegisterTest("DetectFilemagicTestParse02", DetectFilemagicTestParse02, 1);
UtRegisterTest("DetectFilemagicTestParse03", DetectFilemagicTestParse03, 1);
#endif /* UNITTESTS */
}

39
src/detect-filemagic.h
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@ -0,0 +1,39 @@
/* Copyright (C) 2007-2011 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 Victor Julien <victor@inliniac.net>
*/
#ifndef __DETECT_FILEMAGIC_H__
#define __DETECT_FILEMAGIC_H__
#include "util-spm-bm.h"
typedef struct DetectFilemagicData {
uint8_t *name; /** name of the file to match */
BmCtx *bm_ctx; /** BM context */
uint16_t len; /** name length */
uint32_t flags;
} DetectFilemagicData;
/* prototypes */
void DetectFilemagicRegister (void);
#endif /* __DETECT_FILEMAGIC_H__ */

2
src/detect-filename.c
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@ -1,4 +1,4 @@
/* Copyright (C) 2007-2010 Open Information Security Foundation
/* Copyright (C) 2007-2011 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

2
src/detect.c
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@ -93,6 +93,7 @@
#include "detect-filename.h"
#include "detect-fileext.h"
#include "detect-filestore.h"
#include "detect-filemagic.h"
#include "detect-dsize.h"
#include "detect-flowvar.h"
#include "detect-flowint.h"
@ -4333,6 +4334,7 @@ void SigTableSetup(void) {
DetectFilenameRegister();
DetectFileextRegister();
DetectFilestoreRegister();
DetectFilemagicRegister();
uint8_t i = 0;
for (i = 0; i < DETECT_TBLSIZE; i++) {

1
src/detect.h
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@ -1042,6 +1042,7 @@ enum {
DETECT_FILENAME,
DETECT_FILEEXT,
DETECT_FILESTORE,
DETECT_FILEMAGIC,
/* make sure this stays last */
DETECT_TBLSIZE,

1
src/flow-file.h
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@ -58,6 +58,7 @@ typedef struct FlowFile_ {
uint16_t name_len;
int16_t state;
int fd; /**< file discriptor for storing files */
const char *magic;
FlowFileData *chunks_head;
FlowFileData *chunks_tail;
struct FlowFile_ *next;

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