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suricata/src/detect-ftp-command-data.c

116 lines
3.6 KiB
C

/* Copyright (C) 2025 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.
*/
/**
*
* \author Jeff Lucovsky <jlucovsky@oisf.net>
*
* Implements the ftp.command_data sticky buffer
*
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-buffer.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-helper.h"
#include "detect-content.h"
#include "flow.h"
#include "util-debug.h"
#include "app-layer.h"
#include "app-layer-ftp.h"
#include "detect-ftp-command-data.h"
#define KEYWORD_NAME "ftp.command_data"
#define KEYWORD_DOC "ftp-keywords.html#ftp-command_data"
#define BUFFER_NAME "ftp.command_data"
#define BUFFER_DESC "ftp command_data"
static int g_ftp_cmd_data_buffer_id = 0;
static int DetectFtpCommandDataSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
if (SCDetectBufferSetActiveList(de_ctx, s, g_ftp_cmd_data_buffer_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_FTP) < 0)
return -1;
return 0;
}
static bool DetectFTPCommandDataGetData(
void *txv, const uint8_t _flow_flags, const uint8_t **buffer, uint32_t *buffer_len)
{
FTPTransaction *tx = (FTPTransaction *)txv;
if (tx->command_descriptor.command_code == FTP_COMMAND_UNKNOWN)
return false;
const char *b;
uint8_t b_len;
if (SCGetFtpCommandInfo(tx->command_descriptor.command_index, &b, NULL, &b_len)) {
if ((tx->request_length - b_len - 1) > 0) {
// command data starts here: advance past command + 1 space
*buffer = tx->request + b_len + 1;
*buffer_len = tx->request_length - b_len - 1;
SCLogDebug("command data: \"%s\" [bytes %d]", *buffer, *buffer_len);
return true;
}
}
*buffer = NULL;
*buffer_len = 0;
return false;
}
static InspectionBuffer *GetDataWrapper(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
const int list_id)
{
return DetectHelperGetData(
det_ctx, transforms, _f, _flow_flags, txv, list_id, DetectFTPCommandDataGetData);
}
void DetectFtpCommandDataRegister(void)
{
/* ftp.command sticky buffer */
sigmatch_table[DETECT_FTP_COMMAND_DATA].name = KEYWORD_NAME;
sigmatch_table[DETECT_FTP_COMMAND_DATA].desc =
"sticky buffer to match on the FTP command data buffer";
sigmatch_table[DETECT_FTP_COMMAND_DATA].url = "/rules/" KEYWORD_DOC;
sigmatch_table[DETECT_FTP_COMMAND_DATA].Setup = DetectFtpCommandDataSetup;
sigmatch_table[DETECT_FTP_COMMAND_DATA].flags |= SIGMATCH_NOOPT;
DetectHelperBufferMpmRegister(
BUFFER_NAME, BUFFER_NAME, ALPROTO_FTP, STREAM_TOSERVER, GetDataWrapper);
DetectBufferTypeSetDescriptionByName(BUFFER_NAME, BUFFER_DESC);
g_ftp_cmd_data_buffer_id = DetectBufferTypeGetByName(BUFFER_NAME);
SCLogDebug("registering " BUFFER_NAME " rule option");
}