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/* Copyright (C) 2021-2022 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
*/
#include "suricata-common.h"
#include "threads.h"
#include "decode.h"
#include "detect.h"
#include "app-layer-frames.h"
#include "app-layer-parser.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-content.h"
#include "detect-engine-content-inspection.h"
#include "detect-frame.h"
#include "flow.h"
#include "flow-util.h"
#include "flow-var.h"
#include "conf.h"
#include "conf-yaml-loader.h"
#include "util-debug.h"
#include "util-unittest.h"
#include "util-spm.h"
#include "util-print.h"
static int DetectFrameSetup(DetectEngineCtx *, Signature *, const char *);
/**
* \brief this function setup the sticky buffer used in the rule
*
* \param de_ctx Pointer to the Detection Engine Context
* \param s Pointer to the Signature to which the current keyword belongs
* \param str The frame name. Can be short name 'pdu' or full name 'sip.pdu'
*
* \retval 0 On success
* \retval -1 On failure
*/
static int DetectFrameSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
char value[256] = "";
strlcpy(value, str, sizeof(value));
char buffer_name[512] = ""; // for registering in detect API we always need <proto>.<frame>.
const bool is_tcp = DetectProtoContainsProto(&s->proto, IPPROTO_TCP);
const bool is_udp = DetectProtoContainsProto(&s->proto, IPPROTO_UDP);
if (!(is_tcp || is_udp)) {
SCLogError("'frame' keyword only supported for TCP and UDP");
return -1;
}
char *dot = strchr(value, '.');
if (dot != NULL)
*dot++ = '\0';
const char *val = dot ? dot : value;
const char *proto = dot ? value : NULL;
bool is_short = false;
AppProto keyword_alproto = ALPROTO_UNKNOWN;
AppProto rule_alproto = s->alproto;
if (proto != NULL) {
keyword_alproto = StringToAppProto(proto);
if (!AppProtoIsValid(keyword_alproto)) {
is_short = true;
keyword_alproto = rule_alproto;
}
} else {
is_short = true;
keyword_alproto = rule_alproto;
}
if (is_short && rule_alproto == ALPROTO_UNKNOWN) {
SCLogError("rule protocol unknown, can't use shorthand notation for frame '%s'", str);
return -1;
} else if (rule_alproto == ALPROTO_UNKNOWN) {
if (DetectSignatureSetAppProto(s, keyword_alproto) < 0)
return -1;
} else if (!AppProtoEquals(rule_alproto, keyword_alproto)) {
SCLogError("frame '%s' protocol '%s' mismatch with rule protocol '%s'", str,
AppProtoToString(keyword_alproto), AppProtoToString(s->alproto));
return -1;
}
const char *frame_str = is_short ? str : val;
int raw_frame_type = -1;
if (is_tcp) {
if (strcmp(frame_str, "stream") == 0) {
raw_frame_type = FRAME_STREAM_TYPE;
} else {
raw_frame_type =
AppLayerParserGetFrameIdByName(IPPROTO_TCP, keyword_alproto, frame_str);
}
}
if (is_udp && raw_frame_type < 0)
raw_frame_type = AppLayerParserGetFrameIdByName(IPPROTO_UDP, keyword_alproto, frame_str);
if (raw_frame_type < 0) {
SCLogError("unknown frame '%s' for protocol '%s'", frame_str, proto);
return -1;
}
BUG_ON(raw_frame_type > UINT8_MAX);
if (is_short) {
snprintf(buffer_name, sizeof(buffer_name), "%s.%s", AppProtoToString(s->alproto), str);
SCLogDebug("short name: %s", buffer_name);
} else {
strlcpy(buffer_name, str, sizeof(buffer_name));
SCLogDebug("long name: %s", buffer_name);
}
uint8_t frame_type = (uint8_t)raw_frame_type;
/* TODO we can have TS and TC specific frames */
const int buffer_id = DetectEngineBufferTypeRegisterWithFrameEngines(de_ctx, buffer_name,
SIG_FLAG_TOSERVER | SIG_FLAG_TOCLIENT, keyword_alproto, frame_type);
if (buffer_id < 0)
return -1;
if (DetectBufferSetActiveList(de_ctx, s, buffer_id) < 0)
return -1;
FrameConfigEnable(keyword_alproto, frame_type);
return 0;
}
#ifdef UNITTESTS
static int DetectFrameTestBadRules(void)
{
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
FAIL_IF_NULL(de_ctx);
const char *sigs[] = {
"alert tcp-pkt any any -> any any (frame:tls.pdu; content:\"a\"; sid:1;)",
"alert udp any any -> any any (frame:tls.pdu; content:\"a\"; sid:2;)",
"alert smb any any -> any any (frame:tls.pdu; content:\"a\"; sid:3;)",
"alert tcp any any -> any any (frame:tls; content:\"a\"; sid:4;)",
"alert tls any any -> any any (content:\"abc\"; frame:tls.pdu; content:\"a\"; sid:5;)",
"alert tls any any -> any any (tls.version:1.0; frame:tls.pdu; content:\"a\"; sid:6;)",
"alert tls any any -> any any (frame:smb1.pdu; content:\"a\"; sid:7;)",
NULL,
};
const char **sig = sigs;
while (*sig) {
SCLogDebug("sig %s", *sig);
Signature *s = DetectEngineAppendSig(de_ctx, *sig);
FAIL_IF_NOT_NULL(s);
sig++;
}
DetectEngineCtxFree(de_ctx);
PASS;
}
static void DetectFrameRegisterTests(void)
{
UtRegisterTest("DetectFrameTestBadRules", DetectFrameTestBadRules);
}
#endif
/**
* \brief Registration function for keyword: ja3_hash
*/
void DetectFrameRegister(void)
{
sigmatch_table[DETECT_FRAME].name = "frame";
sigmatch_table[DETECT_FRAME].desc = "sticky buffer for inspecting app-layer frames";
sigmatch_table[DETECT_FRAME].Setup = DetectFrameSetup;
sigmatch_table[DETECT_FRAME].flags = SIGMATCH_INFO_STICKY_BUFFER;
#ifdef UNITTESTS
sigmatch_table[DETECT_FRAME].RegisterTests = DetectFrameRegisterTests;
#endif
}
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