nfqws: rewrite default split pos logic

nfqws: deprecate single split modes, optimize code
2024-11-26 12:10:53 +03:00 · 2024-11-13 13:34:34 +03:00 · 2024-11-13 11:54:40 +03:00
5 changed files with 107 additions and 147 deletions
--- a/nfq/desync.c
+++ b/nfq/desync.c
@ -97,11 +97,11 @@ bool desync_only_first_stage(enum dpi_desync_mode mode)
 }
 bool desync_valid_second_stage(enum dpi_desync_mode mode)
 {
-	return mode==DESYNC_NONE || mode==DESYNC_FAKEDDISORDER || mode==DESYNC_DISORDER2 || mode==DESYNC_FAKEDSPLIT || mode==DESYNC_SPLIT2 || mode==DESYNC_MULTISPLIT || mode==DESYNC_MULTIDISORDER || mode==DESYNC_IPFRAG2 || mode==DESYNC_UDPLEN || mode==DESYNC_TAMPER;
+	return mode==DESYNC_NONE || mode==DESYNC_FAKEDDISORDER || mode==DESYNC_FAKEDSPLIT || mode==DESYNC_MULTISPLIT || mode==DESYNC_MULTIDISORDER || mode==DESYNC_IPFRAG2 || mode==DESYNC_UDPLEN || mode==DESYNC_TAMPER;
 }
 bool desync_valid_second_stage_tcp(enum dpi_desync_mode mode)
 {
-	return mode==DESYNC_NONE || mode==DESYNC_FAKEDDISORDER || mode==DESYNC_DISORDER2 || mode==DESYNC_FAKEDSPLIT || mode==DESYNC_SPLIT2 || mode==DESYNC_MULTISPLIT || mode==DESYNC_MULTIDISORDER || mode==DESYNC_IPFRAG2;
+	return mode==DESYNC_NONE || mode==DESYNC_FAKEDDISORDER || mode==DESYNC_FAKEDSPLIT || mode==DESYNC_MULTISPLIT || mode==DESYNC_MULTIDISORDER || mode==DESYNC_IPFRAG2;
 }
 bool desync_valid_second_stage_udp(enum dpi_desync_mode mode)
 {
@ -125,15 +125,11 @@ enum dpi_desync_mode desync_mode_from_string(const char *s)
 		return DESYNC_SYNDATA;
 	else if (!strcmp(s,"fakeddisorder") || !strcmp(s,"disorder"))
 		return DESYNC_FAKEDDISORDER;
-	else if (!strcmp(s,"disorder2"))
-		return DESYNC_DISORDER2;
 	else if (!strcmp(s,"fakedsplit") || !strcmp(s,"split"))
 		return DESYNC_FAKEDSPLIT;
-	else if (!strcmp(s,"split2"))
-		return DESYNC_SPLIT2;
-	else if (!strcmp(s,"multisplit"))
+	else if (!strcmp(s,"multisplit") || !strcmp(s,"split2"))
 		return DESYNC_MULTISPLIT;
-	else if (!strcmp(s,"multidisorder"))
+	else if (!strcmp(s,"multidisorder") || !strcmp(s,"disorder2"))
 		return DESYNC_MULTIDISORDER;
 	else if (!strcmp(s,"ipfrag2"))
 		return DESYNC_IPFRAG2;
@ -1118,23 +1114,19 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 			DLOG("dpi desync src=%s dst=%s\n",s1,s2);
 		}

-		const struct proto_pos *spos;
 		switch(l7proto)
 		{
 			case HTTP:
 				fake = dp->fake_http;
 				fake_size = dp->fake_http_size;
-				spos = &dp->split_http;
 				break;
 			case TLS:
 				fake = dp->fake_tls;
 				fake_size = dp->fake_tls_size;
-				spos = &dp->split_tls;
 				break;
 			default:
 				fake = dp->fake_unknown;
 				fake_size = dp->fake_unknown_size;
-				spos = &dp->split_unknown;
 				break;
 		}
 		if (dp->desync_mode==DESYNC_MULTISPLIT || dp->desync_mode==DESYNC_MULTIDISORDER || dp->desync_mode2==DESYNC_MULTISPLIT || dp->desync_mode2==DESYNC_MULTIDISORDER)
@ -1174,12 +1166,19 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 				}
 			}
 		}
-		else if (dp->desync_mode==DESYNC_FAKEDSPLIT || dp->desync_mode==DESYNC_SPLIT2 || dp->desync_mode==DESYNC_FAKEDDISORDER || dp->desync_mode==DESYNC_DISORDER2 ||
-			dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_SPLIT2 || dp->desync_mode2==DESYNC_FAKEDDISORDER || dp->desync_mode2==DESYNC_DISORDER2)
+		else if (dp->desync_mode==DESYNC_FAKEDSPLIT || dp->desync_mode==DESYNC_FAKEDDISORDER || dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_FAKEDDISORDER)
 		{
 			multisplit_count=0;
-			split_pos = ResolvePos(rdata_payload, rlen_payload, l7proto, spos);
-			if (!split_pos) split_pos = dp->split_unknown.pos;
+			// first look for non-abs split
+			for(i=0,split_pos=0;i<dp->split_count && !split_pos;i++)
+				if (dp->splits[i].marker!=PM_ABS)
+					split_pos = ResolvePos(rdata_payload, rlen_payload, l7proto, dp->splits+i);
+			// second look for abs split
+			if (!split_pos)
+				for(i=0,split_pos=0;i<dp->split_count && !split_pos;i++)
+					if (dp->splits[i].marker==PM_ABS)
+						split_pos = ResolvePos(rdata_payload, rlen_payload, l7proto, dp->splits+i);
+			if (!split_pos) split_pos = 1;
 			DLOG("regular split pos: %zu\n",split_pos);
 			if (!split_pos || split_pos>rlen_payload) split_pos=1;
 			split_pos=pos_normalize(split_pos,reasm_offset,dis->len_payload);
@ -1241,7 +1240,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 			case DESYNC_IPFRAG1:
 				fooling_orig = (dp->desync_mode==DESYNC_HOPBYHOP) ? FOOL_HOPBYHOP : (dp->desync_mode==DESYNC_DESTOPT) ? FOOL_DESTOPT : FOOL_IPFRAG1;
 				if (dis->ip6 && (dp->desync_mode2==DESYNC_NONE || !desync_valid_second_stage_tcp(dp->desync_mode2) ||
-					(!split_pos && (dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_SPLIT2 || dp->desync_mode2==DESYNC_FAKEDDISORDER || dp->desync_mode2==DESYNC_DISORDER2)) ||
+					(!split_pos && (dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_FAKEDDISORDER)) ||
 					(!multisplit_count && (dp->desync_mode2==DESYNC_MULTISPLIT || dp->desync_mode2==DESYNC_MULTIDISORDER))))
 				{
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
@ -1352,10 +1351,13 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 						seg = dis->data_payload+from;
 						seg_len = to-from;
 						seqovl = 0;
-						if (i>=0 && dp->desync_seqovl)
+						// do seqovl only to the second packet
+						// otherwise sequence overlap becomes problematic. overlap algorithm is not too obvious.
+						// real observations revealed that server can receive overlap junk instead of real data
+						if (i==0)
 						{
 							if (dp->desync_seqovl>=from)
-								DLOG("seqovl>=split_pos (%u>=%zu). cancelling seqovl for part %d.\n",dp->desync_seqovl,from,i+2);
+								DLOG("seqovl>=split_pos (%u>=%zu). cancelling seqovl for part %d.\n",seqovl,from,i+2);
 							else
 							{
 								seqovl = dp->desync_seqovl;
@ -1389,30 +1391,32 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 				}
 				break;
 			case DESYNC_FAKEDDISORDER:
-			case DESYNC_DISORDER2:
 				if (split_pos)
 				{
 					uint8_t fakeseg[DPI_DESYNC_MAX_FAKE_LEN+100], *seg;
 					size_t seg_len;
+					unsigned int seqovl;

 					if (dp->desync_seqovl>=split_pos)
 					{
-						DLOG("seqovl>=split_pos. desync is not possible.\n");
-						return verdict;
+						DLOG("seqovl>=split_pos (%u>=%zu). cancelling seqovl.\n",dp->desync_seqovl,split_pos);
+						seqovl = 0;
 					}
+					else
+						seqovl = dp->desync_seqovl;

 					if (split_pos<dis->len_payload)
 					{
-						if (dp->desync_seqovl)
+						if (seqovl)
 						{
-							seg_len = dis->len_payload-split_pos+dp->desync_seqovl;
+							seg_len = dis->len_payload-split_pos+seqovl;
 							if (seg_len>sizeof(fakeseg))
 							{
 								DLOG("seqovl is too large\n");
 								return verdict;
 							}
-							fill_pattern(fakeseg,dp->desync_seqovl,dp->seqovl_pattern,sizeof(dp->seqovl_pattern));
-							memcpy(fakeseg+dp->desync_seqovl,dis->data_payload+split_pos,dis->len_payload-split_pos);
+							fill_pattern(fakeseg,seqovl,dp->seqovl_pattern,sizeof(dp->seqovl_pattern));
+							memcpy(fakeseg+seqovl,dis->data_payload+split_pos,dis->len_payload-split_pos);
 							seg = fakeseg;
 						}
 						else
@ -1422,31 +1426,27 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 						}

 						pkt1_len = sizeof(pkt1);
-						if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(dis->tcp->th_seq , split_pos - dp->desync_seqovl), dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
+						if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(dis->tcp->th_seq , split_pos - seqovl), dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
 								ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
 								fooling_orig,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 								seg, seg_len, pkt1, &pkt1_len))
 							return verdict;
-						DLOG("sending 2nd out-of-order tcp segment %zu-%zu len=%zu seqovl=%u : ",split_pos,dis->len_payload-1, dis->len_payload-split_pos, dp->desync_seqovl);
+						DLOG("sending 2nd out-of-order tcp segment %zu-%zu len=%zu seqovl=%u : ",split_pos,dis->len_payload-1, dis->len_payload-split_pos, seqovl);
 						hexdump_limited_dlog(seg,seg_len,PKTDATA_MAXDUMP); DLOG("\n");
 						if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
 							return verdict;
 					}

-
-					if (desync_mode==DESYNC_FAKEDDISORDER)
-					{
-						seg_len = sizeof(fakeseg);
-						if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-								ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
-								dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
-								zeropkt, split_pos, fakeseg, &seg_len))
-							return verdict;
-						DLOG("sending fake(1) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
-						hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
-						if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, seg_len))
-							return verdict;
-					}
+					seg_len = sizeof(fakeseg);
+					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
+							ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
+							zeropkt, split_pos, fakeseg, &seg_len))
+						return verdict;
+					DLOG("sending fake(1) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
+					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
+					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, seg_len))
+						return verdict;

 					pkt1_len = sizeof(pkt1);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
@ -1459,37 +1459,30 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
 						return verdict;

-					if (desync_mode==DESYNC_FAKEDDISORDER)
-					{
-						DLOG("sending fake(2) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
-						hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
-						if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, seg_len))
-							return verdict;
-					}
+					DLOG("sending fake(2) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
+					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
+					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, seg_len))
+						return verdict;

 					return VERDICT_DROP;
 				}
 				break;
 			case DESYNC_FAKEDSPLIT:
-			case DESYNC_SPLIT2:
 				if (split_pos)
 				{
 					uint8_t fakeseg[DPI_DESYNC_MAX_FAKE_LEN+100],ovlseg[DPI_DESYNC_MAX_FAKE_LEN+100], *seg;
 					size_t fakeseg_len,seg_len;

-					if (desync_mode==DESYNC_FAKEDSPLIT)
-					{
-						fakeseg_len = sizeof(fakeseg);
-						if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-								ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
-								dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
-								zeropkt, split_pos, fakeseg, &fakeseg_len))
-							return verdict;
-						DLOG("sending fake(1) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
-						hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
-						if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
-							return verdict;
-					}
+					fakeseg_len = sizeof(fakeseg);
+					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
+							ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
+							zeropkt, split_pos, fakeseg, &fakeseg_len))
+						return verdict;
+					DLOG("sending fake(1) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
+					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
+					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
+						return verdict;

 					unsigned int seqovl = dp->desync_seqovl;
 #ifdef __linux__
@ -1539,13 +1532,11 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					}
 #endif

-					if (desync_mode==DESYNC_FAKEDSPLIT)
-					{
-						DLOG("sending fake(2) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
-						hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
-						if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
-							return verdict;
-					}
+					DLOG("sending fake(2) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
+					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
+					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
+						return verdict;
+
 					if (split_pos<dis->len_payload)
 					{
 						pkt1_len = sizeof(pkt1);
@ -1738,7 +1729,6 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 	{
 		const uint8_t *fake;
 		size_t fake_size;
-		bool b;
 		char host[256];
 		bool bHaveHost=false;

@ -1990,7 +1980,6 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint

 		ttl_fake = (ctrack_replay && ctrack_replay->autottl) ? ctrack_replay->autottl : (dis->ip6 ? (dp->desync_ttl6 ? dp->desync_ttl6 : ttl_orig) : (dp->desync_ttl ? dp->desync_ttl : ttl_orig));

-		enum dpi_desync_mode desync_mode = dp->desync_mode;
 		uint32_t fooling_orig = FOOL_NONE;

 		if (params.debug)
@ -2001,15 +1990,14 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 			DLOG("dpi desync src=%s dst=%s\n",s1,s2);
 		}

+		bool bFake = false;
 		pkt1_len = sizeof(pkt1);
-		b = false;
-		switch(desync_mode)
+		switch(dp->desync_mode)
 		{
 			case DESYNC_FAKE_KNOWN:
 				if (l7proto==UNKNOWN)
 				{
 					DLOG("not applying fake because of unknown protocol\n");
-					desync_mode = dp->desync_mode2;
 					break;
 				}
 			case DESYNC_FAKE:
@ -2019,12 +2007,12 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 				hexdump_limited_dlog(fake,fake_size,PKTDATA_MAXDUMP); DLOG("\n");
 				if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
 					return verdict;
-				b = true;
+				bFake = true;
 				break;
 			case DESYNC_HOPBYHOP:
 			case DESYNC_DESTOPT:
 			case DESYNC_IPFRAG1:
-				fooling_orig = (desync_mode==DESYNC_HOPBYHOP) ? FOOL_HOPBYHOP : (desync_mode==DESYNC_DESTOPT) ? FOOL_DESTOPT : FOOL_IPFRAG1;
+				fooling_orig = (dp->desync_mode==DESYNC_HOPBYHOP) ? FOOL_HOPBYHOP : (dp->desync_mode==DESYNC_DESTOPT) ? FOOL_DESTOPT : FOOL_IPFRAG1;
 				if (dis->ip6 && (dp->desync_mode2==DESYNC_NONE || !desync_valid_second_stage_udp(dp->desync_mode2)))
 				{
 					if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst,
@ -2040,26 +2028,13 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 					// this mode is final, no other options available
 					return ct_new_postnat_fix_udp(ctrack, dis->ip, dis->ip6, dis->udp, &dis->len_pkt);
 				}
-				desync_mode = dp->desync_mode2;
 				break;
 			default:
 				pkt1_len=0;
 				break;
 		}

-		if (b)
-		{
-			if (dp->desync_mode2==DESYNC_NONE || !desync_valid_second_stage_udp(dp->desync_mode2))
-			{
-				DLOG("reinjecting original packet. len=%zu len_payload=%zu\n", dis->len_pkt, dis->len_payload);
-				verdict_udp_csum_fix(verdict, dis->udp, dis->transport_len, dis->ip, dis->ip6);
-				if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , dis->data_pkt, dis->len_pkt))
-					return verdict;
-				return ct_new_postnat_fix_udp(ctrack, dis->ip, dis->ip6, dis->udp, &dis->len_pkt);
-			}
-			desync_mode = dp->desync_mode2;
-		}
-
+		enum dpi_desync_mode desync_mode = dp->desync_mode2==DESYNC_NONE ? dp->desync_mode : dp->desync_mode2;
 		switch(desync_mode)
 		{
 			case DESYNC_UDPLEN:
@ -2067,7 +2042,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 				if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6), fooling_orig, dp->udplen_pattern, sizeof(dp->udplen_pattern), dp->udplen_increment, dis->data_payload, dis->len_payload, pkt1, &pkt1_len))
 				{
 					DLOG("could not construct packet with modified length. too large ?\n");
-					return verdict;
+					break;
 				}
 				DLOG("resending original packet with increased by %d length\n", dp->udplen_increment);
 				if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
@ -2084,7 +2059,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 					if (szcopy>szbuf)
 					{
 						DLOG("packet is too long to tamper");
-						return verdict;
+						break;
 					}
 					memcpy(pkt2+pkt2_len,dis->data_payload+1,szcopy);
 					pkt2_len+=szcopy;
@ -2092,7 +2067,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 					if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6), fooling_orig, NULL, 0 , 0, pkt2, pkt2_len, pkt1, &pkt1_len))
 					{
 						DLOG("could not construct packet with modified length. too large ?\n");
-						return verdict;
+						break;
 					}
 					DLOG("resending tampered DHT\n");
 					if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
@ -2102,7 +2077,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 				else
 				{
 					DLOG("payload is not tamperable\n");
-					return verdict;
+					break;
 				}
 			case DESYNC_IPFRAG2:
 				{
@ -2150,6 +2125,16 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 				break;
 		}

+		if (bFake)
+		{
+			// if we are here original message was not sent in any form
+			// allowing system to pass the message to queue can result in unpredicted send order
+			DLOG("reinjecting original packet. len=%zu len_payload=%zu\n", dis->len_pkt, dis->len_payload);
+			verdict_udp_csum_fix(verdict, dis->udp, dis->transport_len, dis->ip, dis->ip6);
+			if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , dis->data_pkt, dis->len_pkt))
+				return verdict;
+			return ct_new_postnat_fix_udp(ctrack, dis->ip, dis->ip6, dis->udp, &dis->len_pkt);
+		}
 	}

 	return verdict;
--- a/nfq/desync.h
+++ b/nfq/desync.h
@ -28,8 +28,6 @@ enum dpi_desync_mode {
 	DESYNC_RSTACK,
 	DESYNC_SYNACK,
 	DESYNC_SYNDATA,
-	DESYNC_SPLIT2,
-	DESYNC_DISORDER2,
 	DESYNC_FAKEDSPLIT,
 	DESYNC_FAKEDDISORDER,
 	DESYNC_MULTISPLIT,
--- a/nfq/nfqws.c
+++ b/nfq/nfqws.c
@ -752,7 +752,7 @@ static bool parse_tlspos(const char *s, struct proto_pos *sp)
 	else if (!strcmp(s, "sniext"))
 	{
 		sp->marker = PM_SNI_EXT;
-		sp->pos=0;
+		sp->pos=1;
 	}
 	else if (!strcmp(s, "snisld"))
 	{
@ -838,39 +838,14 @@ static bool parse_split_pos_list(char *opt, struct proto_pos *splits, int splits
 }
 static void split_compat(struct desync_profile *dp)
 {
-	// make it mostly compatible with old versions
-	int i;
-	dp->split_unknown.marker=PM_ABS;
-	dp->split_unknown.pos=2;
-	for (i=0;i<dp->split_count;i++)
+	if (!dp->split_count)
 	{
-		if (dp->splits[i].marker==PM_ABS)
-		{
-			dp->split_unknown.pos=dp->splits[i].pos;
-			break;
-		}
-	}
-	if (PROTO_POS_EMPTY(&dp->split_http))
-	{
-		dp->split_http=dp->split_unknown;
-		for (i=0;i<dp->split_count;i++)
-			if (IsHostMarker(dp->splits[i].marker) || dp->splits[i].marker==PM_HTTP_METHOD)
-			{
-				dp->split_http = dp->splits[i];
-				break;
-			}
-	}
-	if (PROTO_POS_EMPTY(&dp->split_tls))
-	{
-		dp->split_tls=dp->split_unknown;
-		for (i=0;i<dp->split_count;i++)
-			if (IsHostMarker(dp->splits[i].marker) || dp->splits[i].marker==PM_SNI_EXT)
-			{
-				dp->split_tls = dp->splits[i];
-				break;
-			}
+		dp->splits[dp->split_count].marker = PM_ABS;
+		dp->splits[dp->split_count].pos = 2;
+		dp->split_count++;
 	}
 }
+
 static void SplitDebug(void)
 {
 	struct desync_profile_list *dpl;
@ -878,9 +853,6 @@ static void SplitDebug(void)
 	LIST_FOREACH(dpl, &params.desync_profiles, next)
 	{
 		dp = &dpl->dp;
-		DLOG("profile %d split_http %s %d\n",dp->n,posmarker_name(dp->split_http.marker),dp->split_http.pos);
-		DLOG("profile %d split_tls %s %d\n",dp->n,posmarker_name(dp->split_tls.marker),dp->split_tls.pos);
-		DLOG("profile %d split_unknown %s %d\n",dp->n,posmarker_name(dp->split_unknown.marker),dp->split_unknown.pos);
 		for(int x=0;x<dp->split_count;x++)
 			DLOG("profile %d multisplit %s %d\n",dp->n,posmarker_name(dp->splits[x].marker),dp->splits[x].pos);
 	}
@ -1066,7 +1038,7 @@ static void exithelp(void)
 		" --domcase\t\t\t\t\t; mix domain case : Host: TeSt.cOm\n"
 		" --dpi-desync=[<mode0>,]<mode>[,<mode2>]\t; try to desync dpi state. modes :\n"
 		"\t\t\t\t\t\t; synack syndata fake fakeknown rst rstack hopbyhop destopt ipfrag1\n"
-		"\t\t\t\t\t\t; disorder2 split2 multisplit multidisorder fakedsplit fakeddisorder ipfrag2 udplen tamper\n"
+		"\t\t\t\t\t\t; multisplit multidisorder fakedsplit fakeddisorder ipfrag2 udplen tamper\n"
 #ifdef __linux__
 		" --dpi-desync-fwmark=<int|0xHEX>\t\t; override fwmark for desync packet. default = 0x%08X (%u)\n"
 #elif defined(SO_USER_COOKIE)
@ -1079,9 +1051,10 @@ static void exithelp(void)
 		" --dpi-desync-fooling=<mode>[,<mode>]\t\t; can use multiple comma separated values. modes : none md5sig ts badseq badsum datanoack hopbyhop hopbyhop2\n"
 		" --dpi-desync-repeats=<N>\t\t\t; send every desync packet N times\n"
 		" --dpi-desync-skip-nosni=0|1\t\t\t; 1(default)=do not act on ClientHello without SNI (ESNI ?)\n"
-		" --dpi-desync-split-pos=N|-N|marker+N|marker-N\t; comma separated list of split positions. markers: method,host,endhost,sld,endsld,midsld,sniext\n"
+		" --dpi-desync-split-pos=N|-N|marker+N|marker-N\t; comma separated list of split positions\n"
+		"\t\t\t\t\t\t; markers: method,host,endhost,sld,endsld,midsld,sniext\n"
 		"\t\t\t\t\t\t; full list is only used by multisplit and multidisorder\n"
-		"\t\t\t\t\t\t; single split takes first l7-protocol-compatible parameter if present, first abs value otherwise\n"
+		"\t\t\t\t\t\t; fakedsplit/fakeddisorder use first l7-protocol-compatible parameter if present, first abs value otherwise\n"
 		" --dpi-desync-split-seqovl=<int>\t\t; use sequence overlap before first sent original split segment\n"
 		" --dpi-desync-split-seqovl-pattern=<filename>|0xHEX ; pattern for the fake part of overlap\n"
 		" --dpi-desync-ipfrag-pos-tcp=<8..%u>\t\t; ip frag position starting from the transport header. multiple of 8, default %u.\n"
@ -1589,19 +1562,33 @@ int main(int argc, char **argv)
 			break;
 		case 24: /* dpi-desync-split-http-req */
 			// obsolete arg
-			if (!parse_httpreqpos(optarg, &dp->split_http))
+			DLOG_CONDUP("WARNING ! --dpi-desync-split-http-req is deprecated. use --dpi-desync-split-pos with markers.\n",MAX_SPLITS);
+			if (dp->split_count>=MAX_SPLITS)
+			{
+				DLOG_ERR("Too much splits. max splits: %u\n",MAX_SPLITS);
+				exit_clean(1);
+			}
+			if (!parse_httpreqpos(optarg, dp->splits + dp->split_count))
 			{
 				DLOG_ERR("Invalid argument for dpi-desync-split-http-req\n");
 				exit_clean(1);
 			}
+			dp->split_count++;
 			break;
 		case 25: /* dpi-desync-split-tls */
 			// obsolete arg
-			if (!parse_tlspos(optarg, &dp->split_tls))
+			DLOG_CONDUP("WARNING ! --dpi-desync-split-tls is deprecated. use --dpi-desync-split-pos with markers.\n",MAX_SPLITS);
+			if (dp->split_count>=MAX_SPLITS)
+			{
+				DLOG_ERR("Too much splits. max splits: %u\n",MAX_SPLITS);
+				exit_clean(1);
+			}
+			if (!parse_tlspos(optarg, dp->splits + dp->split_count))
 			{
 				DLOG_ERR("Invalid argument for dpi-desync-split-tls\n");
 				exit_clean(1);
 			}
+			dp->split_count++;
 			break;
 		case 26: /* dpi-desync-split-seqovl */
 			if (sscanf(optarg,"%u",&dp->desync_seqovl)<1)
@ -2048,13 +2035,6 @@ int main(int argc, char **argv)
 	LIST_FOREACH(dpl, &params.desync_profiles, next)
 	{
 		dp = &dpl->dp;
-
-		if (!dp->split_count && (dp->desync_mode==DESYNC_MULTISPLIT || dp->desync_mode==DESYNC_MULTIDISORDER || dp->desync_mode2==DESYNC_MULTISPLIT || dp->desync_mode2==DESYNC_MULTIDISORDER))
-		{
-			DLOG_ERR("multisplit requires explicit split pos\n");
-			exit_clean(1);
-		}
-
 		// not specified - use desync_ttl value instead
 		if (dp->desync_ttl6 == 0xFF) dp->desync_ttl6=dp->desync_ttl;
 		if (!AUTOTTL_ENABLED(dp->desync_autottl6)) dp->desync_autottl6 = dp->desync_autottl;
--- a/nfq/params.h
+++ b/nfq/params.h
@ -60,8 +60,6 @@ struct desync_profile
 	// multisplit
 	struct proto_pos splits[MAX_SPLITS];
 	int split_count;
-	// single split pos cache
-	struct proto_pos split_http,split_tls,split_unknown;

 	char desync_start_mode, desync_cutoff_mode; // n - packets, d - data packets, s - relative sequence
 	unsigned int desync_start, desync_cutoff;
--- a/nfq/protocol.c
+++ b/nfq/protocol.c
@ -511,8 +511,7 @@ size_t TLSPos(uint8_t posmarker, int16_t pos, const uint8_t *data, size_t sz)
 			{
 				if (posmarker==PM_SNI_EXT)
 				{
-					offset = ext-data+1+pos;
-					return (offset>=0 && offset<sz) ? offset : 0;
+					return CheckPos(sz,ext-data+pos);
 				}
 				else
 				{
Author	SHA1	Message	Date
bol-van	611292281c	nfqws: rewrite default split pos logic	2024-11-13 13:34:34 +03:00
bol-van	14e9fc4d43	nfqws: deprecate single split modes, optimize code	2024-11-13 11:54:40 +03:00