zapret-lib, zapret-antidpi: http_reconstruct_req, http_unixeol

lua/zapret-antidpi.lua

@@ -185,6 +185,40 @@ function http_methodeol(ctx, desync)
 	end
 end
 
+-- nfqws1 : not available
+-- tpws : --unixeol
+-- standard args : direction
+function http_unixeol(ctx, desync)
+	if not desync.dis.tcp then
+		instance_cutoff_shim(ctx, desync)
+		return
+	end
+	direction_cutoff_opposite(ctx, desync)
+	if desync.l7payload=="http_req" and direction_check(desync) then
+		local hdis = http_dissect_req(desync.dis.payload)
+		if hdis then
+			if hdis.headers["user-agent"] then
+				local http = http_reconstruct_req(hdis, true)
+				if #http < #desync.dis.payload then
+					hdis.headers["user-agent"].value = hdis.headers["user-agent"].value .. string.rep(" ", #desync.dis.payload - #http)
+				end
+				local http = http_reconstruct_req(hdis, true)
+				if #http==#desync.dis.payload then
+					desync.dis.payload = http
+					DLOG("http_unixeol: applied")
+					return VERDICT_MODIFY
+				else
+					DLOG("http_unixeol: reconstruct differs in size from original: "..#http.."!="..#desync.dis.payload)
+				end
+			else
+				DLOG("http_unixeol: user-agent header absent")
+			end
+		else
+			DLOG("http_unixeol: could not dissect http")
+		end
+	end
+end
+
 -- nfqws1 : "--synack-split"
 -- standard args : rawsend, reconstruct, ipfrag
 -- arg : mode=syn|synack|acksyn . "synack" by default

lua/zapret-lib.lua

@@ -304,7 +304,7 @@ function pos_str(desync, pos)
 	return pos.mode..pos_get(desync, pos.mode)
 end
 
--- convert array a to packed string using 'packer' function
+-- convert array a to packed string using 'packer' function. only numeric indexes starting from 1, order preserved
 function barray(a, packer)
 	if a then
 		local s=""
@@ -314,6 +314,16 @@ function barray(a, packer)
 		return s
 	end
 end
+-- convert table a to packed string using 'packer' function. any indexes, any order
+function btable(a, packer)
+	if a then
+		local s=""
+		for k,v in pairs(a) do
+			s = s .. packer(v)
+		end
+		return s
+	end
+end
 
 -- sequence comparision functions. they work only within 2G interval
 -- seq1>=seq2
@@ -1423,19 +1433,22 @@ function http_dissect_header(header)
 end
 -- make table with structured http header representation
 function http_dissect_headers(http, pos)
-	local eol,pnext,header,value,idx,headers,pos_endheader,pos_startvalue
+	local eol,pnext,header,value,idx,headers,pos_endheader,pos_startvalue,pos_headers_next
 	headers={}
 	while pos do
 		eol,pnext = find_next_line(http,pos)
 		header = string.sub(http,pos,eol)
-		if #header == 0 then break end
+		if #header == 0 then
+			pos_headers_end = pnext
+			break
+		end
 		header,value,pos_endheader,pos_startvalue = http_dissect_header(header)
 		if header then
 			headers[string.lower(header)] = { header = header, value = value, pos_start = pos, pos_end = eol, pos_header_end = pos+pos_endheader-1, pos_value_start = pos+pos_startvalue-1 }
 		end
 		pos=pnext
 	end
-	return headers
+	return headers, pos_headers_end
 end
 -- make table with structured http request representation
 function http_dissect_req(http)
@@ -1457,9 +1470,21 @@ function http_dissect_req(http)
 	pos = string.find(req,"[^ \t]",pos+1)
 	if not pos then return nil end
 	pnext = string.find(req,"[ \t]",pos+1)
-	if not pnext then pnext = #http + 1 end
+	if not pnext then pnext = #req + 1 end
 	local uri = string.sub(req,pos,pnext-1)
-	return { method = method, uri = uri, headers = http_dissect_headers(http,hdrpos) }
+	pos = string.find(req,"[^ \t]",pnext)
+	local http_ver
+	if pos then
+		pnext = string.find(req,"[\r\n]",pos)
+		if not pnext then pnext = #req + 1 end
+		http_ver = string.sub(req,pos,pnext-1)
+	end
+	local hdis = { method = method, uri = uri, http_ver = http_ver }
+	hdis.headers, hdis.pos_headers_end = http_dissect_headers(http,hdrpos)
+	if hdis.pos_headers_end then
+		hdis.body = string.sub(http, hdis.pos_headers_end)
+	end
+	return hdis
 end
 function http_dissect_reply(http)
 	if not http then return nil; end
@@ -1472,6 +1497,14 @@ function http_dissect_reply(http)
 	pos = find_next_line(http,pos)
 	return { code = code, headers = http_dissect_headers(http,pos) }
 end
+function http_reconstruct_headers(headers, unixeol)
+	local eol = unixeol and "\n" or "\r\n"
+	return headers and btable(headers, function(a) return a.header..": "..a.value..eol end) or ""
+end
+function http_reconstruct_req(hdis, unixeol)
+	local eol = unixeol and "\n" or "\r\n"
+	return hdis.method.." "..hdis.uri..(hdis.http_ver and (" "..hdis.http_ver) or "")..eol..http_reconstruct_headers(hdis.headers, unixeol)..eol..(hdis.body or "")
+end
 
 function dissect_url(url)
 	local p1,pb,pstart,pend