From f3960eeb471e745d1dfedc87ee82c42809ce83e1 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Tue, 25 Jan 2022 20:56:00 +0100
Subject: [PATCH] gluon-web: improve error handling of parse_message_body()

Actually raise an error and turn it into an HTTP 400 return code when
something goes wrong, rather than ignoring the error.

We also improve the conditions under which errors are thrown before
pump() is called: We don't need to check for the multipart/form-data
content-type twice, and a POST without this content-type is now always
an error.
---
 .../usr/lib/lua/gluon/web/dispatcher.lua      | 10 ++++++--
 .../usr/lib/lua/gluon/web/http/protocol.lua   | 23 +++++++------------
 2 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/package/gluon-web/luasrc/usr/lib/lua/gluon/web/dispatcher.lua b/package/gluon-web/luasrc/usr/lib/lua/gluon/web/dispatcher.lua
index 336b2832..d2a6b500 100644
--- a/package/gluon-web/luasrc/usr/lib/lua/gluon/web/dispatcher.lua
+++ b/package/gluon-web/luasrc/usr/lib/lua/gluon/web/dispatcher.lua
@@ -184,9 +184,15 @@ local function dispatch(config, http, request)
 		return
 	end
 
-	http:parse_input(node.filehandler)
+	local ok, err = pcall(http.parse_input, http, node.filehandler)
+	if not ok then
+		http:status(400, "Bad request")
+		http:prepare_content("text/plain")
+		http:write(err .. "\r\n")
+		return
+	end
 
-	local ok, err = pcall(node.target)
+	ok, err = pcall(node.target)
 	if not ok then
 		http:status(500, "Internal Server Error")
 		renderer.render_layout("error/500", {
diff --git a/package/gluon-web/luasrc/usr/lib/lua/gluon/web/http/protocol.lua b/package/gluon-web/luasrc/usr/lib/lua/gluon/web/http/protocol.lua
index 8d070d95..62b60bdc 100644
--- a/package/gluon-web/luasrc/usr/lib/lua/gluon/web/http/protocol.lua
+++ b/package/gluon-web/luasrc/usr/lib/lua/gluon/web/http/protocol.lua
@@ -108,16 +108,11 @@ end
 --  o String value containing a chunk of the file data
 --  o Boolean which indicates whether the current chunk is the last one (eof)
 local function mimedecode_message_body(src, msg, filecb)
-
-	if msg and msg.env.CONTENT_TYPE then
-		msg.mime_boundary = msg.env.CONTENT_TYPE:match("^multipart/form%-data; boundary=(.+)$")
+	local mime_boundary = (msg.env.CONTENT_TYPE or ''):match("^multipart/form%-data; boundary=(.+)$")
+	if not mime_boundary then
+		error("Invalid Content-Type found")
 	end
 
-	if not msg.mime_boundary then
-		return nil, "Invalid Content-Type found"
-	end
-
-
 	local tlen   = 0
 	local inhdr  = false
 	local field  = nil
@@ -188,10 +183,10 @@ local function mimedecode_message_body(src, msg, filecb)
 			local spos, epos, found
 
 			repeat
-				spos, epos = data:find("\r\n--" .. msg.mime_boundary .. "\r\n", 1, true)
+				spos, epos = data:find("\r\n--" .. mime_boundary .. "\r\n", 1, true)
 
 				if not spos then
-					spos, epos = data:find("\r\n--" .. msg.mime_boundary .. "--\r\n", 1, true)
+					spos, epos = data:find("\r\n--" .. mime_boundary .. "--\r\n", 1, true)
 				end
 
 
@@ -250,20 +245,18 @@ local function mimedecode_message_body(src, msg, filecb)
 		return true
 	end
 
-	return pump(src, snk)
+	assert(pump(src, snk))
 end
 
 -- This function will examine the Content-Type within the given message object
 -- to select the appropriate content decoder.
 -- Currently only the multipart/form-data mime type is supported.
 function M.parse_message_body(src, msg, filecb)
-	if not (msg.env.REQUEST_METHOD == "POST" and msg.env.CONTENT_TYPE) then
+	if msg.env.REQUEST_METHOD ~= "POST" then
 		return
 	end
 
-	if msg.env.CONTENT_TYPE:match("^multipart/form%-data") then
-		return mimedecode_message_body(src, msg, filecb)
-	end
+	mimedecode_message_body(src, msg, filecb)
 end
 
 return M