BUG/MEDIUM: lua: possible CLOSE-WAIT state with '\n' headers

The Lua parser doesn't takes in account end-of-headers containing
only '\n'. It expects always '\r\n'. If a '\n' is processes the Lua
parser considers it miss 1 byte, and wait indefinitely for new data.

When the client reaches their timeout, it closes the connection.
This close is not detected and the connection keep in CLOSE-WAIT
state.

I guess that this patch fix only a visible part of the problem.
If the Lua HTTP parser wait for data, the timeout server or the
connectio closed by the client may stop the applet.

How reproduce the problem:

HAProxy conf:

   global
      lua-load bug38.lua
   frontend frt
      timeout client 2s
      timeout server 2s
      mode http
      bind *:8080
      http-request use-service lua.donothing

Lua conf

   core.register_service("donothing", "http", function(applet) end)

Client request:

   echo -ne 'GET / HTTP/1.1\n\n' | nc 127.0.0.1 8080

Look for CLOSE-WAIT in the connection with "netstat" or "ss". I
use this script:

   while sleep 1; do ss | grep CLOSE-WAIT; done

This patch must be backported in 1.6, 1.7 and 1.8

Workaround: enable the "hard-stop-after" directive, and perform
periodic reload.

diff --git a/src/hlua.c b/src/hlua.c
index 93ec44c3b7543002263a5abd3b6456d179805b70..4715639a16ffb52d6eba6c0437d8ceb4603b3a9a 100644 (file)
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -6663,13 +6663,13 @@ static void hlua_applet_http_fct(struct appctx *ctx)
                        len2 = 0;
                if (ret == 0)
                        len1 = 0;
-               if (len1 + len2 < strm->txn->req.eoh + 2) {
+               if (len1 + len2 < strm->txn->req.eoh + strm->txn->req.eol) {
                        si_applet_cant_get(si);
                        return;
                }
 
                /* skip the requests bytes. */
-               co_skip(si_oc(si), strm->txn->req.eoh + 2);
+               co_skip(si_oc(si), strm->txn->req.eoh + strm->txn->req.eol);
        }
 
        /* Executes The applet if it is not done. */