[pgpool-general: 890] Re: read_startup_packet: out of memory

[Tatsuo Ishii]

> Greetings,
> I'm currently testing pgpool-3.2.0 in a staging environment.  While
> doing so, my IT department decided to perform some sort of security
> scan of the servers in my network, including the 3.2.0 server.  When
> this happened, I saw the following in the pgpool log:
> 
> 2012-08-08 09:58:33 ERROR: pid 3595: read_startup_packet: invalid startup packet
> 2012-08-08 09:58:42 ERROR: pid 2049: read_startup_packet: invalid startup packet
> 2012-08-08 09:58:51 ERROR: pid 3435: read_startup_packet: invalid startup packet
> 2012-08-08 09:59:00 ERROR: pid 2049: read_startup_packet: invalid startup packet
> 2012-08-08 09:59:05 ERROR: pid 2049: read_startup_packet: invalid startup packet
> 2012-08-08 09:59:09 ERROR: pid 2508: read_startup_packet: invalid startup packet
> 2012-08-08 09:59:21 ERROR: pid 2549: read_startup_packet: incorrect
> packet length (-2139750145)
> 2012-08-08 09:59:21 ERROR: pid 2549: read_startup_packet: out of memory
> 2012-08-08 09:59:26 ERROR: pid 2905: read_startup_packet: invalid startup packet
> 
> I don't know how to trigger this manually, but it seems like something
> that is potentially bad.  I don't understand how a packet can have a
> huge negative length, but I'm most concerned that pgpool seemed to
> exhaust memory somehow.  Any ideas what is going on here?

These are all happen in from frontend to pgpool connecting phase. To
initiate the connection, frontend must send a special packet called
"startup packet" first.

> 2012-08-08 09:58:33 ERROR: pid 3595: read_startup_packet: invalid startup packet

This means the startup packet length is greater than 10000 bytes. I
believe PostgreSQL has the same limitation. This is necessary to
prevent from denial-of-service attacks.

> 2012-08-08 09:59:21 ERROR: pid 2549: read_startup_packet: incorrect packet length (-2139750145)

The startup packet has a field which is indicating the length of
packet. If the length is minus, denfinitely the packet is borken.

> 2012-08-08 09:59:21 ERROR: pid 2549: read_startup_packet: out of memory

Pgpool failed to allocate memory (the size is not known from the log
but definitely less than 10000 bytes). Maybe swap space is not enough?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp