[syslinux] tftpd-hpa wrong data

[ryan wamsley]

I believe I have encountered a problem with tftpd-hpa very similar to the problem described in the following link:

  http://syslinux.zytor.com/archives/2003-May/001955.html

We were running tftpd-hpa version 0.29 on RedHat 8.0 (on an older Dell desktop), and upgraded to tftpd-hpa version 0.42 when the problem was discovered; however, we are seeing the same thing after the upgrade.

The TFTP client I am using times out after 500ms (it is a client on an embedded device so I cannot provide an example). Occasionally, after a write request is sent, the client times-out and resends the write request. The TFTP server ends up responding to both requests, and the log reads:

Mar 30 19:49:57 pderob019 in.tftpd[30818]: WRQ from 172.22.194.248 filename pderob224/bak/from00.img
Mar 30 19:50:01 pderob019 in.tftpd[30828]: WRQ from 172.22.194.248 filename pderob224/bak/from01.img
Mar 30 19:50:01 pderob019 in.tftpd[30830]: WRQ from 172.22.194.248 filename pderob224/bak/from01.img
Mar 30 19:50:05 pderob019 in.tftpd[30832]: WRQ from 172.22.194.248 filename pderob224/bak/from02.img
Mar 30 19:50:06 pderob019 in.tftpd[30830]: tftpd: read: Connection refused

So in this case the file from01.img was opened twice--and a read error is always printed a little later. The end result is the file (from01.img in this case) is the correct size, but contains only zeros (in the binary sense). I verified through ethereal that the correct data was actually sent. I have the capture file if it would help clear things up.

Re-reading the TFTP RFC I don't see anything that indicates the client is doing anything wrong by re-sending the write request... Is this a legitimate bug with tftp-hpa?

Thanks in advance for any help.