vsftp 2.0.7 ftp(s) connect -> 500 oops child died
the following problem happend (and still happens) on one of my debian boxes.
When trying to connect via ftp or ftps the client states waiting for the welcome message and than breaks the connection after reaching a timeout. When trying the same with a commanshell ftp (instead of filezilla in this case) it generally works but with the same symptoms of having a very loong time after the welcome message but I get a loginprompt and the rest works.
While trying to troubleshoot, as vsftpd logs are empty, I took a short view on the tcpdump captures which showed the following error:
"00 oops child died: vsf_sysutil_recv_peek: no data". Googling did not help much except stating something about mod capability.
So I tried to lock it down to several things I change on the server since this problem occured:
- Snort + OSSEC
- Kernel 2.6.26-1-686-bigmem to 2.6.26-2-686-bigmem
- deletion of /tmp with recration -> root:root, chmod 1777
- ISPConfig2 upgrade to the most recent version
Snort and OSSEC, as well as the changed kernel do not seem to be the problem, as the problem occurs when deactivating them and switching back the kernel to the old one, the problem persists. Also this modprobe thing is the same no matter of the kernel version so I'd assume that this solution would not help at all.
Well as vsftpd is the debian one, controlled by the ispconfig_tcpserver, maybe there could be the problem located.
@Till / Falko: Did this binary change since the last two upgrades of ispconfig2?
The /tmp thing should not be a problem but I actually do not know if vsftpd needs /tmp in a special way like other services, e.g. samba would not be able to accept connections wihout a writeable /tmp.