[CentOS] vsftpd writing files 2 times - once as root

[Stephen John Smoogen]

On Tue, Apr 6, 2010 at 12:58 PM, Dirk H. Schulz
<dirk.schulz at kinzesberg.de> wrote:
> I have configured my vsftpd with virtual users all of which are mapped
> to a system user for file system permissions (let's call him
> 'ftpsystemuser').

What is the vsftpd process running as? It is most likely root as it
needs to have permission to open ports 20:21 for access. In most cases
a file is going to be opened up as root, written as root, and then
chowned to the configured user..


> That means, if someone uploads files they are writting using owner and
> group of the system user:
>> -rw-r--r-- 1 ftpsystemuser ftpsystemuser 19968 16. Mär 11:24 Termine
>> Leistungspr?fungen.doc
> Now we have the phenomenon that some files and folders are written
> twice, one instance as it should be and the other with owner and group
> 'root' and with html-like file name syntax. For example:
>> -rw-r--r-- 1 root          root          19968 16. Mär 11:24 Termine
>> Leistungspr%FCfungen.doc
>> -rw-r--r-- 1 ftpsystemuser ftpsystemuser 19968 16. Mär 11:24 Termine
>> Leistungspr?fungen.doc
> This looks like a  security problem: the process writing these files
> should not be able to do this as root, should it?
> And then it is very annoying.
>
> Has anyone seen that? Is that something I can configure off somehow?
>
> Any hint or help is appreciated, any deeper insight very welcome.
>
> Dirk
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-- 
Stephen J Smoogen.

Ah, but a man's reach should exceed his grasp. Or what's a heaven for?
-- Robert Browning