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vsftpd corruption problem (Re: proftpd (and vsftpd too))

On Tue, Apr 22, 2003 at 05:38:12PM +0200, Corinna Vinschen wrote:
> On Tue, Apr 22, 2003 at 10:42:25AM -0400, Jason Tishler wrote:
> >     1. vsftpd.conf must be in binary mode on a binary mount
> >     2. file transfers from/to text mounts can cause "corruption"
> >     3. ASCII transfer mode does not seem to work properly
> > [...]
> > I'm willing to contribute vsftpd with the above caveats and the
> > intention to solve the binary/text issues as time permits.  Is this
> > acceptable?
> As a "test" release, sure!

I may have to renege on the above offer or at least add a *big* caveat
to the README.  Over the last few months, we have transferred tens of
thousands (possibly hundreds of thousands) of "normal" sized (i.e.,
<=100K) files with vsftpd put tunneled through ssh without any problems.
Unfortunately, I have recently discovered a corruption problem when
transferring large files (i.e., >=200MB) with vsftpd get tunneled
through ssh.

So far, I have been able to only trigger the problem on 4-way, NT 4.0
boxes with get when tunneled through ssh on a "slowish" (e.g., ~600
KB/s) network connection.  I cannot reproduce the problem on 1-way
systems, 2000, without ssh, put, or fast network connections (e.g., same

By constructing a specially formating file, I was able to determine that
after about 150 MB is transferred, a chunk of the file is erroneously

The special file contains lines with the following format:


where LLLLLLL is the line number zero padded to 7 digits.

The corruption looks like the following:


So in this case, after starting to transfer line 3327918, for some
reason vsftpd started to transfer data from line 3326607 and onward
again.  But, the file is otherwise not corrupt.  BTW, I have noticed a
200 MB file will be exactly 64 KB larger and a 300 MB file will be
exactly 128 KB larger.

Any ideas on how to debug this further will be greatly appreciate.

BTW, since proftpd CVS works under Cygwin now, should I just give up on
vsftpd and save my head banging for other more productive activities?


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