scp filename quoting

[Patrick Cernko]

Hi,

I just made a patch to "correctly" support special characters in scp at
the remote side. First let me explain the problem:

# cd /tmp
# touch this is a test
# cp this\ is\ a\ test a\ test
# scp localhost:$PWD/a\ test this\ is\ a\ test
scp: /tmp/a: No such file or directory
scp: test: No such file or directory

but

# scp localhost:$PWD/a\\\ test this\ is\ a\ test
a test                              100%    0     0.0KB/s   00:00
errror at defiant:/tmp> ls a\ test -l
-rw-rw-r--  1 errror errror 0 2005-07-26 11:50 a test

So: As scp stringifies the remote side filename, ignoring special
characters like ' ', the remote side get the wrong arguments. The
correct way to go would be to redesign the scp client-server-protocol,
but this is not desired (see http://www.openssh.com/faq.html#2.10) and
would take years to reach all running server's implementations. A quiet
easier fix is, to "correctly" quote the filenames for the remote side.
Here an example with my patch scp client:

# scp -v localhost:$PWD/a\ test this\ is\ a\ test
Unquoted target: "/tmp/a test"
Quoted target = "/tmp/a\ test"
Executing: program /usr/bin/ssh host localhost, user (unspecified),
command scp -v -t /tmp/a\ test
a test                              100%    0     0.0KB/s   00:00

I made the patch against the version of openssh I am currently running
on Linux Debian/sarge (openssh-3.8.1p1). It worked fine. For your
convenience, I also adopted the patch to the current cvs head version of
scp.c, but I did not test nor even compiled it.

I would be happy to see the functionality integrated in further
releases. Maybe this should be wrapped into an non-default option to
avoid incompatibility with existing setups.

So, what do you, the developers, think of my patch?

P.S.: Before I started developing the patch, I also noticed that the
sftp program has the same problems.
-- 
Patrick Cernko | mailto:errror at errror.org | http://www.errror.org
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