SCP in SFTP mode

[Damien Miller]

I haven't had time to investigate this yet

On Wed, 2 Feb 2022, Dmitry Belyavskiy wrote:

> Dear Damien,
> Sorry for being repetitive - but should we consider it to be a known
> limitation?
> 
> Many thanks in advance!
> 
> On Fri, Jan 28, 2022 at 10:53 AM Dmitry Belyavskiy <dbelyavs at redhat.com>
> wrote:
>       Dear Damien,
> 
> On Fri, Jan 28, 2022 at 1:40 AM Damien Miller <djm at mindrot.org> wrote:
>       On Thu, 27 Jan 2022, Dmitry Belyavskiy wrote:
> 
>       > Hello,
>       >
>       > When we use scp in sftp mode to copy folder to the
>       machines with the "old"
>       > version of ssh, we get the following error:
>       > ======
>       > $ scp -vvv -r test/ touser at machine:/home/touser
> 
>       What version of OpenSSH are you using? There are a bunch
>       of fixes in git
>       HEAD after 8.8.
> 
>       > If I understand correctly, the failure is caused by the
>       lack of the "
>       > expand-path at openssh.com"
>       > extension to sftp protocol in old releases and (lack of)
>       processing it on
>       > the server side.
> 
>       No, that extension is only invoked when a ~-prefixed path
>       is used.
> 
>       AFAIK this was juat a behaviour difference: scp in sftp
>       mode wasn't
>       creating the destination directory if it didn't exist,
>       whereas legacy
>       scp would do so. It was fixed in the commit you identify
>       below.
> 
>       > For the recent version self-compatibility it was fixed
>       in
>       >https://github.com/openssh/openssh-portable/commit/ac7c9ec894ed0825d04ef69c
>       55babb49bab1d32e
> 
>       -d
> 
> I've just retested with the recent master
> $ ./scp -S `pwd`/ssh -vvv -r -s `pwd`/openbsd-compat/ user at machine:
> 
> debug2: subsystem request accepted on channel 0
> ./scp: debug2: Remote version: 3
> ./scp: debug2: Server supports extension "posix-rename at openssh.com"
> revision 1
> ./scp: debug2: Server supports extension "statvfs at openssh.com"
> revision 2
> ./scp: debug2: Server supports extension "fstatvfs at openssh.com"
> revision 2
> ./scp: debug2: Server supports extension "hardlink at openssh.com"
> revision 1
> ./scp: debug2: Server supports extension "fsync at openssh.com" revision
> 1
> ./scp: debug2: Server supports extension "lsetstat at openssh.com"
> revision 1
> ./scp: debug2: Sending SSH2_FXP_STAT "/root"
> ./scp: debug3: Sent message fd 6 T:17 I:1
> ./scp: debug3: Received stat reply T:105 I:1 F:0x000f M:40550
> ./scp: debug3: source_sftp: copying local
> /home/dbelyavs/work/upstream/openssh-portable/openbsd-compat to remote
> /root/openbsd-compat
> ./scp: debug2: Sending SSH2_FXP_REALPATH "/root/openbsd-compat"
> ./scp: debug3: Sent message fd 6 T:16 I:2
> ./scp: realpath /root/openbsd-compat: No such file
> ./scp: upload "/root/openbsd-compat": path canonicalization failed
> ./scp: failed to upload directory
> /home/dbelyavs/work/upstream/openssh-portable/openbsd-compat to
> /root/openbsd-compat
> 
> The failure occurs even when I specify absolute paths on the
> source/destination machine.
> 
> The destination machine has OpenSSH_8.0p1 with patches.
> 
> --
> Dmitry Belyavskiy
> 
> 
> 
> --
> Dmitry Belyavskiy
> 
>