rsync - Jan 2022 - --copy-unsafe-links unexpected behavior with unsafe symlinks

On Sun, Nov 28, 2021 at 12:53 PM Cristian via rsync <rsync at
lists.samba.org>
wrote:
> $ rsync --copy-unsafe-links -avz --delete tree XXX
>
In this case, the "tree" directory is a part of the transfer inside
the
top-of-transfer dir (the current directory). Thus any symlinks that don't
try to escape the current directory are considered to be OK.  You should
instead suffix "tree" with a slash and add "tree" to your
destination path:

$ rsync --copy-unsafe-links -aivz --delete tree/ host:/old/path/tree/

This is discussed in the man page
<https://download.samba.org/pub/rsync/rsync.1> (search for
"unsafe").

..wayne..
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Hello Wayne

Thank you very much for trying to help,

I have the following three observations:


1) As recommended, I have searched the manual of rsync in order to try
 ?? to find your interpretation about what is going on but the only relevant
 ?? fact that I was able to find was how rsync defines unsafe links:

 ???? Symbolic links are considered unsafe if? they? are? absolute
 ???? symlinks (start with /), empty, or if they contain enough ".."
 ???? components to ascend from the directory being copied.

 ?? In my case? (I copy and paste below my original example for commodity)

 ?? TST/
 ?? +-- outside1
 ?? |??? |
 ?? |??? +-- outside1-file.txt
 ?? |
 ?? +-- outside2-file.txt
 ?? |
 ?? +-- tree
 ??????? +-- inside.txt
 ??????? |
 ??????? +-- lnk-ans.txt -> ../../ans.txt
 ??????? |
 ??????? +-- o1-file.txt -> ../outside1/outside1-file.txt
 ??????? |
 ??????? +-- o1-folder -> ../outside1
 ??????? |
 ??????? +-- o2-file.txt -> ../outside2-file.txt

 ?? when I run the commands

 ?????? $ cd TST
 ?????? $ rsync --copy-unsafe-links -avz --delete tree XXX

 ?? In my opinion

 ?????? tree/o1-file.txt
 ?????? tree/o1-folder
 ?????? tree/o2-file.txt

 ?? contain enough .. to ascend from the directory being copied (which
 ?? is "tree")


2) I've also taken into account your observation that

 ??? In this case, the "tree" directory is a part of the transfer
 ??? inside the top-of-transfer dir (the current directory)

 ?? which seems unusual to me (because in my case the directory being
 ?? copied is "tree" and not the current directory (am I missing
something?))
 ?? and started the command rsync command from a another folder:

 ?? $ cd ~/dev
 ?? $ rsync --copy-unsafe-links -avz --delete ~/tmp/TST/tree ~/tmp/XXX

 ?? The result is the same

 ??????? ~/tmp/TST/tree/lnk-ans.txt

 ?? is copied as a file


 ?? And

 ??????? ~/tmp/TST/tree/o1-file.txt
 ??????? ~/tmp/TST/tree/o1-folder
 ??????? ~/tmp/TST/tree/o2-file.txt

 ?? are copied as broken symblinks.

3) I don't think that the intended behavior of rsync is to consider safe
 ?? the symlinks that point to files and folders that are located just above
 ?? the directory being copied ("tree" in this case).

 ?? If this would be the intended behavior, then there will not be possibile
 ?? to specify that you want and entire directory to be copied (with copies
 ?? of the files pointed by unsafe links), because independently of what you
 ?? specify in the command line as the source tree to be copied there will
 ?? always be the posibility that the tree contains some symlink that points
 ?? to a file that is outside the subtree but located under the parent that
 ?? contains the tree and this file will not be copied.

Best regards
Cristian

> On Sun, Nov 28, 2021 at 12:53 PM Cristian via rsync <rsync at
lists.samba.org>
> wrote:
>
>> $ rsync --copy-unsafe-links -avz --delete tree XXX
>>
> In this case, the "tree" directory is a part of the transfer
inside the
> top-of-transfer dir (the current directory). Thus any symlinks that
don't
> try to escape the current directory are considered to be OK.  You should
> instead suffix "tree" with a slash and add "tree" to
your destination path:
>
> $ rsync --copy-unsafe-links -aivz --delete tree/ host:/old/path/tree/
>
> This is discussed in the man page
> <https://download.samba.org/pub/rsync/rsync.1> (search for
"unsafe").
>
> ..wayne..
>

> On Sun, Nov 28, 2021 at 12:53 PM Cristian via rsync <rsync at
lists.samba.org>
> wrote:
>
>> $ rsync --copy-unsafe-links -avz --delete tree XXX
>>
> In this case, the "tree" directory is a part of the transfer
inside the
> top-of-transfer dir (the current directory). Thus any symlinks that
don't
> try to escape the current directory are considered to be OK.  You should
> instead suffix "tree" with a slash and add "tree" to
your destination path:
>
> $ rsync --copy-unsafe-links -aivz --delete tree/ host:/old/path/tree/
>
> This is discussed in the man page
> <https://download.samba.org/pub/rsync/rsync.1> (search for
"unsafe").
Hello Wayne

The first time when I read your answer above it when I saw "in the man
page" I looked
in the manual page on my local computer but the explanations for the
|--copy-unsafe-links|
option do not contain the section regarding the "cut-off point"

Now it happened to me to repoen this email and to check the link above and I
had the pleasant surprise to find the part about the "cut-off point"
that explains
what is going on.

Thank you Wayne for your answer.

Cristian.
> ..wayne..