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restrictive umask vs gnupload

From: Jim Meyering
Subject: restrictive umask vs gnupload
Date: Tue, 06 Dec 2011 21:37:56 +0100

I use a umask of 077.
That is rather irregular (022 is more common), but for a good reason.
It might have saved me from exploit via at least one flaw (the automake
"dist" abuse CVE).

Anyhow, many tools fail to account for the possibility of a restrictive
umask, and gnupload is one of them.

If I'm not careful, gnupload will create a .sig file that is
neither group- nor world-writable (0600 permissions).
In some contexts, if I upload and preserve those permissions,
the file will be inaccessible.

I have a few ways to avoid that:
  - change gnupload to set umask 022
  - change gnupload to run chmod go+r on each uploaded file (may not
      always be appropriate?)
  - temporarily set umask 022 before running gnupload
    (which would mean changing the gnupload command that maint.mk emits,
  - "remember" always to set permissions of files I'm uploading so that
    they include go+r
  - set umask 022 via a .gnuploadrc file in every build directory

So far, this happens only when I make gnupload use scp (i.e., not to

I'd prefer to change gnupload.
The umask-in-gnupload change would fix it only for .sig,
but unless I'm careful, the .tar.xz file is also go-r,
so from that perspective, the chmod go+r would be better.

You can argue that this whole problem would go away if I
would just use (umask 022; make stable), but that is exactly
the context in which I did not want to use a permissive umask.
However, now that all of my working directories are go-rwx,
it should be mostly moot.  But you never know when some tool
you run might decide to create a directory in /tmp ...

Opinions, preferences, "get over it!" ;-)

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