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bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display
From: |
Michalis V. |
Subject: |
bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display |
Date: |
Wed, 25 Aug 2021 11:37:34 +0300 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Lars Ingebrigtsen <larsi@gnus.org> writes:
> In Linux you can't change the permissions on a symlink (they're always
> 777):
>
> chmod never changes the permissions of symbolic links; the chmod system
> call cannot change their permissions. This is not a problem since the
> permissions of symbolic links are never used.
>
> So I'm surprised that the `M' command even tries to do the chmod on the
> symlink. This was apparently done as part of a security audit:
>
> commit 9d626dffc6ba62c0d7a1a5c712f576ed8684fd66
> Author: Paul Eggert <eggert@cs.ucla.edu>
> AuthorDate: Sun Feb 23 16:19:42 2020 -0800
>
> Add 'nofollow' flag to set-file-modes etc.
>
> This avoids some race conditions (Bug#39683). E.g., if some other
> program changes a file to a symlink between the time Emacs creates
> the file and the time it changes the file’s permissions, using the
> new flag prevents Emacs from inadvertently changing the
> permissions of a victim in some completely unrelated directory.
>
> Hm. I'm not sure why this should affect the `M' command in dired, though...
>
> I've added Paul to the CCs; perhaps he has some comments.
that's true; but doing chmod on the symlink from bash will actually
have effect on the symlinked file itself, so from a user perspective
i'd expect dired to behave similarly (that is, M to resolve the symlink
and apply the chmod mask to the actual file). But i never thought of
race conditions and potential security problems so the current behavior
looks like the best one.
thanks,
Michalis
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, (continued)
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Lars Ingebrigtsen, 2021/08/24
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Paul Eggert, 2021/08/24
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Richard Stallman, 2021/08/25
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Lars Ingebrigtsen, 2021/08/26
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Andreas Schwab, 2021/08/26
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Paul Eggert, 2021/08/26
- bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display, Richard Stallman, 2021/08/26
bug#11912: 24.1; 'M' in Dired on a symlink does not refresh the display,
Michalis V. <=