Re: [PATCH v2 2/4] hurd: Implement MSG_CMSG_CLOEXEC

[Sergey Bugaev <bugaevc@gmail.com>]

On Tue, Apr 25, 2023 at 12:10 AM Samuel Thibault
<samuel.thibault@gnu.org> wrote:
> Applied, thanks!

Thank you -- but I see you changed it to say "fds[j] | fd_flags".

For one thing it would be nice of you to indicate that this was your
change, not mine, because as things are it looks like I wrote that,
but I didn't. Linux docs (I was about to write "kernel docs", heh)
suggest this pattern:

> it is recommended that you add a line between the last
> Signed-off-by header and yours, indicating the nature of your
> changes. While there is nothing mandatory about this, it seems like
> prepending the description with your mail and/or name, all enclosed
> in square brackets, is noticeable enough to make it obvious that you
> are responsible for last-minute changes. Example :
>
> Signed-off-by: Random J Developer <random@developer.example.org>
> [lucky@maintainer.example.org: struct foo moved from foo.c to foo.h]
> Signed-off-by: Lucky K Maintainer <lucky@maintainer.example.org>

But on the technical side of things, I don't think we should take
whatever integer arrives in the message and use it as flags. We never
check it for sanity; who knows what might be there; the fd management
subsystem is not generally written with the assumption that 'flags'
might be attacker-controlled/malicious. I don't see how anything
actually bad could happen in this case, but it could specify O_CLOEXEC
and/or O_IGNORE_CTTY when we don't want them, for instance.

Sergey