linux-kernel - Re: [GIT PULL] pidfd updates

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAHk-=wgFt+rPoEH1bPG2A9K3GNebraLNcbnDiKK=Wp0i6D_0Ww@mail.gmail.com>
Date:   Mon, 24 Apr 2023 13:35:03 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Christian Brauner <brauner@...nel.org>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [GIT PULL] pidfd updates

On Mon, Apr 24, 2023 at 1:24 PM Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
> But I really think a potentially much nicer model would have been to
> extend our "get_unused_fd_flags()" model.
>
> IOW, we could have instead marked the 'struct file *' in the file
> descriptor table as being "not ready yet".

Maybe that isn't worth it just for pdfd, but I have this feeling that
it might make some other code simpler too.

That pidfd case isn't the only one that has to carry both a file
pointer and a fd around.

Looking around, I get the feeling that quite a lot of users of
"fd_install()" might actually have been happier if they could just
install it early, and then just have a "fd_expose(fd)" for the success
case, and for the error cases have "put_unused_fd(fd)" also do the
fput on the file descriptor even if the low bit was set. One less
thing to worry about.

I dunno. Maybe not worth it. That "two return values" just made me go "Eww".

               Linus