Re: [PATCH 1/3] treewide: Add SOCK_CLOEXEC to accept() calls that are missing it

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, May 20, 2026 at 02:37:02AM +0200, Stefano Brivio wrote:
> On Mon, 18 May 2026 12:28:57 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > On Sat, May 16, 2026 at 05:46:11PM +0200, Stefano Brivio wrote:
> > > On Wed, 13 May 2026 14:14:21 +1000
> > > David Gibson <david@gibson.dropbear.id.au> wrote:
> > >   
> > > > Generally we try to set the O_CLOEXEC flag on every fd we create.  This
> > > > seems to be generally accepted security best practice these days, and we
> > > > never fork(), so certainly have no need to pass fds to children.  
> > > 
> > > But we do clone() with CLONE_FILES (even though when we clone() to call
> > > execvp() later, we don't set CLONE_FILES), so, even though I don't see
> > > a reason to skip O_CLOEXEC for c->fd_tap, this conclusion shouldn't be
> > > automatic from the fact we don't fork().  
> > 
> > So, I did think about that when  wrote it, but went for the short
> > version rather than saying clone() with CLONE_FILES doesn't count.
> > 
> > Now, I realised that we've both fallen for the trap again, forgetting
> > that this has nothing to do with fork() or clone() and is, as it says
> > right there in the name, about exec().
> 
> No, wait, I didn't fall for it, not this time. :) That's why I was
> mentioning that when we call clone() and execvp() later (which would be

Uh...?  I'm pretty sure the only execve(2) in the entire program is
where we spawn passt.avx2.  That's essentially the very first thing we
do, long before this point.

> the only path that matters), we don't set CLONE_FILES anyway.

CLONE_FILES is irrelevant, it's lost during execve(2).

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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