linux-kernel - Re: [PATCH 1/2] uaccess: Simplify code pattern for masked user copies

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: <20250209190211.5a11d6d6@pumpkin>
Date: Sun, 9 Feb 2025 19:02:11 +0000
From: David Laight <david.laight.linux@...il.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, Alexander
 Viro <viro@...iv.linux.org.uk>, Christian Brauner <brauner@...nel.org>, Jan
 Kara <jack@...e.cz>, Arnd Bergmann <arnd@...db.de>, Kees Cook
 <kees@...nel.org>
Subject: Re: [PATCH 1/2] uaccess: Simplify code pattern for masked user
 copies

On Sun, 9 Feb 2025 10:46:03 -0800
Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> On Sun, 9 Feb 2025 at 10:40, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
> >
> > It's *really* easy to miss the "oh, that changes X" when the only
> > little tiny sign of it is that "&" character inside the argument list,
> > and then the *normal* mental model is that arguments are arguments
> > *to* the function, not returns *from* the function.  
> 
> While I'm ranting, this is just another case of "C++ really got this
> very very wrong".
> 
> C++ made pass-by-reference really easy, and removed the need for even
> that tiny marker in the caller.
> 
> So then you really can't even visually see that "oh, that call changes
> its argument", and have to just know.

Or make a habit of appending '+ 0' to every argument :-)

> 
>               Linus