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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 4 May 2021 13:24:55 -0700
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Subject: Re: [PATCH v3] proc: Use seq_read_iter for /proc/*/maps
To:     Arusekk <arek_koz@o2.pl>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>
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On Tue, May 4, 2021 at 1:21 PM Arusekk <arek_koz@o2.pl> wrote:
>
> Keeping it the way it is for the sake of security of userspace applications
> looks more like security through obscurity to me.

No, it's simply "no valid use" and "why expose interfaces that don't
need to be exposed".

splice() _has_ been a security issue before. It's why I want to limit
it now. I want to enable it only for cases that seem to be worth
enabling for.

Have we fixed all the splice security issues? I certainly hope so. Are
you correct in stating that there are probably other places that might
be more interesting to attackers? Sure. But none of that changes the
basic issue: why expose this?

                Linus