[HEADSUP] Disallowing read() of a directory fd

[Chris]

On Fri, 15 May 2020 17:06:27 +0200 arne at Steinkamm.COM said

> On Fri, May 15, 2020 at 10:48:15AM -0400, Diane Bruce wrote:
> > All I have to say on this noisy bikeshed is, let's resurrect the mkdir
> > bug of V7 because it's tradition and the BSD way and history and stuff.
> > (I only expect a few of you to remember this one.)
> 
> Oh, this "bug" was alive until Sys V 3.2 times...
> 
> Implementing mkdir as library function without a syscall wasn't a good idea.
> ken and dmr saw no reason to implement mkdir as atomic operation.
> So it was easy, even with a shell script, to jump between the
> mknod(2) and the chown(2) to replace the directory node with a symlink to
> /etc/passwd.
> 
> This was from a todays point of view a stupid mistake. Reading a directory
> node
> is lightyears away from "a stupid mistake".
> 
> Make it switchable with a sysctl switch... would be the best of both worlds.
So long as it were not read only, might be acceptable. But given the potential
gains for all this, are trivial at best. Why was this proposal not dropped?
It's spooling up a massive buffer, for little, to no significant value.

Move on to something of _actual_ importance -- *please*.

--Chris
> 
> .//. Arne
> 
> -- 
> Arne Steinkamm         | Home:     Mail: arne<at>steinkamm<dot>com
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