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From: Alejandro Colomar <alx@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
	Eric Biederman <ebiederm@xmission.com>,
	Kees Cook <keescook@chromium.org>,
	linux-mm@kvack.org, Rolf Eike Beer <eb@emlix.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Dave Jones <davej@redhat.com>
Subject: Re: 'struct dynamic': struct tag leak in UAPI headers
Date: Tue, 29 Aug 2023 16:20:42 +0200	[thread overview]
Message-ID: <8a7df4fd-9cf6-9a2e-feec-1c70197ed5fa@kernel.org> (raw)
In-Reply-To: <ZO3+Clf1WjBWA4Ty@casper.infradead.org>


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On 2023-08-29 16:17, Matthew Wilcox wrote:
> Ooh, story time!  Long, long ago, we did not separate "Linux headers"
> from "libc headers".  It used to be somebody's job to take the files
> in /usr/src/linux/include/linux and copy them to /usr/include/linux.
> Bold people used a symlink.  People who cared about things like "Well,
> POSIX says that" would edit the files after copying them to remove things
> that POSIX said shouldn't be there or put _GNU_SOURCE markers around them.
> 
> At some point, we decided to split the headers to create the uapi headers
> to make this job easier.  Refinements are, of course, possible, and now
> easier than ever, but I think it's fair to say that anybody who included
> <linux/elf.h> at any time in history got given a struct dynamic.

Thanks for the story!  :-)


> Well, it's a compile-time failure either way.  Code that depended on it
> is compiling happily today, and the code that would want to use it
> doesn't exist yet, so I'd rather err on the side of keeping code written
> in the last 30 years working.

Fair enough.

Cheers,
Alex

-- 
<http://www.alejandro-colomar.es/>
GPG key fingerprint: A9348594CE31283A826FBDD8D57633D441E25BB5


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  reply	other threads:[~2023-08-29 14:20 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-29 12:08 Alejandro Colomar
2023-08-29 12:24 ` Matthew Wilcox
2023-08-29 13:27   ` Alejandro Colomar
2023-08-29 14:17     ` Matthew Wilcox
2023-08-29 14:20       ` Alejandro Colomar [this message]
2023-08-29 16:48         ` Eric W. Biederman
2023-08-29 17:46           ` Alejandro Colomar
     [not found] ` <20230829185121.326228-1-alx@kernel.org>
     [not found]   ` <6bd4800d-5e99-48a0-a407-2213112f4fb2@kernel.org>
     [not found]     ` <202309220940.B2730B3B@keescook>
2023-09-22 16:44       ` Ping: [PATCH v1] elf, uapi: Remove struct tag 'dynamic' Kees Cook
2023-09-22 17:01         ` Alejandro Colomar
2023-09-22 17:03   ` Kees Cook

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