From: Christoph Hellwig <hch@infradead.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
alyssa.milburn@intel.com, scott.d.constable@intel.com,
joao@overdrivepizza.com, andrew.cooper3@citrix.com,
jpoimboe@kernel.org, alexei.starovoitov@gmail.com,
ebiggers@kernel.org, samitolvanen@google.com, kees@kernel.org
Subject: Re: [PATCH 1/8] x86,kcfi: Fix EXPORT_SYMBOL vs kCFI
Date: Tue, 5 Nov 2024 06:32:12 -0800 [thread overview]
Message-ID: <ZyosbEMNzMU6fOe_@infradead.org> (raw)
In-Reply-To: <20241105142720.GG10375@noisy.programming.kicks-ass.net>
On Tue, Nov 05, 2024 at 03:27:20PM +0100, Peter Zijlstra wrote:
> > I don't think that is the case at all. The is a relatively small number
> > of exported symbols that are called indirectly. I'd much rather mark
> > those explicitly.
>
> I'm not claiming they have their address taken -- just saying that
> traditionally this has always been a valid thing to do.
>
> Anyway, I raised this point last time, and I think back then the
> consensus was to explicitly mark those you should not be able to call.
Who came to that consensus? There really is just a relatively well
bounded number of functions that are used as either default methods
or as ready made callbacks. Everything else has no business being
called indirectly. While disallowing this might be a bit of work,
I think it would be a great security improvement.
next prev parent reply other threads:[~2024-11-05 14:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-05 11:39 [PATCH 0/8] x86: kCFI and IBT cleanups Peter Zijlstra
2024-11-05 11:39 ` [PATCH 1/8] x86,kcfi: Fix EXPORT_SYMBOL vs kCFI Peter Zijlstra
2024-11-05 14:16 ` Christoph Hellwig
2024-11-05 14:27 ` Peter Zijlstra
2024-11-05 14:32 ` Christoph Hellwig [this message]
2024-11-05 14:58 ` Peter Zijlstra
2024-11-05 15:41 ` Christoph Hellwig
2024-11-05 15:47 ` Peter Zijlstra
2024-11-05 16:11 ` Peter Zijlstra
2024-11-09 9:14 ` David Laight
2024-11-05 11:39 ` [PATCH 2/8] x86/cfi: Clean up linkage Peter Zijlstra
2024-11-05 11:39 ` [PATCH 3/8] x86/boot: Mark start_secondary() with __noendbr Peter Zijlstra
2024-11-05 11:39 ` [PATCH 4/8] x86/alternative: Simplify callthunk patching Peter Zijlstra
2024-11-05 11:39 ` [PATCH 5/8] x86/traps: Cleanup and robustify decode_bug() Peter Zijlstra
2024-11-05 15:19 ` Andrew Cooper
2024-11-05 11:39 ` [PATCH 6/8] x86/ibt: Clean up is_endbr() Peter Zijlstra
2024-11-05 11:39 ` [PATCH 7/8] x86/ibt: Clean up poison_endbr() Peter Zijlstra
2024-11-05 11:39 ` [PATCH 8/8] x86/early_printk: Harden early_serial Peter Zijlstra
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