From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
libc-alpha@sourceware.org, Kees Cook <keescook@chromium.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Jeremy Linton <jeremy.linton@arm.com>,
Will Deacon <will@kernel.org>, Dave Martin <Dave.Martin@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: bti: Set PROT_BTI on all BTI executables mapped by the kernel
Date: Mon, 8 Feb 2021 16:50:59 +0000 [thread overview]
Message-ID: <20210208165059.GB16506@arm.com> (raw)
In-Reply-To: <20210208150620.GG8645@sirena.org.uk>
The 02/08/2021 15:06, Mark Brown via Libc-alpha wrote:
> On Mon, Feb 08, 2021 at 02:53:16PM +0000, Dave Martin wrote:
>
> > Question: will this change prevent BTI executables from working under a
> > non-BTI-aware ld.so? And do we care? (I think "probably not" for both,
> > but I'd be interested in others' views.)
>
> Yes, I'd expect that we'd end up allowing a BTIed main executable
> without a BTI ld.so. We already have the case where we will enable BTI
> for the vDSO even if nothing outside the kernel supports BTI and BTI is
> intended to interwork happily so I'd be surprised if there were
> problems.
note that this is unlikely to happen (as opposed
to the other way: bti marked ld.so & non-bti exe)
because if the libc is not built with bti then
the start code (crt1.o) has no bti marking either
so the exe will not get bti marked.
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prev parent reply other threads:[~2021-02-08 16:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-05 17:38 [PATCH] arm64: bti: Set PROT_BTI on all BTI executables mapped by the kernel Mark Brown
2021-02-05 17:51 ` Catalin Marinas
2021-02-05 19:01 ` Mark Brown
2021-02-08 12:44 ` Will Deacon
2021-02-08 14:13 ` Szabolcs Nagy
2021-02-08 16:47 ` Szabolcs Nagy
2021-02-08 17:40 ` Dave Martin
2021-02-08 18:49 ` Catalin Marinas
2021-02-08 14:53 ` Dave Martin
2021-02-08 15:06 ` Mark Brown
2021-02-08 16:50 ` Szabolcs Nagy [this message]
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