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From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Will Deacon <will@kernel.org>,
	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>,
	Mark Brown <broonie@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 16:47:45 +0000	[thread overview]
Message-ID: <20210208164744.GA16506@arm.com> (raw)
In-Reply-To: <20210208141329.GC8542@arm.com>

The 02/08/2021 14:13, Szabolcs Nagy via Libc-alpha wrote:
> The 02/08/2021 12:44, Will Deacon wrote:
> > I'd like an Ack from Szabolcs before we queue this.
> 
> i'm ok with this in principle, but i will rerun
> the glibc tests over night to be sure.


the patch applied cleanly on top of arm64 for-next/core

but it does not work as i expected:

executables that do not have the bti property note
set seems to get bti guarded by the kernel.

at least i see crash in _start when the dynamic
linker (which has bti marking) transfers control
to it and the start code has no bti c.

(according to strace the dynamic linker did not
remap/mprotect the main exe with bti so i assume
this is the kernel's doing)

can somebody verify that the notes are checked
on the executable too and not just on ld.so?

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  reply	other threads:[~2021-02-08 16:49 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 [this message]
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

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