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Date:   Mon, 26 Oct 2020 16:51:25 +0000
From:   Mark Brown <broonie@kernel.org>
To:     Dave Martin <Dave.Martin@arm.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Topi Miettinen <toiwoton@gmail.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Salvatore Mesoraca <s.mesoraca16@gmail.com>,
        systemd-devel@lists.freedesktop.org,
        Kees Cook <keescook@chromium.org>,
        kernel-hardening@lists.openwall.com,
        Will Deacon <will.deacon@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jeremy Linton <jeremy.linton@arm.com>,
        linux-hardening@vger.kernel.org, libc-alpha@sourceware.org,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: BTI interaction between seccomp filters in systemd and glibc
 mprotect calls, causing service failures
Message-ID: <20201026165125.GF7402@sirena.org.uk>
References: <8584c14f-5c28-9d70-c054-7c78127d84ea@arm.com>
 <20201022075447.GO3819@arm.com>
 <78464155-f459-773f-d0ee-c5bdbeb39e5d@gmail.com>
 <202010221256.A4F95FD11@keescook>
 <20201023090232.GA25736@gaia>
 <cf655c11-d854-281a-17ae-262ddf0aaa08@gmail.com>
 <20201026145245.GD3117@gaia>
 <20201026155628.GA27285@arm.com>
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On Mon, Oct 26, 2020 at 03:56:35PM +0000, Dave Martin wrote:
> On Mon, Oct 26, 2020 at 02:52:46PM +0000, Catalin Marinas via Libc-alpha wrote:

> > Now, if the dynamic loader silently ignores the mprotect() failure on
> > the main executable, is there much value in exposing a flag in the aux
> > vectors? It saves a few (one?) mprotect() calls but I don't think it
> > matters much. Anyway, I don't mind the flag.

> I don't see a problem with the aforementioned patch [2] to pre-set BTI
> on the pages of the main binary.

Me either FWIW.

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