linux-hardening - Re: [PATCH 0/4] aarch64: avoid mprotect(PROT_BTI|PROT

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Message-ID: <87ft5p2naf.fsf@oldenburg2.str.redhat.com>
Date:   Wed, 04 Nov 2020 15:45:44 +0100
From:   Florian Weimer <fweimer@...hat.com>
To:     Catalin Marinas <catalin.marinas@....com>
Cc:     Szabolcs Nagy <szabolcs.nagy@....com>,
        Jeremy Linton <jeremy.linton@....com>,
        Mark Brown <broonie@...nel.org>, libc-alpha@...rceware.org,
        Mark Rutland <mark.rutland@....com>,
        Will Deacon <will@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Salvatore Mesoraca <s.mesoraca16@...il.com>,
        Lennart Poettering <mzxreary@...inter.de>,
        Topi Miettinen <toiwoton@...il.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kernel-hardening@...ts.openwall.com,
        linux-hardening@...r.kernel.org
Subject: Re: [PATCH 0/4] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) [BZ
 #26831]

* Catalin Marinas:

> Can the dynamic loader mmap() the main exe again while munmap'ing the
> original one? (sorry if it was already discussed)

No, we don't have a descriptor for that.  /proc may not be mounted, and
using the path stored there has a race condition anyway.

Thanks,
Florian
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