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From: Salvatore Mesoraca <s.mesoraca16@gmail.com>
To: Topi Miettinen <toiwoton@gmail.com>
Cc: Kees Cook <keescook@chromium.org>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	 Jeremy Linton <jeremy.linton@arm.com>,
	 "linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	libc-alpha@sourceware.org,  systemd-devel@lists.freedesktop.org,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	 Mark Brown <broonie@kernel.org>,
	Dave Martin <dave.martin@arm.com>,
	 Catalin Marinas <Catalin.Marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	 Kernel Hardening <kernel-hardening@lists.openwall.com>,
	linux-hardening@vger.kernel.org
Subject: Re: BTI interaction between seccomp filters in systemd and glibc mprotect calls, causing service failures
Date: Fri, 23 Oct 2020 18:52:50 +0100	[thread overview]
Message-ID: <CAJHCu1Jrtx=OVEiTVwPJg7CxRkV83tS=HsYeLoAGRf_tgYq_iQ@mail.gmail.com> (raw)
In-Reply-To: <180cd894-d42d-2bdb-093c-b5360b0ecb1e@gmail.com>

Hi,

On Thu, 22 Oct 2020 at 23:24, Topi Miettinen <toiwoton@gmail.com> wrote:
> SARA looks interesting. What is missing is a prctl() to enable all W^X
> protections irrevocably for the current process, then systemd could
> enable it for services with MemoryDenyWriteExecute=yes.

SARA actually has a procattr[0] interface to do just that.
There is also a library[1] to help using it.

> I didn't also see specific measures against memfd_create() or file
> system W&X, but perhaps those can be added later.

You are right, there are no measures against those vectors.
It would be interesting to add them, though.

> Maybe pkey_mprotect()
> is not handled either unless it uses the same LSM hook as mprotect().

IIRC mprotect is implemented more or less as a pkey_mprotect with -1 as pkey.
The same LSM hook should cover both.

Salvatore

[0] https://lore.kernel.org/lkml/1562410493-8661-10-git-send-email-s.mesoraca16@gmail.com/
[1] https://github.com/smeso/libsara

  reply	other threads:[~2020-10-23 17:53 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <8584c14f-5c28-9d70-c054-7c78127d84ea@arm.com>
     [not found] ` <20201022075447.GO3819@arm.com>
     [not found]   ` <78464155-f459-773f-d0ee-c5bdbeb39e5d@gmail.com>
2020-10-22 20:02     ` BTI interaction between seccomp filters in systemd and glibc mprotect calls, causing service failures Kees Cook
2020-10-22 22:24       ` Topi Miettinen
2020-10-23 17:52         ` Salvatore Mesoraca [this message]
2020-10-24 11:34           ` Topi Miettinen
2020-10-24 14:12             ` Salvatore Mesoraca
2020-10-25 13:42               ` Jordan Glover
2020-10-23  9:02       ` Catalin Marinas
2020-10-24 11:01         ` Topi Miettinen
2020-10-26 14:52           ` Catalin Marinas
2020-10-26 15:56             ` Dave Martin
2020-10-26 16:51               ` Mark Brown
2020-10-26 16:31             ` Topi Miettinen

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