From: Will Deacon <will@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Jeremy Linton <jeremy.linton@arm.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
Yu-cheng Yu <yu-cheng.yu@intel.com>,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
libc-alpha@sourceware.org
Subject: Re: [PATCH v8 0/4] arm64: Enable BTI for the executable as well as the interpreter
Date: Tue, 15 Feb 2022 18:34:56 +0000 [thread overview]
Message-ID: <20220215183456.GB9026@willie-the-truck> (raw)
In-Reply-To: <20220124150704.2559523-1-broonie@kernel.org>
On Mon, Jan 24, 2022 at 03:07:00PM +0000, Mark Brown wrote:
> Deployments of BTI on arm64 have run into issues interacting with
> systemd's MemoryDenyWriteExecute feature. Currently for dynamically
> linked executables the kernel will only handle architecture specific
> properties like BTI for the interpreter, the expectation is that the
> interpreter will then handle any properties on the main executable.
> For BTI this means remapping the executable segments PROT_EXEC |
> PROT_BTI.
>
> This interacts poorly with MemoryDenyWriteExecute since that is
> implemented using a seccomp filter which prevents setting PROT_EXEC on
> already mapped memory and lacks the context to be able to detect that
> memory is already mapped with PROT_EXEC. This series resolves this by
> handling the BTI property for both the interpreter and the main
> executable.
This appears to be a user-visible change which cannot be detected or
disabled from userspace. If there is code out there which does not work
when BTI is enabled, won't that now explode when the kernel enables it?
How are we supposed to handle such a regression?
Will
next prev parent reply other threads:[~2022-02-15 18:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 15:07 Mark Brown
2022-01-24 15:07 ` [PATCH v8 1/4] elf: Allow architectures to parse properties on the main executable Mark Brown
2022-02-04 13:00 ` Catalin Marinas
2022-01-24 15:07 ` [PATCH v8 2/4] arm64: Enable BTI for main executable as well as the interpreter Mark Brown
2022-02-04 13:11 ` Catalin Marinas
2022-01-24 15:07 ` [PATCH v8 3/4] elf: Remove has_interp property from arch_adjust_elf_prot() Mark Brown
2022-02-04 14:53 ` Catalin Marinas
2022-01-24 15:07 ` [PATCH v8 4/4] elf: Remove has_interp property from arch_parse_elf_property() Mark Brown
2022-02-04 14:54 ` Catalin Marinas
2022-02-15 18:34 ` Will Deacon [this message]
2022-02-16 13:34 ` [PATCH v8 0/4] arm64: Enable BTI for the executable as well as the interpreter Catalin Marinas
2022-02-16 16:49 ` Szabolcs Nagy
2022-02-16 17:01 ` Mark Brown
2022-02-17 8:17 ` Szabolcs Nagy
2022-02-22 14:15 ` Mark Brown
2022-02-25 13:53 ` Will Deacon
2022-02-25 15:11 ` Mark Brown
2022-02-25 15:54 ` Will Deacon
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