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From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Jeremy Linton <jeremy.linton@arm.com>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	Will Deacon <will@kernel.org>, "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, Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v7 0/4] arm64: Enable BTI for the executable as well as the interpreter
Date: Mon, 17 Jan 2022 17:54:14 +0000	[thread overview]
Message-ID: <YeWtRk0H30q38eM8@arm.com> (raw)
In-Reply-To: <YdgrjWVxRGRtnf5b@arm.com>

On Fri, Jan 07, 2022 at 12:01:17PM +0000, Catalin Marinas wrote:
> I think we can look at this from two angles:
> 
> 1. Ignoring MDWE, should whoever does the original mmap() also honour
>    PROT_BTI? We do this for static binaries but, for consistency, should
>    we extend it to dynamic executable?
> 
> 2. A 'simple' fix to allow MDWE together with BTI.

Thinking about it, (1) is not that different from the kernel setting
PROT_EXEC on the main executable when the dynamic loader could've done
it as well. There is a case for making this more consistent: whoever
does the mmap() should use the full attributes.

Question for the toolchain people: would the compiler ever generate
relocations in the main executable that the linker needs to resolve via
an mprotect(READ|WRITE) followed by mprotect(READ|EXEC)? If yes, we'd
better go for a proper MDWE implementation in the kernel.

-- 
Catalin

WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Jeremy Linton <jeremy.linton@arm.com>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	Will Deacon <will@kernel.org>, "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, Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v7 0/4] arm64: Enable BTI for the executable as well as the interpreter
Date: Mon, 17 Jan 2022 17:54:14 +0000	[thread overview]
Message-ID: <YeWtRk0H30q38eM8@arm.com> (raw)
In-Reply-To: <YdgrjWVxRGRtnf5b@arm.com>

On Fri, Jan 07, 2022 at 12:01:17PM +0000, Catalin Marinas wrote:
> I think we can look at this from two angles:
> 
> 1. Ignoring MDWE, should whoever does the original mmap() also honour
>    PROT_BTI? We do this for static binaries but, for consistency, should
>    we extend it to dynamic executable?
> 
> 2. A 'simple' fix to allow MDWE together with BTI.

Thinking about it, (1) is not that different from the kernel setting
PROT_EXEC on the main executable when the dynamic loader could've done
it as well. There is a case for making this more consistent: whoever
does the mmap() should use the full attributes.

Question for the toolchain people: would the compiler ever generate
relocations in the main executable that the linker needs to resolve via
an mprotect(READ|WRITE) followed by mprotect(READ|EXEC)? If yes, we'd
better go for a proper MDWE implementation in the kernel.

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-01-17 17:54 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-15 15:27 [PATCH v7 0/4] arm64: Enable BTI for the executable as well as the interpreter Mark Brown
2021-11-15 15:27 ` Mark Brown
2021-11-15 15:27 ` [PATCH v7 1/4] elf: Allow architectures to parse properties on the main executable Mark Brown
2021-11-15 15:27   ` Mark Brown
2021-11-15 15:27 ` [PATCH v7 2/4] arm64: Enable BTI for main executable as well as the interpreter Mark Brown
2021-11-15 15:27   ` Mark Brown
2021-11-15 15:27 ` [PATCH v7 3/4] elf: Remove has_interp property from arch_adjust_elf_prot() Mark Brown
2021-11-15 15:27   ` Mark Brown
2021-11-15 15:27 ` [PATCH v7 4/4] elf: Remove has_interp property from arch_parse_elf_property() Mark Brown
2021-11-15 15:27   ` Mark Brown
2021-12-08 18:23 ` [PATCH v7 0/4] arm64: Enable BTI for the executable as well as the interpreter Catalin Marinas
2021-12-08 18:23   ` Catalin Marinas
2021-12-09 11:10   ` Szabolcs Nagy
2021-12-09 11:10     ` Szabolcs Nagy
2022-01-04 17:32     ` Mark Brown
2022-01-04 17:32       ` Mark Brown
2022-01-05 22:42       ` Jeremy Linton
2022-01-05 22:42         ` Jeremy Linton
2022-01-06 11:00         ` Catalin Marinas
2022-01-06 11:00           ` Catalin Marinas
2022-01-06 16:09           ` Jeremy Linton
2022-01-06 16:09             ` Jeremy Linton
2022-01-06 18:13             ` Catalin Marinas
2022-01-06 18:13               ` Catalin Marinas
2022-01-06 19:07               ` Mark Brown
2022-01-06 19:07                 ` Mark Brown
2022-01-07 12:01                 ` Catalin Marinas
2022-01-07 12:01                   ` Catalin Marinas
2022-01-07 13:10                   ` Mark Brown
2022-01-07 13:10                     ` Mark Brown
2022-01-17 17:54                   ` Catalin Marinas [this message]
2022-01-17 17:54                     ` Catalin Marinas
2022-01-17 18:16                     ` Adhemerval Zanella
2022-01-17 18:16                       ` Adhemerval Zanella
2022-01-17 19:01                       ` H.J. Lu
2022-01-17 19:01                         ` H.J. Lu
2022-01-18 11:22                         ` Szabolcs Nagy
2022-01-18 11:22                           ` Szabolcs Nagy
2022-01-18 12:55                           ` H.J. Lu
2022-01-18 12:55                             ` H.J. Lu
2022-01-18 11:02                     ` Szabolcs Nagy
2022-01-18 11:02                       ` Szabolcs Nagy
2022-01-27 12:24                       ` Catalin Marinas
2022-01-27 12:24                         ` Catalin Marinas
2022-01-27 14:48                         ` Szabolcs Nagy
2022-01-27 14:48                           ` Szabolcs Nagy

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