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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-kernel@vger.kernel.org,
	Arvind Yadav <arvind.yadav.cs@gmail.com>,
	Matt Fleming <matt@codeblueprint.co.uk>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Tyler Baicar <tbaicar@codeaurora.org>,
	Vasyl Gomonovych <gomonovych@gmail.com>
Subject: [PATCH 2/5] arm64: efi: ignore EFI_MEMORY_XP attribute if RP and/or WP are set
Date: Tue,  2 Jan 2018 18:10:39 +0000	[thread overview]
Message-ID: <20180102181042.19074-3-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20180102181042.19074-1-ard.biesheuvel@linaro.org>

The UEFI memory map is a bit vague about how to interpret the
EFI_MEMORY_XP attribute when it is combined with EFI_MEMORY_RP and/or
EFI_MEMORY_WP, which have retroactively been redefined as cacheability
attributes rather than permission attributes.

So let's ignore EFI_MEMORY_XP if _RP and/or _WP are also set. In this
case, it is likely that they are being used to describe the capability
of the region (i.e., whether it has the controls to reconfigure it as
non-executable) rather than the nature of the contents of the region
(i.e., whether it contains data that we will never attempt to execute)

Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/kernel/efi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 82cd07592519..f85ac58d08a3 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -48,7 +48,9 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
 		return pgprot_val(PAGE_KERNEL_ROX);
 
 	/* RW- */
-	if (attr & EFI_MEMORY_XP || type != EFI_RUNTIME_SERVICES_CODE)
+	if (((attr & (EFI_MEMORY_RP | EFI_MEMORY_WP | EFI_MEMORY_XP)) ==
+	     EFI_MEMORY_XP) ||
+	    type != EFI_RUNTIME_SERVICES_CODE)
 		return pgprot_val(PAGE_KERNEL);
 
 	/* RWX */
-- 
2.11.0

WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
To: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	"H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
Cc: Ard Biesheuvel
	<ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Arvind Yadav
	<arvind.yadav.cs-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Matt Fleming
	<matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>,
	Stephen Boyd <sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Tyler Baicar <tbaicar-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Vasyl Gomonovych
	<gomonovych-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: [PATCH 2/5] arm64: efi: ignore EFI_MEMORY_XP attribute if RP and/or WP are set
Date: Tue,  2 Jan 2018 18:10:39 +0000	[thread overview]
Message-ID: <20180102181042.19074-3-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20180102181042.19074-1-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

The UEFI memory map is a bit vague about how to interpret the
EFI_MEMORY_XP attribute when it is combined with EFI_MEMORY_RP and/or
EFI_MEMORY_WP, which have retroactively been redefined as cacheability
attributes rather than permission attributes.

So let's ignore EFI_MEMORY_XP if _RP and/or _WP are also set. In this
case, it is likely that they are being used to describe the capability
of the region (i.e., whether it has the controls to reconfigure it as
non-executable) rather than the nature of the contents of the region
(i.e., whether it contains data that we will never attempt to execute)

Reported-by: Stephen Boyd <sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Tested-by: Stephen Boyd <sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 arch/arm64/kernel/efi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 82cd07592519..f85ac58d08a3 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -48,7 +48,9 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
 		return pgprot_val(PAGE_KERNEL_ROX);
 
 	/* RW- */
-	if (attr & EFI_MEMORY_XP || type != EFI_RUNTIME_SERVICES_CODE)
+	if (((attr & (EFI_MEMORY_RP | EFI_MEMORY_WP | EFI_MEMORY_XP)) ==
+	     EFI_MEMORY_XP) ||
+	    type != EFI_RUNTIME_SERVICES_CODE)
 		return pgprot_val(PAGE_KERNEL);
 
 	/* RWX */
-- 
2.11.0

  parent reply	other threads:[~2018-01-02 18:11 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-02 18:10 [GIT PULL 0/5] EFI updates for v4.16 Ard Biesheuvel
2018-01-02 18:10 ` Ard Biesheuvel
2018-01-02 18:10 ` [PATCH 1/5] efi/capsule-loader: pr_err() strings should end with newlines Ard Biesheuvel
2018-01-02 18:10   ` Ard Biesheuvel
2018-01-03 16:19   ` [tip:efi/core] efi/capsule-loader: Fix pr_err() string to end with newline tip-bot for Arvind Yadav
2018-01-02 18:10 ` Ard Biesheuvel [this message]
2018-01-02 18:10   ` [PATCH 2/5] arm64: efi: ignore EFI_MEMORY_XP attribute if RP and/or WP are set Ard Biesheuvel
2018-01-03 16:19   ` [tip:efi/core] arm64/efi: Ignore " tip-bot for Ard Biesheuvel
2018-01-02 18:10 ` [PATCH 3/5] efi: Use PTR_ERR_OR_ZERO() Ard Biesheuvel
2018-01-03 16:19   ` [tip:efi/core] " tip-bot for Vasyl Gomonovych
2018-01-02 18:10 ` [PATCH 4/5] efi: move ARM CPER code to new file Ard Biesheuvel
2018-01-02 18:10   ` Ard Biesheuvel
2018-01-03 16:20   ` [tip:efi/core] efi: Move " tip-bot for Tyler Baicar
2018-01-02 18:10 ` [PATCH 5/5] efi: parse ARM error information value Ard Biesheuvel
2018-01-03 16:21   ` [tip:efi/core] efi: Parse " tip-bot for Tyler Baicar

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