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From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com, will@kernel.org, maz@kernel.org,
	mark.rutland@arm.com, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 2/2] arm64: mm: avoid writable executable mappings in kexec/hibernate code
Date: Fri, 29 Apr 2022 15:13:47 +0200	[thread overview]
Message-ID: <20220429131347.3621090-3-ardb@kernel.org> (raw)
In-Reply-To: <20220429131347.3621090-1-ardb@kernel.org>

The temporary mappings of the low-level kexec and hibernate helpers are
created with both writable and executable attributes, which is not
necessary here, and generally best avoided. So use read-only, executable
attributes instead.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/mm/trans_pgd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index d7da8ca40d2e..4ea2eefbc053 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -238,7 +238,7 @@ int trans_pgd_idmap_page(struct trans_pgd_info *info, phys_addr_t *trans_ttbr0,
 	int this_level, index, level_lsb, level_msb;
 
 	dst_addr &= PAGE_MASK;
-	prev_level_entry = pte_val(pfn_pte(pfn, PAGE_KERNEL_EXEC));
+	prev_level_entry = pte_val(pfn_pte(pfn, PAGE_KERNEL_ROX));
 
 	for (this_level = 3; this_level >= 0; this_level--) {
 		levels[this_level] = trans_alloc(info);
-- 
2.30.2


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  parent reply	other threads:[~2022-04-29 13:15 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-29 13:13 [PATCH 0/2] arm64: pair of minor hardening tweaks Ard Biesheuvel
2022-04-29 13:13 ` [PATCH 1/2] arm64: lds: move special code sections out of kernel exec segment Ard Biesheuvel
2022-05-04 18:59   ` Catalin Marinas
2022-05-05  7:10     ` Ard Biesheuvel
2022-04-29 13:13 ` Ard Biesheuvel [this message]
2022-05-04 11:52 ` [PATCH 0/2] arm64: pair of minor hardening tweaks Mark Rutland
2022-05-17  8:38 ` Catalin Marinas

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