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authorSteve Capper <steve.capper@linaro.org>2013-05-02 16:25:42 +0100
committerSteve Capper <steve.capper@linaro.org>2013-06-14 09:42:46 +0100
commit072b1b62a6436b71ab951faae4500db2fbed63de (patch)
tree7cf891feaa8224363173a3c9cb1fa8d0c472d101
parentf6bc87c39d52b2b7aa83f16fcee46daefd26cd4d (diff)
downloadlinux-072b1b62a6436b71ab951faae4500db2fbed63de.tar.gz
ARM64: mm: Make PAGE_NONE pages read only and no-execute.
If we consider the following code sequence: my_pte = pte_modify(entry, myprot); x = pte_write(my_pte); y = pte_exec(my_pte); If myprot comes from a PROT_NONE page, then x and y will both be true which is undesireable behaviour. This patch sets the no-execute and read-only bits for PAGE_NONE such that the code above will return false for both x and y. Signed-off-by: Steve Capper <steve.capper@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--arch/arm64/include/asm/pgtable.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index e333a243bfc..77b09d6fee2 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -66,7 +66,7 @@ extern pgprot_t pgprot_default;
#define _MOD_PROT(p, b) __pgprot_modify(p, 0, b)
-#define PAGE_NONE __pgprot_modify(pgprot_default, PTE_TYPE_MASK, PTE_PROT_NONE)
+#define PAGE_NONE __pgprot_modify(pgprot_default, PTE_TYPE_MASK, PTE_PROT_NONE | PTE_RDONLY | PTE_PXN | PTE_UXN)
#define PAGE_SHARED _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
#define PAGE_SHARED_EXEC _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN)
#define PAGE_COPY _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_RDONLY)
@@ -76,7 +76,7 @@ extern pgprot_t pgprot_default;
#define PAGE_KERNEL _MOD_PROT(pgprot_default, PTE_PXN | PTE_UXN | PTE_DIRTY)
#define PAGE_KERNEL_EXEC _MOD_PROT(pgprot_default, PTE_UXN | PTE_DIRTY)
-#define __PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE)
+#define __PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_RDONLY | PTE_PXN | PTE_UXN)
#define __PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
#define __PAGE_SHARED_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
#define __PAGE_COPY __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_RDONLY)