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| author | Steve Capper <steve.capper@linaro.org> | 2013-05-02 17:25:42 +0200 |
|---|---|---|
| committer | Steve Capper <steve.capper@linaro.org> | 2013-06-14 10:42:46 +0200 |
| commit | 072b1b62a6436b71ab951faae4500db2fbed63de (patch) | |
| tree | 7cf891feaa8224363173a3c9cb1fa8d0c472d101 | |
| parent | ARM64: mm: Restore memblock limit when map_mem finished. (diff) | |
| download | linux-072b1b62a6436b71ab951faae4500db2fbed63de.tar.xz linux-072b1b62a6436b71ab951faae4500db2fbed63de.zip | |
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.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index e333a243bfcc..77b09d6fee23 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) |