diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2017-10-25 11:04:14 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2017-11-21 14:45:36 +0000 |
| commit | 1ee5e87f86deca84fdcb7c71bb8368cacc4c24e3 (patch) | |
| tree | 3cc57239ce382599dec14cc6cd440cefdbadc4fe /arch/arm | |
| parent | b9dd05c7002ee0ca8b676428b2268c26399b5e31 (diff) | |
ARM: fix get_user_pages_fast
Ensure that get_user_pages_fast() is not able to access memory which
has been mapped with PROT_NONE.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/pgtable.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index 1c462381c225..150ece66ddf3 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -232,6 +232,18 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd) #define pte_valid_user(pte) \ (pte_valid(pte) && pte_isset((pte), L_PTE_USER) && pte_young(pte)) +static inline bool pte_access_permitted(pte_t pte, bool write) +{ + pteval_t mask = L_PTE_PRESENT | L_PTE_USER; + pteval_t needed = mask; + + if (write) + mask |= L_PTE_RDONLY; + + return (pte_val(pte) & mask) == needed; +} +#define pte_access_permitted pte_access_permitted + #if __LINUX_ARM_ARCH__ < 6 static inline void __sync_icache_dcache(pte_t pteval) { |