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Revert "arm64: Introduce execute-only page access permissions"

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This reverts commit bc07c2c6e9.

While the aim is increased security for --x memory maps, it does not
protect against kernel level reads. Until SECCOMP is implemented for
arm64, revert this patch to avoid giving a false idea of execute-only
mappings.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas 2014-05-16 16:44:32 +01:00
parent cf5c95db57
commit 5a0fdfada3
2 changed files with 8 additions and 8 deletions
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11
arch/arm64/include/asm/pgtable.h
View File

@ -86,13 +86,12 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
#define PAGE_COPY_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
#define PAGE_READONLY __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
#define PAGE_READONLY_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
#define PAGE_EXECONLY __pgprot(_PAGE_DEFAULT | PTE_NG | PTE_PXN)
#define __P000 PAGE_NONE
#define __P001 PAGE_READONLY
#define __P010 PAGE_COPY
#define __P011 PAGE_COPY
#define __P100 PAGE_EXECONLY
#define __P100 PAGE_READONLY_EXEC
#define __P101 PAGE_READONLY_EXEC
#define __P110 PAGE_COPY_EXEC
#define __P111 PAGE_COPY_EXEC
@ -101,7 +100,7 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
#define __S001 PAGE_READONLY
#define __S010 PAGE_SHARED
#define __S011 PAGE_SHARED
#define __S100 PAGE_EXECONLY
#define __S100 PAGE_READONLY_EXEC
#define __S101 PAGE_READONLY_EXEC
#define __S110 PAGE_SHARED_EXEC
#define __S111 PAGE_SHARED_EXEC
@ -137,8 +136,8 @@ extern struct page *empty_zero_page;
#define pte_write(pte) (!!(pte_val(pte) & PTE_WRITE))
#define pte_exec(pte) (!(pte_val(pte) & PTE_UXN))
#define pte_valid_ng(pte) \
((pte_val(pte) & (PTE_VALID | PTE_NG)) == (PTE_VALID | PTE_NG))
#define pte_valid_user(pte) \
((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER))
static inline pte_t pte_wrprotect(pte_t pte)
{
@ -192,7 +191,7 @@ extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
if (pte_valid_ng(pte)) {
if (pte_valid_user(pte)) {
if (!pte_special(pte) && pte_exec(pte))
__sync_icache_dcache(pte, addr);
if (pte_dirty(pte) && pte_write(pte))

5
arch/arm64/mm/fault.c
View File

@ -173,7 +173,8 @@ static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
good_area:
/*
* Check that the permissions on the VMA allow for the fault which
* occurred.
* occurred. If we encountered a write or exec fault, we must have
* appropriate permissions, otherwise we allow any permission.
*/
if (!(vma->vm_flags & vm_flags)) {
fault = VM_FAULT_BADACCESS;
@ -195,7 +196,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code;
unsigned long vm_flags = VM_READ | VM_WRITE;
unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC;
unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
tsk = current;