On Fri, Dec 5, 2014 at 9:28 AM, David Daney <ddaney.cavm@xxxxxxxxx> wrote:
On 12/02/2014 05:58 PM, Leonid Yegoshin wrote:
This is a last step of 3 patches which shift FPU emulation out of
stack into protected area. So, it disables a default executable stack.
Additionally, it sets a default data area non-executable protection.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
Some programs require an executable stack, this patch will break them.
Have you tested this?
You can only select a non-executable stack in response to PT_GNU_STACK
program headers in the ELF file of the executable program.
This is already handled by fs/binfmt_elf.c. It does the parsing of the
PT_GNU_STACK needs, and sets up the stack flags appropriately. All the
change to VM_DATA_DEFAULT_FLAGS does is make sure that EXSTACK_DEFAULT
now means no VM_EXEC by default. If PT_GNU_STACK requires it, it gets
added back in.
arch/mips/include/asm/page.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index 3be81803595d..d49ba81cb4ed 100644
@@ -230,7 +230,7 @@ extern int __virt_addr_valid(const volatile void
__virt_addr_valid((const volatile void *) (kaddr))
-#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
+#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
#define UNCAC_ADDR(addr) ((addr) - PAGE_OFFSET + UNCAC_BASE)