[ARM] Improve non-executable support
Add support for detecting non-executable stack binaries, and adjust
permissions to prevent execution from data and stack areas. Also,
ensure that READ_IMPLIES_EXEC is enabled for older CPUs where that
is true, and for any executable-stack binary.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h
index cf2e268..bed1c0a 100644
--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -184,8 +184,9 @@
#endif /* !__ASSEMBLY__ */
-#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
- VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+#define VM_DATA_DEFAULT_FLAGS \
+ (((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0) | \
+ VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
/*
* With EABI on ARMv5 and above we must have 64-bit aligned slab pointers.