[PATCH v1 24/27] x86/mm: Make the x86 GOT read-only
From: Thomas Garnier via Virtualization <hidden>
Date: 2017-10-11 20:30:24
Subsystem:
generic include/asm header files, the rest · Maintainers:
Arnd Bergmann, Linus Torvalds
The GOT is changed during early boot when relocations are applied. Make it read-only directly. This table exists only for PIE binary. Position Independent Executable (PIE) support will allow to extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier <redacted> --- include/asm-generic/vmlinux.lds.h | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index e549bff87c5b..a2301c292e26 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h@@ -279,6 +279,17 @@ VMLINUX_SYMBOL(__end_ro_after_init) = .; #endif +#ifdef CONFIG_X86_PIE +#define RO_GOT_X86 \ + .got : AT(ADDR(.got) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start_got) = .; \ + *(.got); \ + VMLINUX_SYMBOL(__end_got) = .; \ + } +#else +#define RO_GOT_X86 +#endif + /* * Read only Data */
@@ -335,6 +346,7 @@ VMLINUX_SYMBOL(__end_builtin_fw) = .; \ } \ \ + RO_GOT_X86 \ TRACEDATA \ \ /* Kernel symbol table: Normal symbols */ \
--
2.15.0.rc0.271.g36b669edcc-goog