diff options
| author | Laura Abbott <lauraa@codeaurora.org> | 2015-01-21 17:36:06 -0800 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-01-22 14:54:29 +0000 |
| commit | da141706aea52c1a9fbd28cb8d289b78819f5436 (patch) | |
| tree | 6fb0fb5a11c98030393c5915802c9ec891b6df51 /arch/arm64/kernel/vmlinux.lds.S | |
| parent | 2f896d5866107e2926dcdec34a7d40bc56dd2951 (diff) | |
arm64: add better page protections to arm64
Add page protections for arm64 similar to those in arm.
This is for security reasons to prevent certain classes
of exploits. The current method:
- Map all memory as either RWX or RW. We round to the nearest
section to avoid creating page tables before everything is mapped
- Once everything is mapped, if either end of the RWX section should
not be X, we split the PMD and remap as necessary
- When initmem is to be freed, we change the permissions back to
RW (using stop machine if necessary to flush the TLB)
- If CONFIG_DEBUG_RODATA is set, the read only sections are set
read only.
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/arm64/kernel/vmlinux.lds.S | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 9965ec87cbec..5d9d2dca530d 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -8,6 +8,7 @@ #include <asm/thread_info.h> #include <asm/memory.h> #include <asm/page.h> +#include <asm/pgtable.h> #include "image.h" @@ -49,6 +50,14 @@ PECOFF_FILE_ALIGNMENT = 0x200; #define PECOFF_EDATA_PADDING #endif +#ifdef CONFIG_DEBUG_ALIGN_RODATA +#define ALIGN_DEBUG_RO . = ALIGN(1<<SECTION_SHIFT); +#define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO +#else +#define ALIGN_DEBUG_RO +#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(min); +#endif + SECTIONS { /* @@ -71,6 +80,7 @@ SECTIONS _text = .; HEAD_TEXT } + ALIGN_DEBUG_RO .text : { /* Real text segment */ _stext = .; /* Text and read-only data */ __exception_text_start = .; @@ -87,19 +97,22 @@ SECTIONS *(.got) /* Global offset table */ } + ALIGN_DEBUG_RO RO_DATA(PAGE_SIZE) EXCEPTION_TABLE(8) NOTES + ALIGN_DEBUG_RO _etext = .; /* End of text and rodata section */ - . = ALIGN(PAGE_SIZE); + ALIGN_DEBUG_RO_MIN(PAGE_SIZE) __init_begin = .; INIT_TEXT_SECTION(8) .exit.text : { ARM_EXIT_KEEP(EXIT_TEXT) } - . = ALIGN(16); + + ALIGN_DEBUG_RO_MIN(16) .init.data : { INIT_DATA INIT_SETUP(16) |