From mboxrd@z Thu Jan 1 00:00:00 1970 From: jeremy.linton@arm.com (Jeremy Linton) Date: Wed, 17 Feb 2016 10:41:13 -0600 Subject: [PATCH v2 1/2] arm64: mm: Mark .rodata as RO In-Reply-To: <1455727274-16328-1-git-send-email-jeremy.linton@arm.com> References: <1455727274-16328-1-git-send-email-jeremy.linton@arm.com> Message-ID: <1455727274-16328-2-git-send-email-jeremy.linton@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Currently the .rodata section is actually still executable when DEBUG_RODATA is enabled. This changes that so the .rodata is actually read only, no execute. Signed-off-by: Jeremy Linton --- arch/arm64/kernel/vmlinux.lds.S | 5 +++-- arch/arm64/mm/mmu.c | 17 +++++++++++++---- 2 files changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 8f4fc2c..9208f53 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -114,8 +114,9 @@ SECTIONS *(.got) /* Global offset table */ } - RO_DATA(PAGE_SIZE) - EXCEPTION_TABLE(8) + ALIGN_DEBUG_RO_MIN(0) + RO_DATA(PAGE_SIZE) /* everything from this point to */ + EXCEPTION_TABLE(8) /* _etext will be marked RO NX */ NOTES ALIGN_DEBUG_RO_MIN(PAGE_SIZE) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ab69a99..9aa5201 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -453,10 +453,18 @@ static void __init map_mem(pgd_t *pgd) #ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void) { - create_mapping_late(__pa(_stext), (unsigned long)_stext, - (unsigned long)_etext - (unsigned long)_stext, - PAGE_KERNEL_ROX); + unsigned long section_size; + section_size = (unsigned long)__start_rodata - (unsigned long)_stext; + create_mapping_late(__pa(_stext), (unsigned long)_stext, + section_size, PAGE_KERNEL_ROX); + /* + * mark .rodata as read only. Use _etext rather than __end_rodata to + * cover NOTES and EXCEPTION_TABLE. + */ + section_size = (unsigned long)_etext - (unsigned long)__start_rodata; + create_mapping_late(__pa(__start_rodata), (unsigned long)__start_rodata, + section_size, PAGE_KERNEL_RO); } #endif @@ -486,7 +494,8 @@ static void __init map_kernel_chunk(pgd_t *pgd, void *va_start, void *va_end, static void __init map_kernel(pgd_t *pgd) { - map_kernel_chunk(pgd, _stext, _etext, PAGE_KERNEL_EXEC); + map_kernel_chunk(pgd, _stext, __start_rodata, PAGE_KERNEL_EXEC); + map_kernel_chunk(pgd, __start_rodata, _etext, PAGE_KERNEL_EXEC); map_kernel_chunk(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC); map_kernel_chunk(pgd, _data, _end, PAGE_KERNEL); -- 2.4.3