From 2f39b5f91eb4bccd786d194e70db1dccad784755 Mon Sep 17 00:00:00 2001
From: Jeremy Linton <jeremy.linton@arm.com>
Date: Fri, 19 Feb 2016 11:50:32 -0600
Subject: [PATCH] arm64: mm: Mark .rodata as RO
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.
It also adds the .rodata section to the mem_init banner.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
[catalin.marinas@arm.com: added vm_struct vmlinux_rodata in map_kernel()]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm64/kernel/vmlinux.lds.S | 5 +++--
arch/arm64/mm/init.c | 4 +++-
arch/arm64/mm/mmu.c | 19 +++++++++++++------
3 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index e3f6cd740ea34..4c56e7a0621bc 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(PAGE_SIZE)
+ 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/init.c b/arch/arm64/mm/init.c
index 80c8bdeeb41ab..b938de23dc779 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -363,6 +363,7 @@ void __init mem_init(void)
" vmalloc : 0x%16lx - 0x%16lx (%6ld GB)\n"
" .init : 0x%p" " - 0x%p" " (%6ld KB)\n"
" .text : 0x%p" " - 0x%p" " (%6ld KB)\n"
+ " .rodata : 0x%p" " - 0x%p" " (%6ld KB)\n"
" .data : 0x%p" " - 0x%p" " (%6ld KB)\n"
#ifdef CONFIG_SPARSEMEM_VMEMMAP
" vmemmap : 0x%16lx - 0x%16lx (%6ld GB maximum)\n"
@@ -377,7 +378,8 @@ void __init mem_init(void)
MLM(MODULES_VADDR, MODULES_END),
MLG(VMALLOC_START, VMALLOC_END),
MLK_ROUNDUP(__init_begin, __init_end),
- MLK_ROUNDUP(_text, _etext),
+ MLK_ROUNDUP(_text, __start_rodata),
+ MLK_ROUNDUP(__start_rodata, _etext),
MLK_ROUNDUP(_sdata, _edata),
#ifdef CONFIG_SPARSEMEM_VMEMMAP
MLG((unsigned long)vmemmap,
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 00d166465ff46..d2d8b8c2e17f7 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -449,12 +449,18 @@ static void __init map_mem(pgd_t *pgd)
void mark_rodata_ro(void)
{
- if (!IS_ENABLED(CONFIG_DEBUG_RODATA))
- return;
+ unsigned long section_size;
+ section_size = (unsigned long)__start_rodata - (unsigned long)_stext;
create_mapping_late(__pa(_stext), (unsigned long)_stext,
- (unsigned long)_etext - (unsigned long)_stext,
- PAGE_KERNEL_ROX);
+ 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);
}
void fixup_init(void)
@@ -493,9 +499,10 @@ static void __init map_kernel_chunk(pgd_t *pgd, void *va_start, void *va_end,
*/
static void __init map_kernel(pgd_t *pgd)
{
- static struct vm_struct vmlinux_text, vmlinux_init, vmlinux_data;
+ static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
- map_kernel_chunk(pgd, _stext, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
+ map_kernel_chunk(pgd, _stext, __start_rodata, PAGE_KERNEL_EXEC, &vmlinux_text);
+ map_kernel_chunk(pgd, __start_rodata, _etext, PAGE_KERNEL, &vmlinux_rodata);
map_kernel_chunk(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
&vmlinux_init);
map_kernel_chunk(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
--
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