From: jeremy.linton@arm.com (Jeremy Linton)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/2] arm64: mm: Mark .rodata as RO
Date: Wed, 17 Feb 2016 10:41:13 -0600 [thread overview]
Message-ID: <1455727274-16328-2-git-send-email-jeremy.linton@arm.com> (raw)
In-Reply-To: <1455727274-16328-1-git-send-email-jeremy.linton@arm.com>
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 <jeremy.linton@arm.com>
---
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
next prev parent reply other threads:[~2016-02-17 16:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 16:41 [PATCH v2 0/2] arm64: mm: Mark .rodata as RO Jeremy Linton
2016-02-17 16:41 ` Jeremy Linton [this message]
2016-02-17 16:46 ` [PATCH v2 1/2] " Ard Biesheuvel
2016-02-17 16:54 ` Jeremy Linton
2016-02-17 16:55 ` Ard Biesheuvel
2016-02-17 17:02 ` Mark Rutland
2016-02-17 16:41 ` [PATCH v2 2/2] arm64/mm: Add .rodata to kernel virtual memory boot notice Jeremy Linton
2016-02-17 17:04 ` Mark Rutland
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