From: Laura Abbott <labbott@fedoraproject.org>
To: Russell King <linux@arm.linux.org.uk>, Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <labbott@fedoraproject.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH] arm: Use kernel mm when updating section permissions
Date: Wed, 4 Nov 2015 17:00:39 -0800 [thread overview]
Message-ID: <1446685239-28522-1-git-send-email-labbott@fedoraproject.org> (raw)
Currently, read only permissions are not being applied even
when CONFIG_DEBUG_RODATA is set. This is because section_update
uses current->mm for adjusting the page tables. current->mm
need not be equivalent to the kernel version. Use pgd_offset_k
to get the proper page directory for updating.
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
I found this while trying to convince myself of something.
Dumping the page table via debugfs and writing to kernel text were both
showing the lack of mappings. This was observed on QEMU. Maybe it's just a
QEMUism but if not it probably should go to stable.
---
arch/arm/mm/init.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 8a63b4c..4bb936a 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -629,11 +629,9 @@ static struct section_perm ro_perms[] = {
static inline void section_update(unsigned long addr, pmdval_t mask,
pmdval_t prot)
{
- struct mm_struct *mm;
pmd_t *pmd;
- mm = current->active_mm;
- pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
+ pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
#ifdef CONFIG_ARM_LPAE
pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
--
2.5.0
WARNING: multiple messages have this Message-ID (diff)
From: Laura Abbott <labbott@fedoraproject.org>
To: Russell King <linux@arm.linux.org.uk>, Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <labbott@fedoraproject.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH] arm: Use kernel mm when updating section permissions
Date: Wed, 4 Nov 2015 17:00:39 -0800 [thread overview]
Message-ID: <1446685239-28522-1-git-send-email-labbott@fedoraproject.org> (raw)
Currently, read only permissions are not being applied even
when CONFIG_DEBUG_RODATA is set. This is because section_update
uses current->mm for adjusting the page tables. current->mm
need not be equivalent to the kernel version. Use pgd_offset_k
to get the proper page directory for updating.
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
I found this while trying to convince myself of something.
Dumping the page table via debugfs and writing to kernel text were both
showing the lack of mappings. This was observed on QEMU. Maybe it's just a
QEMUism but if not it probably should go to stable.
---
arch/arm/mm/init.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 8a63b4c..4bb936a 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -629,11 +629,9 @@ static struct section_perm ro_perms[] = {
static inline void section_update(unsigned long addr, pmdval_t mask,
pmdval_t prot)
{
- struct mm_struct *mm;
pmd_t *pmd;
- mm = current->active_mm;
- pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
+ pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
#ifdef CONFIG_ARM_LPAE
pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
--
2.5.0
--
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WARNING: multiple messages have this Message-ID (diff)
From: labbott@fedoraproject.org (Laura Abbott)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: Use kernel mm when updating section permissions
Date: Wed, 4 Nov 2015 17:00:39 -0800 [thread overview]
Message-ID: <1446685239-28522-1-git-send-email-labbott@fedoraproject.org> (raw)
Currently, read only permissions are not being applied even
when CONFIG_DEBUG_RODATA is set. This is because section_update
uses current->mm for adjusting the page tables. current->mm
need not be equivalent to the kernel version. Use pgd_offset_k
to get the proper page directory for updating.
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
I found this while trying to convince myself of something.
Dumping the page table via debugfs and writing to kernel text were both
showing the lack of mappings. This was observed on QEMU. Maybe it's just a
QEMUism but if not it probably should go to stable.
---
arch/arm/mm/init.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 8a63b4c..4bb936a 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -629,11 +629,9 @@ static struct section_perm ro_perms[] = {
static inline void section_update(unsigned long addr, pmdval_t mask,
pmdval_t prot)
{
- struct mm_struct *mm;
pmd_t *pmd;
- mm = current->active_mm;
- pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
+ pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
#ifdef CONFIG_ARM_LPAE
pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
--
2.5.0
next reply other threads:[~2015-11-05 1:00 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-05 1:00 Laura Abbott [this message]
2015-11-05 1:00 ` [PATCH] arm: Use kernel mm when updating section permissions Laura Abbott
2015-11-05 1:00 ` Laura Abbott
2015-11-05 1:06 ` Kees Cook
2015-11-05 1:06 ` Kees Cook
2015-11-05 1:06 ` Kees Cook
2015-11-05 1:13 ` Kees Cook
2015-11-05 1:13 ` Kees Cook
2015-11-05 1:13 ` Kees Cook
2015-11-05 9:46 ` Russell King - ARM Linux
2015-11-05 9:46 ` Russell King - ARM Linux
2015-11-05 9:46 ` Russell King - ARM Linux
2015-11-05 16:20 ` Laura Abbott
2015-11-05 16:20 ` Laura Abbott
2015-11-05 16:20 ` Laura Abbott
2015-11-05 16:27 ` Russell King - ARM Linux
2015-11-05 16:27 ` Russell King - ARM Linux
2015-11-05 16:27 ` Russell King - ARM Linux
2015-11-06 1:05 ` Laura Abbott
2015-11-06 1:05 ` Laura Abbott
2015-11-06 1:05 ` Laura Abbott
2015-11-06 1:15 ` Kees Cook
2015-11-06 1:15 ` Kees Cook
2015-11-06 1:15 ` Kees Cook
2015-11-06 18:44 ` Laura Abbott
2015-11-06 18:44 ` Laura Abbott
2015-11-06 18:44 ` Laura Abbott
2015-11-06 19:08 ` Kees Cook
2015-11-06 19:08 ` Kees Cook
2015-11-06 19:08 ` Kees Cook
2015-11-06 19:12 ` Kees Cook
2015-11-06 19:12 ` Kees Cook
2015-11-06 19:12 ` Kees Cook
2015-11-06 20:11 ` Kevin Hilman
2015-11-06 20:11 ` Kevin Hilman
2015-11-06 20:11 ` Kevin Hilman
2015-11-06 20:28 ` Kees Cook
2015-11-06 20:28 ` Kees Cook
2015-11-06 20:28 ` Kees Cook
2015-11-06 21:06 ` Kevin Hilman
2015-11-06 21:06 ` Kevin Hilman
2015-11-06 21:06 ` Kevin Hilman
2015-11-06 21:19 ` Kees Cook
2015-11-06 21:19 ` Kees Cook
2015-11-06 21:19 ` Kees Cook
2015-11-06 22:37 ` Kevin Hilman
2015-11-06 22:37 ` Kevin Hilman
2015-11-06 22:37 ` Kevin Hilman
2015-11-06 23:05 ` Kevin Hilman
2015-11-06 23:05 ` Kevin Hilman
2015-11-06 23:05 ` Kevin Hilman
2015-11-06 23:47 ` Kees Cook
2015-11-06 23:47 ` Kees Cook
2015-11-06 23:47 ` Kees Cook
2015-11-06 20:46 ` Russell King - ARM Linux
2015-11-06 20:46 ` Russell King - ARM Linux
2015-11-06 20:46 ` Russell King - ARM Linux
2015-11-06 23:41 ` Laura Abbott
2015-11-06 23:41 ` Laura Abbott
2015-11-06 23:41 ` Laura Abbott
2015-11-06 23:49 ` Kees Cook
2015-11-06 23:49 ` Kees Cook
2015-11-06 23:49 ` Kees Cook
2015-11-07 0:20 ` Laura Abbott
2015-11-07 0:20 ` Laura Abbott
2015-11-07 0:20 ` Laura Abbott
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