* [PATCH v4 1/2] x86/pti: check the return value of pti_user_pagetable_walk_p4d
@ 2018-07-20 0:06 Jiang Biao
2018-07-20 0:06 ` [PATCH v4 2/2] x86/pti: check the return value of pti_user_pagetable_walk_pmd Jiang Biao
2018-07-20 5:09 ` [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_p4d() tip-bot for Jiang Biao
0 siblings, 2 replies; 4+ messages in thread
From: Jiang Biao @ 2018-07-20 0:06 UTC (permalink / raw)
To: tglx, mingo
Cc: dave.hansen, luto, hpa, x86, albcamus, linux-kernel,
zhong.weidong, jiang.biao2
pti_user_pagetable_walk_p4d() may return NULL, we should check the
return value to avoid NULL pointer dereference. And add warning
for fail allocation where NULL returned.
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
---
arch/x86/mm/pti.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 4d418e7..8679c64 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -176,7 +176,7 @@ static p4d_t *pti_user_pagetable_walk_p4d(unsigned long address)
if (pgd_none(*pgd)) {
unsigned long new_p4d_page = __get_free_page(gfp);
- if (!new_p4d_page)
+ if (WARN_ON_ONCE(!new_p4d_page))
return NULL;
set_pgd(pgd, __pgd(_KERNPG_TABLE | __pa(new_p4d_page)));
@@ -195,9 +195,13 @@ static p4d_t *pti_user_pagetable_walk_p4d(unsigned long address)
static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
{
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- p4d_t *p4d = pti_user_pagetable_walk_p4d(address);
+ p4d_t *p4d;
pud_t *pud;
+ p4d = pti_user_pagetable_walk_p4d(address);
+ if (!p4d)
+ return NULL;
+
BUILD_BUG_ON(p4d_large(*p4d) != 0);
if (p4d_none(*p4d)) {
unsigned long new_pud_page = __get_free_page(gfp);
@@ -354,6 +358,9 @@ static void __init pti_clone_p4d(unsigned long addr)
pgd_t *kernel_pgd;
user_p4d = pti_user_pagetable_walk_p4d(addr);
+ if (!user_p4d)
+ return;
+
kernel_pgd = pgd_offset_k(addr);
kernel_p4d = p4d_offset(kernel_pgd, addr);
*user_p4d = *kernel_p4d;
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v4 2/2] x86/pti: check the return value of pti_user_pagetable_walk_pmd
2018-07-20 0:06 [PATCH v4 1/2] x86/pti: check the return value of pti_user_pagetable_walk_p4d Jiang Biao
@ 2018-07-20 0:06 ` Jiang Biao
2018-07-20 5:10 ` [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_pmd() tip-bot for Jiang Biao
2018-07-20 5:09 ` [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_p4d() tip-bot for Jiang Biao
1 sibling, 1 reply; 4+ messages in thread
From: Jiang Biao @ 2018-07-20 0:06 UTC (permalink / raw)
To: tglx, mingo
Cc: dave.hansen, luto, hpa, x86, albcamus, linux-kernel,
zhong.weidong, jiang.biao2
Check the return value of pti_user_pagetable_walk_pmd() to avoid
NULL pointer dereference. And add warning for fail allocation.
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
---
arch/x86/mm/pti.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 8679c64..5cd7b82 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -205,7 +205,7 @@ static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
BUILD_BUG_ON(p4d_large(*p4d) != 0);
if (p4d_none(*p4d)) {
unsigned long new_pud_page = __get_free_page(gfp);
- if (!new_pud_page)
+ if (WARN_ON_ONCE(!new_pud_page))
return NULL;
set_p4d(p4d, __p4d(_KERNPG_TABLE | __pa(new_pud_page)));
@@ -219,7 +219,7 @@ static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
}
if (pud_none(*pud)) {
unsigned long new_pmd_page = __get_free_page(gfp);
- if (!new_pmd_page)
+ if (WARN_ON_ONCE(!new_pmd_page))
return NULL;
set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page)));
@@ -241,9 +241,13 @@ static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
static __init pte_t *pti_user_pagetable_walk_pte(unsigned long address)
{
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- pmd_t *pmd = pti_user_pagetable_walk_pmd(address);
+ pmd_t *pmd;
pte_t *pte;
+ pmd = pti_user_pagetable_walk_pmd(address);
+ if (!pmd)
+ return NULL;
+
/* We can't do anything sensible if we hit a large mapping. */
if (pmd_large(*pmd)) {
WARN_ON(1);
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_pmd()
2018-07-20 0:06 ` [PATCH v4 2/2] x86/pti: check the return value of pti_user_pagetable_walk_pmd Jiang Biao
@ 2018-07-20 5:10 ` tip-bot for Jiang Biao
0 siblings, 0 replies; 4+ messages in thread
From: tip-bot for Jiang Biao @ 2018-07-20 5:10 UTC (permalink / raw)
To: linux-tip-commits; +Cc: mingo, hpa, tglx, linux-kernel, jiang.biao2
Commit-ID: 8c934e01a7ce685d98e970880f5941d79272c654
Gitweb: https://git.kernel.org/tip/8c934e01a7ce685d98e970880f5941d79272c654
Author: Jiang Biao <jiang.biao2@zte.com.cn>
AuthorDate: Fri, 20 Jul 2018 08:06:32 +0800
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 20 Jul 2018 07:07:39 +0200
x86/pti: Check the return value of pti_user_pagetable_walk_pmd()
pti_user_pagetable_walk_pmd() can return NULL, so the return value should
be checked to prevent a NULL pointer dereference.
Add the check and a warning when the PMD allocation fails.
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@linux.intel.com
Cc: luto@kernel.org
Cc: hpa@zytor.com
Cc: albcamus@gmail.com
Cc: zhong.weidong@zte.com.cn
Link: https://lkml.kernel.org/r/1532045192-49622-2-git-send-email-jiang.biao2@zte.com.cn
---
arch/x86/mm/pti.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 001ee6b0619e..bcf35dac1920 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -205,7 +205,7 @@ static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
BUILD_BUG_ON(p4d_large(*p4d) != 0);
if (p4d_none(*p4d)) {
unsigned long new_pud_page = __get_free_page(gfp);
- if (!new_pud_page)
+ if (WARN_ON_ONCE(!new_pud_page))
return NULL;
set_p4d(p4d, __p4d(_KERNPG_TABLE | __pa(new_pud_page)));
@@ -219,7 +219,7 @@ static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
}
if (pud_none(*pud)) {
unsigned long new_pmd_page = __get_free_page(gfp);
- if (!new_pmd_page)
+ if (WARN_ON_ONCE(!new_pmd_page))
return NULL;
set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page)));
@@ -241,9 +241,13 @@ static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
static __init pte_t *pti_user_pagetable_walk_pte(unsigned long address)
{
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- pmd_t *pmd = pti_user_pagetable_walk_pmd(address);
+ pmd_t *pmd;
pte_t *pte;
+ pmd = pti_user_pagetable_walk_pmd(address);
+ if (!pmd)
+ return NULL;
+
/* We can't do anything sensible if we hit a large mapping. */
if (pmd_large(*pmd)) {
WARN_ON(1);
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_p4d()
2018-07-20 0:06 [PATCH v4 1/2] x86/pti: check the return value of pti_user_pagetable_walk_p4d Jiang Biao
2018-07-20 0:06 ` [PATCH v4 2/2] x86/pti: check the return value of pti_user_pagetable_walk_pmd Jiang Biao
@ 2018-07-20 5:09 ` tip-bot for Jiang Biao
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Jiang Biao @ 2018-07-20 5:09 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, tglx, jiang.biao2
Commit-ID: b2b7d986a89b6c94b1331a909de1217214fb08c1
Gitweb: https://git.kernel.org/tip/b2b7d986a89b6c94b1331a909de1217214fb08c1
Author: Jiang Biao <jiang.biao2@zte.com.cn>
AuthorDate: Fri, 20 Jul 2018 08:06:31 +0800
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 20 Jul 2018 07:07:39 +0200
x86/pti: Check the return value of pti_user_pagetable_walk_p4d()
pti_user_pagetable_walk_p4d() can return NULL, so the return value should
be checked to prevent a NULL pointer dereference.
Add the check and a warning when the P4D allocation fails.
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: dave.hansen@linux.intel.com
Cc: luto@kernel.org
Cc: hpa@zytor.com
Cc: albcamus@gmail.com
Cc: zhong.weidong@zte.com.cn
Link: https://lkml.kernel.org/r/1532045192-49622-1-git-send-email-jiang.biao2@zte.com.cn
---
arch/x86/mm/pti.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 7b1c85759005..001ee6b0619e 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -176,7 +176,7 @@ static p4d_t *pti_user_pagetable_walk_p4d(unsigned long address)
if (pgd_none(*pgd)) {
unsigned long new_p4d_page = __get_free_page(gfp);
- if (!new_p4d_page)
+ if (WARN_ON_ONCE(!new_p4d_page))
return NULL;
set_pgd(pgd, __pgd(_KERNPG_TABLE | __pa(new_p4d_page)));
@@ -195,9 +195,13 @@ static p4d_t *pti_user_pagetable_walk_p4d(unsigned long address)
static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
{
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- p4d_t *p4d = pti_user_pagetable_walk_p4d(address);
+ p4d_t *p4d;
pud_t *pud;
+ p4d = pti_user_pagetable_walk_p4d(address);
+ if (!p4d)
+ return NULL;
+
BUILD_BUG_ON(p4d_large(*p4d) != 0);
if (p4d_none(*p4d)) {
unsigned long new_pud_page = __get_free_page(gfp);
@@ -359,6 +363,9 @@ static void __init pti_clone_p4d(unsigned long addr)
pgd_t *kernel_pgd;
user_p4d = pti_user_pagetable_walk_p4d(addr);
+ if (!user_p4d)
+ return;
+
kernel_pgd = pgd_offset_k(addr);
kernel_p4d = p4d_offset(kernel_pgd, addr);
*user_p4d = *kernel_p4d;
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-07-20 5:10 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-07-20 0:06 [PATCH v4 1/2] x86/pti: check the return value of pti_user_pagetable_walk_p4d Jiang Biao
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2018-07-20 5:10 ` [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_pmd() tip-bot for Jiang Biao
2018-07-20 5:09 ` [tip:x86/pti] x86/pti: Check the return value of pti_user_pagetable_walk_p4d() tip-bot for Jiang Biao
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