From: Julien Thierry <julien.thierry@arm.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: mingo@redhat.com, peterz@infradead.org, catalin.marinas@arm.com,
will.deacon@arm.com, james.morse@arm.com, hpa@zytor.com,
valentin.schneider@arm.com,
Julien Thierry <julien.thierry@arm.com>
Subject: [PATCH v3 2/4] arm64: uaccess: Implement unsafe accessors
Date: Tue, 15 Jan 2019 13:58:27 +0000 [thread overview]
Message-ID: <1547560709-56207-3-git-send-email-julien.thierry@arm.com> (raw)
In-Reply-To: <1547560709-56207-1-git-send-email-julien.thierry@arm.com>
Current implementation of get/put_user_unsafe default to get/put_user
which toggle PAN before each access, despite having been told by the caller
that multiple accesses to user memory were about to happen.
Provide implementations for user_access_begin/end to turn PAN off/on and
implement unsafe accessors that assume PAN was already turned off.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/uaccess.h | 79 ++++++++++++++++++++++++++++++----------
1 file changed, 59 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 8e40808..6a70c75 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -270,31 +270,26 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
#define __raw_get_user(x, ptr, err) \
do { \
- unsigned long __gu_val; \
- __chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
switch (sizeof(*(ptr))) { \
case 1: \
- __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \
+ __get_user_asm("ldrb", "ldtrb", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
case 2: \
- __get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \
+ __get_user_asm("ldrh", "ldtrh", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
case 4: \
- __get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \
+ __get_user_asm("ldr", "ldtr", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
case 8: \
- __get_user_asm("ldr", "ldtr", "%x", __gu_val, (ptr), \
+ __get_user_asm("ldr", "ldtr", "%x", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
default: \
BUILD_BUG(); \
} \
- uaccess_disable_not_uao(); \
- (x) = (__force __typeof__(*(ptr)))__gu_val; \
} while (0)
#define __get_user_error(x, ptr, err) \
@@ -302,8 +297,13 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
__typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
if (access_ok(__p, sizeof(*__p))) { \
+ unsigned long __gu_val; \
+ __chk_user_ptr(__p); \
__p = uaccess_mask_ptr(__p); \
- __raw_get_user((x), __p, (err)); \
+ uaccess_enable_not_uao(); \
+ __raw_get_user(__gu_val, __p, (err)); \
+ uaccess_disable_not_uao(); \
+ (x) = (__force __typeof__(*__p)) __gu_val; \
} else { \
(x) = 0; (err) = -EFAULT; \
} \
@@ -334,30 +334,26 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
#define __raw_put_user(x, ptr, err) \
do { \
- __typeof__(*(ptr)) __pu_val = (x); \
- __chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
switch (sizeof(*(ptr))) { \
case 1: \
- __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \
+ __put_user_asm("strb", "sttrb", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
case 2: \
- __put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \
+ __put_user_asm("strh", "sttrh", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
case 4: \
- __put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \
+ __put_user_asm("str", "sttr", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
case 8: \
- __put_user_asm("str", "sttr", "%x", __pu_val, (ptr), \
+ __put_user_asm("str", "sttr", "%x", (x), (ptr), \
(err), ARM64_HAS_UAO); \
break; \
default: \
BUILD_BUG(); \
} \
- uaccess_disable_not_uao(); \
} while (0)
#define __put_user_error(x, ptr, err) \
@@ -365,9 +361,13 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
__typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
if (access_ok(__p, sizeof(*__p))) { \
+ __typeof__(*(ptr)) __pu_val = (x); \
+ __chk_user_ptr(__p); \
__p = uaccess_mask_ptr(__p); \
- __raw_put_user((x), __p, (err)); \
- } else { \
+ uaccess_enable_not_uao(); \
+ __raw_put_user(__pu_val, __p, (err)); \
+ uaccess_disable_not_uao(); \
+ } else { \
(err) = -EFAULT; \
} \
} while (0)
@@ -381,6 +381,45 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
#define put_user __put_user
+static __must_check inline bool user_access_begin(const void __user *ptr,
+ size_t len)
+{
+ if (unlikely(!access_ok(ptr, len)))
+ return false;
+
+ uaccess_enable_not_uao();
+ return true;
+}
+#define user_access_begin(ptr, len) user_access_begin(ptr, len)
+#define user_access_end() uaccess_disable_not_uao()
+
+#define unsafe_get_user(x, ptr, err) \
+do { \
+ __typeof__(*(ptr)) __user *__p = (ptr); \
+ unsigned long __gu_val; \
+ int __gu_err = 0; \
+ might_fault(); \
+ __chk_user_ptr(__p); \
+ __p = uaccess_mask_ptr(__p); \
+ __raw_get_user(__gu_val, __p, __gu_err); \
+ (x) = (__force __typeof__(*__p)) __gu_val; \
+ if (__gu_err != 0) \
+ goto err; \
+} while (0)
+
+#define unsafe_put_user(x, ptr, err) \
+do { \
+ __typeof__(*(ptr)) __user *__p = (ptr); \
+ __typeof__(*(ptr)) __pu_val = (x); \
+ int __pu_err = 0; \
+ might_fault(); \
+ __chk_user_ptr(__p); \
+ __p = uaccess_mask_ptr(__p); \
+ __raw_put_user(__pu_val, __p, __pu_err); \
+ if (__pu_err != 0) \
+ goto err; \
+} while (0)
+
extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
#define raw_copy_from_user(to, from, n) \
({ \
--
1.9.1
next prev parent reply other threads:[~2019-01-15 13:58 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 13:58 [PATCH v3 0/4] uaccess: Add unsafe accessors for arm64 Julien Thierry
2019-01-15 13:58 ` [PATCH v3 1/4] arm64: uaccess: Cleanup get/put_user() Julien Thierry
2019-01-15 13:58 ` Julien Thierry [this message]
2019-01-15 13:58 ` [PATCH v3 3/4] uaccess: Check no rescheduling function is called in unsafe region Julien Thierry
2019-01-30 16:58 ` Valentin Schneider
2019-02-04 13:27 ` Julien Thierry
2019-02-11 13:45 ` Ingo Molnar
2019-02-11 13:51 ` Peter Zijlstra
2019-02-12 9:15 ` Julien Thierry
2019-02-13 8:21 ` Ingo Molnar
2019-02-13 10:35 ` Peter Zijlstra
2019-02-13 10:50 ` Julien Thierry
2019-02-13 13:17 ` Peter Zijlstra
2019-02-13 13:20 ` Peter Zijlstra
2019-02-13 14:00 ` Will Deacon
2019-02-13 14:07 ` Julien Thierry
2019-02-13 14:17 ` Peter Zijlstra
2019-02-13 14:24 ` Julien Thierry
2019-02-13 14:40 ` Peter Zijlstra
2019-02-13 15:08 ` Peter Zijlstra
2019-02-13 14:25 ` Peter Zijlstra
2019-02-13 14:39 ` Julien Thierry
2019-02-13 14:41 ` Peter Zijlstra
2019-02-13 15:45 ` Peter Zijlstra
2019-02-13 18:54 ` Peter Zijlstra
[not found] ` <D61C430D-4321-4114-AB85-671A3C7B8EAE@amacapital.net>
2019-02-13 22:21 ` Peter Zijlstra
2019-02-13 22:49 ` Andy Lutomirski
2019-02-14 10:14 ` [PATCH] sched/x86: Save [ER]FLAGS on context switch Peter Zijlstra
2019-02-14 16:18 ` Brian Gerst
2019-02-14 19:34 ` Peter Zijlstra
2019-02-15 14:34 ` Brian Gerst
2019-02-15 17:18 ` Linus Torvalds
2019-02-15 17:40 ` Peter Zijlstra
2019-02-15 18:28 ` Andy Lutomirski
2019-02-15 23:34 ` Peter Zijlstra
2019-02-16 0:21 ` Linus Torvalds
2019-02-16 10:32 ` Peter Zijlstra
2019-02-16 4:06 ` hpa
2019-02-16 10:30 ` Peter Zijlstra
2019-02-18 22:30 ` H. Peter Anvin
2019-02-19 0:24 ` Linus Torvalds
2019-02-19 2:20 ` Andy Lutomirski
2019-02-19 2:46 ` H. Peter Anvin
2019-02-19 9:07 ` Julien Thierry
2019-02-19 8:53 ` Julien Thierry
2019-02-19 9:15 ` Peter Zijlstra
2019-02-19 9:19 ` Peter Zijlstra
2019-02-19 9:04 ` Peter Zijlstra
2019-02-19 9:21 ` hpa
2019-02-19 9:44 ` Peter Zijlstra
2019-02-19 11:38 ` Thomas Gleixner
2019-02-19 11:58 ` Peter Zijlstra
2019-02-19 12:48 ` Will Deacon
2019-02-20 22:55 ` H. Peter Anvin
2019-02-21 12:06 ` Julien Thierry
2019-02-21 21:35 ` Thomas Gleixner
2019-02-21 22:08 ` Linus Torvalds
2019-02-22 12:58 ` Peter Zijlstra
2019-02-22 18:10 ` Thomas Gleixner
2019-02-22 22:26 ` [RFC][PATCH] objtool: STAC/CLAC validation Peter Zijlstra
2019-02-22 23:34 ` Linus Torvalds
2019-02-23 8:43 ` Peter Zijlstra
2019-02-22 23:39 ` hpa
2019-02-23 8:39 ` Peter Zijlstra
2019-02-25 8:47 ` hpa
2019-02-25 13:21 ` Peter Zijlstra
2019-03-01 15:07 ` Peter Zijlstra
2019-02-25 8:49 ` hpa
2019-02-22 23:55 ` Andy Lutomirski
2019-02-23 8:37 ` Peter Zijlstra
2019-02-23 10:52 ` Peter Zijlstra
2019-02-25 10:51 ` Peter Zijlstra
2019-02-25 11:53 ` Peter Zijlstra
2019-02-25 15:36 ` Andy Lutomirski
2019-02-25 8:33 ` Julien Thierry
2019-02-25 11:55 ` Peter Zijlstra
2019-02-21 12:46 ` [PATCH] sched/x86: Save [ER]FLAGS on context switch Will Deacon
2019-02-21 22:06 ` Andy Lutomirski
2019-02-18 9:03 ` [PATCH v2] " Peter Zijlstra
2019-02-13 23:19 ` [PATCH v3 3/4] uaccess: Check no rescheduling function is called in unsafe region Linus Torvalds
2019-01-15 13:58 ` [PATCH v3 4/4] arm64: uaccess: Implement user_access_region_active Julien Thierry
2019-01-25 14:27 ` [PATCH v3 0/4] uaccess: Add unsafe accessors for arm64 Catalin Marinas
2019-01-30 16:17 ` Julien Thierry
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