ARM: 7527/1: uaccess: explicitly check __user pointer when !CPU_USE_DOMAINS
The {get,put}_user macros don't perform range checking on the provided
__user address when !CPU_HAS_DOMAINS.
This patch reworks the out-of-line assembly accessors to check the user
address against a specified limit, returning -EFAULT if is is out of
range.
[will: changed get_user register allocation to match put_user]
[rmk: fixed building on older ARM architectures]
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S
index 11093a7..9b06bb4 100644
--- a/arch/arm/lib/getuser.S
+++ b/arch/arm/lib/getuser.S
@@ -16,8 +16,9 @@
* __get_user_X
*
* Inputs: r0 contains the address
+ * r1 contains the address limit, which must be preserved
* Outputs: r0 is the error code
- * r2, r3 contains the zero-extended value
+ * r2 contains the zero-extended value
* lr corrupted
*
* No other registers must be altered. (see <asm/uaccess.h>
@@ -27,33 +28,39 @@
* Note also that it is intended that __get_user_bad is not global.
*/
#include <linux/linkage.h>
+#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/domain.h>
ENTRY(__get_user_1)
+ check_uaccess r0, 1, r1, r2, __get_user_bad
1: TUSER(ldrb) r2, [r0]
mov r0, #0
mov pc, lr
ENDPROC(__get_user_1)
ENTRY(__get_user_2)
-#ifdef CONFIG_THUMB2_KERNEL
-2: TUSER(ldrb) r2, [r0]
-3: TUSER(ldrb) r3, [r0, #1]
+ check_uaccess r0, 2, r1, r2, __get_user_bad
+#ifdef CONFIG_CPU_USE_DOMAINS
+rb .req ip
+2: ldrbt r2, [r0], #1
+3: ldrbt rb, [r0], #0
#else
-2: TUSER(ldrb) r2, [r0], #1
-3: TUSER(ldrb) r3, [r0]
+rb .req r0
+2: ldrb r2, [r0]
+3: ldrb rb, [r0, #1]
#endif
#ifndef __ARMEB__
- orr r2, r2, r3, lsl #8
+ orr r2, r2, rb, lsl #8
#else
- orr r2, r3, r2, lsl #8
+ orr r2, rb, r2, lsl #8
#endif
mov r0, #0
mov pc, lr
ENDPROC(__get_user_2)
ENTRY(__get_user_4)
+ check_uaccess r0, 4, r1, r2, __get_user_bad
4: TUSER(ldr) r2, [r0]
mov r0, #0
mov pc, lr