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ARM: 7527/1: uaccess: explicitly check __user pointer when !CPU_USE_DOMAINS

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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>
This commit is contained in:
Russell King 2012-09-07 18:22:28 +01:00
parent 2b2040af0b
commit 8404663f81
4 changed files with 56 additions and 21 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

8
arch/arm/include/asm/assembler.h
View file

@ -320,4 +320,12 @@
.size \name , . - \name
.endm
.macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req
#ifndef CONFIG_CPU_USE_DOMAINS
adds \tmp, \addr, #\size - 1
sbcccs \tmp, \tmp, \limit
bcs \bad
#endif
.endm
#endif /* __ASM_ASSEMBLER_H__ */

38
arch/arm/include/asm/uaccess.h
View file

@ -101,28 +101,39 @@ extern int __get_user_1(void *);
extern int __get_user_2(void *);
extern int __get_user_4(void *);
#define __get_user_x(__r2,__p,__e,__s,__i...) \
#define __GUP_CLOBBER_1 "lr", "cc"
#ifdef CONFIG_CPU_USE_DOMAINS
#define __GUP_CLOBBER_2 "ip", "lr", "cc"
#else
#define __GUP_CLOBBER_2 "lr", "cc"
#endif
#define __GUP_CLOBBER_4 "lr", "cc"
#define __get_user_x(__r2,__p,__e,__l,__s) \
__asm__ __volatile__ ( \
__asmeq("%0", "r0") __asmeq("%1", "r2") \
__asmeq("%3", "r1") \
"bl __get_user_" #__s \
: "=&r" (__e), "=r" (__r2) \
: "0" (__p) \
: __i, "cc")
: "0" (__p), "r" (__l) \
: __GUP_CLOBBER_##__s)
#define get_user(x,p) \
({ \
unsigned long __limit = current_thread_info()->addr_limit - 1; \
register const typeof(*(p)) __user *__p asm("r0") = (p);\
register unsigned long __r2 asm("r2"); \
register unsigned long __l asm("r1") = __limit; \
register int __e asm("r0"); \
switch (sizeof(*(__p))) { \
case 1: \
__get_user_x(__r2, __p, __e, 1, "lr"); \
__get_user_x(__r2, __p, __e, __l, 1); \
break; \
case 2: \
__get_user_x(__r2, __p, __e, 2, "r3", "lr"); \
__get_user_x(__r2, __p, __e, __l, 2); \
break; \
case 4: \
__get_user_x(__r2, __p, __e, 4, "lr"); \
__get_user_x(__r2, __p, __e, __l, 4); \
break; \
default: __e = __get_user_bad(); break; \
} \
@ -135,31 +146,34 @@ extern int __put_user_2(void *, unsigned int);
extern int __put_user_4(void *, unsigned int);
extern int __put_user_8(void *, unsigned long long);
#define __put_user_x(__r2,__p,__e,__s) \
#define __put_user_x(__r2,__p,__e,__l,__s) \
__asm__ __volatile__ ( \
__asmeq("%0", "r0") __asmeq("%2", "r2") \
__asmeq("%3", "r1") \
"bl __put_user_" #__s \
: "=&r" (__e) \
: "0" (__p), "r" (__r2) \
: "0" (__p), "r" (__r2), "r" (__l) \
: "ip", "lr", "cc")
#define put_user(x,p) \
({ \
unsigned long __limit = current_thread_info()->addr_limit - 1; \
register const typeof(*(p)) __r2 asm("r2") = (x); \
register const typeof(*(p)) __user *__p asm("r0") = (p);\
register unsigned long __l asm("r1") = __limit; \
register int __e asm("r0"); \
switch (sizeof(*(__p))) { \
case 1: \
__put_user_x(__r2, __p, __e, 1); \
__put_user_x(__r2, __p, __e, __l, 1); \
break; \
case 2: \
__put_user_x(__r2, __p, __e, 2); \
__put_user_x(__r2, __p, __e, __l, 2); \
break; \
case 4: \
__put_user_x(__r2, __p, __e, 4); \
__put_user_x(__r2, __p, __e, __l, 4); \
break; \
case 8: \
__put_user_x(__r2, __p, __e, 8); \
__put_user_x(__r2, __p, __e, __l, 8); \
break; \
default: __e = __put_user_bad(); break; \
} \

23
arch/arm/lib/getuser.S
View file

@ -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

6
arch/arm/lib/putuser.S
View file

@ -16,6 +16,7 @@
* __put_user_X
*
* Inputs: r0 contains the address
* r1 contains the address limit, which must be preserved
* r2, r3 contains the value
* Outputs: r0 is the error code
* lr corrupted
@ -27,16 +28,19 @@
* Note also that it is intended that __put_user_bad is not global.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/domain.h>
ENTRY(__put_user_1)
check_uaccess r0, 1, r1, ip, __put_user_bad
1: TUSER(strb) r2, [r0]
mov r0, #0
mov pc, lr
ENDPROC(__put_user_1)
ENTRY(__put_user_2)
check_uaccess r0, 2, r1, ip, __put_user_bad
mov ip, r2, lsr #8
#ifdef CONFIG_THUMB2_KERNEL
#ifndef __ARMEB__
@ -60,12 +64,14 @@ ENTRY(__put_user_2)
ENDPROC(__put_user_2)
ENTRY(__put_user_4)
check_uaccess r0, 4, r1, ip, __put_user_bad
4: TUSER(str) r2, [r0]
mov r0, #0
mov pc, lr
ENDPROC(__put_user_4)
ENTRY(__put_user_8)
check_uaccess r0, 8, r1, ip, __put_user_bad
#ifdef CONFIG_THUMB2_KERNEL
5: TUSER(str) r2, [r0]
6: TUSER(str) r3, [r0, #4]