From 8404663f81d212918ff85f493649a7991209fa04 Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 7 Sep 2012 18:22:28 +0100 Subject: [PATCH] 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 Signed-off-by: Will Deacon Cc: stable@vger.kernel.org Signed-off-by: Russell King --- arch/arm/include/asm/assembler.h | 8 +++++++ arch/arm/include/asm/uaccess.h | 40 +++++++++++++++++++++----------- arch/arm/lib/getuser.S | 23 +++++++++++------- arch/arm/lib/putuser.S | 6 +++++ 4 files changed, 56 insertions(+), 21 deletions(-) diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 03fb93621d0d..5c8b3bf4d825 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -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__ */ diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 479a6352e0b5..6f83ad6e4d3d 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -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"); \ - break; \ + __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; \ } \ diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S index 11093a7c3e32..9b06bb41fca6 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 @@ -27,33 +28,39 @@ * Note also that it is intended that __get_user_bad is not global. */ #include +#include #include #include 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 diff --git a/arch/arm/lib/putuser.S b/arch/arm/lib/putuser.S index 7db25990c589..3d73dcb959b0 100644 --- a/arch/arm/lib/putuser.S +++ b/arch/arm/lib/putuser.S @@ -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 +#include #include #include 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] -- 2.30.2