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powerpc: Use barrier_nospec in copy_from_user() 

Based on the x86 commit doing the same.

See commit 304ec1b050 ("x86/uaccess: Use __uaccess_begin_nospec()
and uaccess_try_nospec") and b3bbfb3fb5 ("x86: Introduce
__uaccess_begin_nospec() and uaccess_try_nospec") for more detail.

In all cases we are ordering the load from the potentially
user-controlled pointer vs a previous branch based on an access_ok()
check or similar.

Base on a patch from Michal Suchanek.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Ellerman 2018-04-24 14:15:58 +10:00
parent cb3d6759a9
commit ddf35cf376
1 changed files with 10 additions and 1 deletions
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11
arch/powerpc/include/asm/uaccess.h
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@ -258,6 +258,7 @@ do { \
__chk_user_ptr(ptr); \
if (!is_kernel_addr((unsigned long)__gu_addr)) \
might_fault(); \
barrier_nospec(); \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
(x) = (__typeof__(*(ptr)))__gu_val; \
__gu_err; \
@ -269,8 +270,10 @@ do { \
unsigned long __gu_val = 0; \
const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
might_fault(); \
if (access_ok(VERIFY_READ, __gu_addr, (size))) \
if (access_ok(VERIFY_READ, __gu_addr, (size))) { \
barrier_nospec(); \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
} \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
__gu_err; \
})
@ -281,6 +284,7 @@ do { \
unsigned long __gu_val; \
const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
__chk_user_ptr(ptr); \
barrier_nospec(); \
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
__gu_err; \
@ -308,15 +312,19 @@ static inline unsigned long raw_copy_from_user(void *to,
switch (n) {
case 1:
barrier_nospec();
__get_user_size(*(u8 *)to, from, 1, ret);
break;
case 2:
barrier_nospec();
__get_user_size(*(u16 *)to, from, 2, ret);
break;
case 4:
barrier_nospec();
__get_user_size(*(u32 *)to, from, 4, ret);
break;
case 8:
barrier_nospec();
__get_user_size(*(u64 *)to, from, 8, ret);
break;
}
@ -324,6 +332,7 @@ static inline unsigned long raw_copy_from_user(void *to,
return 0;
}
barrier_nospec();
return __copy_tofrom_user((__force void __user *)to, from, n);
}