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arm64: don't zero in __copy_from_user{,_inatomic} 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-09-10 16:50:00 -04:00
parent 91344493b7
commit 4855bd255f
2 changed files with 7 additions and 10 deletions
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10
arch/arm64/include/asm/uaccess.h
View File

@ -278,14 +278,16 @@ static inline unsigned long __must_check __copy_to_user(void __user *to, const v
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
kasan_check_write(to, n);
if (access_ok(VERIFY_READ, from, n)) {
check_object_size(to, n, false);
n = __arch_copy_from_user(to, from, n);
} else /* security hole - plug it */
memset(to, 0, n);
return n;
res = __arch_copy_from_user(to, from, n);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)

7
arch/arm64/lib/copy_from_user.S
View File

@ -79,11 +79,6 @@ ENDPROC(__arch_copy_from_user)
.section .fixup,"ax"
.align 2
9998:
sub x0, end, dst
9999:
strb wzr, [dst], #1 // zero remaining buffer space
cmp dst, end
b.lo 9999b
9998: sub x0, end, dst // bytes not copied
ret
.previous