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arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()

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adjust copy_from_user(), obviously

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-09-10 16:44:03 -04:00
parent 7798bf2140
commit 91344493b7
2 changed files with 9 additions and 11 deletions
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11
arch/arm/include/asm/uaccess.h
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@ -533,11 +533,12 @@ __clear_user(void __user *addr, unsigned long n)
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
n = __copy_from_user(to, from, n);
else /* security hole - plug it */
memset(to, 0, n);
return n;
unsigned long res = n;
if (likely(access_ok(VERIFY_READ, from, n)))
res = __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)

9
arch/arm/lib/copy_from_user.S
View file

@ -98,12 +98,9 @@ ENDPROC(arm_copy_from_user)
.pushsection .fixup,"ax"
.align 0
copy_abort_preamble
ldmfd sp!, {r1, r2}
sub r3, r0, r1
rsb r1, r3, r2
str r1, [sp]
bl __memzero
ldr r0, [sp], #4
ldmfd sp!, {r1, r2, r3}
sub r0, r0, r1
rsb r0, r0, r2
copy_abort_end
.popsection