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cris: buggered copy_from_user/copy_to_user/clear_user 

* copy_from_user() on access_ok() failure ought to zero the destination
* none of those primitives should skip the access_ok() check in case of
small constant size.

Cc: stable@vger.kernel.org
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-08-18 19:34:00 -04:00
parent 9ad18b75c2
commit eb47e0293b
1 changed files with 32 additions and 39 deletions
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71
arch/cris/include/asm/uaccess.h
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@ -194,30 +194,6 @@ extern unsigned long __copy_user(void __user *to, const void *from, unsigned lon
extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n); extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n);
extern unsigned long __do_clear_user(void __user *to, unsigned long n); extern unsigned long __do_clear_user(void __user *to, unsigned long n);
static inline unsigned long
__generic_copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
return __copy_user(to, from, n);
return n;
}
static inline unsigned long
__generic_copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
return __copy_user_zeroing(to, from, n);
return n;
}
static inline unsigned long
__generic_clear_user(void __user *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
return __do_clear_user(to, n);
return n;
}
static inline long static inline long
__strncpy_from_user(char *dst, const char __user *src, long count) __strncpy_from_user(char *dst, const char __user *src, long count)
{ {
@ -282,7 +258,7 @@ __constant_copy_from_user(void *to, const void __user *from, unsigned long n)
else if (n == 24) else if (n == 24)
__asm_copy_from_user_24(to, from, ret); __asm_copy_from_user_24(to, from, ret);
else else
ret = __generic_copy_from_user(to, from, n); ret = __copy_user_zeroing(to, from, n);
return ret; return ret;
} }
@ -333,7 +309,7 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
else if (n == 24) else if (n == 24)
__asm_copy_to_user_24(to, from, ret); __asm_copy_to_user_24(to, from, ret);
else else
ret = __generic_copy_to_user(to, from, n); ret = __copy_user(to, from, n);
return ret; return ret;
} }
@ -366,26 +342,43 @@ __constant_clear_user(void __user *to, unsigned long n)
else if (n == 24) else if (n == 24)
__asm_clear_24(to, ret); __asm_clear_24(to, ret);
else else
ret = __generic_clear_user(to, n); ret = __do_clear_user(to, n);
return ret; return ret;
} }
#define clear_user(to, n) \ static inline size_t clear_user(void __user *to, size_t n)
(__builtin_constant_p(n) ? \ {
__constant_clear_user(to, n) : \ if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
__generic_clear_user(to, n)) return n;
if (__builtin_constant_p(n))
return __constant_clear_user(to, n);
else
return __do_clear_user(to, n);
}
#define copy_from_user(to, from, n) \ static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
(__builtin_constant_p(n) ? \ {
__constant_copy_from_user(to, from, n) : \ if (unlikely(!access_ok(VERIFY_READ, from, n))) {
__generic_copy_from_user(to, from, n)) memset(to, 0, n);
return n;
}
if (__builtin_constant_p(n))
return __constant_copy_from_user(to, from, n);
else
return __copy_user_zeroing(to, from, n);
}
#define copy_to_user(to, from, n) \ static inline size_t copy_to_user(void __user *to, const void *from, size_t n)
(__builtin_constant_p(n) ? \ {
__constant_copy_to_user(to, from, n) : \ if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
__generic_copy_to_user(to, from, n)) return n;
if (__builtin_constant_p(n))
return __constant_copy_to_user(to, from, n);
else
return __copy_user(to, from, n);
}
/* We let the __ versions of copy_from/to_user inline, because they're often /* We let the __ versions of copy_from/to_user inline, because they're often
* used in fast paths and have only a small space overhead. * used in fast paths and have only a small space overhead.