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    Subject[PATCH 3.16 274/346] frv: fix clear_user()
    3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Al Viro <viro@zeniv.linux.org.uk>

    commit 3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90 upstream.

    It should check access_ok(). Otherwise a bunch of places turn into
    trivially exploitable rootholes.

    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    arch/frv/include/asm/uaccess.h | 12 +++++++++---
    1 file changed, 9 insertions(+), 3 deletions(-)

    --- a/arch/frv/include/asm/uaccess.h
    +++ b/arch/frv/include/asm/uaccess.h
    @@ -263,19 +263,25 @@ do { \
    extern long __memset_user(void *dst, unsigned long count);
    extern long __memcpy_user(void *dst, const void *src, unsigned long count);

    -#define clear_user(dst,count) __memset_user(____force(dst), (count))
    +#define __clear_user(dst,count) __memset_user(____force(dst), (count))
    #define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n))
    #define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n))

    #else

    -#define clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
    +#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
    #define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0)
    #define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0)

    #endif

    -#define __clear_user clear_user
    +static inline unsigned long __must_check
    +clear_user(void __user *to, unsigned long n)
    +{
    + if (likely(__access_ok(to, n)))
    + n = __clear_user(to, n);
    + return n;
    +}

    static inline unsigned long __must_check
    __copy_to_user(void __user *to, const void *from, unsigned long n)
    \
     
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      Last update: 2016-11-14 04:31    [W:2.667 / U:0.416 seconds]
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