uaccess: fix integer overflow on access_ok()

Three architectures check the end of a user access against the
address limit without taking a possible overflow into account.
Passing a negative length or another overflow in here returns
success when it should not.

Use the most common correct implementation here, which optimizes
for a constant 'size' argument, and turns the common case into a
single comparison.

Cc: [email protected]
Fixes: da551281947c ("csky: User access")
Fixes: f663b60f5215 ("microblaze: Fix uaccess_ok macro")
Fixes: 7567746e1c0d ("Hexagon: Add user access functions")
Reported-by: David Laight <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>

0 files changed, 0 insertions, 0 deletions