Re: [PATCH 1/8] powerpc/uaccess: Add unsafe_copy_from_user

From: Christophe Leroy
Date: Fri Oct 16 2020 - 09:18:21 EST




Le 16/10/2020 à 08:54, Christoph Hellwig a écrit :
On Thu, Oct 15, 2020 at 10:01:52AM -0500, Christopher M. Riedl wrote:
Implement raw_copy_from_user_allowed() which assumes that userspace read
access is open. Use this new function to implement raw_copy_from_user().
Finally, wrap the new function to follow the usual "unsafe_" convention
of taking a label argument. The new raw_copy_from_user_allowed() calls
__copy_tofrom_user() internally, but this is still safe to call in user
access blocks formed with user_*_access_begin()/user_*_access_end()
since asm functions are not instrumented for tracing.

Please also add a fallback unsafe_copy_from_user to linux/uaccess.h
so this can be used as a generic API.


I guess this can be done in a separate patch independant of that series ?

Christophe