On 9/12/19 10:50 pm, Christophe Leroy wrote:
Le 09/12/2019 à 11:59, Andrew Donnellan a écrit :
The KUAP implementation adds calls in clear_user() to enable and disable
access to userspace memory. However, it doesn't add these to
__clear_user(), which is used in the ptrace regset code.
As there's only one direct user of __clear_user(), and the time taken to
set the AMR for KUAP purposes is going to dominate the cost of a quick
access_ok(), there's not much point having a separate path.
No risk that access_ok() fails ?
The only user of __clear_user() is the regset code, and
copy_regset_{to,from}_user() already checks access_ok().
I think ideally we could get rid of __clear_user() completely.
There is also a call to might_fault() in clear_user(), isn't it a problem ?
I don't think it's a problem, just some lockdep debugging?
--
Andrew Donnellan OzLabs, ADL Canberra
a...@linux.ibm.com IBM Australia Limited
