Re: [PATCH 3/6] arm64: untag user addresses in copy_from_user and others

On Thu, Apr 26, 2018 at 5:47 PM, Catalin Marinas wrote: > On Wed, Apr 18, 2018 at 08:53:12PM +0200, Andrey Konovalov wrote: >> @@ -238,12 +239,15 @@ static inline void uaccess_enable_not_uao(void) >> /* >> * Sanitise a uaccess pointer such that it becomes NULL if above

Re: [PATCH 3/6] arm64: untag user addresses in copy_from_user and others

On Wed, Apr 18, 2018 at 08:53:12PM +0200, Andrey Konovalov wrote: > @@ -238,12 +239,15 @@ static inline void uaccess_enable_not_uao(void) > /* > * Sanitise a uaccess pointer such that it becomes NULL if above the > * current addr_limit. > + * Also untag user pointers that have the top byte

[PATCH 3/6] arm64: untag user addresses in copy_from_user and others

copy_from_user (and a few other similar functions) are used to copy data from user memory into the kernel memory or vice versa. Since a user can provided a tagged pointer to one of the syscalls that use copy_from_user, we need to correctly handle such pointers. Do this by untagging user pointers