This reverts commit 3ce2cd63e8 which is
commit aa838896d87af561a33ecefea1caa4c15a68bc47 upstream.
Ben writes:
When I looked into the referenced security issue, it seemed to only be
exploitable through wakelock names, and in the upstream kernel only
after commit c8377adfa781 "PM / wakeup: Show wakeup sources stats in
sysfs" (first included in 5.4). So I would be interested to know if
and why a fix was needed for 4.19.
More importantly, this backported version uniformly converts to
sysfs_emit(), but there are 3 places sysfs_emit_at() must be used
instead:
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Link: https://lore.kernel.org/r/95831df76c41a53bc3e1ac8ece64915dd63763a1.camel@decadent.org.uk
Cc: Joe Perches <joe@perches.com>
Cc: Brennan Lamoreaux <blamoreaux@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ce63d45f45