[PATCH 0/5] vt: get rid of worst cases of __put_user/__get_user

From: Adam Borowski
Date: Sat Jun 03 2017 - 03:33:03 EST


Hi!
In a recent discussion, Linus and Al Viro said quite a bit of expletives
about __put_user() and __get_user(), that it's a bad interface that's
almost always the wrong thing to use:
https://marc.info/?l=linux-kernel&m=149463725626316&w=2
https://marc.info/?l=linux-kernel&m=149465866929092&w=2

Here's a few patches applying the lessons from that discussion to vt.
None of the uses is performance-critical, but at least we get a nice bit
of code simplification. And, it's a start of manual review + conversion
that Al Viro wants.


Adam Borowski (5):
vt: use copy_from/to_user instead of __get/put_user for scrnmap ioctls
vt: fix unchecked __put_user() in tioclinux ioctls
vt: use copy_to_user instead of __put_user in GIO_UNIMAP ioctl
vt: use memdup_user in PIO_UNIMAP ioctl
vt: drop access_ok() calls in unimap ioctls

drivers/tty/vt/consolemap.c | 56 ++++++++++++++++----------------------------------------
drivers/tty/vt/vt.c | 6 +++---
drivers/tty/vt/vt_ioctl.c | 8 --------
3 files changed, 19 insertions(+), 51 deletions(-)

--
âââââââ A tit a day keeps the vet away.
âââââââ
âââââââ (Rejoice as my small-animal-murder-machine got unbroken after
âââââââ nearly two years of no catch!)