Commits
Joerg Roedel committed e324fc82ea4
vfio: Fix bug in vfio_device_get_from_name()
The vfio_device_get_from_name() function might return a
non-NULL pointer, when called with a device name that is not
found in the list. This causes undefined behavior, in my
case calling an invalid function pointer later on:
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffff8800cb3ddc08
[...]
Call Trace:
[<ffffffffa03bd733>] ? vfio_group_fops_unl_ioctl+0x253/0x410 [vfio]
[<ffffffff811efc4d>] do_vfs_ioctl+0x2cd/0x4c0
[<ffffffff811f9657>] ? __fget+0x77/0xb0
[<ffffffff811efeb9>] SyS_ioctl+0x79/0x90
[<ffffffff81001bb0>] ? syscall_return_slowpath+0x50/0x130
[<ffffffff8167f776>] entry_SYSCALL_64_fastpath+0x16/0x75
Fix the issue by returning NULL when there is no device with
the requested name in the list.
Cc: stable@vger.kernel.org # v4.2+
Fixes: 4bc94d5dc95d ("vfio: Fix lockdep issue")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>