linux-stable/drivers/xen/xenbus
Juergen Gross 3777ea7bac xen/xenbus: don't let xenbus_grant_ring() remove grants in error case
Letting xenbus_grant_ring() tear down grants in the error case is
problematic, as the other side could already have used these grants.
Calling gnttab_end_foreign_access_ref() without checking success is
resulting in an unclear situation for any caller of xenbus_grant_ring()
as in the error case the memory pages of the ring page might be
partially mapped. Freeing them would risk unwanted foreign access to
them, while not freeing them would leak memory.

In order to remove the need to undo any gnttab_grant_foreign_access()
calls, use gnttab_alloc_grant_references() to make sure no further
error can occur in the loop granting access to the ring pages.

It should be noted that this way of handling removes leaking of
grant entries in the error case, too.

This is CVE-2022-23040 / part of XSA-396.

Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2022-03-07 09:48:54 +01:00
..
Makefile
xenbus.h bus: Make remove callback return void 2021-07-21 11:53:42 +02:00
xenbus_client.c xen/xenbus: don't let xenbus_grant_ring() remove grants in error case 2022-03-07 09:48:54 +01:00
xenbus_comms.c xen: Fix event channel callback via INTX/GSI 2021-01-13 16:12:00 +01:00
xenbus_dev_backend.c
xenbus_dev_frontend.c xen/xenbus: fix self-deadlock after killing user process 2019-10-02 16:40:11 -04:00
xenbus_probe.c xen: detect uninitialized xenbus in xenbus_init 2021-11-24 08:55:15 -06:00
xenbus_probe_backend.c xenbus/xenbus_backend: Disallow pending watch messages 2020-12-14 10:08:40 +01:00
xenbus_probe_frontend.c xen: add "not_essential" flag to struct xenbus_driver 2021-11-23 13:41:29 -06:00
xenbus_xs.c xen/xenbus: Count pending messages for each watch 2020-12-14 10:07:13 +01:00