linux-stable.git/drivers/xen, branch v5.4.263

xen/events: fix delayed eoi list handling

2023-11-28T16:50:16+00:00

[ Upstream commit 47d970204054f859f35a2237baa75c2d84fcf436 ]

When delaying eoi handling of events, the related elements are queued
into the percpu lateeoi list. In case the list isn't empty, the
elements should be sorted by the time when eoi handling is to happen.

Unfortunately a new element will never be queued at the start of the
list, even if it has a handling time lower than all other list
elements.

Fix that by handling that case the same way as for an empty list.

Fixes: e99502f76271 ("xen/events: defer eoi in case of excessive number of events")
Reported-by: Jan Beulich 
Signed-off-by: Juergen Gross 
Reviewed-by: Oleksandr Tyshchenko 
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen/events: replace evtchn_rwlock with RCU

2023-10-10T19:46:46+00:00

commit 87797fad6cce28ec9be3c13f031776ff4f104cfc upstream.

In unprivileged Xen guests event handling can cause a deadlock with
Xen console handling. The evtchn_rwlock and the hvc_lock are taken in
opposite sequence in __hvc_poll() and in Xen console IRQ handling.
Normally this is no problem, as the evtchn_rwlock is taken as a reader
in both paths, but as soon as an event channel is being closed, the
lock will be taken as a writer, which will cause read_lock() to block:

CPU0                     CPU1                CPU2
(IRQ handling)           (__hvc_poll())      (closing event channel)

read_lock(evtchn_rwlock)
                         spin_lock(hvc_lock)
                                             write_lock(evtchn_rwlock)
                                                 [blocks]
spin_lock(hvc_lock)
    [blocks]
                        read_lock(evtchn_rwlock)
                            [blocks due to writer waiting,
                             and not in_interrupt()]

This issue can be avoided by replacing evtchn_rwlock with RCU in
xen_free_irq(). Note that RCU is used only to delay freeing of the
irq_info memory. There is no RCU based dereferencing or replacement of
pointers involved.

In order to avoid potential races between removing the irq_info
reference and handling of interrupts, set the irq_info pointer to NULL
only when freeing its memory. The IRQ itself must be freed at that
time, too, as otherwise the same IRQ number could be allocated again
before handling of the old instance would have been finished.

This is XSA-441 / CVE-2023-34324.

Fixes: 54c9de89895e ("xen/events: add a new "late EOI" evtchn framework")
Reported-by: Marek Marczykowski-Górecki 
Signed-off-by: Juergen Gross 
Reviewed-by: Julien Grall 
Signed-off-by: Greg Kroah-Hartman

xen/pvcalls-back: fix double frees with pvcalls_new_active_socket()

2023-05-30T11:44:10+00:00

commit 8fafac202d18230bb9926bda48e563fd2cce2a4f upstream.

In the pvcalls_new_active_socket() function, most error paths call
pvcalls_back_release_active(fedata->dev, fedata, map) which calls
sock_release() on "sock".  The bug is that the caller also frees sock.

Fix this by making every error path in pvcalls_new_active_socket()
release the sock, and don't free it in the caller.

Fixes: 5db4d286a8ef ("xen/pvcalls: implement connect command")
Signed-off-by: Dan Carpenter 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/e5f98dc2-0305-491f-a860-71bbd1398a2f@kili.mountain
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

dma-mapping: drop the dev argument to arch_sync_dma_for_*

2023-04-05T09:16:43+00:00

[ Upstream commit 56e35f9c5b87ec1ae93e483284e189c84388de16 ]

These are pure cache maintainance routines, so drop the unused
struct device argument.

Signed-off-by: Christoph Hellwig 
Suggested-by: Daniel Vetter 
Stable-dep-of: ab327f8acdf8 ("mips: bmips: BCM6358: disable RAC flush for TP1")
Signed-off-by: Sasha Levin

fix "direction" argument of iov_iter_kvec()

2023-02-22T11:50:23+00:00

[ Upstream commit fc02f33787d8dd227b54f263eba983d5b249c032 ]

Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin

xen/privcmd: Fix a possible warning in privcmd_ioctl_mmap_resource()

2023-01-18T10:40:57+00:00

[ Upstream commit 8b997b2bb2c53b76a6db6c195930e9ab8e4b0c79 ]

As 'kdata.num' is user-controlled data, if user tries to allocate
memory larger than(>=) MAX_ORDER, then kcalloc() will fail, it
creates a stack trace and messes up dmesg with a warning.

Call trace:
-> privcmd_ioctl
--> privcmd_ioctl_mmap_resource

Add __GFP_NOWARN in order to avoid too large allocation warning.
This is detected by static analysis using smatch.

Fixes: 3ad0876554ca ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE")
Signed-off-by: Harshit Mogalapalli 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20221126050745.778967-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen/events: only register debug interrupt for 2-level events

2023-01-18T10:40:57+00:00

[ Upstream commit d04b1ae5a9b0c868dda8b4b34175ef08f3cb9e93 ]

xen_debug_interrupt() is specific to 2-level event handling. So don't
register it with fifo event handling being active.

Signed-off-by: Juergen Gross 
Reviewed-by: Jan Beulich 
Link: https://lore.kernel.org/r/20201022094907.28560-4-jgross@suse.com
Signed-off-by: Boris Ostrovsky 
Stable-dep-of: 69143f60868b ("x86/xen: Fix memory leak in xen_smp_intr_init{_pv}()")
Signed-off-by: Sasha Levin

xen/platform-pci: add missing free_irq() in error path

2022-12-08T10:23:00+00:00

[ Upstream commit c53717e1e3f0d0f9129b2e0dbc6dcc5e0a8132e9 ]

free_irq() is missing in case of error in platform_pci_probe(), fix that.

Signed-off-by: ruanjinjie 
Reviewed-by: Oleksandr Tyshchenko 
Link: https://lore.kernel.org/r/20221114112124.1965611-1-ruanjinjie@huawei.com
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen/pcpu: fix possible memory leak in register_pcpu()

2022-11-25T16:42:16+00:00

[ Upstream commit da36a2a76b01b210ffaa55cdc2c99bc8783697c5 ]

In device_add(), dev_set_name() is called to allocate name, if it returns
error, the name need be freed. As comment of device_register() says, it
should use put_device() to give up the reference in the error path. So fix
this by calling put_device(), then the name can be freed in kobject_cleanup().

Fixes: f65c9bb3fb72 ("xen/pcpu: Xen physical cpus online/offline sys interface")
Signed-off-by: Yang Yingliang 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20221110152441.401630-1-yangyingliang@huawei.com
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen/gntdev: Prevent leaking grants

2022-11-03T14:56:54+00:00

commit 0991028cd49567d7016d1b224fe0117c35059f86 upstream.

Prior to this commit, if a grant mapping operation failed partially,
some of the entries in the map_ops array would be invalid, whereas all
of the entries in the kmap_ops array would be valid. This in turn would
cause the following logic in gntdev_map_grant_pages to become invalid:

  for (i = 0; i < map->count; i++) {
    if (map->map_ops[i].status == GNTST_okay) {
      map->unmap_ops[i].handle = map->map_ops[i].handle;
      if (!use_ptemod)
        alloced++;
    }
    if (use_ptemod) {
      if (map->kmap_ops[i].status == GNTST_okay) {
        if (map->map_ops[i].status == GNTST_okay)
          alloced++;
        map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
      }
    }
  }
  ...
  atomic_add(alloced, &map->live_grants);

Assume that use_ptemod is true (i.e., the domain mapping the granted
pages is a paravirtualized domain). In the code excerpt above, note that
the "alloced" variable is only incremented when both kmap_ops[i].status
and map_ops[i].status are set to GNTST_okay (i.e., both mapping
operations are successful).  However, as also noted above, there are
cases where a grant mapping operation fails partially, breaking the
assumption of the code excerpt above.

The aforementioned causes map->live_grants to be incorrectly set. In
some cases, all of the map_ops mappings fail, but all of the kmap_ops
mappings succeed, meaning that live_grants may remain zero. This in turn
makes it impossible to unmap the successfully grant-mapped pages pointed
to by kmap_ops, because unmap_grant_pages has the following snippet of
code at its beginning:

  if (atomic_read(&map->live_grants) == 0)
    return; /* Nothing to do */

In other cases where only some of the map_ops mappings fail but all
kmap_ops mappings succeed, live_grants is made positive, but when the
user requests unmapping the grant-mapped pages, __unmap_grant_pages_done
will then make map->live_grants negative, because the latter function
does not check if all of the pages that were requested to be unmapped
were actually unmapped, and the same function unconditionally subtracts
"data->count" (i.e., a value that can be greater than map->live_grants)
from map->live_grants. The side effects of a negative live_grants value
have not been studied.

The net effect of all of this is that grant references are leaked in one
of the above conditions. In Qubes OS v4.1 (which uses Xen's grant
mechanism extensively for X11 GUI isolation), this issue manifests
itself with warning messages like the following to be printed out by the
Linux kernel in the VM that had granted pages (that contain X11 GUI
window data) to dom0: "g.e. 0x1234 still pending", especially after the
user rapidly resizes GUI VM windows (causing some grant-mapping
operations to partially or completely fail, due to the fact that the VM
unshares some of the pages as part of the window resizing, making the
pages impossible to grant-map from dom0).

The fix for this issue involves counting all successful map_ops and
kmap_ops mappings separately, and then adding the sum to live_grants.
During unmapping, only the number of successfully unmapped grants is
subtracted from live_grants. The code is also modified to check for
negative live_grants values after the subtraction and warn the user.

Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci 
Acked-by: Demi Marie Obenour 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com
Signed-off-by: Juergen Gross 
Signed-off-by: Demi Marie Obenour 
Signed-off-by: Greg Kroah-Hartman