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  1. 21 6月, 2022 1 次提交
  3. 15 6月, 2022 2 次提交
  5. 14 6月, 2022 1 次提交
  7. 02 6月, 2022 5 次提交
  9. 24 5月, 2022 1 次提交
  11. 23 5月, 2022 1 次提交
  13. 17 5月, 2022 1 次提交
  15. 13 5月, 2022 1 次提交
  17. 07 5月, 2022 2 次提交
  19. 29 4月, 2022 1 次提交
  21. 20 4月, 2022 2 次提交
  23. 19 4月, 2022 1 次提交
  25. 16 4月, 2022 2 次提交
  27. 15 4月, 2022 1 次提交
  29. 14 4月, 2022 1 次提交
  31. 12 4月, 2022 1 次提交
    • I
      Revert "module, async: async_synchronize_full() on module init iff async is used" · dc8da50c
      由 Igor Pylypiv 提交于 
      stable inclusion
from linux-4.19.231
commit a0c66ac8b72f816d5631fde0ca0b39af602dce48

--------------------------------

[ Upstream commit 67d6212a ]

This reverts commit 774a1221.

We need to finish all async code before the module init sequence is
done.  In the reverted commit the PF_USED_ASYNC flag was added to mark a
thread that called async_schedule().  Then the PF_USED_ASYNC flag was
used to determine whether or not async_synchronize_full() needs to be
invoked.  This works when modprobe thread is calling async_schedule(),
but it does not work if module dispatches init code to a worker thread
which then calls async_schedule().

For example, PCI driver probing is invoked from a worker thread based on
a node where device is attached:

	if (cpu < nr_cpu_ids)
		error = work_on_cpu(cpu, local_pci_probe, &ddi);
	else
		error = local_pci_probe(&ddi);

We end up in a situation where a worker thread gets the PF_USED_ASYNC
flag set instead of the modprobe thread.  As a result,
async_synchronize_full() is not invoked and modprobe completes without
waiting for the async code to finish.

The issue was discovered while loading the pm80xx driver:
(scsi_mod.scan=async)

modprobe pm80xx                      worker
...
  do_init_module()
  ...
    pci_call_probe()
      work_on_cpu(local_pci_probe)
                                     local_pci_probe()
                                       pm8001_pci_probe()
                                         scsi_scan_host()
                                           async_schedule()
                                           worker->flags |= PF_USED_ASYNC;
                                     ...
      < return from worker >
  ...
  if (current->flags & PF_USED_ASYNC) <--- false
  	async_synchronize_full();

Commit 21c3c5d2 ("block: don't request module during elevator init")
fixed the deadlock issue which the reverted commit 774a1221
("module, async: async_synchronize_full() on module init iff async is
used") tried to fix.

Since commit 0fdff3ec ("async, kmod: warn on synchronous
request_module() from async workers") synchronous module loading from
async is not allowed.

Given that the original deadlock issue is fixed and it is no longer
allowed to call synchronous request_module() from async we can remove
PF_USED_ASYNC flag to make module init consistently invoke
async_synchronize_full() unless async module probe is requested.
Signed-off-by: NIgor Pylypiv <ipylypiv@google.com>
Reviewed-by: NChangyuan Lyu <changyuanl@google.com>
Reviewed-by: NLuis Chamberlain <mcgrof@kernel.org>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
Signed-off-by: NLaibin Qiu <qiulaibin@huawei.com>
      dc8da50c
  33. 02 4月, 2022 2 次提交
    • L
      Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE"" · 3e109690
      由 Linus Torvalds 提交于 
      mainline inclusion
from mainline-v5.18-rc1
commit 901c7280
category: bugfix
bugzilla: 186478, https://gitee.com/openeuler/kernel/issues/I4Z86P
CVE: CVE-2022-0854

--------------------------------

Halil Pasic points out [1] that the full revert of that commit (revert
in bddac7c1), and that a partial revert that only reverts the
problematic case, but still keeps some of the cleanups is probably
better.  

And that partial revert [2] had already been verified by Oleksandr
Natalenko to also fix the issue, I had just missed that in the long
discussion.

So let's reinstate the cleanups from commit aa6f8dcb ("swiotlb:
rework "fix info leak with DMA_FROM_DEVICE""), and effectively only
revert the part that caused problems.

Link: https://lore.kernel.org/all/20220328013731.017ae3e3.pasic@linux.ibm.com/ [1]
Link: https://lore.kernel.org/all/20220324055732.GB12078@lst.de/ [2]
Link: https://lore.kernel.org/all/4386660.LvFx2qVVIh@natalenko.name/ [3]
Suggested-by: NHalil Pasic <pasic@linux.ibm.com>
Tested-by: NOleksandr Natalenko <oleksandr@natalenko.name>
Cc: Christoph Hellwig" <hch@lst.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Conflicts:
	Documentation/core-api/dma-attributes.rst
	include/linux/dma-mapping.h
	kernel/dma/swiotlb.c
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
      3e109690
    • L
      Revert "swiotlb: rework "fix info leak with DMA_FROM_DEVICE"" · a5e62d73
      由 Linus Torvalds 提交于 
      mainline inclusion
from mainline-v5.18-rc1
commit bddac7c1
category: bugfix
bugzilla: 186478, https://gitee.com/openeuler/kernel/issues/I4Z86P
CVE: CVE-2022-0854

--------------------------------

This reverts commit aa6f8dcb.

It turns out this breaks at least the ath9k wireless driver, and
possibly others.

What the ath9k driver does on packet receive is to set up the DMA
transfer with:

  int ath_rx_init(..)
  ..
                bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
                                                 common->rx_bufsize,
                                                 DMA_FROM_DEVICE);

and then the receive logic (through ath_rx_tasklet()) will fetch
incoming packets

  static bool ath_edma_get_buffers(..)
  ..
        dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
                                common->rx_bufsize, DMA_FROM_DEVICE);

        ret = ath9k_hw_process_rxdesc_edma(ah, rs, skb->data);
        if (ret == -EINPROGRESS) {
                /*let device gain the buffer again*/
                dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
                                common->rx_bufsize, DMA_FROM_DEVICE);
                return false;
        }

and it's worth noting how that first DMA sync:

    dma_sync_single_for_cpu(..DMA_FROM_DEVICE);

is there to make sure the CPU can read the DMA buffer (possibly by
copying it from the bounce buffer area, or by doing some cache flush).
The iommu correctly turns that into a "copy from bounce bufer" so that
the driver can look at the state of the packets.

In the meantime, the device may continue to write to the DMA buffer, but
we at least have a snapshot of the state due to that first DMA sync.

But that _second_ DMA sync:

    dma_sync_single_for_device(..DMA_FROM_DEVICE);

is telling the DMA mapping that the CPU wasn't interested in the area
because the packet wasn't there.  In the case of a DMA bounce buffer,
that is a no-op.

Note how it's not a sync for the CPU (the "for_device()" part), and it's
not a sync for data written by the CPU (the "DMA_FROM_DEVICE" part).

Or rather, it _should_ be a no-op.  That's what commit aa6f8dcb
broke: it made the code bounce the buffer unconditionally, and changed
the DMA_FROM_DEVICE to just unconditionally and illogically be
DMA_TO_DEVICE.

[ Side note: purely within the confines of the swiotlb driver it wasn't
  entirely illogical: The reason it did that odd DMA_FROM_DEVICE ->
  DMA_TO_DEVICE conversion thing is because inside the swiotlb driver,
  it uses just a swiotlb_bounce() helper that doesn't care about the
  whole distinction of who the sync is for - only which direction to
  bounce.

  So it took the "sync for device" to mean that the CPU must have been
  the one writing, and thought it meant DMA_TO_DEVICE. ]

Also note how the commentary in that commit was wrong, probably due to
that whole confusion, claiming that the commit makes the swiotlb code

                                  "bounce unconditionally (that is, also
    when dir == DMA_TO_DEVICE) in order do avoid synchronising back stale
    data from the swiotlb buffer"

which is nonsensical for two reasons:

 - that "also when dir == DMA_TO_DEVICE" is nonsensical, as that was
   exactly when it always did - and should do - the bounce.

 - since this is a sync for the device (not for the CPU), we're clearly
   fundamentally not coping back stale data from the bounce buffers at
   all, because we'd be copying *to* the bounce buffers.

So that commit was just very confused.  It confused the direction of the
synchronization (to the device, not the cpu) with the direction of the
DMA (from the device).
Reported-and-bisected-by: NOleksandr Natalenko <oleksandr@natalenko.name>
Reported-by: NOlha Cherevyk <olha.cherevyk@gmail.com>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Toke Høiland-Jørgensen <toke@toke.dk>
Cc: Maxime Bizon <mbizon@freebox.fr>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Conflicts:
	Documentation/core-api/dma-attributes.rst
	include/linux/dma-mapping.h
	kernel/dma/swiotlb.c
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
      a5e62d73
  35. 30 3月, 2022 1 次提交
  37. 23 3月, 2022 2 次提交
    • H
      swiotlb: rework "fix info leak with DMA_FROM_DEVICE" · 3f80e186
      由 Halil Pasic 提交于 
      mainline inclusion
from mainline-v5.17-rc8
commit aa6f8dcb
category: bugfix
bugzilla: 186478, https://gitee.com/openeuler/kernel/issues/I4Z86P
CVE: CVE-2022-0854

--------------------------------

Unfortunately, we ended up merging an old version of the patch "fix info
leak with DMA_FROM_DEVICE" instead of merging the latest one. Christoph
(the swiotlb maintainer), he asked me to create an incremental fix
(after I have pointed this out the mix up, and asked him for guidance).
So here we go.

The main differences between what we got and what was agreed are:
* swiotlb_sync_single_for_device is also required to do an extra bounce
* We decided not to introduce DMA_ATTR_OVERWRITE until we have exploiters
* The implantation of DMA_ATTR_OVERWRITE is flawed: DMA_ATTR_OVERWRITE
  must take precedence over DMA_ATTR_SKIP_CPU_SYNC

Thus this patch removes DMA_ATTR_OVERWRITE, and makes
swiotlb_sync_single_for_device() bounce unconditionally (that is, also
when dir == DMA_TO_DEVICE) in order do avoid synchronising back stale
data from the swiotlb buffer.

Let me note, that if the size used with dma_sync_* API is less than the
size used with dma_[un]map_*, under certain circumstances we may still
end up with swiotlb not being transparent. In that sense, this is no
perfect fix either.

To get this bullet proof, we would have to bounce the entire
mapping/bounce buffer. For that we would have to figure out the starting
address, and the size of the mapping in
swiotlb_sync_single_for_device(). While this does seem possible, there
seems to be no firm consensus on how things are supposed to work.
Signed-off-by: NHalil Pasic <pasic@linux.ibm.com>
Fixes: ddbd89de ("swiotlb: fix info leak with DMA_FROM_DEVICE")
Cc: stable@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Conflicts:
	Documentation/core-api/dma-attributes.rst
	include/linux/dma-mapping.h
	kernel/dma/swiotlb.c
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
      3f80e186
    • H
      swiotlb: fix info leak with DMA_FROM_DEVICE · 04c20fc8
      由 Halil Pasic 提交于 
      mainline inclusion
from mainline-v5.17-rc6
commit ddbd89de
category: bugfix
bugzilla: 186478, https://gitee.com/openeuler/kernel/issues/I4Z86P
CVE: CVE-2022-0854

--------------------------------

The problem I'm addressing was discovered by the LTP test covering
cve-2018-1000204.

A short description of what happens follows:
1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO
   interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV
   and a corresponding dxferp. The peculiar thing about this is that TUR
   is not reading from the device.
2) In sg_start_req() the invocation of blk_rq_map_user() effectively
   bounces the user-space buffer. As if the device was to transfer into
   it. Since commit a45b599a ("scsi: sg: allocate with __GFP_ZERO in
   sg_build_indirect()") we make sure this first bounce buffer is
   allocated with GFP_ZERO.
3) For the rest of the story we keep ignoring that we have a TUR, so the
   device won't touch the buffer we prepare as if the we had a
   DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device
   and the  buffer allocated by SG is mapped by the function
   virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here
   scatter-gather and not scsi generics). This mapping involves bouncing
   via the swiotlb (we need swiotlb to do virtio in protected guest like
   s390 Secure Execution, or AMD SEV).
4) When the SCSI TUR is done, we first copy back the content of the second
   (that is swiotlb) bounce buffer (which most likely contains some
   previous IO data), to the first bounce buffer, which contains all
   zeros.  Then we copy back the content of the first bounce buffer to
   the user-space buffer.
5) The test case detects that the buffer, which it zero-initialized,
  ain't all zeros and fails.

One can argue that this is an swiotlb problem, because without swiotlb
we leak all zeros, and the swiotlb should be transparent in a sense that
it does not affect the outcome (if all other participants are well
behaved).

Copying the content of the original buffer into the swiotlb buffer is
the only way I can think of to make swiotlb transparent in such
scenarios. So let's do just that if in doubt, but allow the driver
to tell us that the whole mapped buffer is going to be overwritten,
in which case we can preserve the old behavior and avoid the performance
impact of the extra bounce.
Signed-off-by: NHalil Pasic <pasic@linux.ibm.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Conflicts:
	Documentation/core-api/dma-attributes.rst
	include/linux/dma-mapping.h
	kernel/dma/swiotlb.c
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
      04c20fc8
  39. 14 3月, 2022 2 次提交
  41. 09 3月, 2022 2 次提交
  43. 06 3月, 2022 2 次提交
  45. 04 3月, 2022 2 次提交
  47. 01 3月, 2022 3 次提交