kernel/linux.git/Documentation, branch v4.14.284

x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data

2022-06-16T11:01:55+00:00

commit 8d50cdf8b8341770bc6367bce40c0c1bb0e1d5b3 upstream Add the sysfs reporting file for Processor MMIO Stale Data vulnerability. It exposes the vulnerability and mitigation state similar to the existing files for the other hardware vulnerabilities. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data

2022-06-16T11:01:55+00:00

commit 8cb861e9e3c9a55099ad3d08e1a3b653d29c33ca upstream Processor MMIO Stale Data is a class of vulnerabilities that may expose data after an MMIO operation. For details please refer to Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst. These vulnerabilities are broadly categorized as: Device Register Partial Write (DRPW): Some endpoint MMIO registers incorrectly handle writes that are smaller than the register size. Instead of aborting the write or only copying the correct subset of bytes (for example, 2 bytes for a 2-byte write), more bytes than specified by the write transaction may be written to the register. On some processors, this may expose stale data from the fill buffers of the core that created the write transaction. Shared Buffers Data Sampling (SBDS): After propagators may have moved data around the uncore and copied stale data into client core fill buffers, processors affected by MFBDS can leak data from the fill buffer. Shared Buffers Data Read (SBDR): It is similar to Shared Buffer Data Sampling (SBDS) except that the data is directly read into the architectural software-visible state. An attacker can use these vulnerabilities to extract data from CPU fill buffers using MDS and TAA methods. Mitigate it by clearing the CPU fill buffers using the VERW instruction before returning to a user or a guest. On CPUs not affected by MDS and TAA, user application cannot sample data from CPU fill buffers using MDS or TAA. A guest with MMIO access can still use DRPW or SBDR to extract data architecturally. Mitigate it with VERW instruction to clear fill buffers before VMENTER for MMIO capable guests. Add a kernel parameter mmio_stale_data={off|full|full,nosmt} to control the mitigation. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner [cascardo: arch/x86/kvm/vmx.c has been moved] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

Documentation: Add documentation for Processor MMIO Stale Data

2022-06-16T11:01:54+00:00

commit 4419470191386456e0b8ed4eb06a70b0021798a6 upstream Add the admin guide for Processor MMIO stale data vulnerabilities. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

ata: libata-transport: fix {dma|pio|xfer}_mode sysfs files

2022-06-14T14:54:01+00:00

commit 72aad489f992871e908ff6d9055b26c6366fb864 upstream. The {dma|pio}_mode sysfs files are incorrectly documented as having a list of the supported DMA/PIO transfer modes, while the corresponding fields of the *struct* ata_device hold the transfer mode IDs, not masks. To match these docs, the {dma|pio}_mode (and even xfer_mode!) sysfs files are handled by the ata_bitfield_name_match() macro which leads to reading such kind of nonsense from them: $ cat /sys/class/ata_device/dev3.0/pio_mode XFER_UDMA_7, XFER_UDMA_6, XFER_UDMA_5, XFER_UDMA_4, XFER_MW_DMA_4, XFER_PIO_6, XFER_PIO_5, XFER_PIO_4, XFER_PIO_3, XFER_PIO_2, XFER_PIO_1, XFER_PIO_0 Using the correct ata_bitfield_name_search() macro fixes that: $ cat /sys/class/ata_device/dev3.0/pio_mode XFER_PIO_4 While fixing the file documentation, somewhat reword the {dma|pio}_mode file doc and add a note about being mostly useful for PATA devices to the xfer_mode file doc... Fixes: d9027470b886 ("[libata] Add ATA transport class") Signed-off-by: Sergey Shtylyov Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Signed-off-by: Greg Kroah-Hartman

dt-bindings: gpio: altera: correct interrupt-cells

2022-06-14T14:53:55+00:00

commit 3a21c3ac93aff7b4522b152399df8f6a041df56d upstream. update documentation to correctly state the interrupt-cells to be 2. Cc: stable@vger.kernel.org Fixes: 4fd9bbc6e071 ("drivers/gpio: Altera soft IP GPIO driver devicetree binding") Signed-off-by: Dinh Nguyen Signed-off-by: Greg Kroah-Hartman

docs/conf.py: Cope with removal of language=None in Sphinx 5.0.0

2022-06-14T14:53:55+00:00

commit 627f01eab93d8671d4e4afee9b148f9998d20e7c upstream. One of the changes in Sphinx 5.0.0 [1] says [sic]: 5.0.0 final - #10474: language does not accept None as it value. The default value of language becomes to 'en' now. [1]: https://www.sphinx-doc.org/en/master/changes.html#release-5-0-0-released-may-30-2022 It results in a new warning from Sphinx 5.0.0 [sic]: WARNING: Invalid configuration value found: 'language = None'. Update your configuration to a valid langauge code. Falling back to 'en' (English). Silence the warning by using 'en'. It works with all the Sphinx versions required for building kernel documentation (1.7.9 or later). Signed-off-by: Akira Yokosawa Link: https://lore.kernel.org/r/bd0c2ddc-2401-03cb-4526-79ca664e1cbe@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet Signed-off-by: Greg Kroah-Hartman

docs: submitting-patches: Fix crossref to 'The canonical patch format'

2022-06-06T06:20:57+00:00

commit 6d5aa418b3bd42cdccc36e94ee199af423ef7c84 upstream. The reference to `explicit_in_reply_to` is pointless as when the reference was added in the form of "#15" [1], Section 15) was "The canonical patch format". The reference of "#15" had not been properly updated in a couple of reorganizations during the plain-text SubmittingPatches era. Fix it by using `the_canonical_patch_format`. [1]: 2ae19acaa50a ("Documentation: Add "how to write a good patch summary" to SubmittingPatches") Signed-off-by: Akira Yokosawa Fixes: 5903019b2a5e ("Documentation/SubmittingPatches: convert it to ReST markup") Fixes: 9b2c76777acc ("Documentation/SubmittingPatches: enrich the Sphinx output") Cc: Jonathan Corbet Cc: Mauro Carvalho Chehab Cc: stable@vger.kernel.org # v4.9+ Link: https://lore.kernel.org/r/64e105a5-50be-23f2-6cae-903a2ea98e18@gmail.com Signed-off-by: Jonathan Corbet Signed-off-by: Greg Kroah-Hartman

Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""

2022-05-25T06:41:22+00:00

commit 901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544 upstream. Halil Pasic points out [1] that the full revert of that commit (revert in bddac7c1e02b), 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 aa6f8dcbab47 ("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: Halil Pasic Tested-by: Oleksandr Natalenko Cc: Christoph Hellwig" Signed-off-by: Linus Torvalds [OP: backport to 4.14: apply swiotlb_tbl_map_single() changes in lib/swiotlb.c] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

swiotlb: fix info leak with DMA_FROM_DEVICE

2022-05-25T06:41:22+00:00

commit ddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e upstream. 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 a45b599ad808 ("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: Halil Pasic Signed-off-by: Christoph Hellwig [OP: backport to 4.14: apply swiotlb_tbl_map_single() changes in lib/swiotlb.c] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

Documentation: update stable tree link

2022-04-20T07:08:09+00:00

commit 555d44932c67e617d89bc13c81c7efac5b51fcfa upstream. The link to stable tree is redirected to https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git. Update accordingly. Cc: Greg Kroah-Hartman Cc: Sasha Levin Cc: Jonathan Corbet Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Bagas Sanjaya Link: https://lore.kernel.org/r/20220314113329.485372-6-bagasdotme@gmail.com Signed-off-by: Greg Kroah-Hartman