CVE-2024-40970 Avoid hw_desc array overrun in dw-axi-dmac

2024-07-1212:32:08

Linux

www.cve.org

linux kernel

vulnerability

resolution

dw-axi-dmac

overrun

dma channel

kernel panic

axi_desc_put

axi_dma_desc

axi_desc_alloc

axi_chan_start_first_queued

EPSS

Percentile

5.1%

JSON

In the Linux kernel, the following vulnerability has been resolved:

Avoid hw_desc array overrun in dw-axi-dmac

I have a use case where nr_buffers = 3 and in which each descriptor is composed by 3
segments, resulting in the DMA channel descs_allocated to be 9. Since axi_desc_put()
handles the hw_desc considering the descs_allocated, this scenario would result in a
kernel panic (hw_desc array will be overrun).

To fix this, the proposal is to add a new member to the axi_dma_desc structure,
where we keep the number of allocated hw_descs (axi_desc_alloc()) and use it in
axi_desc_put() to handle the hw_desc array correctly.

Additionally I propose to remove the axi_chan_start_first_queued() call after completing
the transfer, since it was identified that unbalance can occur (started descriptors can
be interrupted and transfer ignored due to DMA channel not being enabled).

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c",
      "drivers/dma/dw-axi-dmac/dw-axi-dmac.h"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "7c3bb96a20cd",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "dd42570018f5",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "e151ae1ee065",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "9004784e8d68",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "333e11bf47fa",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c",
      "drivers/dma/dw-axi-dmac/dw-axi-dmac.h"
    ],
    "versions": [
      {
        "version": "5.15.162",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.96",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.36",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9.7",
        "lessThanOrEqual": "6.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]