CVE-2022-49963 (GCVE-0-2022-49963)
Vulnerability from cvelistv5
Published
2025-06-18 11:00
Modified
2026-08-05 08:56
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/i915/ttm: fix CCS handling Crucible + recent Mesa seems to sometimes hit: GEM_BUG_ON(num_ccs_blks > NUM_CCS_BLKS_PER_XFER) And it looks like we can also trigger this with gem_lmem_swapping, if we modify the test to use slightly larger object sizes. Looking closer it looks like we have the following issues in migrate_copy(): - We are using plain integer in various places, which we can easily overflow with a large object. - We pass the entire object size (when the src is lmem) into emit_pte() and then try to copy it, which doesn't work, since we only have a few fixed sized windows in which to map the pages and perform the copy. With an object > 8M we therefore aren't properly copying the pages. And then with an object > 64M we trigger the GEM_BUG_ON(num_ccs_blks > NUM_CCS_BLKS_PER_XFER). So it looks like our copy handling for any object > 8M (which is our CHUNK_SZ) is currently broken on DG2. Testcase: igt@gem_lmem_swapping (cherry picked from commit 8676145eb2f53a9940ff70910caf0125bd8a4bc2)
References
Impacted products
Vendor Product Version
Linux Linux Version: da0595ae91da837929a00470ab40546090e5b9ae
Version: da0595ae91da837929a00470ab40546090e5b9ae
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/i915/gt/intel_migrate.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "97434cb55bd884bd268626ec41489f79b261b2d4",
              "status": "affected",
              "version": "da0595ae91da837929a00470ab40546090e5b9ae",
              "versionType": "git"
            },
            {
              "lessThan": "8d905254162965c8e6be697d82c7dbf5d08f574d",
              "status": "affected",
              "version": "da0595ae91da837929a00470ab40546090e5b9ae",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/i915/gt/intel_migrate.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "lessThan": "5.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.19.*",
              "status": "unaffected",
              "version": "5.19.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.19.8",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/i915/ttm: fix CCS handling\n\nCrucible + recent Mesa seems to sometimes hit:\n\nGEM_BUG_ON(num_ccs_blks \u003e NUM_CCS_BLKS_PER_XFER)\n\nAnd it looks like we can also trigger this with gem_lmem_swapping, if we\nmodify the test to use slightly larger object sizes.\n\nLooking closer it looks like we have the following issues in\nmigrate_copy():\n\n  - We are using plain integer in various places, which we can easily\n    overflow with a large object.\n\n  - We pass the entire object size (when the src is lmem) into\n    emit_pte() and then try to copy it, which doesn\u0027t work, since we\n    only have a few fixed sized windows in which to map the pages and\n    perform the copy. With an object \u003e 8M we therefore aren\u0027t properly\n    copying the pages. And then with an object \u003e 64M we trigger the\n    GEM_BUG_ON(num_ccs_blks \u003e NUM_CCS_BLKS_PER_XFER).\n\nSo it looks like our copy handling for any object \u003e 8M (which is our\nCHUNK_SZ) is currently broken on DG2.\n\nTestcase: igt@gem_lmem_swapping\n(cherry picked from commit 8676145eb2f53a9940ff70910caf0125bd8a4bc2)"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached via i915 GEM ioctls on a local DRM render node (GEM_CREATE_EXT of lmem-only objects plus TTM eviction into intel_context_migrate_copy), not via network packet processing.\nAC:L - An attacker can reliably create Flat-CCS lmem objects larger than CHUNK_SZ (8M) and force lmem pressure to trigger eviction; the failure is deterministic once migrate_copy runs on such an object, as shown by gem_lmem_swapping and Mesa/Crucible hits.\nPR:L - Triggering requires only unprivileged access to /dev/dri/renderD* (DRM_RENDER_ALLOW for GEM_CREATE_EXT and related ioctls), not root or init-namespace capabilities.\nUI:N - The attacker opens the render node and allocates/evicts their own objects; no separate victim action is required.\nS:U - Impact stays within the host kernel/GPU driver authority (migration PPGTT corruption and GEM buffer corruption), not a guest-to-host or IOMMU-boundary escape.\nC:H - Oversized blits past the fixed 8M windows can read the migrate VM\u2019s self-mapped PTE region and adjacent mappings into attacker-readable smem backup pages, and can mishandle CCS/metadata during eviction of other clients\u2019 buffers under memory pressure.\nI:H - The same oversized XY copy can write past the destination window into the migration page tables and leave incomplete/incorrect main and CCS copies, corrupting GPU PTEs and buffer contents with no CCS-capable CPU memcpy fallback.\nA:H - Out-of-bounds GTT access and invalid CCS transfer sizing can hang or wedge the GPU (and trip GEM_BUG_ON on debug builds), denying GPU service to the system."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:56:54.694Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/97434cb55bd884bd268626ec41489f79b261b2d4"
        },
        {
          "url": "https://git.kernel.org/stable/c/8d905254162965c8e6be697d82c7dbf5d08f574d"
        }
      ],
      "title": "drm/i915/ttm: fix CCS handling",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49963",
    "datePublished": "2025-06-18T11:00:24.021Z",
    "dateReserved": "2025-06-18T10:57:27.384Z",
    "dateUpdated": "2026-08-05T08:56:54.694Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.