ghsa-q342-fw2j-5cj8
Vulnerability from github
Published
2024-04-17 12:32
Modified
2024-06-27 15:30
Details

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

drm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip

It's possible that mtk_crtc->event is NULL in mtk_drm_crtc_finish_page_flip().

pending_needs_vblank value is set by mtk_crtc->event, but in mtk_drm_crtc_atomic_flush(), it's is not guarded by the same lock in mtk_drm_finish_page_flip(), thus a race condition happens.

Consider the following case:

CPU1 CPU2 step 1: mtk_drm_crtc_atomic_begin() mtk_crtc->event is not null, step 1: mtk_drm_crtc_atomic_flush: mtk_drm_crtc_update_config( !!mtk_crtc->event) step 2: mtk_crtc_ddp_irq -> mtk_drm_finish_page_flip: lock mtk_crtc->event set to null, pending_needs_vblank set to false unlock pending_needs_vblank set to true,

                              step 2:
                              mtk_crtc_ddp_irq ->
                              mtk_drm_finish_page_flip called again,
                              pending_needs_vblank is still true
                              //null pointer

Instead of guarding the entire mtk_drm_crtc_atomic_flush(), it's more efficient to just check if mtk_crtc->event is null before use.

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2024-26874"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-04-17T11:15:09Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/mediatek: Fix a null pointer crash in mtk_drm_crtc_finish_page_flip\n\nIt\u0027s possible that mtk_crtc-\u003eevent is NULL in\nmtk_drm_crtc_finish_page_flip().\n\npending_needs_vblank value is set by mtk_crtc-\u003eevent, but in\nmtk_drm_crtc_atomic_flush(), it\u0027s is not guarded by the same\nlock in mtk_drm_finish_page_flip(), thus a race condition happens.\n\nConsider the following case:\n\nCPU1                              CPU2\nstep 1:\nmtk_drm_crtc_atomic_begin()\nmtk_crtc-\u003eevent is not null,\n                                  step 1:\n                                  mtk_drm_crtc_atomic_flush:\n                                  mtk_drm_crtc_update_config(\n                                      !!mtk_crtc-\u003eevent)\nstep 2:\nmtk_crtc_ddp_irq -\u003e\nmtk_drm_finish_page_flip:\nlock\nmtk_crtc-\u003eevent set to null,\npending_needs_vblank set to false\nunlock\n                                  pending_needs_vblank set to true,\n\n                                  step 2:\n                                  mtk_crtc_ddp_irq -\u003e\n                                  mtk_drm_finish_page_flip called again,\n                                  pending_needs_vblank is still true\n                                  //null pointer\n\nInstead of guarding the entire mtk_drm_crtc_atomic_flush(), it\u0027s more\nefficient to just check if mtk_crtc-\u003eevent is null before use.",
  "id": "GHSA-q342-fw2j-5cj8",
  "modified": "2024-06-27T15:30:38Z",
  "published": "2024-04-17T12:32:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26874"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3fc88b246a2fc16014e374040fc15af1d3752535"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4688be96d20ffa49d2186523ee84f475f316fd49"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9acee29a38b4d4b70f1f583e5ef9a245db4db710"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9beec711a17245b853d64488fd5b739031612340"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a3dd12b64ae8373a41a216a0b621df224210860a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/accdac6b71d5a2b84040c3d2234f53a60edc398e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c958e86e9cc1b48cac004a6e245154dfba8e163b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d2bd30c710475b2e29288827d2c91f9e6e2b91d7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfde84cc6c589f2a9f820f12426d97365670b731"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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