ghsa-g32h-2c9h-xpxj
Vulnerability from github
Published
2024-02-28 09:30
Modified
2024-12-31 18:30
Details

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

usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4

commit 4dbc6a4ef06d ("usb: typec: ucsi: save power data objects in PD mode") introduced retrieval of the PDOs when connected to a PD-capable source. But only the first 4 PDOs are received since that is the maximum number that can be fetched at a time given the MESSAGE_IN length limitation (16 bytes). However, as per the PD spec a connected source may advertise up to a maximum of 7 PDOs.

If such a source is connected it's possible the PPM could have negotiated a power contract with one of the PDOs at index greater than 4, and would be reflected in the request data object's (RDO) object position field. This would result in an out-of-bounds access when the rdo_index() is used to index into the src_pdos array in ucsi_psy_get_voltage_now().

With the help of the UBSAN -fsanitize=array-bounds checker enabled this exact issue is revealed when connecting to a PD source adapter that advertise 5 PDOs and the PPM enters a contract having selected the 5th one.

[ 151.545106][ T70] Unexpected kernel BRK exception at EL1 [ 151.545112][ T70] Internal error: BRK handler: f2005512 [#1] PREEMPT SMP ... [ 151.545499][ T70] pc : ucsi_psy_get_prop+0x208/0x20c [ 151.545507][ T70] lr : power_supply_show_property+0xc0/0x328 ... [ 151.545542][ T70] Call trace: [ 151.545544][ T70] ucsi_psy_get_prop+0x208/0x20c [ 151.545546][ T70] power_supply_uevent+0x1a4/0x2f0 [ 151.545550][ T70] dev_uevent+0x200/0x384 [ 151.545555][ T70] kobject_uevent_env+0x1d4/0x7e8 [ 151.545557][ T70] power_supply_changed_work+0x174/0x31c [ 151.545562][ T70] process_one_work+0x244/0x6f0 [ 151.545564][ T70] worker_thread+0x3e0/0xa64

We can resolve this by instead retrieving and storing up to the maximum of 7 PDOs in the con->src_pdos array. This would involve two calls to the GET_PDOS command.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2021-46980"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-28T09:15:37Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: typec: ucsi: Retrieve all the PDOs instead of just the first 4\n\ncommit 4dbc6a4ef06d (\"usb: typec: ucsi: save power data objects\nin PD mode\") introduced retrieval of the PDOs when connected to a\nPD-capable source. But only the first 4 PDOs are received since\nthat is the maximum number that can be fetched at a time given the\nMESSAGE_IN length limitation (16 bytes). However, as per the PD spec\na connected source may advertise up to a maximum of 7 PDOs.\n\nIf such a source is connected it\u0027s possible the PPM could have\nnegotiated a power contract with one of the PDOs at index greater\nthan 4, and would be reflected in the request data object\u0027s (RDO)\nobject position field. This would result in an out-of-bounds access\nwhen the rdo_index() is used to index into the src_pdos array in\nucsi_psy_get_voltage_now().\n\nWith the help of the UBSAN -fsanitize=array-bounds checker enabled\nthis exact issue is revealed when connecting to a PD source adapter\nthat advertise 5 PDOs and the PPM enters a contract having selected\nthe 5th one.\n\n[  151.545106][   T70] Unexpected kernel BRK exception at EL1\n[  151.545112][   T70] Internal error: BRK handler: f2005512 [#1] PREEMPT SMP\n...\n[  151.545499][   T70] pc : ucsi_psy_get_prop+0x208/0x20c\n[  151.545507][   T70] lr : power_supply_show_property+0xc0/0x328\n...\n[  151.545542][   T70] Call trace:\n[  151.545544][   T70]  ucsi_psy_get_prop+0x208/0x20c\n[  151.545546][   T70]  power_supply_uevent+0x1a4/0x2f0\n[  151.545550][   T70]  dev_uevent+0x200/0x384\n[  151.545555][   T70]  kobject_uevent_env+0x1d4/0x7e8\n[  151.545557][   T70]  power_supply_changed_work+0x174/0x31c\n[  151.545562][   T70]  process_one_work+0x244/0x6f0\n[  151.545564][   T70]  worker_thread+0x3e0/0xa64\n\nWe can resolve this by instead retrieving and storing up to the\nmaximum of 7 PDOs in the con-\u003esrc_pdos array. This would involve\ntwo calls to the GET_PDOS command.",
  "id": "GHSA-g32h-2c9h-xpxj",
  "modified": "2024-12-31T18:30:50Z",
  "published": "2024-02-28T09:30:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-46980"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1f4642b72be79757f050924a9b9673b6a02034bc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5e9c6f58b01e6fdfbc740390c01f542a35c97e57"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a453bfd7ef15fd9d524004d3ca7b05353a302911"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e5366bea0277425e1868ba20eeb27c879d5a6e2d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

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.
  • 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.


Loading…

Loading…