Vulnerability-Lookup

GHSA-3WH6-H4GJ-WJR7

Vulnerability from github – Published: 2024-05-21 15:31 – Updated: 2025-04-30 15:30

Details

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

spi: bcm2835: Fix out-of-bounds access with more than 4 slaves

Commit 571e31fa60b3 ("spi: bcm2835: Cache CS register value for ->prepare_message()") limited the number of slaves to 3 at compile-time. The limitation was necessitated by a statically-sized array prepare_cs[] in the driver private data which contains a per-slave register value.

The commit sought to enforce the limitation at run-time by setting the controller's num_chipselect to 3: Slaves with a higher chipselect are rejected by spi_add_device().

However the commit neglected that num_chipselect only limits the number of native chipselects. If GPIO chipselects are specified in the device tree for more than 3 slaves, num_chipselect is silently raised by of_spi_get_gpio_numbers() and the result are out-of-bounds accesses to the statically-sized array prepare_cs[].

As a bandaid fix which is backportable to stable, raise the number of allowed slaves to 24 (which "ought to be enough for anybody"), enforce the limitation on slave ->setup and revert num_chipselect to 3 (which is the number of native chipselects supported by the controller). An upcoming for-next commit will allow an arbitrary number of slaves.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2021-47282"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-21T15:15:16Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nspi: bcm2835: Fix out-of-bounds access with more than 4 slaves\n\nCommit 571e31fa60b3 (\"spi: bcm2835: Cache CS register value for\n-\u003eprepare_message()\") limited the number of slaves to 3 at compile-time.\nThe limitation was necessitated by a statically-sized array prepare_cs[]\nin the driver private data which contains a per-slave register value.\n\nThe commit sought to enforce the limitation at run-time by setting the\ncontroller\u0027s num_chipselect to 3:  Slaves with a higher chipselect are\nrejected by spi_add_device().\n\nHowever the commit neglected that num_chipselect only limits the number\nof *native* chipselects.  If GPIO chipselects are specified in the\ndevice tree for more than 3 slaves, num_chipselect is silently raised by\nof_spi_get_gpio_numbers() and the result are out-of-bounds accesses to\nthe statically-sized array prepare_cs[].\n\nAs a bandaid fix which is backportable to stable, raise the number of\nallowed slaves to 24 (which \"ought to be enough for anybody\"), enforce\nthe limitation on slave -\u003esetup and revert num_chipselect to 3 (which is\nthe number of native chipselects supported by the controller).\nAn upcoming for-next commit will allow an arbitrary number of slaves.",
  "id": "GHSA-3wh6-h4gj-wjr7",
  "modified": "2025-04-30T15:30:44Z",
  "published": "2024-05-21T15:31:41Z",
  "references": [
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      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47282"
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    },
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      "type": "CVSS_V3"
    }
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}

CVE-2021-47282 (GCVE-0-2021-47282)

Vulnerability from cvelistv5 – Published: 2024-05-21 14:20 – Updated: 2026-08-05 08:47

Title

spi: bcm2835: Fix out-of-bounds access with more than 4 slaves

Summary

In the Linux kernel, the following vulnerability has been resolved: spi: bcm2835: Fix out-of-bounds access with more than 4 slaves Commit 571e31fa60b3 ("spi: bcm2835: Cache CS register value for ->prepare_message()") limited the number of slaves to 3 at compile-time. The limitation was necessitated by a statically-sized array prepare_cs[] in the driver private data which contains a per-slave register value. The commit sought to enforce the limitation at run-time by setting the controller's num_chipselect to 3: Slaves with a higher chipselect are rejected by spi_add_device(). However the commit neglected that num_chipselect only limits the number of *native* chipselects. If GPIO chipselects are specified in the device tree for more than 3 slaves, num_chipselect is silently raised by of_spi_get_gpio_numbers() and the result are out-of-bounds accesses to the statically-sized array prepare_cs[]. As a bandaid fix which is backportable to stable, raise the number of allowed slaves to 24 (which "ought to be enough for anybody"), enforce the limitation on slave ->setup and revert num_chipselect to 3 (which is the number of native chipselects supported by the controller). An upcoming for-next commit will allow an arbitrary number of slaves.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/b5502580cf958b094…
https://git.kernel.org/stable/c/82a8ffba54d31e975…
https://git.kernel.org/stable/c/01415ff85a2430805…
https://git.kernel.org/stable/c/13817d466eb8713a1…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 571e31fa60b3697d5db26140e16d5c45c51c9815 , < b5502580cf958b094f3b69dfe4eece90eae01fbc (git) Affected: 571e31fa60b3697d5db26140e16d5c45c51c9815 , < 82a8ffba54d31e97582051cb56ba1f988018681e (git) Affected: 571e31fa60b3697d5db26140e16d5c45c51c9815 , < 01415ff85a24308059e06ca3e97fd7bf75648690 (git) Affected: 571e31fa60b3697d5db26140e16d5c45c51c9815 , < 13817d466eb8713a1ffd254f537402f091d48444 (git)
Linux	Linux	Affected: 5.4 Unaffected: 0 , < 5.4 (semver) Unaffected: 5.4.126 , ≤ 5.4.* (semver) Unaffected: 5.10.44 , ≤ 5.10.* (semver) Unaffected: 5.12.11 , ≤ 5.12.* (semver) Unaffected: 5.13 , ≤ * (original_commit_for_fix)

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

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GHSA-3WH6-H4GJ-WJR7

CVE-2021-47282 (GCVE-0-2021-47282)

Tags

Sightings

Nomenclature