{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-56681",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2024-56681"
  ],
  "published": "2024-12-28T09:46:17Z",
  "summary": "crypto: bcm - add error check in the ahash_hmac_init function",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: bcm - add error check in the ahash_hmac_init function\n\nThe ahash_init functions may return fails. The ahash_hmac_init should\nnot return ok when ahash_init returns error. For an example, ahash_init\nwill return -ENOMEM when allocation memory is error.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.120",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-56681"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8f1a9a960b1107bd0e0ec3736055f5ed0e717edf"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/75e1e38e5d80d6d9011b7322698ffba3dd3db30a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/28f8ffa945f7d7150463e15097ea73b19529d6f5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4ea3e3b761e371102bb1486778e2f8dbc9e37413"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/05f0a3f5477ecaa1cf46448504afe9e7c2e96fcc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ae5253313e0ea5f00c06176074592b7f493c8546"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ee36db8e8203420e6d5c42eb9428920c2fc36532"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bba9e38c5ad41d0a88b22a59e5b6dd3e31825118"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/19630cf57233e845b6ac57c9c969a4888925467b"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:52:36Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The reliable trigger is a local unprivileged process driving the driver's ahash through AF_ALG (algif_hash) socket syscalls; in-kernel remote consumers of crypto_ahash_init() on hmac algorithms (tcp_ao, gss_krb5) would additionally require an allocation failure the remote peer cannot control.\nAC:L - The attacker sets a zero-length HMAC key via ALG_SET_KEY, which makes ahash_init() skip setkey and hit the deterministic -ENOKEY error path that frees ctx->shash without clearing it \u2014 no race, no memory pressure, and the freed object can be groomed between syscalls before the update() use.\nPR:L - Any unprivileged local user can open an AF_ALG hash socket and bind to the driver's algorithm/driver name (hmac-sha1-iproc); no capability check exists on this path.\nUI:N - The attacker performs the entire socket/setkey/sendmsg sequence itself; no victim action is involved.\nS:U - The corruption is confined to kernel heap memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The stale ctx->shash is dereferenced as a shash_desc, so an attacker who reclaims the freed slab object controls the tfm pointer and the resulting digest data returned to userspace, giving a use-after-free read primitive over kernel memory.\nI:H - crypto_shash_update()/final() perform an indirect call through a function-pointer table reached from the freed object, and ahash_final() then does crypto_free_shash(ctx->shash->tfm) plus kfree(ctx->shash) \u2014 a double free and a free of an attacker-supplied pointer, which is a control-flow-hijack/arbitrary-write primitive.\nA:H - In the -ENOMEM case ctx->shash is NULL and the subsequent crypto_shash_update()/final() dereference NULL, and in the -ENOKEY case the use-after-free and double free reliably oops or panic the kernel."
    }
  }
}