FKIE_CVE-2026-64192

Vulnerability from fkie_nvd - Published: 2026-07-20 17:18 - Updated: 2026-07-20 17:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized When CONFIG_BPF_LSM=y is set, BPF inode storage maps (BPF_MAP_TYPE_INODE_STORAGE) are compiled into the kernel. However, if the BPF LSM is not explicitly enabled at boot time (e.g. omitted from the "lsm=" boot parameter), lsm_prepare() is never executed for the BPF LSM. Consequently, the BPF inode security blob offset (bpf_lsm_blob_sizes.lbs_inode) is never initialized and remains at its default compiled size of 8 bytes instead of being updated to a valid offset past the reserved struct rcu_head (typically 16 bytes or more). When a privileged user creates and updates a BPF_MAP_TYPE_INODE_STORAGE map, bpf_inode() evaluates inode->i_security + 8. This erroneously aliases the struct rcu_head.func callback pointer at the beginning of the inode->i_security blob. During subsequent map element cleanup or inode destruction, writing NULL to owner_storage clears the queued RCU callback pointer. When rcu_do_batch() later executes the queued callback, it attempts an instruction fetch at address 0x0, triggering an immediate kernel panic. Fix this by introducing a global bpf_lsm_initialized boolean flag marked with __ro_after_init. Set this flag to true inside bpf_lsm_init() when the LSM framework successfully registers the BPF LSM. Gate map allocation in inode_storage_map_alloc() on this flag, returning -EOPNOTSUPP if the BPF LSM is in turn uninitialized. This fail-fast approach prevents userspace from allocating inode storage maps when the supporting BPF LSM infrastructure is absent, avoiding zombie map states.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c76b8abce575e0c6e4096957220b4515ed847d89
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf_lsm.h",
            "kernel/bpf/bpf_inode_storage.c",
            "security/bpf/hooks.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c76b8abce575e0c6e4096957220b4515ed847d89",
              "status": "affected",
              "version": "8ea636848aca35b9f97c5b5dee30225cf2dd0fe6",
              "versionType": "git"
            },
            {
              "lessThan": "a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4",
              "status": "affected",
              "version": "8ea636848aca35b9f97c5b5dee30225cf2dd0fe6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf_lsm.h",
            "kernel/bpf/bpf_inode_storage.c",
            "security/bpf/hooks.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.10"
            },
            {
              "lessThan": "5.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized\n\nWhen CONFIG_BPF_LSM=y is set, BPF inode storage maps\n(BPF_MAP_TYPE_INODE_STORAGE) are compiled into the kernel. However,\nif the BPF LSM is not explicitly enabled at boot time (e.g. omitted\nfrom the \"lsm=\" boot parameter), lsm_prepare() is never executed for\nthe BPF LSM.\n\nConsequently, the BPF inode security blob offset\n(bpf_lsm_blob_sizes.lbs_inode) is never initialized and remains at\nits default compiled size of 8 bytes instead of being updated to a\nvalid offset past the reserved struct rcu_head (typically 16 bytes\nor more).\n\nWhen a privileged user creates and updates a BPF_MAP_TYPE_INODE_STORAGE\nmap, bpf_inode() evaluates inode-\u003ei_security + 8. This erroneously\naliases the struct rcu_head.func callback pointer at the beginning\nof the inode-\u003ei_security blob. During subsequent map element cleanup\nor inode destruction, writing NULL to owner_storage clears the queued\nRCU callback pointer. When rcu_do_batch() later executes the queued\ncallback, it attempts an instruction fetch at address 0x0, triggering\nan immediate kernel panic.\n\nFix this by introducing a global bpf_lsm_initialized boolean flag\nmarked with __ro_after_init. Set this flag to true inside bpf_lsm_init()\nwhen the LSM framework successfully registers the BPF LSM. Gate map\nallocation in inode_storage_map_alloc() on this flag, returning\n-EOPNOTSUPP if the BPF LSM is in turn uninitialized.\n\nThis fail-fast approach prevents userspace from allocating inode\nstorage maps when the supporting BPF LSM infrastructure is absent,\navoiding zombie map states."
    }
  ],
  "id": "CVE-2026-64192",
  "lastModified": "2026-07-20T17:18:22.367",
  "metrics": {},
  "published": "2026-07-20T17:18:22.367",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c76b8abce575e0c6e4096957220b4515ed847d89"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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