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proc: fix UAF in proc_get_inode()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... dereference. rmmod lookup sys_delete_module proc_lookup_de pde_get(de); proc_get_inode(dir->i_sb, de); mod->exit() proc_remove remove_proc_subtree proc_entry_rundown(de); free_module(mod); if (S_ISREG(inode->i_mode)) if (de->proc_ops->proc_read_iter) --> As module is already freed, will trigger UAF BUG: unable to handle page fault for address: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78

Announced Source revision 1
Original source ↗

CVE-2025-21999

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2025-21999

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "eda279586e571b05dff44d48e05f8977ad05855d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "966f331403dc3ed04ff64eaf3930cf1267965e53",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "63b53198aff2e4e6c5866a4ff73c7891f958ffa4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "ede3e8ac90ae106f0b29cd759aadebc1568f1308",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "64dc7c68e040251d9ec6e989acb69f8f6ae4a10b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
        "lessThan": "654b33ada4ab5e926cd9c570196fefa7bec7c1df",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/proc/generic.c",
      "fs/proc/inode.c",
      "fs/proc/internal.h",
      "include/linux/proc_fs.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.6"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.6",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.236",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.180",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.132",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.85",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.21",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.13.9",
        "versionType": "semver",
        "lessThanOrEqual": "6.13.*"
      },
      {
        "status": "unaffected",
        "version": "6.14",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/proc/generic.c",
      "fs/proc/inode.c",
      "fs/proc/internal.h",
      "include/linux/proc_fs.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2025-21999

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#26971 · Revision 1
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Publisher date
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