fkie_cve-2023-53246
Vulnerability from fkie_nvd
Published
2025-09-15 15:15
Modified
2025-09-15 15:22
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL When compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount is NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to S_AUTOMOUNT and corresponding dentry flags is retained regardless of CONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in VFS follow_automount() when traversing a DFS referral link: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: <TASK> __traverse_mounts+0xb5/0x220 ? cifs_revalidate_mapping+0x65/0xc0 [cifs] step_into+0x195/0x610 ? lookup_fast+0xe2/0xf0 path_lookupat+0x64/0x140 filename_lookup+0xc2/0x140 ? __create_object+0x299/0x380 ? kmem_cache_alloc+0x119/0x220 ? user_path_at_empty+0x31/0x50 user_path_at_empty+0x31/0x50 __x64_sys_chdir+0x2a/0xd0 ? exit_to_user_mode_prepare+0xca/0x100 do_syscall_64+0x42/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc This fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler when CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to avoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This approach was chosen as it provides more control over the error path.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/179a88a8558bbf42991d361595281f3e45d7edfc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1e144b68208e98fd4602c842a7149ba5f41d87fb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/26a32a212bc540f4773cd6af8cf73e967d72569c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/657d7c215ca974d366ab1808213f716e1e3aa950
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8afb1fabcec1929db46977e84baeee0cc0e79242
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8cd7dbc9c46d51e00a0a8372e07cc1cbb8d24a77
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b64305185b76f1d5145ce594ff48f3f0e70695bd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b7d854c33ab48e55fc233699bbefe39ec9bb5c05
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL\n\nWhen compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount\nis NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to\nS_AUTOMOUNT and corresponding dentry flags is retained regardless of\nCONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in\nVFS follow_automount() when traversing a DFS referral link:\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  ...\n  Call Trace:\n   \u003cTASK\u003e\n   __traverse_mounts+0xb5/0x220\n   ? cifs_revalidate_mapping+0x65/0xc0 [cifs]\n   step_into+0x195/0x610\n   ? lookup_fast+0xe2/0xf0\n   path_lookupat+0x64/0x140\n   filename_lookup+0xc2/0x140\n   ? __create_object+0x299/0x380\n   ? kmem_cache_alloc+0x119/0x220\n   ? user_path_at_empty+0x31/0x50\n   user_path_at_empty+0x31/0x50\n   __x64_sys_chdir+0x2a/0xd0\n   ? exit_to_user_mode_prepare+0xca/0x100\n   do_syscall_64+0x42/0x90\n   entry_SYSCALL_64_after_hwframe+0x72/0xdc\n\nThis fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler\nwhen CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to\navoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This\napproach was chosen as it provides more control over the error path."
    }
  ],
  "id": "CVE-2023-53246",
  "lastModified": "2025-09-15T15:22:27.090",
  "metrics": {},
  "published": "2025-09-15T15:15:51.803",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/179a88a8558bbf42991d361595281f3e45d7edfc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1e144b68208e98fd4602c842a7149ba5f41d87fb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/26a32a212bc540f4773cd6af8cf73e967d72569c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/657d7c215ca974d366ab1808213f716e1e3aa950"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8afb1fabcec1929db46977e84baeee0cc0e79242"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8cd7dbc9c46d51e00a0a8372e07cc1cbb8d24a77"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b64305185b76f1d5145ce594ff48f3f0e70695bd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b7d854c33ab48e55fc233699bbefe39ec9bb5c05"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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