ghsa-rvgw-688x-x595
Vulnerability from github
Published
2024-10-21 18:30
Modified
2024-10-25 15:31
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

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

cachefiles: fix dentry leak in cachefiles_open_file()

A dentry leak may be caused when a lookup cookie and a cull are concurrent:

        P1             |             P2

cachefiles_lookup_cookie cachefiles_look_up_object lookup_one_positive_unlocked // get dentry cachefiles_cull inode->i_flags |= S_KERNEL_FILE; cachefiles_open_file cachefiles_mark_inode_in_use __cachefiles_mark_inode_in_use can_use = false if (!(inode->i_flags & S_KERNEL_FILE)) can_use = true return false return false // Returns an error but doesn't put dentry

After that the following WARNING will be triggered when the backend folder is umounted:

================================================================== BUG: Dentry 000000008ad87947{i=7a,n=Dx_1_1.img} still in use (1) [unmount of ext4 sda] WARNING: CPU: 4 PID: 359261 at fs/dcache.c:1767 umount_check+0x5d/0x70 CPU: 4 PID: 359261 Comm: umount Not tainted 6.6.0-dirty #25 RIP: 0010:umount_check+0x5d/0x70 Call Trace: d_walk+0xda/0x2b0 do_one_tree+0x20/0x40 shrink_dcache_for_umount+0x2c/0x90 generic_shutdown_super+0x20/0x160 kill_block_super+0x1a/0x40 ext4_kill_sb+0x22/0x40 deactivate_locked_super+0x35/0x80 cleanup_mnt+0x104/0x160 ==================================================================

Whether cachefiles_open_file() returns true or false, the reference count obtained by lookup_positive_unlocked() in cachefiles_look_up_object() should be released.

Therefore release that reference count in cachefiles_look_up_object() to fix the above issue and simplify the code.

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{
   affected: [],
   aliases: [
      "CVE-2024-49870",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-401",
      ],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-10-21T18:15:08Z",
      severity: "MODERATE",
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\ncachefiles: fix dentry leak in cachefiles_open_file()\n\nA dentry leak may be caused when a lookup cookie and a cull are concurrent:\n\n            P1             |             P2\n-----------------------------------------------------------\ncachefiles_lookup_cookie\n  cachefiles_look_up_object\n    lookup_one_positive_unlocked\n     // get dentry\n                            cachefiles_cull\n                              inode->i_flags |= S_KERNEL_FILE;\n    cachefiles_open_file\n      cachefiles_mark_inode_in_use\n        __cachefiles_mark_inode_in_use\n          can_use = false\n          if (!(inode->i_flags & S_KERNEL_FILE))\n            can_use = true\n\t  return false\n        return false\n        // Returns an error but doesn't put dentry\n\nAfter that the following WARNING will be triggered when the backend folder\nis umounted:\n\n==================================================================\nBUG: Dentry 000000008ad87947{i=7a,n=Dx_1_1.img}  still in use (1) [unmount of ext4 sda]\nWARNING: CPU: 4 PID: 359261 at fs/dcache.c:1767 umount_check+0x5d/0x70\nCPU: 4 PID: 359261 Comm: umount Not tainted 6.6.0-dirty #25\nRIP: 0010:umount_check+0x5d/0x70\nCall Trace:\n <TASK>\n d_walk+0xda/0x2b0\n do_one_tree+0x20/0x40\n shrink_dcache_for_umount+0x2c/0x90\n generic_shutdown_super+0x20/0x160\n kill_block_super+0x1a/0x40\n ext4_kill_sb+0x22/0x40\n deactivate_locked_super+0x35/0x80\n cleanup_mnt+0x104/0x160\n==================================================================\n\nWhether cachefiles_open_file() returns true or false, the reference count\nobtained by lookup_positive_unlocked() in cachefiles_look_up_object()\nshould be released.\n\nTherefore release that reference count in cachefiles_look_up_object() to\nfix the above issue and simplify the code.",
   id: "GHSA-rvgw-688x-x595",
   modified: "2024-10-25T15:31:25Z",
   published: "2024-10-21T18:30:56Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2024-49870",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/7fa2382f97421978514a419c93054eca69f5247b",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/c7d10fa7d7691558ff967668494672415f5fa151",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/d32ff64c872d7e08e893c32ba6a2374583444410",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/da6ef2dffe6056aad3435e6cf7c6471c2a62187c",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/e4a28489b310339b2b8187bec0a437709be551c1",
      },
   ],
   schema_version: "1.4.0",
   severity: [
      {
         score: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
         type: "CVSS_V3",
      },
   ],
}


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