fkie_cve-2025-38710
Vulnerability from fkie_nvd
Published
2025-09-04 16:15
Modified
2025-09-05 17:47
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: gfs2: Validate i_depth for exhash directories A fuzzer test introduced corruption that ends up with a depth of 0 in dir_e_read(), causing an undefined shift by 32 at: index = hash >> (32 - dip->i_depth); As calculated in an open-coded way in dir_make_exhash(), the minimum depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time. So we can avoid the undefined behaviour by checking for depth values lower than the minimum in gfs2_dinode_in(). Values greater than the maximum are already being checked for there. Also switch the calculation in dir_make_exhash() to use ilog2() to clarify how the depth is calculated. Tested with the syzkaller repro.c and xfstests '-g quick'.
Impacted products
Vendor Product Version



{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: Validate i_depth for exhash directories\n\nA fuzzer test introduced corruption that ends up with a depth of 0 in\ndir_e_read(), causing an undefined shift by 32 at:\n\n  index = hash \u003e\u003e (32 - dip-\u003ei_depth);\n\nAs calculated in an open-coded way in dir_make_exhash(), the minimum\ndepth for an exhash directory is ilog2(sdp-\u003esd_hash_ptrs) and 0 is\ninvalid as sdp-\u003esd_hash_ptrs is fixed as sdp-\u003ebsize / 16 at mount time.\n\nSo we can avoid the undefined behaviour by checking for depth values\nlower than the minimum in gfs2_dinode_in(). Values greater than the\nmaximum are already being checked for there.\n\nAlso switch the calculation in dir_make_exhash() to use ilog2() to\nclarify how the depth is calculated.\n\nTested with the syzkaller repro.c and xfstests \u0027-g quick\u0027."
    }
  ],
  "id": "CVE-2025-38710",
  "lastModified": "2025-09-05T17:47:24.833",
  "metrics": {},
  "published": "2025-09-04T16:15:40.137",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/53a0249d68a210c16e961b83adfa82f94ee0a53d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/557c024ca7250bb65ae60f16c02074106c2f197b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9680c58675b82348ab84d387e4fa727f7587e1a0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b5f46951e62377b6e406fadc18bc3c5bdf1632a7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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