dcache: Limit the minimal number of bucket to two (Linux Linux)

CVE-2026-43071
CRITICAL 9.1

En bref

Source
NVD
EPSS
EPSS 0.46 % · centile 40 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: dcache: Limit the minimal number of bucket to two There is an OOB read problem on dentry_hashtable when user sets 'dhash_entries=1': BUG: unable to handle page fault for address: ffff888b30b774b0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: Oops: 0000 [#1] SMP PTI RIP: 0010:__d_lookup+0x56/0x120 Call Trace: d_lookup.cold+0x16/0x5d lookup_dcache+0x27/0xf0 lookup_one_qstr_excl+0x2a/0x180 start_dirop+0x55/0xa0 simple_start_creating+0x8d/0xa0 debugfs_start_creating+0x8c/0x180 debugfs_create_dir+0x1d/0x1c0 pinctrl_init+0x6d/0x140 do_one_initcall+0x6d/0x3d0 kernel_init_freeable+0x39f/0x460 kernel_init+0x2a/0x260 There will be only one bucket in dentry_hashtable when dhash_entries is set as one, and d_hash_shift is calculated as 32 by dcache_init(). Then, following process will access more than one buckets(which memory region is not allocated) in dentry_hashtable: d_lookup b = d_hash(hash) dentry_hashtable + ((u32)hashlen >> d_hash_shift) // The C standard defines the behavior of right shift amounts // exceeding the bit width of the operand as undefined. The // result of '(u32)hashlen >> d_hash_shift' becomes 'hashlen', // so 'b' will point to an unallocated memory region. hlist_bl_for_each_entry_rcu(b) hlist_bl_first_rcu(head) h->first // read OOB! Fix it by limiting the minimal number of dentry_hashtable bucket to two, so that 'd_hash_shift' won't exceeds the bit width of type u32.

Faiblesses (CWE)

  • CWE-125 — Lecture hors limites

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1CRITICAL 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HLinux
CVSS 3.1CRITICAL 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 < 45b06bb5ea96f75ad81d7ef446f832ea6b0026fe ; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 < 426ef05e82ee52c8d0e95fc0808b7383d8352d73 ; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 < ddd57ebce245f9c7e2f6902a6c087d6186d2385d ; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 < 755b40903eff563768d4d96fd4ef51ec48adde3b ; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 < 5718df131ab78897a9dd1f2e71c3ba732d4392af ; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 < 277cedabb0ab86baae83fa58218be13c6d3e5526
Linux · Linuxaffected 3.17 ; unaffected 0 < 3.17 ; unaffected 6.1.175 ≤ 6.1.* ; unaffected 6.6.136 ≤ 6.6.* ; unaffected 6.12.83 ≤ 6.12.* ; unaffected 6.18.24 ≤ 6.18.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD