Description (CNA)
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.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 45b06bb5ea96f75ad81d7ef446f832ea6b0026fe; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 426ef05e82ee52c8d0e95fc0808b7383d8352d73; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before ddd57ebce245f9c7e2f6902a6c087d6186d2385d; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 755b40903eff563768d4d96fd4ef51ec48adde3b; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 5718df131ab78897a9dd1f2e71c3ba732d4392af; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before 277cedabb0ab86baae83fa58218be13c6d3e5526; affected 99d263d4c5b2f541dfacb5391e22e8c91ea982a6 before f08fe8891c3eeb63b73f9f1f6d97aa629c821579; affected d4c96061fddd129778ce8b70fb093aa532f422d0; affected be2378cbffe50ce0161f0fdee914adee98af53dc; affected a8be8af18485f9fade90e1743d940252a39eec84; affected b5cf3193759f7cd1cfbeef11f5cf067bbce22e55; affected 3.10.55 before 3.11; affected 3.12.29 before 3.13; affected 3.14.19 before 3.15; affected 3.16.3 before 3.17 |
| Linux / Linux | affected 3.17; unaffected 0 before 3.17; unaffected 6.1.175 through 6.1.*; unaffected 6.6.136 through 6.6.*; unaffected 6.12.83 through 6.12.*; unaffected 6.18.24 through 6.18.*; unaffected 6.19.14 through 6.19.*; unaffected 7.0.1 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/45b06bb5ea96f75ad81d7ef446f832ea6b0026fe
- https://git.kernel.org/stable/c/426ef05e82ee52c8d0e95fc0808b7383d8352d73
- https://git.kernel.org/stable/c/ddd57ebce245f9c7e2f6902a6c087d6186d2385d
- https://git.kernel.org/stable/c/755b40903eff563768d4d96fd4ef51ec48adde3b
- https://git.kernel.org/stable/c/5718df131ab78897a9dd1f2e71c3ba732d4392af
- https://git.kernel.org/stable/c/277cedabb0ab86baae83fa58218be13c6d3e5526
- https://git.kernel.org/stable/c/f08fe8891c3eeb63b73f9f1f6d97aa629c821579
ADP enrichment
No English description supplied.
No English description supplied.
No references supplied.