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CVE-2023-54170: keys: Fix linking a duplicate key to a keyring's assoc_array

In the Linux kernel, the following vulnerability has been resolved: keys: Fix linking a duplicate key to a keyring's assoc_array When making a DNS query inside the kernel using dns_query(), the request code can in rare cases end up creating a duplicate index key in the assoc_array of the destination keyring. It is eventually found by a BUG_ON() check in the assoc_array implementation and results in a crash. Example report: [2158499.700025] kernel BUG at ../lib/assoc_array.c:652! [2158499.700039] invalid opcode: 0000 [#1] SMP PTI [2158499.700065] CPU: 3 PID: 31985 Comm: kworker/3:1 Kdump: loaded Not tainted 5.3.18-150300.59.90-default #1 SLE15-SP3 [2158499.700096] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 [2158499.700351] Workqueue: cifsiod cifs_resolve_server [cifs] [2158499.700380] RIP: 0010:assoc_array_insert+0x85f/0xa40 [2158499.700401] Code: ff 74 2b 48 8b 3b 49 8b 45 18 4c 89 e6 48 83 e7 fe e8 95 ec 74 00 3b 45 88 7d db 85 c0 79 d4 0f 0b 0f 0b 0f 0b e8 41 f2 be ff <0f> 0b 0f 0b 81 7d 88 ff ff ff 7f 4c 89 eb 4c 8b ad 58 ff ff ff 0f [2158499.700448] RSP: 0018:ffffc0bd6187faf0 EFLAGS: 00010282 [2158499.700470] RAX: ffff9f1ea7da2fe8 RBX: ffff9f1ea7da2fc1 RCX: 0000000000000005 [2158499.700492] RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000 [2158499.700515] RBP: ffffc0bd6187fbb0 R08: ffff9f185faf1100 R09: 0000000000000000 [2158499.700538] R10: ffff9f1ea7da2cc0 R11: 000000005ed8cec8 R12: ffffc0bd6187fc28 [2158499.700561] R13: ffff9f15feb8d000 R14: ffff9f1ea7da2fc0 R15: ffff9f168dc0d740 [2158499.700585] FS: 0000000000000000(0000) GS:ffff9f185fac0000(0000) knlGS:0000000000000000 [2158499.700610] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [2158499.700630] CR2: 00007fdd94fca238 CR3: 0000000809d8c006 CR4: 00000000003706e0 [2158499.700702] Call Trace: [2158499.700741] ? key_alloc+0x447/0x4b0 [2158499.700768] ? __key_link_begin+0x43/0xa0 [2158499.700790] __key_link_begin+0x43/0xa0 [2158499.700814] request_key_and_link+0x2c7/0x730 [2158499.700847] ? dns_resolver_read+0x20/0x20 [dns_resolver] [2158499.700873] ? key_default_cmp+0x20/0x20 [2158499.700898] request_key_tag+0x43/0xa0 [2158499.700926] dns_query+0x114/0x2ca [dns_resolver] [2158499.701127] dns_resolve_server_name_to_ip+0x194/0x310 [cifs] [2158499.701164] ? scnprintf+0x49/0x90 [2158499.701190] ? __switch_to_asm+0x40/0x70 [2158499.701211] ? __switch_to_asm+0x34/0x70 [2158499.701405] reconn_set_ipaddr_from_hostname+0x81/0x2a0 [cifs] [2158499.701603] cifs_resolve_server+0x4b/0xd0 [cifs] [2158499.701632] process_one_work+0x1f8/0x3e0 [2158499.701658] worker_thread+0x2d/0x3f0 [2158499.701682] ? process_one_work+0x3e0/0x3e0 [2158499.701703] kthread+0x10d/0x130 [2158499.701723] ? kthread_park+0xb0/0xb0 [2158499.701746] ret_from_fork+0x1f/0x40 The situation occurs as follows: * Some kernel facility invokes dns_query() to resolve a hostname, for example, "abcdef". The function registers its global DNS resolver cache as current->cred.thread_keyring and passes the query to request_key_net() -> request_key_tag() -> request_key_and_link(). * Function request_key_and_link() creates a keyring_search_context object. Its match_data.cmp method gets set via a call to type->match_preparse() (resolves to dns_resolver_match_preparse()) to dns_resolver_cmp(). * Function request_key_and_link() continues and invokes search_process_keyrings_rcu() which returns that a given key was not found. The control is then passed to request_key_and_link() -> construct_alloc_key(). * Concurrently to that, a second task similarly makes a DNS query for "abcdef." and its result gets inserted into the DNS resolver cache. * Back on the first task, function construct_alloc_key() first runs __key_link_begin() to determine an assoc_array_edit operation to insert a new key. Index keys in the array are compared exactly as-is, using keyring_compare_object(). The operation ---truncated---

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2023-54170 is a Linux kernel reliability bug that can crash a system in rare DNS-resolution races inside the kernel. The reported path involves kernel DNS queries and CIFS name resolution. The public record does not provide CVSS, active exploitation, or a full operational workaround.

Executive priority

Treat this as a reliability and availability risk, not a confirmed remote compromise issue. Patch during normal kernel maintenance, faster for file-serving, CIFS-heavy, or business-critical Linux systems.

Technical view

The flaw is in Linux kernel key handling. Concurrent dns_query() requests can create duplicate index keys in a keyring assoc_array. A later BUG_ON() in assoc_array_insert detects the inconsistency and triggers a kernel crash. The fix changes duplicate-key handling in stable kernel branches.

Likely exposure

Exposure is most relevant to Linux systems using affected kernel versions where kernel facilities perform DNS queries, including the documented CIFS resolver path. Internet exposure is not established by the source bundle.

Exploitation context

The bundle describes a rare race condition and a crash report, not a weaponized exploit. KEV is false, and no cited source states active exploitation. Practical exploitability and attacker prerequisites are not established.

Researcher notes

Evidence supports a kernel denial-of-service condition via a race in dns_resolver key insertion. The public bundle is incomplete on exact version ranges, triggerability, privilege requirements, and distribution backports, so validation should rely on vendor advisories and installed kernel builds.

Mitigation direction

  • Identify systems running affected Linux kernel versions.
  • Upgrade to a vendor kernel containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fixes.
  • Prioritize systems using CIFS or kernel DNS resolution paths.
  • Monitor for kernel BUG reports in assoc_array_insert.

Validation and detection

  • Inventory kernel versions across Linux assets.
  • Compare installed kernels against vendor fixed package versions.
  • Review logs for crashes mentioning assoc_array_insert or dns_query.
  • Confirm vendor advisories map to CVE-2023-54170.
  • Validate CIFS-dependent systems after kernel updates.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
7Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxdf593ee23e05cdda16c8c995e5818779431bb29f, df593ee23e05cdda16c8c995e5818779431bb29f, df593ee23e05cdda16c8c995e5818779431bb29f, df593ee23e05cdda16c8c995e5818779431bb29f, df593ee23e05cdda16c8c995e5818779431bb29f, df593ee23e05cdda16c8c995e5818779431bb29funaffected
LinuxLinux5.3, 0, 5.4.253, 5.10.188, 5.15.123, 6.1.42, 6.4.7, 6.5affected
Weakness

CWE details

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