CVE-2023-54170
Unknown Unknown - Not Provided
Duplicate Key Insertion Bug Causes Linux Kernel Crash

Publication date: 2025-12-30

Last updated on: 2025-12-30

Assigner: kernel.org

Description
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---
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Meta Information
Published
2025-12-30
Last Modified
2025-12-30
Generated
2026-05-07
AI Q&A
2025-12-30
EPSS Evaluated
2026-05-05
NVD
CVE-2023-54170
EUVD
EUVD-2023-60471
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's key management system when making DNS queries using the dns_query() function. In rare cases, the code can create a duplicate index key in the assoc_array of the destination keyring. This duplication triggers a BUG_ON() check in the assoc_array implementation, causing the kernel to crash. The issue arises when concurrent DNS queries for the same hostname lead to duplicate keys being inserted into the keyring's assoc_array, resulting in a kernel crash.


How can this vulnerability impact me? :

The vulnerability can cause the Linux kernel to crash unexpectedly due to a BUG_ON() triggered by duplicate keys in the keyring assoc_array during DNS queries. This can lead to system instability, potential denial of service, and interruption of services running on the affected system.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring the system logs for kernel BUG messages related to assoc_array.c, specifically messages like 'kernel BUG at ../lib/assoc_array.c:652!' and invalid opcode errors indicating a crash caused by duplicate keys in the keyring assoc_array. You can check the kernel logs using commands such as 'dmesg | grep assoc_array' or 'journalctl -k | grep assoc_array' to find these crash reports.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation involves updating the Linux kernel to a version where this vulnerability is fixed, as the issue is resolved by a patch that prevents duplicate keys in the keyring assoc_array. Until an update is applied, monitoring for crashes and avoiding workloads that trigger concurrent DNS queries inside the kernel may reduce the risk.


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