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Unity Linux 20.1070a Security Update: kernel (UTSA-2025-394310)
high Nessus Plugin ID 267727
Synopsis
The Unity Linux host is missing one or more security updates.Description
The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-394310 advisory.In the Linux kernel, the following vulnerability has been resolved:
security/keys: fix slab-out-of-bounds in key_task_permission
KASAN reports an out of bounds read:
BUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:36 BUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [inline] BUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410 security/keys/permission.c:54 Read of size 4 at addr ffff88813c3ab618 by task stress-ng/4362
CPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3ede #15 Call Trace:
__dump_stack lib/dump_stack.c:82 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:123 print_address_description.constprop.0+0x19/0x170 mm/kasan/report.c:400
__kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560 kasan_report+0x3a/0x50 mm/kasan/report.c:585
__kuid_val include/linux/uidgid.h:36 [inline] uid_eq include/linux/uidgid.h:63 [inline] key_task_permission+0x394/0x410 security/keys/permission.c:54 search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793
This issue was also reported by syzbot.
It can be reproduced by following these steps(more details [1]):
1. Obtain more than 32 inputs that have similar hashes, which ends with the pattern '0xxxxxxxe6'.
2. Reboot and add the keys obtained in step 1.
The reproducer demonstrates how this issue happened:
1. In the search_nested_keyrings function, when it iterates through the slots in a node(below tag ascend_to_node), if the slot pointer is meta and node->back_pointer != NULL(it means a root), it will proceed to descend_to_node. However, there is an exception. If node is the root, and one of the slots points to a shortcut, it will be treated as a keyring.
2. Whether the ptr is keyring decided by keyring_ptr_is_keyring function.
However, KEYRING_PTR_SUBTYPE is 0x2UL, the same as ASSOC_ARRAY_PTR_SUBTYPE_MASK.
3. When 32 keys with the similar hashes are added to the tree, the ROOT has keys with hashes that are not similar (e.g. slot 0) and it splits NODE A without using a shortcut. When NODE A is filled with keys that all hashes are xxe6, the keys are similar, NODE A will split with a shortcut. Finally, it forms the tree as shown below, where slot 6 points to a shortcut.
NODE A +------>+---+ ROOT | | 0 | xxe6 +---+ | +---+ xxxx | 0 | shortcut : : xxe6 +---+ | +---+ xxe6 : : | | | xxe6 +---+ | +---+ | 6 |---+ : : xxe6 +---+ +---+ xxe6 : : | f | xxe6 +---+ +---+ xxe6 | f | +---+
4. As mentioned above, If a slot(slot 6) of the root points to a shortcut, it may be mistakenly transferred to a key*, leading to a read out-of-bounds read.
To fix this issue, one should jump to descend_to_node if the ptr is a shortcut, regardless of whether the node is root or not.
[1] https://lore.kernel.org/linux-kernel/[email protected]/
[jarkko: tweaked the commit message a bit to have an appropriate closes tag.]
Tenable has extracted the preceding description block directly from the Unity Linux security advisory.
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
See Also
Plugin Details
Severity: High
ID: 267727
File Name: unity_linux_UTSA-2025-394310.nasl
Version: 1.1
Type: local
Published: 10/7/2025
Updated: 10/7/2025
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 6.0
CVSS v2
Risk Factor: Medium
Base Score: 6.2
Temporal Score: 4.6
Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:N/A:C
CVSS Score Source: CVE-2024-50301
CVSS v3
Risk Factor: High
Base Score: 7.1
Temporal Score: 6.2
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 7/8/2025
Vulnerability Publication Date: 12/12/2023
Reference Information
CVE: CVE-2024-50301