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Unity Linux 20.1060a / 20.1070a Security Update: kernel (UTSA-2025-992846)

medium Nessus Plugin ID 281175

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-2025-992846 advisory.

 In the Linux kernel, the following vulnerability has been resolved:

 rxrpc: Fix locking in rxrpc's sendmsg

 Fix three bugs in the rxrpc's sendmsg implementation:

 (1) rxrpc_new_client_call() should release the socket lock when returning an error from rxrpc_get_call_slot().

 (2) rxrpc_wait_for_tx_window_intr() will return without the call mutex held in the event that we're interrupted by a signal whilst waiting for tx space on the socket or relocking the call mutex afterwards.

 Fix this by: (a) moving the unlock/lock of the call mutex up to rxrpc_send_data() such that the lock is not held around all of rxrpc_wait_for_tx_window*() and (b) indicating to higher callers whether we're return with the lock dropped. Note that this means recvmsg() will not block on this call whilst we're waiting.

 (3) After dropping and regaining the call mutex, rxrpc_send_data() needs to go and recheck the state of the tx_pending buffer and the tx_total_len check in case we raced with another sendmsg() on the same call.

 Thinking on this some more, it might make sense to have different locks for sendmsg() and recvmsg(). There's probably no need to make recvmsg() wait for sendmsg(). It does mean that recvmsg() can return MSG_EOR indicating that a call is dead before a sendmsg() to that call returns - but that can currently happen anyway.

 Without fix (2), something like the following can be induced:

 WARNING: bad unlock balance detected! 5.16.0-rc6-syzkaller #0 Not tainted
 ------------------------------------- syz-executor011/3597 is trying to release lock (&call->user_mutex) at:
 [<ffffffff885163a3>] rxrpc_do_sendmsg+0xc13/0x1350 net/rxrpc/sendmsg.c:748 but there are no more locks to release!

 other info that might help us debug this:
 no locks held by syz-executor011/3597.
 ...
 Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_unlock_imbalance_bug include/trace/events/lock.h:58 [inline]
 __lock_release kernel/locking/lockdep.c:5306 [inline] lock_release.cold+0x49/0x4e kernel/locking/lockdep.c:5657
 __mutex_unlock_slowpath+0x99/0x5e0 kernel/locking/mutex.c:900 rxrpc_do_sendmsg+0xc13/0x1350 net/rxrpc/sendmsg.c:748 rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:561 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

 [Thanks to Hawkins Jiawei and Khalid Masum for their attempts to fix this]

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.

Solution

Update the affected kernel package.

See Also

http://www.nessus.org/u?3dfd4bf4

http://www.nessus.org/u?76d41ddc

https://nvd.nist.gov/vuln/detail/CVE-2022-49998

Plugin Details

Severity: Medium

ID: 281175

File Name: unity_linux_UTSA-2025-992846.nasl

Version: 1.1

Type: local

Published: 12/31/2025

Updated: 12/31/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2022-49998

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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: 12/31/2025

Vulnerability Publication Date: 10/11/2022

Reference Information

CVE: CVE-2022-49998