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CVE-2022-49300 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: nbd: fix race between nbd_alloc_config() and module removal When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it. The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000040 Oops: 0000 [#1] SMP PTI CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: knbd16-recv recv_work [nbd] RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd] Call Trace: recv_work+0x3b/0xb0 [nbd] process_one_work+0x1ed/0x390 worker_thread+0x4a/0x3d0 kthread+0x12a/0x150 ret_from_fork+0x22/0x30 Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd->config only when nbd_alloc_config() succeeds to ensure the value of nbd->config is binary (valid or NULL). Also adding a debug message to check the reference counter of nbd_config during module removal.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
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URL Source(s) Tag(s)
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 
kernel.org Patch 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') cwe source acceptance level NIST  
CWE-476 NULL Pointer Dereference cwe source acceptance level NIST   CISA-ADP  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2022-49300
NVD Published Date:
02/26/2025
NVD Last Modified:
10/01/2025
Source:
kernel.org