In the Linux kernel, the following vulnerability has been resolved:
net: vlan: fix underflow for the real_dev refcnt
Inject error before dev_hold(real_dev) in register_vlan_dev(),
and execute the following testcase:
ip link add dev dummy1 type dummy
ip link add name dummy1.100 link dummy1 type vlan id 100
ip link del dev dummy1
When the dummy netdevice is removed, we will get a WARNING as following:
=======================================================================
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0
and an endless loop of:
=======================================================================
unregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824
That is because dev_put(real_dev) in vlan_dev_free() be called without
dev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev
underflow.
Move the dev_hold(real_dev) to vlan_dev_init() which is the call-back of
ndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev
symmetrical.
Metrics
Affected Vendors & Products
References
History
Mon, 04 Nov 2024 12:15:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
ssvc
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Fri, 06 Sep 2024 13:45:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Weaknesses | CWE-911 | |
Metrics |
cvssV3_1
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cvssV3_1
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-05-24T15:09:57.302Z
Updated: 2024-11-04T20:18:51.592Z
Reserved: 2024-05-24T15:02:54.833Z
Link: CVE-2021-47555
Vulnrichment
Updated: 2024-08-04T05:39:59.857Z
NVD
Status : Awaiting Analysis
Published: 2024-05-24T15:15:20.237
Modified: 2024-11-04T21:35:02.123
Link: CVE-2021-47555
Redhat