Improper Update of Reference Count Affecting perf package, versions *
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Test your applications- Snyk ID SNYK-CENTOS7-PERF-7145323
- published 27 May 2024
- disclosed 24 May 2024
How to fix?
There is no fixed version for Centos:7 perf.
NVD Description
Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by Centos.
See How to fix? for Centos:7 relevant fixed versions and status.
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.
References
- https://access.redhat.com/security/cve/CVE-2021-47555
- https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00
- https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d
- https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555
- https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890