CVE-2023-53855
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net: dsa: ocelot: call dsa_tag_8021q_unregister() under rtnl_lock() on driver remove When the tagging protocol in current use is "ocelot-8021q" and we unbind the driver, we see this splat: $ echo '0000:00:00.2' > /sys/bus/pci/drivers/fsl_enetc/unbind mscc_felix 0000:00:00.5 swp0: left promiscuous mode sja1105 spi2.0: Link is Down DSA: tree 1 torn down mscc_felix 0000:00:00.5 swp2: left promiscuous mode sja1105 spi2.2: Link is Down DSA: tree 3 torn down fsl_enetc 0000:00:00.2 eno2: left promiscuous mode mscc_felix 0000:00:00.5: Link is Down ------------[ cut here ]------------ RTNL: assertion failed at net/dsa/tag_8021q.c (409) WARNING: CPU: 1 PID: 329 at net/dsa/tag_8021q.c:409 dsa_tag_8021q_unregister+0x12c/0x1a0 Modules linked in: CPU: 1 PID: 329 Comm: bash Not tainted 6.5.0-rc3+ #771 pc : dsa_tag_8021q_unregister+0x12c/0x1a0 lr : dsa_tag_8021q_unregister+0x12c/0x1a0 Call trace: dsa_tag_8021q_unregister+0x12c/0x1a0 felix_tag_8021q_teardown+0x130/0x150 felix_teardown+0x3c/0xd8 dsa_tree_teardown_switches+0xbc/0xe0 dsa_unregister_switch+0x168/0x260 felix_pci_remove+0x30/0x60 pci_device_remove+0x4c/0x100 device_release_driver_internal+0x188/0x288 device_links_unbind_consumers+0xfc/0x138 device_release_driver_internal+0xe0/0x288 device_driver_detach+0x24/0x38 unbind_store+0xd8/0x108 drv_attr_store+0x30/0x50 ---[ end trace 0000000000000000 ]--- ------------[ cut here ]------------ RTNL: assertion failed at net/8021q/vlan_core.c (376) WARNING: CPU: 1 PID: 329 at net/8021q/vlan_core.c:376 vlan_vid_del+0x1b8/0x1f0 CPU: 1 PID: 329 Comm: bash Tainted: G W 6.5.0-rc3+ #771 pc : vlan_vid_del+0x1b8/0x1f0 lr : vlan_vid_del+0x1b8/0x1f0 dsa_tag_8021q_unregister+0x8c/0x1a0 felix_tag_8021q_teardown+0x130/0x150 felix_teardown+0x3c/0xd8 dsa_tree_teardown_switches+0xbc/0xe0 dsa_unregister_switch+0x168/0x260 felix_pci_remove+0x30/0x60 pci_device_remove+0x4c/0x100 device_release_driver_internal+0x188/0x288 device_links_unbind_consumers+0xfc/0x138 device_release_driver_internal+0xe0/0x288 device_driver_detach+0x24/0x38 unbind_store+0xd8/0x108 drv_attr_store+0x30/0x50 DSA: tree 0 torn down This was somewhat not so easy to spot, because "ocelot-8021q" is not the default tagging protocol, and thus, not everyone who tests the unbinding path may have switched to it beforehand. The default felix_tag_npi_teardown() does not require rtnl_lock() to be held.
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Meta Information
Published
2025-12-09
Last Modified
2025-12-09
Generated
2026-05-07
AI Q&A
2025-12-09
EPSS Evaluated
2026-05-05
NVD
CVE-2023-53855
EUVD
EUVD-2023-60141
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's network subsystem, specifically in the Distributed Switch Architecture (DSA) driver for the 'ocelot-8021q' tagging protocol. When the driver is removed (unbound) while using this tagging protocol, the kernel can hit an assertion failure and crash (splat) due to improper locking (missing rtnl_lock) during the call to dsa_tag_8021q_unregister(). This leads to kernel warnings and potential instability during driver removal.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash or become unstable when the 'ocelot-8021q' tagging protocol driver is removed. This can lead to system downtime, loss of network connectivity, and potential disruption of services relying on the affected network driver.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by observing kernel logs for specific assertion failures and warnings related to the 'ocelot-8021q' tagging protocol when unbinding the driver. For example, running the command to unbind the driver and then checking dmesg or kernel logs for messages like 'RTNL: assertion failed at net/dsa/tag_8021q.c' or 'WARNING: CPU: ... dsa_tag_8021q_unregister'. A sample command to trigger and detect this is: echo '0000:00:00.2' > /sys/bus/pci/drivers/fsl_enetc/unbind followed by dmesg | grep -i 'dsa_tag_8021q_unregister' or dmesg | grep -i 'RTNL: assertion failed'.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation involves avoiding unbinding the driver when the 'ocelot-8021q' tagging protocol is in use, as this triggers the vulnerability. Applying the patch or update that ensures dsa_tag_8021q_unregister() is called under rtnl_lock() on driver remove will resolve the issue. Until then, refrain from unbinding the affected driver or switching to the 'ocelot-8021q' tagging protocol in production environments.


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