fix TOCTOU race for reported vlans
Summary
In the Linux kernel, the following vulnerability has been resolved: batman-adv: tt: fix TOCTOU race for reported vlans The local TT based TVLV is generated by first checking the number of VLANs which have at least one TT entry. A new buffer with the correct size for the VLANs is then allocated. Only then, the list of VLANs s used to fill the VLAN entries in the buffer. During this time, the meshif_vlan_list_lock is held. But the prefilter used in the buffer size calculation might still cause an increase of the number of VLANs which need to be stored. Simply because a VLAN might now suddenly have at least one entry when it had none in the pre-alloc check - and then needs to occupy space which was not allocated. A flaw was found in the Linux kernel's batman-adv (Better Approach To Mobile Ad-hoc Networking - Advanced) component. A time-of-check to time-of-use (TOCTOU) race condition exists when processing reported VLANs. This could lead to memory corruption, potentially resulting in a denial of service or other unpredictable system behavior. Red Hat severity: not rated. Weakness: CWE-367. Red Hat lists Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected.
What this means
In plain English
In the Linux kernel, the following vulnerability has been resolved: batman-adv: tt: fix TOCTOU race for reported vlans The local TT based TVLV is generated by first checking the number of VLANs which have at least one TT entry. A new buffer with the correct size for the VLANs is then allocated. Only then, the list of VLANs s used to fill the VLAN entries in the buffer. During this time, the meshif_vlan_list_lock is held. But the prefilter used in the buffer size calculation might still cause an increase of the number of VLANs which need to be stored. Memory corruption can crash the affected process and, where the advisory states code execution is possible, may expose the host to further compromise.
Recommended action
The parsed official advisory does not currently specify a fixed release, mitigation, or workaround. Review the linked vendor advisory for the latest guidance before making changes.
Rewritten locally from the scraped official advisory data above; no generative API is used. The vendor advisory is authoritative.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 59 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 59 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 59 minutes ago·verify at source
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