Linux Kernel up to 6.8.6 batman-adv infinite loop

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.8.6 and classified as critical. Affected is an unknown function of the component batman-adv. Performing a manipulation results in infinite loop. This vulnerability is known as CVE-2024-35982. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.8.6. This affects an unknown part of the component batman-adv. The manipulation with an unknown input leads to a infinite loop vulnerability. CWE is classifying the issue as CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: batman-adv: Avoid infinite loop trying to resize local TT If the MTU of one of an attached interface becomes too small to transmit the local translation table then it must be resized to fit inside all fragments (when enabled) or a single packet. But if the MTU becomes too low to transmit even the header + the VLAN specific part then the resizing of the local TT will never succeed. This can for example happen when the usable space is 110 bytes and 11 VLANs are on top of batman-adv. In this case, at least 116 byte would be needed. There will just be an endless spam of batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (110) in the log but the function will never finish. Problem here is that the timeout will be halved all the time and will then stagnate at 0 and therefore never be able to reduce the table even more. There are other scenarios possible with a similar result. The number of BATADV_TT_CLIENT_NOPURGE entries in the local TT can for example be too high to fit inside a packet. Such a scenario can therefore happen also with only a single VLAN + 7 non-purgable addresses - requiring at least 120 bytes. While this should be handled proactively when: * interface with too low MTU is added * VLAN is added * non-purgeable local mac is added * MTU of an attached interface is reduced * fragmentation setting gets disabled (which most likely requires dropping attached interfaces) not all of these scenarios can be prevented because batman-adv is only consuming events without the the possibility to prevent these actions (non-purgable MAC address added, MTU of an attached interface is reduced). It is therefore necessary to also make sure that the code is able to handle also the situations when there were already incompatible system configuration are present.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2024-35982 since 05/17/2024. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 215880 (Azure Linux 3.0 Security Update: kernel (CVE-2024-35982)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.19.313, 5.4.275, 5.10.216, 5.15.156, 6.1.87, 6.6.28 or 6.8.7 eliminates this vulnerability. Applying the patch 04720ea2e6c6/b3ddf6904073/70a8be9dc2fb/87b6af1a7683/3fe79b2c8346/4ca2a5fb54ea/ca54e2671548/b1f532a3b1e6 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (215880). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.19.312
• 5.4.274
• 5.10.215
• 5.15.155
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.1.25
• 6.1.26
• 6.1.27
• 6.1.28
• 6.1.29
• 6.1.30
• 6.1.31
• 6.1.32
• 6.1.33
• 6.1.34
• 6.1.35
• 6.1.36
• 6.1.37
• 6.1.38
• 6.1.39
• 6.1.40
• 6.1.41
• 6.1.42
• 6.1.43
• 6.1.44
• 6.1.45
• 6.1.46
• 6.1.47
• 6.1.48
• 6.1.49
• 6.1.50
• 6.1.51
• 6.1.52
• 6.1.53
• 6.1.54
• 6.1.55
• 6.1.56
• 6.1.57
• 6.1.58
• 6.1.59
• 6.1.60
• 6.1.61
• 6.1.62
• 6.1.63
• 6.1.64
• 6.1.65
• 6.1.66
• 6.1.67
• 6.1.68
• 6.1.69
• 6.1.70
• 6.1.71
• 6.1.72
• 6.1.73
• 6.1.74
• 6.1.75
• 6.1.76
• 6.1.77
• 6.1.78
• 6.1.79
• 6.1.80
• 6.1.81
• 6.1.82
• 6.1.83
• 6.1.84
• 6.1.85
• 6.1.86
• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.6.17
• 6.6.18
• 6.6.19
• 6.6.20
• 6.6.21
• 6.6.22
• 6.6.23
• 6.6.24
• 6.6.25
• 6.6.26
• 6.6.27
• 6.8.0
• 6.8.1
• 6.8.2
• 6.8.3
• 6.8.4
• 6.8.5
• 6.8.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion