Linux Kernel up to 5.5.13 net_sched tcindex_alloc_perfect_hash allocation of resources

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 5.5.13. Affected is the function tcindex_alloc_perfect_hash of the component net_sched. This manipulation causes allocation of resources. This vulnerability is registered as CVE-2020-36791. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.5.13. It has been declared as problematic. Affected by this vulnerability is the function tcindex_alloc_perfect_hash of the component net_sched. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net_sched: keep alloc_hash updated after hash allocation In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex") I moved cp->hash calculation before the first tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched. This difference could lead to another out of bound access. cp->alloc_hash should always be the size allocated, we should update it after this tcindex_alloc_perfect_hash().

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2020-36791 since 02/26/2024. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 4.4.218, 4.9.218, 4.14.175, 4.19.114, 5.4.29 or 5.5.14 eliminates this vulnerability. Applying the patch d6cdc5bb19b595486fb2e6661e5138d73a57f454/c4453d2833671e3a9f6bd52f0f581056c3736386/9f8b6c44be178c2498a00b270872a6e30e7c8266/557d015ffb27b672e24e6ad141fd887783871dc2/d23faf32e577922b6da20bf3740625c1105381bf/bd3ee8fb6371b45c71c9345cc359b94da2ddefa9/0d1c3530e1bd38382edef72591b78e877e0edcd3 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.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.4.217
• 4.9.217
• 4.14.174
• 4.19.113
• 5.4.0
• 5.4.1
• 5.4.2
• 5.4.3
• 5.4.4
• 5.4.5
• 5.4.6
• 5.4.7
• 5.4.8
• 5.4.9
• 5.4.10
• 5.4.11
• 5.4.12
• 5.4.13
• 5.4.14
• 5.4.15
• 5.4.16
• 5.4.17
• 5.4.18
• 5.4.19
• 5.4.20
• 5.4.21
• 5.4.22
• 5.4.23
• 5.4.24
• 5.4.25
• 5.4.26
• 5.4.27
• 5.4.28
• 5.5.0
• 5.5.1
• 5.5.2
• 5.5.3
• 5.5.4
• 5.5.5
• 5.5.6
• 5.5.7
• 5.5.8
• 5.5.9
• 5.5.10
• 5.5.11
• 5.5.12
• 5.5.13

License

• open-source

Website

• Vendor: https://www.kernel.org/

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