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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.1622 USN-4950-1: Linux kernel vulnerabilities 12 May 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: kernel Publisher: Ubuntu Operating System: Ubuntu Linux variants Impact/Access: Execute Arbitrary Code/Commands -- Existing Account Denial of Service -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2021-3491 CVE-2021-3490 CVE-2021-3489 Original Bulletin: https://ubuntu.com/security/notices/USN-4950-1 Comment: This advisory references vulnerabilities in the Linux kernel that also affect distributions other than Ubuntu. It is recommended that administrators running Linux check for an updated version of the kernel for their system. - --------------------------BEGIN INCLUDED TEXT-------------------- USN-4950-1: Linux kernel vulnerabilities 11 May 2021 Several security issues were fixed in the Linux kernel. Releases o Ubuntu 21.04 Packages o linux - Linux kernel o linux-aws - Linux kernel for Amazon Web Services (AWS) systems o linux-azure - Linux kernel for Microsoft Azure Cloud systems o linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems o linux-kvm - Linux kernel for cloud environments o linux-oracle - Linux kernel for Oracle Cloud systems o linux-raspi - Linux kernel for Raspberry Pi (V8) systems Details Ryota Shiga discovered that the eBPF implementation in the Linux kernel did not properly verify that a BPF program only reserved as much memory for a ring buffer as was allocated. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. ( CVE-2021-3489 ) Manfred Paul discovered that the eBPF implementation in the Linux kernel did not properly track bounds on bitwise operations. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. ( CVE-2021-3490 ) Billy Jheng Bing-Jhong discovered that the io_uring implementation of the Linux kernel did not properly enforce the MAX_RW_COUNT limit in some situations. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. ( CVE-2021-3491 ) Norbert Slusarek discovered that the CAN ISOTP protocol implementation in the Linux kernel contained a race condition. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. Please note that to address this issue, SF_BROADCAST support was removed temporarily from the CAN ISOTP implementation in Ubuntu 21.04 kernels. (LP: #1927409) Update instructions The problem can be corrected by updating your system to the following package versions: Ubuntu 21.04 o linux-image-5.11.0-17-generic-64k - 5.11.0-17.18 o linux-image-gke - 5.11.0.1007.7 o linux-image-5.11.0-17-generic-lpae - 5.11.0-17.18 o linux-image-5.11.0-1007-gcp - 5.11.0-1007.7 o linux-image-5.11.0-17-generic - 5.11.0-17.18 o linux-image-5.11.0-1006-oracle - 5.11.0-1006.6 o linux-image-oracle - 5.11.0.1006.6 o linux-image-5.11.0-17-lowlatency - 5.11.0-17.18 o linux-image-azure - 5.11.0.1005.5 o linux-image-raspi-nolpae - 5.11.0.1008.6 o linux-image-virtual - 5.11.0.17.18 o linux-image-raspi - 5.11.0.1008.6 o linux-image-5.11.0-1008-raspi - 5.11.0-1008.8 o linux-image-generic-64k - 5.11.0.17.18 o linux-image-generic - 5.11.0.17.18 o linux-image-5.11.0-1008-raspi-nolpae - 5.11.0-1008.8 o linux-image-aws - 5.11.0.1007.7 o linux-image-kvm - 5.11.0.1007.7 o linux-image-5.11.0-1005-azure - 5.11.0-1005.5 o linux-image-generic-lpae - 5.11.0.17.18 o linux-image-gcp - 5.11.0.1007.7 o linux-image-5.11.0-1007-aws - 5.11.0-1007.7 o linux-image-lowlatency - 5.11.0.17.18 o linux-image-5.11.0-1007-kvm - 5.11.0-1007.7 After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well. References o CVE-2021-3489 o CVE-2021-3490 o CVE-2021-3491 o https://launchpad.net/bugs/1927409 Related notices o USN-4948-1 : linux-oem-5.10, linux-image-5.10.0-1026-oem, linux-image-oem-20.04b o USN-4949-1 : linux-hwe-5.8, linux-image-generic-64k, linux-image-gke, linux-image-5.8.0-53-generic, linux-image-raspi-nolpae, linux-image-5.8.0-1027-kvm, linux-image-kvm, linux-image-gcp, linux-image-generic-64k-hwe-20.04, linux-image-oem-20.04, linux-image-5.8.0-1032-azure, linux-image-5.8.0-1024-raspi-nolpae, linux-image-raspi, linux-image-generic-lpae, linux, linux-image-generic-lpae-hwe-20.04, linux-image-virtual-hwe-20.04, linux-gcp, linux-image-5.8.0-53-lowlatency, linux-raspi, linux-image-aws, linux-image-generic, linux-image-lowlatency-hwe-20.04, linux-image-virtual, linux-image-5.8.0-1024-raspi, linux-image-5.8.0-53-generic-lpae, linux-aws, linux-image-5.8.0-1033-aws, linux-kvm, linux-image-5.8.0-1029-oracle, linux-azure, linux-image-generic-hwe-20.04, linux-image-oracle, linux-image-5.8.0-53-generic-64k, linux-oracle, linux-image-5.8.0-1031-gcp, linux-image-azure, linux-image-lowlatency - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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