Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)
CVE-2021-28715 - Medium Severity Vulnerability
The Linux Kernel
Library home page: https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/?wsslib=linux
Found in HEAD commit: 05c0743befb9102e2ecb9fbd0fa8eb43eb8bb5ec
Found in base branch: master
Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)
Publish Date: 2022-01-06
URL: CVE-2021-28715
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Local - Attack Complexity: Low - Privileges Required: Low - User Interaction: None - Scope: Changed - Impact Metrics: - Confidentiality Impact: None - Integrity Impact: None - Availability Impact: High
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: https://www.linuxkernelcves.com/cves/CVE-2021-28715
Release Date: 2022-01-06
Fix Resolution: v4.4.296,v4.9.294,v4.14.259,v4.19.222,v5.4.168,v5.10.88,v5.15.11,v5.16-rc7
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