UBUNTU-CVE-2021-28715
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)
02 / AFFECTED SOFTWARE
Affected packages
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
6 explicit affected versions
15 explicit affected versions
76 explicit affected versions
41 explicit affected versions
56 explicit affected versions
29 explicit affected versions
9 explicit affected versions
88 explicit affected versions
5 explicit affected versions
4 explicit affected versions
121 explicit affected versions
23 explicit affected versions
1 explicit affected versions
1 explicit affected versions
21 explicit affected versions
8 explicit affected versions
1 explicit affected versions
7 explicit affected versions
12 explicit affected versions
12 explicit affected versions
1 explicit affected versions
7 explicit affected versions
12 explicit affected versions
45 explicit affected versions
5 explicit affected versions
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12 explicit affected versions
44 explicit affected versions
120 explicit affected versions
31 explicit affected versions
10 explicit affected versions
28 explicit affected versions
54 explicit affected versions
1 explicit affected versions
26 explicit affected versions
5 explicit affected versions
144 explicit affected versions
1 explicit affected versions
29 explicit affected versions
13 explicit affected versions
70 explicit affected versions
1 explicit affected versions
46 explicit affected versions
33 explicit affected versions
10 explicit affected versions
188 explicit affected versions
55 explicit affected versions
11 explicit affected versions
12 explicit affected versions
78 explicit affected versions
7 explicit affected versions
44 explicit affected versions
2 explicit affected versions
74 explicit affected versions
165 explicit affected versions
41 explicit affected versions
1 explicit affected versions
12 explicit affected versions
23 explicit affected versions
32 explicit affected versions
5 explicit affected versions
1 explicit affected versions
1 explicit affected versions
36 explicit affected versions
5 explicit affected versions
35 explicit affected versions
1 explicit affected versions
34 explicit affected versions
13 explicit affected versions
1 explicit affected versions
32 explicit affected versions
10 explicit affected versions
5 explicit affected versions
31 explicit affected versions
44 explicit affected versions
16 explicit affected versions
13 explicit affected versions
28 explicit affected versions
38 explicit affected versions
9 explicit affected versions
34 explicit affected versions
97 explicit affected versions
14 explicit affected versions
86 explicit affected versions
63 explicit affected versions
4 explicit affected versions
20 explicit affected versions
54 explicit affected versions
34 explicit affected versions
43 explicit affected versions
1 explicit affected versions
103 explicit affected versions
35 explicit affected versions
4 explicit affected versions
23 explicit affected versions
1 explicit affected versions
10 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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)
05 / REFERENCES
Further evidence
- https://ubuntu.com/security/CVE-2021-28715
- https://ubuntu.com/security/notices/USN-5278-1
- https://ubuntu.com/security/notices/USN-5298-1
- https://ubuntu.com/security/notices/USN-5337-1
- https://ubuntu.com/security/notices/USN-5338-1
- https://ubuntu.com/security/notices/USN-5368-1
- https://ubuntu.com/security/notices/USN-5377-1
- https://www.cve.org/CVERecord?id=CVE-2021-28715
- https://xenbits.xen.org/xsa/advisory-392.html