NFSD: Limit the number of concurrent async COPY operations
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
In the Linux kernel, the following vulnerability has been resolved: NFSD: Limit the number of concurrent async COPY operations Nothing appears to limit the number of concurrent async COPY operations that clients can start. In addition, AFAICT each async COPY can copy an unlimited number of 4MB chunks, so can run for a long time. Thus IMO async COPY can become a DoS vector. Add a restriction mechanism that bounds the number of concurrent background COPY operations. Start simple and try to be fair -- this patch implements a per-namespace limit. An async COPY request that occurs while this limit is exceeded gets NFS4ERR_DELAY. The requesting client can choose to send the request again after a delay or fall back to a traditional read/write style copy. If there is need to make the mechanism more sophisticated, we can visit that in future patches.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
4.20
References 7
git.kernel.org
- stable/c/9e52ff544e0bfa09ee339fd7b0937ee3c080c24e
- stable/c/43e46ee5efc03990b223f7aa8b77aa9c3d3acfdf
- stable/c/7ea9260874b779637aff6d24c344b8ef4ac862a0
- stable/c/ae267989b7b7933dfedcd26468d0a88fc3a9da9e
- stable/c/b4e21431a0db4854b5023cd5af001be557e6c3db
- stable/c/6a488ad7745b8f64625c6d3a24ce7e448e83f11b
- stable/c/aadc3bbea163b6caaaebfdd2b6c4667fbc726752