scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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: scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM storvsc_queuecommand() maps the scatter/gather list using scsi_dma_map(), which in a confidential VM allocates swiotlb bounce buffers. If the I/O submission fails in storvsc_do_io(), the I/O is typically retried by higher level code, but the bounce buffer memory is never freed. The mostly like cause of I/O submission failure is a full VMBus channel ring buffer, which is not uncommon under high I/O loads. Eventually enough bounce buffer memory leaks that the confidential VM can't do any I/O. The same problem can arise in a non-confidential VM with kernel boot parameter swiotlb=force. Fix this by doing scsi_dma_unmap() in the case of an I/O submission error, which frees the bounce buffer memory.
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
5.17