CVE-2022-48890: scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM

Vulnerability summary

CVE-2022-48890 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.9% of scored vulnerabilities.

Timeline

1. 21-08-2024
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-401Missing Release of Memory after Effective LifetimeThe product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.