CVE-2021-32846 Information

Description

HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0.20210107 function pci_vtsock_proc_tx in virtio-sock can lead to to uninitialized memory use. In this situation there is a check for the return value to be less or equal to VTSOCK_MAXSEGS but that check is not sufficient because the function can return -1 if it finds an error it cannot recover from. Moreover the negative return value will be used by iovec_pull in a while condition that can further lead to more corruption because the function is not designed to handle a negative iov_len. This issue may lead to a guest crashing the host causing a denial of service and under certain circumstance memory corruption. This issue is fixed in commit af5eba2360a7351c08dfd9767d9be863a50ebaba.

Reference

https://github.com/moby/hyperkit/commit/af5eba2360a7351c08dfd9767d9be863a50ebaba https://github.com/moby/hyperkit/pull/313 https://securitylab.github.com/advisories/GHSL-2021-054_057-moby-hyperkit/