Total vulnerabilities in the database
Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.
| Software | From | Fixed in |
|---|---|---|
| xen / xen | 4.0.0 | 4.0.0.x |
| debian / debian_linux | 11.0 | 11.0.x |
| fedoraproject / fedora | 33 | 33.x |
| fedoraproject / fedora | 34 | 34.x |
| fedoraproject / fedora | 35 | 35.x |