CVE-2022-50257

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

xen/gntdev: Prevent leaking grants

Prior to this commit, if a grant mapping operation failed partially,

some of the entries in the map_ops array would be invalid, whereas all

of the entries in the kmap_ops array would be valid. This in turn would

cause the following logic in gntdev_map_grant_pages to become invalid:

for (i = 0; i < map->count; i++) {

if (map->map_ops[i].status == GNTST_okay) {

map->unmap_ops[i].handle = map->map_ops[i].handle;

if (!use_ptemod)

alloced++;

}

if (use_ptemod) {

if (map->kmap_ops[i].status == GNTST_okay) {

if (map->map_ops[i].status == GNTST_okay)

alloced++;

map->kunmap_ops[i].handle = map->kmap_ops[i].handle;

}

}

}

...

atomic_add(alloced, &map->live_grants);

Assume that use_ptemod is true (i.e., the domain mapping the granted

pages is a paravirtualized domain). In the code excerpt above, note that

the "al

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References