CVE-2022-26356

Racy interactions between dirty vram tracking and paging log dirty hypercalls Activation of log dirty mode done by XEN_DMOP_track_dirty_vram (was named HVMOP_track_dirty_vram before Xen 4.9) is racy with ongoing log dirty hypercalls. A suitably timed call to XEN_DMOP_track_dirty_vram can enable log dirty while another CPU is still in the process of tearing down the structures related to a previously enabled log dirty mode (XEN_DOMCTL_SHADOW_OP_OFF). This is due to lack of mutually exclusive locking between both operations and can lead to entries being added in already freed slots, resulting in a memory leak.

Racy interactions between dirty vram tracking and paging log dirty hypercalls Activation of log dirty mode done by XEN_DMOP_track_dirty_vram (was named HVMOP_track_dirty_vram before Xen 4.9) is racy with ongoing log dirty hypercalls. A suitably timed call to XEN_DMOP_track_dirty_vram can enable log dirty while another CPU is still in the process of tearing down the structures related to a previously enabled log dirty mode (XEN_DOMCTL_SHADOW_OP_OFF). This is due to lack of mutually exclusive locking between both operations and can lead to entries being added in already freed slots, resulting in a memory leak.

Una activación del modo de registro sucio realizada por XEN_DMOP_track_dirty_vram (es llamada HVMOP_track_dirty_vram antes de Xen versión 4.9) es producido con las hiperllamadas de registro sucio en curso. Una llamada a XEN_DMOP_track_dirty_vram con el tiempo apropiado puede habilitar log dirty mientras otra CPU está todavía en el proceso de desmontar las estructuras relacionadas con un modo log dirty previamente habilitado (XEN_DOMCTL_SHADOW_OP_OFF). Esto es debido a una falta de bloqueo mutuamente excluyente entre ambas operaciones y puede conllevar a que son añadidas entradas en ranuras ya liberadas, dando lugar a una pérdida de memoria