CVE-2009-1895

El subsistema de personalidad en el Linux kernel anterior a v2.6.31-rc3 tiene establecido que PER_CLEAR_ON_SETID no borre las banderas ADDR_COMPAT_LAYOUT y MMAP_PAGE_ZERO cuando ejecuta un programa setuid o setgid, lo que facilita a usuarios locales aprovechar los detalles del uso actual de memoria para (1) llevar a cabo ataques de deferencia a punteros NULOS, (2) evitar el mecanismo de protección mmap_min_addr o (3) rechazar aleatoriamente el espacio en la capa de direcciones (ASLR).

Michael Tokarev discovered that the RTL8169 network driver did not correctly validate buffer sizes. A remote attacker on the local network could send specially traffic traffic that would crash the system or potentially grant elevated privileges. Julien Tinnes and Tavis Ormandy discovered that when executing setuid processes the kernel did not clear certain personality flags. A local attacker could exploit this to map the NULL memory page, causing other vulnerabilities to become exploitable. Ubuntu 6.06 was not affected. Matt T. Yourst discovered that KVM did not correctly validate the page table root. A local attacker could exploit this to crash the system, leading to a denial of service. Ubuntu 6.06 was not affected. Ramon de Carvalho Valle discovered that eCryptfs did not correctly validate certain buffer sizes. A local attacker could create specially crafted eCryptfs files to crash the system or gain elevated privileges. Ubuntu 6.06 was not affected.