CVE-2019-6454 – systemd: Insufficient input validation in bus_process_object() resulting in PID 1 crash

https://notcve.org/view.php?id=CVE-2019-6454

An issue was discovered in sd-bus in systemd 239. bus_process_object() in libsystemd/sd-bus/bus-objects.c allocates a variable-length stack buffer for temporarily storing the object path of incoming D-Bus messages. An unprivileged local user can exploit this by sending a specially crafted message to PID1, causing the stack pointer to jump over the stack guard pages into an unmapped memory region and trigger a denial of service (systemd PID1 crash and kernel panic). Se ha descubierto un problema en sd-bus en systemd 239. bus_process_object() en libsystemd/sd-bus/bus-objects.c asigna un búfer de pila de longitud variable para almacenar temporalmente la ruta de objeto de los mensajes D-Bus entrantes. Un usuario local sin privilegios puede explotar esto enviando un mensaje especialmente manipulado a PID1, provocando que el puntero de la pila salte por las páginas guard de la pila hasta una región de memoria no mapeada y desencadene una denegación de servicio (cierre inesperado del PID1 en systemd y pánico del kernel). It was discovered that systemd allocates a buffer large enough to store the path field of a dbus message without performing enough checks. • http://lists.opensuse.org/opensuse-security-announce/2019-02/msg00070.html http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html http://www.openwall.com/lists/oss-security/2019/02/18/3 http://www.openwall.com/lists/oss-security/2019/02/19/1 http://www.openwall.com/lists/oss-security/2021/07/20/2 http://www.securityfocus.com/bid/107081 https://access.redhat.com/errata/RHSA-2019:0368 https://access.redhat.com/errata/RHSA-2019:0990 https://access • CWE-20: Improper Input Validation CWE-787: Out-of-bounds Write •