CVE-2019-9213

This Metasploit module exploits a NULL pointer dereference in the `rds_atomic_free_op` function in the Linux kernel's RDS module (CVE-2018-5333) combined with a MAP_GROWSDOWN mmap_min_addr bypass (CVE-2019-9213) to achieve local privilege escalation on vulnerable Ubuntu 16.04 systems.

This exploit demonstrates a kernel NULL pointer dereference vulnerability (CVE-2019-9213) by mapping virtual address 0 on x86 systems without SMAP. It abuses a capability check flaw in `expand_downwards()` to bypass `dac_mmap_min_addr` restrictions, enabling exploitation of NULL pointer dereferences.

This Metasploit module exploits a NULL pointer dereference in the `rds_atomic_free_op` function in the Linux kernel's RDS module (CVE-2018-5333) combined with a MAP_GROWSDOWN mmap_min_addr bypass (CVE-2019-9213) to achieve local privilege escalation on vulnerable Ubuntu 16.04 systems.