local privilege escalation in Linux Kernel

Another bug in the Kernel’s do_mremap() function, which is unrelated to the bug fixed in SuSE-SA:2004:001, was found by Paul Starzetz. The do_mremap() function of the Linux Kernel is used to manage Virtual Memory Areas (VMAs) which includes moving, removing and resizing of memory areas. To remove old memory areas do_mremap() uses the function du_munmap() without checking the return value. By forcing do_munmap() to return an error the memory management of a process can be tricked into moving page table entries from one VMA to another. The destination VMA may be protected by a different ACL which enables a local attacker to gain write access to previous read-only pages. The result will be local root access to the system.