-
- If you are unsure how to answer this question, answer N.
-
-config SECURITY_DEFAULT_MMAP_MIN_ADDR
- int "Low address space to protect from user allocation"
- depends on SECURITY
- default 0
- help
- This is the portion of low virtual memory which should be protected
- from userspace allocation. Keeping a user from writing to low pages
- can help reduce the impact of kernel NULL pointer bugs.
-
- For most ia64, ppc64 and x86 users with lots of address space
- a value of 65536 is reasonable and should cause no problems.
- On arm and other archs it should not be higher than 32768.
- Programs which use vm86 functionality would either need additional
- permissions from either the LSM or the capabilities module or have
- this protection disabled.
-
- This value can be changed after boot using the
- /proc/sys/vm/mmap_min_addr tunable.