Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6

[sfrench/cifs-2.6.git] / security / Kconfig

diff --git a/security/Kconfig b/security/Kconfig
index 25ffe1b9dc98467d7be1ec373c7024f246172e0b..5dfc206748cfbd76f2e1f3114515aba7294cf67c 100644 (file)
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -104,6 +104,24 @@ config SECURITY_ROOTPLUG
          
          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 users with lots of address space a value of 65536 is
+         reasonable and should cause no problems.  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.
+
+
 source security/selinux/Kconfig
 source security/smack/Kconfig