X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=security%2FKconfig;h=49b51f964897dcb7133be9b58f1b936462bb6309;hb=ffd8211fb18e1052b2d9eded629cc3c0b872d06a;hp=25ffe1b9dc98467d7be1ec373c7024f246172e0b;hpb=3d412f60b71e588544e7b75861084f12aa1d7acd;p=linux-2.6

diff --git a/security/Kconfig b/security/Kconfig
index 25ffe1b9dc..49b51f9648 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -104,6 +104,26 @@ 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 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.
+
+
 source security/selinux/Kconfig
 source security/smack/Kconfig