Security/SELinux: seperate lsm specific mmap_min_addr
Currently SELinux enforcement of controls on the ability to map low memory
is determined by the mmap_min_addr tunable. This patch causes SELinux to
ignore the tunable and instead use a seperate Kconfig option specific to how
much space the LSM should protect.
The tunable will now only control the need for CAP_SYS_RAWIO and SELinux
permissions will always protect the amount of low memory designated by
CONFIG_LSM_MMAP_MIN_ADDR.
This allows users who need to disable the mmap_min_addr controls (usual reason
being they run WINE as a non-root user) to do so and still have SELinux
controls preventing confined domains (like a web server) from being able to
map some area of low memory.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/mm/Kconfig b/mm/Kconfig
index c948d4c..fe5f674 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -225,9 +225,9 @@
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.
+ Programs which use vm86 functionality or have some need to map
+ this low address space will need CAP_SYS_RAWIO or disable this
+ protection by setting the value to 0.
This value can be changed after boot using the
/proc/sys/vm/mmap_min_addr tunable.