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>

1 files changed, 1 insertions, 1 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e6d1432b0800..8d8b69c5664e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3036,7 +3036,7 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
          * at bad behaviour/exploit that we always want to get the AVC, even
          * if DAC would have also denied the operation.
          */
-        if (addr < mmap_min_addr) {
+        if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
                 rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
                                   MEMPROTECT__MMAP_ZERO, NULL);
                 if (rc)