4 files changed, 21 insertions, 35 deletions

diff --git a/security/Kconfig b/security/Kconfig
index 25ffe1b9dc98..5dfc206748cf 100644
--- 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
 
diff --git a/security/security.c b/security/security.c
index b6c57a6b2ff5..d15e56cbaade 100644
--- a/security/security.c
+++ b/security/security.c
@@ -23,7 +23,9 @@ extern struct security_operations dummy_security_ops;
 extern void security_fixup_ops(struct security_operations *ops);
 
 struct security_operations *security_ops;       /* Initialized to NULL */
-unsigned long mmap_min_addr;            /* 0 means no protection */
+
+/* amount of vm to protect from userspace access */
+unsigned long mmap_min_addr = CONFIG_SECURITY_DEFAULT_MMAP_MIN_ADDR;
 
 static inline int verify(struct security_operations *ops)
 {
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index 23137c17f917..837ce420d2f6 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -107,7 +107,6 @@ int security_get_classes(char ***classes, int *nclasses);
 int security_get_permissions(char *class, char ***perms, int *nperms);
 int security_get_reject_unknown(void);
 int security_get_allow_unknown(void);
-int security_get_policycaps(int *len, int **values);
 
 #define SECURITY_FS_USE_XATTR           1 /* use xattr */
 #define SECURITY_FS_USE_TRANS           2 /* use transition SIDs, e.g. devpts/tmpfs */
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index fced6bccee76..f37418601215 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2246,39 +2246,6 @@ int security_get_allow_unknown(void)
 }
 
 /**
- * security_get_policycaps - Query the loaded policy for its capabilities
- * @len: the number of capability bits
- * @values: the capability bit array
- *
- * Description:
- * Get an array of the policy capabilities in @values where each entry in
- * @values is either true (1) or false (0) depending the policy's support of
- * that feature.  The policy capabilities are defined by the
- * POLICYDB_CAPABILITY_* enums.  The size of the array is stored in @len and it
- * is up to the caller to free the array in @values.  Returns zero on success,
- * negative values on failure.
- *
- */
-int security_get_policycaps(int *len, int **values)
-{
-        int rc = -ENOMEM;
-        unsigned int iter;
-
-        POLICY_RDLOCK;
-
-        *values = kcalloc(POLICYDB_CAPABILITY_MAX, sizeof(int), GFP_ATOMIC);
-        if (*values == NULL)
-                goto out;
-        for (iter = 0; iter < POLICYDB_CAPABILITY_MAX; iter++)
-                (*values)[iter] = ebitmap_get_bit(&policydb.policycaps, iter);
-        *len = POLICYDB_CAPABILITY_MAX;
-
-out:
-        POLICY_RDUNLOCK;
-        return rc;
-}
-
-/**
  * security_policycap_supported - Check for a specific policy capability
  * @req_cap: capability
  *