Security/SELinux: seperate lsm specific mmap_min_addr

[sfrench/cifs-2.6.git] / security / min_addr.c

diff --git a/security/min_addr.c b/security/min_addr.c
new file mode 100644 (file)
index 0000000..14cc7b3
--- /dev/null
+++ b/security/min_addr.c
@@ -0,0 +1,49 @@
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/security.h>
+#include <linux/sysctl.h>
+
+/* amount of vm to protect from userspace access by both DAC and the LSM*/
+unsigned long mmap_min_addr;
+/* amount of vm to protect from userspace using CAP_SYS_RAWIO (DAC) */
+unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
+/* amount of vm to protect from userspace using the LSM = CONFIG_LSM_MMAP_MIN_ADDR */
+
+/*
+ * Update mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR)
+ */
+static void update_mmap_min_addr(void)
+{
+#ifdef CONFIG_LSM_MMAP_MIN_ADDR
+       if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
+               mmap_min_addr = dac_mmap_min_addr;
+       else
+               mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
+#else
+       mmap_min_addr = dac_mmap_min_addr;
+#endif
+}
+
+/*
+ * sysctl handler which just sets dac_mmap_min_addr = the new value and then
+ * calls update_mmap_min_addr() so non MAP_FIXED hints get rounded properly
+ */
+int mmap_min_addr_handler(struct ctl_table *table, int write, struct file *filp,
+                         void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       int ret;
+
+       ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+
+       update_mmap_min_addr();
+
+       return ret;
+}
+
+int __init init_mmap_min_addr(void)
+{
+       update_mmap_min_addr();
+
+       return 0;
+}
+pure_initcall(init_mmap_min_addr);