Security/SELinux: seperate lsm specific mmap_min_addr
[linux-3.10.git] / security / min_addr.c
1 #include <linux/init.h>
2 #include <linux/mm.h>
3 #include <linux/security.h>
4 #include <linux/sysctl.h>
5
6 /* amount of vm to protect from userspace access by both DAC and the LSM*/
7 unsigned long mmap_min_addr;
8 /* amount of vm to protect from userspace using CAP_SYS_RAWIO (DAC) */
9 unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
10 /* amount of vm to protect from userspace using the LSM = CONFIG_LSM_MMAP_MIN_ADDR */
11
12 /*
13  * Update mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR)
14  */
15 static void update_mmap_min_addr(void)
16 {
17 #ifdef CONFIG_LSM_MMAP_MIN_ADDR
18         if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
19                 mmap_min_addr = dac_mmap_min_addr;
20         else
21                 mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
22 #else
23         mmap_min_addr = dac_mmap_min_addr;
24 #endif
25 }
26
27 /*
28  * sysctl handler which just sets dac_mmap_min_addr = the new value and then
29  * calls update_mmap_min_addr() so non MAP_FIXED hints get rounded properly
30  */
31 int mmap_min_addr_handler(struct ctl_table *table, int write, struct file *filp,
32                           void __user *buffer, size_t *lenp, loff_t *ppos)
33 {
34         int ret;
35
36         ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
37
38         update_mmap_min_addr();
39
40         return ret;
41 }
42
43 int __init init_mmap_min_addr(void)
44 {
45         update_mmap_min_addr();
46
47         return 0;
48 }
49 pure_initcall(init_mmap_min_addr);