1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/init.h>
 3#include <linux/mm.h>
 4#include <linux/security.h>
 5#include <linux/sysctl.h>
 6
 7/* amount of vm to protect from userspace access by both DAC and the LSM*/
 8unsigned long mmap_min_addr;
 9/* amount of vm to protect from userspace using CAP_SYS_RAWIO (DAC) */
10unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
11/* amount of vm to protect from userspace using the LSM = CONFIG_LSM_MMAP_MIN_ADDR */
12
13/*
14 * Update mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR)
15 */
16static void update_mmap_min_addr(void)
17{
18#ifdef CONFIG_LSM_MMAP_MIN_ADDR
19	if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
20		mmap_min_addr = dac_mmap_min_addr;
21	else
22		mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
23#else
24	mmap_min_addr = dac_mmap_min_addr;
25#endif
26}
27
28/*
29 * sysctl handler which just sets dac_mmap_min_addr = the new value and then
30 * calls update_mmap_min_addr() so non MAP_FIXED hints get rounded properly
31 */
32int mmap_min_addr_handler(struct ctl_table *table, int write,
33			  void *buffer, size_t *lenp, loff_t *ppos)
34{
35	int ret;
36
37	if (write && !capable(CAP_SYS_RAWIO))
38		return -EPERM;
39
40	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
41
42	update_mmap_min_addr();
43
44	return ret;
45}
46
47static int __init init_mmap_min_addr(void)
48{
49	update_mmap_min_addr();
50
51	return 0;
52}
53pure_initcall(init_mmap_min_addr);

 
 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*/
 7unsigned long mmap_min_addr;
 8/* amount of vm to protect from userspace using CAP_SYS_RAWIO (DAC) */
 9unsigned 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 */
15static 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 */
31int mmap_min_addr_handler(struct ctl_table *table, int write,
32			  void __user *buffer, size_t *lenp, loff_t *ppos)
33{
34	int ret;
35
36	if (write && !capable(CAP_SYS_RAWIO))
37		return -EPERM;
38
39	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
40
41	update_mmap_min_addr();
42
43	return ret;
44}
45
46static int __init init_mmap_min_addr(void)
47{
48	update_mmap_min_addr();
49
50	return 0;
51}
52pure_initcall(init_mmap_min_addr);