security: min_addr: move sysctl to security/min_addr.c

The dac_mmap_min_addr belongs to min_addr.c, move it to
min_addr.c from /kernel/sysctl.c. In the previous Linux kernel
boot process, sysctl_init_bases needs to be executed before
init_mmap_min_addr, So, register_sysctl_init should be executed
before update_mmap_min_addr in init_mmap_min_addr. And according
to the compilation condition in security/Makefile:

      obj-$(CONFIG_MMU)            += min_addr.o

if CONFIG_MMU is not defined, min_addr.c would not be included in the
compilation process. So, drop the CONFIG_MMU check.

Signed-off-by: Kaixiong Yu <yukaixiong@huawei.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Joel Granados <joel.granados@kernel.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/security/min_addr.c b/security/min_addr.c
index 0ce267c041ab..df1bc643d886 100644
--- a/security/min_addr.c
+++ b/security/min_addr.c
@@ -44,8 +44,19 @@ int mmap_min_addr_handler(const struct ctl_table *table, int write,
 	return ret;
 }
 
+static const struct ctl_table min_addr_sysctl_table[] = {
+	{
+		.procname	= "mmap_min_addr",
+		.data		= &dac_mmap_min_addr,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= mmap_min_addr_handler,
+	},
+};
+
 static int __init init_mmap_min_addr(void)
 {
+	register_sysctl_init("vm", min_addr_sysctl_table);
 	update_mmap_min_addr();
 
 	return 0;