[PATCH 13/14] security,sysctl: remove proc input checks out of sysctl handlers

[Sasha Levin <levinsasha928@gmail.com>]

Simplify sysctl handler by removing user input checks and using the callback
provided by the sysctl table.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 include/linux/security.h |    3 +--
 kernel/sysctl.c          |    3 ++-
 security/min_addr.c      |   11 +++--------
 3 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index ab0e091..3d3445c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -147,8 +147,7 @@ struct request_sock;
 #define LSM_UNSAFE_NO_NEW_PRIVS	8
 
 #ifdef CONFIG_MMU
-extern int mmap_min_addr_handler(struct ctl_table *table, int write,
-				 void __user *buffer, size_t *lenp, loff_t *ppos);
+extern int mmap_min_addr_handler(void);
 #endif
 
 /* security_inode_init_security callback function to write xattrs */
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index f9ce79b..2104452 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1317,7 +1317,8 @@ static struct ctl_table vm_table[] = {
 		.data		= &dac_mmap_min_addr,
 		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= mmap_min_addr_handler,
+		.proc_handler	= proc_doulongvec_minmax,
+		.callback	= mmap_min_addr_handler,
 	},
 #endif
 #ifdef CONFIG_NUMA
diff --git a/security/min_addr.c b/security/min_addr.c
index f728728..3e5a41c 100644
--- a/security/min_addr.c
+++ b/security/min_addr.c
@@ -28,19 +28,14 @@ static void update_mmap_min_addr(void)
  * 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,
-			  void __user *buffer, size_t *lenp, loff_t *ppos)
+int mmap_min_addr_handler(void)
 {
-	int ret;
-
-	if (write && !capable(CAP_SYS_RAWIO))
+	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
-	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
-
 	update_mmap_min_addr();
 
-	return ret;
+	return 0;
 }
 
 static int __init init_mmap_min_addr(void)
-- 
1.7.8.5

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