security: remove unused security_sysctl hook

The only user for this hook was selinux. sysctl routes every call
through /proc/sys/. Selinux and other security modules use the file
system checks for sysctl too, so no need for this hook any more.

Signed-off-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

include/linux/security.h

@@ -1259,12 +1259,6 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
  *	@cap contains the capability <include/linux/capability.h>.
  *	@audit: Whether to write an audit message or not
  *	Return 0 if the capability is granted for @tsk.
- * @sysctl:
- *	Check permission before accessing the @table sysctl variable in the
- *	manner specified by @op.
- *	@table contains the ctl_table structure for the sysctl variable.
- *	@op contains the operation (001 = search, 002 = write, 004 = read).
- *	Return 0 if permission is granted.
  * @syslog:
  *	Check permission before accessing the kernel message ring or changing
  *	logging to the console.
@@ -1385,7 +1379,6 @@ struct security_operations {
 		       const kernel_cap_t *permitted);
 	int (*capable) (struct task_struct *tsk, const struct cred *cred,
 			int cap, int audit);
-	int (*sysctl) (struct ctl_table *table, int op);
 	int (*quotactl) (int cmds, int type, int id, struct super_block *sb);
 	int (*quota_on) (struct dentry *dentry);
 	int (*syslog) (int type);
@@ -1668,7 +1661,6 @@ int security_capset(struct cred *new, const struct cred *old,
 int security_capable(int cap);
 int security_real_capable(struct task_struct *tsk, int cap);
 int security_real_capable_noaudit(struct task_struct *tsk, int cap);
-int security_sysctl(struct ctl_table *table, int op);
 int security_quotactl(int cmds, int type, int id, struct super_block *sb);
 int security_quota_on(struct dentry *dentry);
 int security_syslog(int type);
@@ -1887,11 +1879,6 @@ int security_real_capable_noaudit(struct task_struct *tsk, int cap)
 	return ret;
 }
 
-static inline int security_sysctl(struct ctl_table *table, int op)
-{
-	return 0;
-}
-
 static inline int security_quotactl(int cmds, int type, int id,
 				     struct super_block *sb)
 {

kernel/sysctl.c

@@ -1691,13 +1691,8 @@ static int test_perm(int mode, int op)
 
 int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
 {
-	int error;
 	int mode;
 
-	error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
-	if (error)
-		return error;
-
 	if (root->permissions)
 		mode = root->permissions(root, current->nsproxy, table);
 	else

security/capability.c

@@ -12,11 +12,6 @@
 
 #include <linux/security.h>
 
-static int cap_sysctl(ctl_table *table, int op)
-{
-	return 0;
-}
-
 static int cap_syslog(int type)
 {
 	return 0;
@@ -881,7 +876,6 @@ void __init security_fixup_ops(struct security_operations *ops)
 	set_to_cap_if_null(ops, capable);
 	set_to_cap_if_null(ops, quotactl);
 	set_to_cap_if_null(ops, quota_on);
-	set_to_cap_if_null(ops, sysctl);
 	set_to_cap_if_null(ops, syslog);
 	set_to_cap_if_null(ops, settime);
 	set_to_cap_if_null(ops, vm_enough_memory);

security/security.c

@@ -182,11 +182,6 @@ int security_real_capable_noaudit(struct task_struct *tsk, int cap)
 	return ret;
 }
 
-int security_sysctl(struct ctl_table *table, int op)
-{
-	return security_ops->sysctl(table, op);
-}
-
 int security_quotactl(int cmds, int type, int id, struct super_block *sb)
 {
 	return security_ops->quotactl(cmds, type, id, sb);