ima: add inode_post_setattr call

Changing an inode's metadata may result in our not needing to appraise
the file.  In such cases, we must remove 'security.ima'.

Changelog v1:
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

fs/attr.c

@@ -14,6 +14,7 @@
 #include <linux/fcntl.h>
 #include <linux/security.h>
 #include <linux/evm.h>
+#include <linux/ima.h>
 
 /**
  * inode_change_ok - check if attribute changes to an inode are allowed
@@ -247,6 +248,7 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
 
 	if (!error) {
 		fsnotify_change(dentry, ia_valid);
+		ima_inode_post_setattr(dentry);
 		evm_inode_post_setattr(dentry, ia_valid);
 	}
 

include/linux/ima.h

@@ -39,5 +39,15 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
 {
 	return 0;
 }
+
 #endif /* CONFIG_IMA_H */
+
+#ifdef CONFIG_IMA_APPRAISE
+extern void ima_inode_post_setattr(struct dentry *dentry);
+#else
+static inline void ima_inode_post_setattr(struct dentry *dentry)
+{
+	return;
+}
+#endif /* CONFIG_IMA_APPRAISE_H */
 #endif /* _LINUX_IMA_H */