1 files changed, 38 insertions, 12 deletions

diff --git a/fs/attr.c b/fs/attr.c
index 42bb42bb3c72..a19a64d41e7e 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -17,19 +17,22 @@
 #include <linux/ima.h>
 
 /**
- * inode_change_ok - check if attribute changes to an inode are allowed
- * @inode:	inode to check
+ * setattr_prepare - check if attribute changes to a dentry are allowed
+ * @dentry:	dentry to check
  * @attr:	attributes to change
  *
  * Check if we are allowed to change the attributes contained in @attr
- * in the given inode.  This includes the normal unix access permission
- * checks, as well as checks for rlimits and others.
+ * in the given dentry.  This includes the normal unix access permission
+ * checks, as well as checks for rlimits and others. The function also clears
+ * SGID bit from mode if user is not allowed to set it. Also file capabilities
+ * and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
  *
  * Should be called as the first thing in ->setattr implementations,
  * possibly after taking additional locks.
  */
-int inode_change_ok(const struct inode *inode, struct iattr *attr)
+int setattr_prepare(struct dentry *dentry, struct iattr *attr)
 {
+	struct inode *inode = d_inode(dentry);
 	unsigned int ia_valid = attr->ia_valid;
 
 	/*
@@ -44,7 +47,7 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr)
 
 	/* If force is set do it anyway. */
 	if (ia_valid & ATTR_FORCE)
-		return 0;
+		goto kill_priv;
 
 	/* Make sure a caller can chown. */
 	if ((ia_valid & ATTR_UID) &&
@@ -77,9 +80,19 @@ int inode_change_ok(const struct inode *inode, struct iattr *attr)
 			return -EPERM;
 	}
 
+kill_priv:
+	/* User has permission for the change */
+	if (ia_valid & ATTR_KILL_PRIV) {
+		int error;
+
+		error = security_inode_killpriv(dentry);
+		if (error)
+			return error;
+	}
+
 	return 0;
 }
-EXPORT_SYMBOL(inode_change_ok);
+EXPORT_SYMBOL(setattr_prepare);
 
 /**
  * inode_newsize_ok - may this inode be truncated to a given size
@@ -202,6 +215,21 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de
 			return -EPERM;
 	}
 
+	/*
+	 * If utimes(2) and friends are called with times == NULL (or both
+	 * times are UTIME_NOW), then we need to check for write permission
+	 */
+	if (ia_valid & ATTR_TOUCH) {
+		if (IS_IMMUTABLE(inode))
+			return -EPERM;
+
+		if (!inode_owner_or_capable(inode)) {
+			error = inode_permission(inode, MAY_WRITE);
+			if (error)
+				return error;
+		}
+	}
+
 	if ((ia_valid & ATTR_MODE)) {
 		umode_t amode = attr->ia_mode;
 		/* Flag setting protected by i_mutex */
@@ -217,13 +245,11 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de
 	if (!(ia_valid & ATTR_MTIME_SET))
 		attr->ia_mtime = now;
 	if (ia_valid & ATTR_KILL_PRIV) {
-		attr->ia_valid &= ~ATTR_KILL_PRIV;
-		ia_valid &= ~ATTR_KILL_PRIV;
 		error = security_inode_need_killpriv(dentry);
-		if (error > 0)
-			error = security_inode_killpriv(dentry);
-		if (error)
+		if (error < 0)
 			return error;
+		if (error == 0)
+			ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
 	}
 
 	/*