Merge remote-tracking branch 'jk/vfs' into work.misc

1 files changed, 23 insertions, 12 deletions

diff --git a/fs/attr.c b/fs/attr.c
index 3c42cab06b5d..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
@@ -232,13 +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;
         }
 
         /*