ovl: fix sgid on directory

[deliverable/linux.git] / fs / overlayfs / dir.c

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 7195306e9f8436285853ebd3228cc71eef49e287..8beeed34dad660a97b9ee630252675a06f617b03 100644 (file)
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -357,6 +357,21 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
        if (err)
                goto out_dput2;
 
+       /*
+        * mode could have been mutilated due to umask (e.g. sgid directory)
+        */
+       if (!S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
+               struct iattr attr = {
+                       .ia_valid = ATTR_MODE,
+                       .ia_mode = stat->mode,
+               };
+               inode_lock(newdentry->d_inode);
+               err = notify_change(newdentry, &attr, NULL);
+               inode_unlock(newdentry->d_inode);
+               if (err)
+                       goto out_cleanup;
+       }
+
        if (S_ISDIR(stat->mode)) {
                err = ovl_set_opaque(newdentry);
                if (err)
@@ -397,7 +412,6 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
        const struct cred *old_cred;
        struct cred *override_cred;
        struct kstat stat = {
-               .mode = mode,
                .rdev = rdev,
        };
 
@@ -410,12 +424,15 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
        if (err)
                goto out_iput;
 
+       inode_init_owner(inode, dentry->d_parent->d_inode, mode);
+       stat.mode = inode->i_mode;
+
        old_cred = ovl_override_creds(dentry->d_sb);
        err = -ENOMEM;
        override_cred = prepare_creds();
        if (override_cred) {
-               override_cred->fsuid = old_cred->fsuid;
-               override_cred->fsgid = old_cred->fsgid;
+               override_cred->fsuid = inode->i_uid;
+               override_cred->fsgid = inode->i_gid;
                put_cred(override_creds(override_cred));
                put_cred(override_cred);
 
@@ -427,8 +444,14 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
                                                        link, hardlink);
        }
        revert_creds(old_cred);
-       if (!err)
+       if (!err) {
+               struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
+
+               WARN_ON(inode->i_mode != realinode->i_mode);
+               WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
+               WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
                inode = NULL;
+       }
 out_iput:
        iput(inode);
 out: