Merge tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:
 "Fix copy up of security related xattrs"

* tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: Do not lose security.capability xattr over metadata file copy-up
  ovl: During copy up, first copy up data and then xattrs

1 files changed, 35 insertions, 20 deletions

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 7c01327b1852..4035e640f402 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -863,28 +863,49 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
 	return (oe->numlower > 1);
 }
 
-char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
+ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
+		     size_t padding)
 {
-	int res;
-	char *s, *next, *buf = NULL;
+	ssize_t res;
+	char *buf = NULL;
 
-	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
+	res = vfs_getxattr(dentry, name, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
-			return NULL;
+			return -ENODATA;
 		goto fail;
 	}
 
-	buf = kzalloc(res + padding + 1, GFP_KERNEL);
-	if (!buf)
-		return ERR_PTR(-ENOMEM);
+	if (res != 0) {
+		buf = kzalloc(res + padding, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
 
-	if (res == 0)
-		goto invalid;
+		res = vfs_getxattr(dentry, name, buf, res);
+		if (res < 0)
+			goto fail;
+	}
+	*value = buf;
+
+	return res;
+
+fail:
+	pr_warn_ratelimited("overlayfs: failed to get xattr %s: err=%zi)\n",
+			    name, res);
+	kfree(buf);
+	return res;
+}
 
-	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
+char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
+{
+	int res;
+	char *s, *next, *buf = NULL;
+
+	res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);
+	if (res == -ENODATA)
+		return NULL;
 	if (res < 0)
-		goto fail;
+		return ERR_PTR(res);
 	if (res == 0)
 		goto invalid;
 
@@ -900,15 +921,9 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
 	}
 
 	return buf;
-
-err_free:
-	kfree(buf);
-	return ERR_PTR(res);
-fail:
-	pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res);
-	goto err_free;
 invalid:
 	pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);
 	res = -EINVAL;
-	goto err_free;
+	kfree(buf);
+	return ERR_PTR(res);
 }