Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759418AbcJSSbu (ORCPT ); Wed, 19 Oct 2016 14:31:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58964 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759073AbcJSSbl (ORCPT ); Wed, 19 Oct 2016 14:31:41 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Artem Savkov , Dave Chinner , Dave Chinner , Eric Sandeen Subject: [PATCH 4.8 3/4] Make __xfs_xattr_put_listen preperly report errors. Date: Wed, 19 Oct 2016 20:31:28 +0200 Message-Id: <20161019182927.880802763@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161019182927.746970025@linuxfoundation.org> References: <20161019182927.746970025@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1741 Lines: 46 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Artem Savkov commit 791cc43b36eb1f88166c8505900cad1b43c7fe1a upstream. Commit 2a6fba6 "xfs: only return -errno or success from attr ->put_listent" changes the returnvalue of __xfs_xattr_put_listen to 0 in case when there is insufficient space in the buffer assuming that setting context->count to -1 would be enough, but all of the ->put_listent callers only check seen_enough. This results in a failed assertion: XFS: Assertion failed: context->count >= 0, file: fs/xfs/xfs_xattr.c, line: 175 in insufficient buffer size case. This is only reproducible with at least 2 xattrs and only when the buffer gets depleted before the last one. Furthermore if buffersize is such that it is enough to hold the last xattr's name, but not enough to hold the sum of preceeding xattr names listxattr won't fail with ERANGE, but will suceed returning last xattr's name without the first character. The first character end's up overwriting data stored at (context->alist - 1). Signed-off-by: Artem Savkov Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner Cc: Eric Sandeen Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_xattr.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/xfs/xfs_xattr.c +++ b/fs/xfs/xfs_xattr.c @@ -147,6 +147,7 @@ __xfs_xattr_put_listent( arraytop = context->count + prefix_len + namelen + 1; if (arraytop > context->firstu) { context->count = -1; /* insufficient space */ + context->seen_enough = 1; return 0; } offset = (char *)context->alist + context->count;