Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754061AbcDZXOE (ORCPT ); Tue, 26 Apr 2016 19:14:04 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:40025 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753926AbcDZXNx (ORCPT ); Tue, 26 Apr 2016 19:13:53 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David S. Miller" , "Willem de Bruijn" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 202/217] ax25: add link layer header validation function In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1341 Lines: 50 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn commit ea47781c26510e5d97f80f9aceafe9065bd5e3aa upstream. As variable length protocol, AX25 fails link layer header validation tests based on a minimum length. header_ops.validate allows protocols to validate headers that are shorter than hard_header_len. Implement this callback for AX25. See also http://comments.gmane.org/gmane.linux.network/401064 Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- net/ax25/ax25_ip.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) --- a/net/ax25/ax25_ip.c +++ b/net/ax25/ax25_ip.c @@ -231,9 +231,24 @@ int ax25_rebuild_header(struct sk_buff * #endif +static bool ax25_validate_header(const char *header, unsigned int len) +{ + ax25_digi digi; + + if (!len) + return false; + + if (header[0]) + return true; + + return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL, + NULL); +} + const struct header_ops ax25_header_ops = { .create = ax25_hard_header, .rebuild = ax25_rebuild_header, + .validate = ax25_validate_header, }; EXPORT_SYMBOL(ax25_hard_header);