Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753364AbcDZSrN (ORCPT ); Tue, 26 Apr 2016 14:47:13 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56226 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752561AbcDZSSE (ORCPT ); Tue, 26 Apr 2016 14:18:04 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Willem de Bruijn , "David S . Miller" , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 10/93] ax25: add link layer header validation function Date: Tue, 26 Apr 2016 11:16:10 -0700 Message-Id: <1461694653-29506-11-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1461694653-29506-1-git-send-email-kamal@canonical.com> References: <1461694653-29506-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1420 Lines: 52 4.2.8-ckt9 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Willem de Bruijn [ Upstream commit ea47781c26510e5d97f80f9aceafe9065bd5e3aa ] 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 Signed-off-by: Kamal Mostafa --- net/ax25/ax25_ip.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/net/ax25/ax25_ip.c b/net/ax25/ax25_ip.c index b563a3f..2fa3be9 100644 --- a/net/ax25/ax25_ip.c +++ b/net/ax25/ax25_ip.c @@ -228,8 +228,23 @@ netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) } #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, + .validate = ax25_validate_header, }; EXPORT_SYMBOL(ax25_header_ops); -- 2.7.4