From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH net 3/3] ax25: add link layer header validation function Date: Fri, 4 Mar 2016 15:44:17 -0500 Message-ID: <1457124257-31486-4-git-send-email-willemdebruijn.kernel@gmail.com> References: <1457124257-31486-1-git-send-email-willemdebruijn.kernel@gmail.com> Cc: davem@davemloft.net, alan@linux.intel.com, hessu@hes.iki.fi, martin.blumenstingl@googlemail.com, linux-hams@vger.kernel.org, Willem de Bruijn To: netdev@vger.kernel.org Return-path: Received: from mail-qg0-f68.google.com ([209.85.192.68]:36538 "EHLO mail-qg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757023AbcCDUo0 (ORCPT ); Fri, 4 Mar 2016 15:44:26 -0500 In-Reply-To: <1457124257-31486-1-git-send-email-willemdebruijn.kernel@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Willem de Bruijn 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. Compile tested only. See also http://comments.gmane.org/gmane.linux.network/401064 Signed-off-by: Willem de Bruijn --- 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..77bc20d 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] != 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); -- 2.7.0.rc3.207.g0ac5344