netdev - [PATCH 01/32] netfilter: conntrack: warn the user if there is a better helper to use

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 15 Jun 2015 23:25:58 +0200
From:	Pablo Neira Ayuso <pablo@...filter.org>
To:	netfilter-devel@...r.kernel.org
Cc:	davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 01/32] netfilter: conntrack: warn the user if there is a better helper to use

From: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>

After db29a9508a92 ("netfilter: conntrack: disable generic tracking for
known protocols"), if the specific helper is built but not loaded
(a standard for most distributions) systems with a restrictive firewall
but weak configuration regarding netfilter modules to load, will
silently stop working.

This patch then puts a warning message so the sysadmin knows where to
start looking into. It's a pr_warn_once regardless of protocol itself
but it should be enough to give a hint on where to look.

Cc: Florian Westphal <fw@...len.de>
Cc: Daniel Borkmann <daniel@...earbox.net>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_conntrack_proto_generic.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_proto_generic.c b/net/netfilter/nf_conntrack_proto_generic.c
index 60865f1..2281be4 100644
--- a/net/netfilter/nf_conntrack_proto_generic.c
+++ b/net/netfilter/nf_conntrack_proto_generic.c
@@ -90,7 +90,13 @@ static int generic_packet(struct nf_conn *ct,
 static bool generic_new(struct nf_conn *ct, const struct sk_buff *skb,
 			unsigned int dataoff, unsigned int *timeouts)
 {
-	return nf_generic_should_process(nf_ct_protonum(ct));
+	bool ret;
+
+	ret = nf_generic_should_process(nf_ct_protonum(ct));
+	if (!ret)
+		pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.\n",
+			     nf_ct_protonum(ct));
+	return ret;
 }
 
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html