On 16/02/11 01:08, Sam Roberts wrote:
> On Wed, Jan 12, 2011 at 1:36 PM, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote:
>> You can implement a user-space conntrack helper with NFQUEUE and
>> libnetfilter_conntrack:
>>
>> http://people.netfilter.org/pablo/userspace-conntrack-helpers/
>>
>> You require Linux kernel >= 2.6.37
>
> I've upgraded the kernel to
> http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.37-rc2-maverick/.
>
> I began experiencing this bug
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=612272
> For me, conntrack -E expect is exiting immediately, on an almost unloaded box.
>
> So I built the two conntrack projects from git master to see if that
> would help - and got a kernel bug (see other message).
>
> Are there any other requirements? Would it be better if I build my own
> kernel? Are there any other dependency issues between the various
> players here: libnfnetlink, libnfconntrack, conntrack, and the kernel?
>
> Or is there a limit to the users of conntrack? Can my own daemon
> (modelled on the ftp userspace example of yours), conntrack -E, and
> other users of conntrack coexist?
Probably you have hit one of the bugs that went into 2.6.37. Please, try
the patch attached. IIRC, this is fixed in -stable and 2.6.38 and later
kernels.
>From cba85b532e4aabdb97f44c18987d45141fd93faa Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date: Thu, 6 Jan 2011 11:25:00 -0800
Subject: [PATCH] netfilter: fix export secctx error handling
In 1ae4de0cdf855305765592647025bde55e85e451, the secctx was exported
via the /proc/net/netfilter/nf_conntrack and ctnetlink interfaces
instead of the secmark.
That patch introduced the use of security_secid_to_secctx() which may
return a non-zero value on error.
In one of my setups, I have NF_CONNTRACK_SECMARK enabled but no
security modules. Thus, security_secid_to_secctx() returns a negative
value that results in the breakage of the /proc and `conntrack -L'
outputs. To fix this, we skip the inclusion of secctx if the
aforementioned function fails.
This patch also fixes the dynamic netlink message size calculation
if security_secid_to_secctx() returns an error, since its logic is
also wrong.
This problem exists in Linux kernel >= 2.6.37.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
.../netfilter/nf_conntrack_l3proto_ipv4_compat.c | 2 +-
net/netfilter/nf_conntrack_netlink.c | 25 +++++++++++--------
net/netfilter/nf_conntrack_standalone.c | 2 +-
3 files changed, 16 insertions(+), 13 deletions(-)
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
index 37f8adb..63f60fc 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c
@@ -97,7 +97,7 @@ static int ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
if (ret)
- return ret;
+ return 0;
ret = seq_printf(s, "secctx=%s ", secctx);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index b729ace..0cdba50 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -254,7 +254,7 @@ ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
if (ret)
- return ret;
+ return 0;
ret = -1;
nest_secctx = nla_nest_start(skb, CTA_SECCTX | NLA_F_NESTED);
@@ -453,16 +453,22 @@ ctnetlink_counters_size(const struct nf_conn *ct)
;
}
-#ifdef CONFIG_NF_CONNTRACK_SECMARK
-static int ctnetlink_nlmsg_secctx_size(const struct nf_conn *ct)
+static inline int
+ctnetlink_secctx_size(const struct nf_conn *ct)
{
- int len;
+#ifdef CONFIG_NF_CONNTRACK_SECMARK
+ int len, ret;
- security_secid_to_secctx(ct->secmark, NULL, &len);
+ ret = security_secid_to_secctx(ct->secmark, NULL, &len);
+ if (ret)
+ return 0;
- return sizeof(char) * len;
-}
+ return nla_total_size(0) /* CTA_SECCTX */
+ + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */
+#else
+ return 0;
#endif
+}
static inline size_t
ctnetlink_nlmsg_size(const struct nf_conn *ct)
@@ -479,10 +485,7 @@ ctnetlink_nlmsg_size(const struct nf_conn *ct)
+ nla_total_size(0) /* CTA_PROTOINFO */
+ nla_total_size(0) /* CTA_HELP */
+ nla_total_size(NF_CT_HELPER_NAME_LEN) /* CTA_HELP_NAME */
-#ifdef CONFIG_NF_CONNTRACK_SECMARK
- + nla_total_size(0) /* CTA_SECCTX */
- + nla_total_size(ctnetlink_nlmsg_secctx_size(ct)) /* CTA_SECCTX_NAME */
-#endif
+ + ctnetlink_secctx_size(ct)
#ifdef CONFIG_NF_NAT_NEEDED
+ 2 * nla_total_size(0) /* CTA_NAT_SEQ_ADJ_ORIG|REPL */
+ 6 * nla_total_size(sizeof(u_int32_t)) /* CTA_NAT_SEQ_OFFSET */
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 0fb6570..b4d7f0f 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -118,7 +118,7 @@ static int ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
if (ret)
- return ret;
+ return 0;
ret = seq_printf(s, "secctx=%s ", secctx);
--
1.7.2.3
