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authorKevin Cernekee <cernekee@chromium.org>2017-01-26 14:49:43 -0800
committerPablo Neira Ayuso <pablo@netfilter.org>2017-02-06 12:48:26 +0100
commita963d710f367f68cd13d562a07db55ccb8daade9 (patch)
treef2f33bbecd14af82f866c6297ac6f5607ba8a90f /net/netfilter
parentdfe75ff8ca74f54b0fa5a326a1aa9afa485ed802 (diff)
netfilter: ctnetlink: Fix regression in CTA_STATUS processing
The libnetfilter_conntrack userland library always sets IPS_CONFIRMED when building a CTA_STATUS attribute. If this toggles the bit from 0->1, the parser will return an error. On Linux 4.4+ this will cause any NFQA_EXP attribute in the packet to be ignored. This breaks conntrackd's userland helpers because they operate on unconfirmed connections. Instead of returning -EBUSY if the user program asks to modify an unchangeable bit, simply ignore the change. Also, fix the logic so that user programs are allowed to clear the bits that they are allowed to change. Signed-off-by: Kevin Cernekee <cernekee@chromium.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/nf_conntrack_netlink.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 27540455dc62..bf04b7e9d6f7 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -2270,6 +2270,30 @@ nla_put_failure:
}
static int
+ctnetlink_update_status(struct nf_conn *ct, const struct nlattr * const cda[])
+{
+ unsigned int status = ntohl(nla_get_be32(cda[CTA_STATUS]));
+ unsigned long d = ct->status ^ status;
+
+ if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
+ /* SEEN_REPLY bit can only be set */
+ return -EBUSY;
+
+ if (d & IPS_ASSURED && !(status & IPS_ASSURED))
+ /* ASSURED bit can only be set */
+ return -EBUSY;
+
+ /* This check is less strict than ctnetlink_change_status()
+ * because callers often flip IPS_EXPECTED bits when sending
+ * an NFQA_CT attribute to the kernel. So ignore the
+ * unchangeable bits but do not error out.
+ */
+ ct->status = (status & ~IPS_UNCHANGEABLE_MASK) |
+ (ct->status & IPS_UNCHANGEABLE_MASK);
+ return 0;
+}
+
+static int
ctnetlink_glue_parse_ct(const struct nlattr *cda[], struct nf_conn *ct)
{
int err;
@@ -2280,7 +2304,7 @@ ctnetlink_glue_parse_ct(const struct nlattr *cda[], struct nf_conn *ct)
return err;
}
if (cda[CTA_STATUS]) {
- err = ctnetlink_change_status(ct, cda);
+ err = ctnetlink_update_status(ct, cda);
if (err < 0)
return err;
}