netfilter: nf_conntrack_amanda: add support for STATE streams

The Amanda CONNECT command has been updated to establish an optional
fourth connection [0]. Previously, a CONNECT command would look like:

    CONNECT DATA port0 MESG port1 INDEX port2

nf_conntrack_amanda analyses the CONNECT command string in order to
learn the port numbers of the related DATA, MESG and INDEX streams. As
of amanda v3.4, the CONNECT command can advertise an additional port:

    CONNECT DATA port0 MESG port1 INDEX port2 STATE port3

The new STATE stream is not handled, thus the connection on the STATE
port cannot be established.

The patch adds support for STATE streams to the amanda conntrack helper.

I tested with max_expected = 3, leaving the other patch hunks
unmodified. Amanda reports "connection refused" and aborts. After I set
max_expected to 4, the backup completes successfully.

[0] https://github.com/zmanda/amanda/commit/3b8384fc9f2941e2427f44c3aee29f561ed67894#diff-711e502fc81a65182c0954765b42919eR456

Signed-off-by: Florian Tham <tham@fidion.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_conntrack_amanda.c b/net/netfilter/nf_conntrack_amanda.c
index 20edd589fe0635c2cb0b989d39e1cb8801a85a60..f2681ec5b5f6eaa1deb3e17a704eeccd46491c5c 100644 (file)
--- a/net/netfilter/nf_conntrack_amanda.c
+++ b/net/netfilter/nf_conntrack_amanda.c
@@ -54,6 +54,7 @@ enum amanda_strings {
        SEARCH_DATA,
        SEARCH_MESG,
        SEARCH_INDEX,
+       SEARCH_STATE,
 };
 
 static struct {
@@ -81,6 +82,10 @@ static struct {
                .string = "INDEX ",
                .len    = 6,
        },
+       [SEARCH_STATE] = {
+               .string = "STATE ",
+               .len    = 6,
+       },
 };
 
 static int amanda_help(struct sk_buff *skb,
@@ -124,7 +129,7 @@ static int amanda_help(struct sk_buff *skb,
                goto out;
        stop += start;
 
-       for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
+       for (i = SEARCH_DATA; i <= SEARCH_STATE; i++) {
                off = skb_find_text(skb, start, stop, search[i].ts);
                if (off == UINT_MAX)
                        continue;
@@ -168,7 +173,7 @@ out:
 }
 
 static const struct nf_conntrack_expect_policy amanda_exp_policy = {
-       .max_expected           = 3,
+       .max_expected           = 4,
        .timeout                = 180,
 };