[PATCH v2] nwfilter: Validate rule after parsing

[Stefan Berger <stefanb@xxxxxxxxxx>]

From: Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>

An IP or IPv6 rule with port specification but without protocol
specification cannot be instantiated by ebtables. The documentation
points to 'protocol' being required but implementation does not
enforce it to be given.

Implement a rule validation function that checks whether the rule is
valid when it is defined. This for example prevents the definition
of rules like:

<ip dstportstart='53'>

where a protocol attribute would be required for it to be valid and for
ebtables to be able to instantiate it. A valid rule then is:

<ip protocol='udp' dstportstart='53'>

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>

Changes:
v1->v2:
  - fixed access to ipv6 structures

---
 src/conf/nwfilter_conf.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/src/conf/nwfilter_conf.c b/src/conf/nwfilter_conf.c
index f5a75e4..69b1d97 100644
--- a/src/conf/nwfilter_conf.c
+++ b/src/conf/nwfilter_conf.c
@@ -2093,6 +2093,66 @@ virNWFilterRuleDefFixupIPSet(ipHdrDataDefPtr ipHdr)
     }
 }
 
+
+/*
+ * virNWFilterRuleValidate
+ *
+ * Perform some basic rule validation to prevent rules from being
+ * defined that cannot be instantiated.
+ */
+static int
+virNWFilterRuleValidate(virNWFilterRuleDefPtr rule)
+{
+    int ret = 0;
+    portDataDefPtr portData = NULL;
+    nwItemDescPtr dataProtocolID;
+    const char *protocol;
+
+    switch (rule->prtclType) {
+    case VIR_NWFILTER_RULE_PROTOCOL_IP:
+        portData = &rule->p.ipHdrFilter.portData;
+        protocol = "IP";
+        dataProtocolID = &rule->p.ipHdrFilter.ipHdr.dataProtocolID;
+        /* fall through */
+    case VIR_NWFILTER_RULE_PROTOCOL_IPV6:
+        if (portData == NULL) {
+            portData = &rule->p.ipv6HdrFilter.portData;
+            protocol = "IPv6";
+            dataProtocolID = &rule->p.ipv6HdrFilter.ipHdr.dataProtocolID;
+        }
+        if (HAS_ENTRY_ITEM(&portData->dataSrcPortStart) ||
+            HAS_ENTRY_ITEM(&portData->dataDstPortStart) ||
+            HAS_ENTRY_ITEM(&portData->dataSrcPortEnd) ||
+            HAS_ENTRY_ITEM(&portData->dataDstPortEnd)) {
+            if (HAS_ENTRY_ITEM(dataProtocolID)) {
+                switch (dataProtocolID->u.u8) {
+                case 6:   /* tcp */
+                case 17:  /* udp */
+                case 33:  /* dccp */
+                case 132: /* sctp */
+                break;
+                default:
+                    ret = -1;
+                }
+            } else {
+                ret = -1;
+            }
+            if (ret < 0) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("%s rule with port specification requires "
+                                 "protocol specification with protocol to be "
+                                 "either one of tcp(6), udp(17), dccp(33), or "
+                                 "sctp(132)"), protocol);
+            }
+        }
+    break;
+    default:
+    break;
+    }
+
+    return ret;
+}
+
 static void
 virNWFilterRuleDefFixup(virNWFilterRuleDefPtr rule)
 {
@@ -2389,6 +2449,8 @@ virNWFilterRuleParse(xmlNodePtr node)
                                                     virAttr[i].att) < 0) {
                         goto err_exit;
                     }
+                    if (virNWFilterRuleValidate(ret) < 0)
+                        goto err_exit;
                     break;
                 }
                 if (!found) {
-- 
1.8.1.4

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