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-rw-r--r--src/dns/dns_sec.c144
1 files changed, 144 insertions, 0 deletions
diff --git a/src/dns/dns_sec.c b/src/dns/dns_sec.c
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+++ b/src/dns/dns_sec.c
@@ -0,0 +1,144 @@
+/*++
+/* NAME
+/* dns_sec 3
+/* SUMMARY
+/* DNSSEC validation availability
+/* SYNOPSIS
+/* #include <dns.h>
+/*
+/* DNS_SEC_STATS_SET(
+/* int flags)
+/*
+/* DNS_SEC_STATS_TEST(
+/* int flags)
+/*
+/* void dns_sec_probe(
+/* int rflags)
+/* DESCRIPTION
+/* This module maintains information about the availability of
+/* DNSSEC validation, in global flags that summarize
+/* process-lifetime history.
+/* .IP DNS_SEC_FLAG_AVAILABLE
+/* The process has received at least one DNSSEC validated
+/* response to a query that requested DNSSEC validation.
+/* .IP DNS_SEC_FLAG_DONT_PROBE
+/* The process has sent a DNSSEC probe (see below), or DNSSEC
+/* probing is disabled by configuration.
+/* .PP
+/* DNS_SEC_STATS_SET() sets one or more DNS_SEC_FLAG_* flags,
+/* and DNS_SEC_STATS_TEST() returns non-zero if any of the
+/* specified flags is set.
+/*
+/* dns_sec_probe() generates a query to the target specified
+/* with the \fBdnssec_probe\fR configuration parameter. It
+/* sets the DNS_SEC_FLAG_DONT_PROBE flag, and it calls
+/* dns_lookup() which sets DNS_SEC_FLAG_AVAILABLE if it receives
+/* a DNSSEC validated response. Preconditions:
+/* .IP \(bu
+/* The rflags argument must request DNSSEC validation (in the
+/* same manner as dns_lookup() rflags argument).
+/* .IP \(bu
+/* The DNS_SEC_FLAG_AVAILABLE and DNS_SEC_FLAG_DONT_PROBE
+/* flags must be false.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* Google, Inc.
+/* 111 8th Avenue
+/* New York, NY 10011, USA
+/*--*/
+
+#include <sys_defs.h>
+
+ /*
+ * Utility library.
+ */
+#include <msg.h>
+#include <mymalloc.h>
+#include <split_at.h>
+#include <vstring.h>
+
+ /*
+ * Global library.
+ */
+#include <mail_params.h>
+
+ /*
+ * DNS library.
+ */
+#include <dns.h>
+
+int dns_sec_stats;
+
+/* dns_sec_probe - send a probe to establish DNSSEC viability */
+
+void dns_sec_probe(int rflags)
+{
+ const char myname[] = "dns_sec_probe";
+ char *saved_dnssec_probe;
+ char *qname;
+ int qtype;
+ DNS_RR *rrlist = 0;
+ int dns_status;
+ VSTRING *why;
+
+ /*
+ * Sanity checks.
+ */
+ if (!DNS_WANT_DNSSEC_VALIDATION(rflags))
+ msg_panic("%s: DNSSEC is not requested", myname);
+ if (DNS_SEC_STATS_TEST(DNS_SEC_FLAG_DONT_PROBE))
+ msg_panic("%s: DNSSEC probe was already sent, or probing is disabled",
+ myname);
+ if (DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE))
+ msg_panic("%s: already have validated DNS response", myname);
+
+ /*
+ * Don't recurse.
+ */
+ DNS_SEC_STATS_SET(DNS_SEC_FLAG_DONT_PROBE);
+
+ /*
+ * Don't probe.
+ */
+ if (*var_dnssec_probe == 0)
+ return;
+
+ /*
+ * Parse the probe spec. Format is type:resource.
+ */
+ saved_dnssec_probe = mystrdup(var_dnssec_probe);
+ if ((qname = split_at(saved_dnssec_probe, ':')) == 0 || *qname == 0
+ || (qtype = dns_type(saved_dnssec_probe)) == 0)
+ msg_fatal("malformed %s value: %s format is qtype:qname",
+ VAR_DNSSEC_PROBE, var_dnssec_probe);
+
+ why = vstring_alloc(100);
+ dns_status = dns_lookup(qname, qtype, rflags, &rrlist, (VSTRING *) 0, why);
+ if (!DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE))
+ msg_warn("DNSSEC validation may be unavailable");
+ else if (msg_verbose)
+ msg_info(VAR_DNSSEC_PROBE
+ " '%s' received a response that is DNSSEC validated",
+ var_dnssec_probe);
+ switch (dns_status) {
+ default:
+ if (!DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE))
+ msg_warn("reason: " VAR_DNSSEC_PROBE
+ " '%s' received a response that is not DNSSEC validated",
+ var_dnssec_probe);
+ if (rrlist)
+ dns_rr_free(rrlist);
+ break;
+ case DNS_RETRY:
+ case DNS_FAIL:
+ msg_warn("reason: " VAR_DNSSEC_PROBE " '%s' received no response: %s",
+ var_dnssec_probe, vstring_str(why));
+ break;
+ }
+ myfree(saved_dnssec_probe);
+ vstring_free(why);
+}