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From 0d8aedb659c1c3892a9ba071ea003530ea8ca1b3 Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwatson@debian.org>
Date: Sun, 9 Feb 2014 16:10:01 +0000
Subject: Force use of DNSSEC even if "options edns0" isn't in resolv.conf
This allows SSHFP DNS records to be verified if glibc 2.11 is installed.
Origin: vendor, https://cvs.fedoraproject.org/viewvc/F-12/openssh/openssh-5.2p1-edns.patch?revision=1.1&view=markup
Bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=572049
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=572049
Last-Update: 2023-06-19
Patch-Name: dnssec-sshfp.patch
---
dns.c | 14 +++++++++++++-
openbsd-compat/getrrsetbyname.c | 10 +++++-----
openbsd-compat/getrrsetbyname.h | 3 +++
3 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/dns.c b/dns.c
index 939241440..bf47a079f 100644
--- a/dns.c
+++ b/dns.c
@@ -198,6 +198,7 @@ verify_host_key_dns(const char *hostname, struct sockaddr *address,
{
u_int counter;
int result;
+ unsigned int rrset_flags = 0;
struct rrsetinfo *fingerprints = NULL;
u_int8_t hostkey_algorithm;
@@ -220,8 +221,19 @@ verify_host_key_dns(const char *hostname, struct sockaddr *address,
return -1;
}
+ /*
+ * Original getrrsetbyname function, found on OpenBSD for example,
+ * doesn't accept any flag and prerequisite for obtaining AD bit in
+ * DNS response is set by "options edns0" in resolv.conf.
+ *
+ * Our version is more clever and use RRSET_FORCE_EDNS0 flag.
+ */
+#ifndef HAVE_GETRRSETBYNAME
+ rrset_flags |= RRSET_FORCE_EDNS0;
+#endif
result = getrrsetbyname(hostname, DNS_RDATACLASS_IN,
- DNS_RDATATYPE_SSHFP, 0, &fingerprints);
+ DNS_RDATATYPE_SSHFP, rrset_flags, &fingerprints);
+
if (result) {
verbose("DNS lookup error: %s", dns_result_totext(result));
return -1;
diff --git a/openbsd-compat/getrrsetbyname.c b/openbsd-compat/getrrsetbyname.c
index ad35148c9..add519441 100644
--- a/openbsd-compat/getrrsetbyname.c
+++ b/openbsd-compat/getrrsetbyname.c
@@ -214,8 +214,8 @@ getrrsetbyname(const char *hostname, unsigned int rdclass,
goto fail;
}
- /* don't allow flags yet, unimplemented */
- if (flags) {
+ /* Allow RRSET_FORCE_EDNS0 flag only. */
+ if ((flags & ~RRSET_FORCE_EDNS0) != 0) {
result = ERRSET_INVAL;
goto fail;
}
@@ -231,9 +231,9 @@ getrrsetbyname(const char *hostname, unsigned int rdclass,
#endif /* DEBUG */
#ifdef RES_USE_DNSSEC
- /* turn on DNSSEC if EDNS0 is configured */
- if (_resp->options & RES_USE_EDNS0)
- _resp->options |= RES_USE_DNSSEC;
+ /* turn on DNSSEC if required */
+ if (flags & RRSET_FORCE_EDNS0)
+ _resp->options |= (RES_USE_EDNS0|RES_USE_DNSSEC);
#endif /* RES_USE_DNSEC */
/* make query */
diff --git a/openbsd-compat/getrrsetbyname.h b/openbsd-compat/getrrsetbyname.h
index 1283f5506..dbbc85a2a 100644
--- a/openbsd-compat/getrrsetbyname.h
+++ b/openbsd-compat/getrrsetbyname.h
@@ -72,6 +72,9 @@
#ifndef RRSET_VALIDATED
# define RRSET_VALIDATED 1
#endif
+#ifndef RRSET_FORCE_EDNS0
+# define RRSET_FORCE_EDNS0 0x0001
+#endif
/*
* Return codes for getrrsetbyname()
|
