Borrow patch from Fedora to add DNSSEC support: if glibc 2.11 is

installed, the host key is published in an SSHFP RR secured with DNSSEC,
and VerifyHostKeyDNS=yes, then ssh will no longer prompt for host key
verification (closes: #572049).

2 files changed, 83 insertions, 0 deletions

diff --git a/debian/patches/dnssec-sshfp.patch b/debian/patches/dnssec-sshfp.patch
new file mode 100644
index 000000000..a71b42f0f
--- /dev/null
+++ b/debian/patches/dnssec-sshfp.patch
@@ -0,0 +1,82 @@
+Description: 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: 2010-04-06
+
+Index: b/dns.c
+===================================================================
+--- a/dns.c
++++ b/dns.c
+@@ -176,6 +176,7 @@
+ {
+        u_int counter;
+        int result;
++       unsigned int rrset_flags = 0;
+        struct rrsetinfo *fingerprints = NULL;
+ 
+        u_int8_t hostkey_algorithm;
+@@ -199,8 +200,19 @@
+                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;
+Index: b/openbsd-compat/getrrsetbyname.c
+===================================================================
+--- a/openbsd-compat/getrrsetbyname.c
++++ b/openbsd-compat/getrrsetbyname.c
+@@ -209,8 +209,8 @@
+                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;
+        }
+@@ -226,9 +226,9 @@
+ #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 */
+Index: b/openbsd-compat/getrrsetbyname.h
+===================================================================
+--- 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()
diff --git a/debian/patches/series b/debian/patches/series
index 03a17ba91..a75b0a0f5 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -28,6 +28,7 @@ scp-quoting.patch
 shell-path.patch
 ssh-copy-id-status-check.patch
 ssh-copy-id-trailing-colons.patch
+dnssec-sshfp.patch
 
 # Versioning
 package-versioning.patch