* Add remaining pieces of Kerberos support (closes: #275472):

  - Add GSSAPI key exchange support from
    http://www.sxw.org.uk/computing/patches/openssh.html (thanks, Stephen
    Frost).

1 files changed, 80 insertions, 0 deletions

diff --git a/sshconnect2.c b/sshconnect2.c
index ee7932d68..e40786f87 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -84,9 +84,26 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 {
         Kex *kex;
 
+#ifdef GSSAPI
+        char *orig, *gss;
+        int len;
+#endif
+
         xxx_host = host;
         xxx_hostaddr = hostaddr;
 
+#ifdef GSSAPI
+        orig = myproposal[PROPOSAL_KEX_ALGS];
+        gss = ssh_gssapi_client_mechanisms(get_canonical_hostname(1));
+        debug("Offering GSSAPI proposal: %s",gss);
+        if (gss) {
+                len = strlen(orig) + strlen(gss) + 2;
+                myproposal[PROPOSAL_KEX_ALGS] = xmalloc(len);
+                snprintf(myproposal[PROPOSAL_KEX_ALGS], len, "%s,%s", gss, 
+                    orig);
+        }
+#endif
+
         if (options.ciphers == (char *)-1) {
                 logit("No valid ciphers for protocol version 2 given, using defaults.");
                 options.ciphers = NULL;
@@ -114,6 +131,16 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
                     options.hostkeyalgorithms;
 
+#ifdef GSSAPI
+        if (gss) {
+                orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
+                len = strlen(orig) + sizeof(",null");
+                myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = xmalloc(len);
+                snprintf(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], len, 
+                    "%s,null", orig);
+        }
+#endif
+
         if (options.rekey_limit)
                 packet_set_rekey_limit(options.rekey_limit);
 
@@ -122,10 +149,17 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
         kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
+#ifdef GSSAPI
+        kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
+#endif
         kex->client_version_string=client_version_string;
         kex->server_version_string=server_version_string;
         kex->verify_host_key=&verify_host_key_callback;
 
+#ifdef GSSAPI
+        kex->gss_deleg_creds = options.gss_deleg_creds;
+#endif
+
         xxx_kex = kex;
 
         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
@@ -208,6 +242,7 @@ void	input_gssapi_token(int type, u_int32_t, void *);
 void    input_gssapi_hash(int type, u_int32_t, void *);
 void    input_gssapi_error(int, u_int32_t, void *);
 void    input_gssapi_errtok(int, u_int32_t, void *);
+int     userauth_gsskeyx(Authctxt *authctxt);
 #endif
 
 void    userauth(Authctxt *, char *);
@@ -223,6 +258,10 @@ static char *authmethods_get(void);
 
 Authmethod authmethods[] = {
 #ifdef GSSAPI
+        {"gssapi-keyx",
+                userauth_gsskeyx,
+                &options.gss_authentication,
+                NULL},
         {"gssapi-with-mic",
                 userauth_gssapi,
                 &options.gss_authentication,
@@ -706,6 +745,47 @@ input_gssapi_error(int type, u_int32_t plen, void *ctxt)
         xfree(msg);
         xfree(lang);
 }
+
+int
+userauth_gsskeyx(Authctxt *authctxt)
+{
+        Buffer b;
+        gss_buffer_desc gssbuf, mic;
+        OM_uint32 ms;
+
+        static int attempt = 0;
+        if (attempt++ >= 1)
+                return (0);
+
+        if (gss_kex_context == NULL) {
+                debug("No valid Key exchange context"); 
+                return (0);
+        }
+
+        ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
+            "gssapi-keyex");
+
+        gssbuf.value = buffer_ptr(&b);
+        gssbuf.length = buffer_len(&b);
+
+        if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
+                buffer_free(&b);
+                return (0);
+        }
+
+        packet_start(SSH2_MSG_USERAUTH_REQUEST);
+        packet_put_cstring(authctxt->server_user);
+        packet_put_cstring(authctxt->service);
+        packet_put_cstring(authctxt->method->name);
+        packet_put_string(mic.value, mic.length);
+        packet_send();
+
+        buffer_free(&b);
+        gss_release_buffer(&ms, &mic);
+
+        return (1);
+}
+
 #endif /* GSSAPI */
 
 int