Drop compatibility with the old gssapi mechanism used in ssh-krb5 <<

3.8.1p1-1.  Simon Wilkinson refused this patch since the old gssapi
mechanism was removed due to a serious security hole, and since these
versions of ssh-krb5 are no longer security-supported by Debian I don't
think there's any point keeping client compatibility for them.

1 files changed, 8 insertions, 34 deletions

diff --git a/sshconnect2.c b/sshconnect2.c
index af322e81c..bc8d206ae 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -314,11 +314,6 @@ Authmethod authmethods[] = {
                 NULL,
                 &options.gss_authentication,
                 NULL},
-        {"gssapi",
-                userauth_gssapi,
-                NULL,
-                &options.gss_authentication,
-                NULL},
 #endif
         {"hostbased",
                 userauth_hostbased,
@@ -606,7 +601,6 @@ userauth_gssapi(Authctxt *authctxt)
         OM_uint32 min;
         int ok = 0;
         const char *gss_host;
-        int old_gssapi_method;
 
         if (options.gss_trust_dns)
                 gss_host = get_canonical_hostname(1);
@@ -645,25 +639,13 @@ userauth_gssapi(Authctxt *authctxt)
         packet_put_cstring(authctxt->service);
         packet_put_cstring(authctxt->method->name);
 
-        old_gssapi_method = !strcmp(authctxt->method->name, "gssapi");
-
-        /* Versions of Debian ssh-krb5 prior to 3.8.1p1-1 don't expect
-         * tagged OIDs.  As such we include both tagged and untagged oids
-         * for the old gssapi method.
-         * We only include tagged oids for the new gssapi-with-mic method.
-         */
-        packet_put_int(old_gssapi_method ? 2 : 1);
+        packet_put_int(1);
 
         packet_put_int((gss_supported->elements[mech].length) + 2);
         packet_put_char(SSH_GSS_OIDTYPE);
         packet_put_char(gss_supported->elements[mech].length);
         packet_put_raw(gss_supported->elements[mech].elements,
             gss_supported->elements[mech].length);
-        if (old_gssapi_method) {
-                packet_put_int(gss_supported->elements[mech].length);
-                packet_put_raw(gss_supported->elements[mech].elements,
-                               gss_supported->elements[mech].length);
-        }
 
         packet_send();
 
@@ -703,10 +685,8 @@ process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
         }
 
         if (status == GSS_S_COMPLETE) {
-                int old_gssapi_method = !strcmp(authctxt->method->name,
-                                                "gssapi");
                 /* send either complete or MIC, depending on mechanism */
-                if (old_gssapi_method || !(flags & GSS_C_INTEG_FLAG)) {
+                if (!(flags & GSS_C_INTEG_FLAG)) {
                         packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
                         packet_send();
                 } else {
@@ -740,7 +720,7 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt)
         Authctxt *authctxt = ctxt;
         Gssctxt *gssctxt;
         u_int oidlen;
-        u_char *oidv, *oidv_free;
+        u_char *oidv;
 
         if (authctxt == NULL)
                 fatal("input_gssapi_response: no authentication context");
@@ -748,28 +728,22 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt)
 
         /* Setup our OID */
         oidv = packet_get_string(&oidlen);
-        oidv_free = oidv;
 
         if (oidlen <= 2 ||
             oidv[0] != SSH_GSS_OIDTYPE ||
             oidv[1] != oidlen - 2) {
+                xfree(oidv);
                 debug("Badly encoded mechanism OID received");
-                if (oidlen < 2) {
-                        xfree(oidv_free);
-                        userauth(authctxt, NULL);
-                        return;
-                }
-        } else {
-                oidlen -= 2;
-                oidv += 2;
+                userauth(authctxt, NULL);
+                return;
         }
 
-        if (!ssh_gssapi_check_oid(gssctxt, oidv, oidlen))
+        if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
                 fatal("Server returned different OID than expected");
 
         packet_check_eom();
 
-        xfree(oidv_free);
+        xfree(oidv);
 
         if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
                 /* Start again with next method on list */