* Update to current GSSAPI patch from

  http://www.sxw.org.uk/computing/patches/openssh-4.3p2-gsskex-20060223.patch
  (closes: #352042).

1 files changed, 110 insertions, 49 deletions

diff --git a/kexgssc.c b/kexgssc.c
index eee96dd23..9830ad384 100644
--- a/kexgssc.c
+++ b/kexgssc.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001-2004 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2005 Simon Wilkinson. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -42,34 +42,65 @@
 
 void
 kexgss_client(Kex *kex) {
-        gss_buffer_desc gssbuf, send_tok, recv_tok, msg_tok, *token_ptr;
+        gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+        gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
         Gssctxt *ctxt;
         OM_uint32 maj_status, min_status, ret_flags;
-        unsigned int klen, kout;
+        u_int klen, kout, slen = 0, hashlen, strlen;
         DH *dh; 
-        BIGNUM *dh_server_pub = 0;
-        BIGNUM *shared_secret = 0;      
-        unsigned char *kbuf;
-        unsigned char *hash;
-        unsigned char *serverhostkey;
+        BIGNUM *dh_server_pub = NULL;
+        BIGNUM *shared_secret = NULL;
+        BIGNUM *p = NULL;
+        BIGNUM *g = NULL;       
+        u_char *kbuf, *hash;
+        u_char *serverhostkey = NULL;
         char *msg;
         char *lang;
         int type = 0;
         int first = 1;
-        int slen = 0;
-        u_int strlen;
-        
+        int gex = 0;
+        int nbits, min, max;
+
+        /* Initialise our GSSAPI world */       
         ssh_gssapi_build_ctx(&ctxt);
-        if (ssh_gssapi_id_kex(ctxt,kex->name) == NULL)
+        if (ssh_gssapi_id_kex(ctxt, kex->name, &gex) == NULL)
                 fatal("Couldn't identify host exchange");
 
-        if (ssh_gssapi_import_name(ctxt,get_canonical_hostname(1)))
-                fatal("Couldn't import hostname ");
+        if (ssh_gssapi_import_name(ctxt, kex->gss_host))
+                fatal("Couldn't import hostname");
+        
+        if (gex) {
+                debug("Doing group exchange\n");
+                nbits = dh_estimate(kex->we_need * 8);
+                min = DH_GRP_MIN;
+                max = DH_GRP_MAX;
+                packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
+                packet_put_int(min);
+                packet_put_int(nbits);
+                packet_put_int(max);
+
+                packet_send();
+
+                packet_read_expect(SSH2_MSG_KEXGSS_GROUP);
+
+                if ((p = BN_new()) == NULL)
+                        fatal("BN_new() failed");
+                packet_get_bignum2(p);
+                if ((g = BN_new()) == NULL)
+                        fatal("BN_new() failed");
+                packet_get_bignum2(g);
+                packet_check_eom();
+
+                if (BN_num_bits(p) < min || BN_num_bits(p) > max)
+                        fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
+                            min, BN_num_bits(p), max);
+
+                dh = dh_new_group(g, p);
+        } else {
+                dh = dh_new_group1();
+        }
         
-        /* This code should match that in ssh_dh1_client */
-                
         /* Step 1 - e is dh->pub_key */
-        dh = dh_new_group1();
         dh_gen_key(dh, kex->we_need * 8);
 
         /* This is f, we initialise it now to make life easier */
@@ -97,7 +128,7 @@ kexgss_client(Kex *kex) {
 
                 /* If we've got an old receive buffer get rid of it */
                 if (token_ptr != GSS_C_NO_BUFFER)
-                        (void) gss_release_buffer(&min_status, &recv_tok);
+                        xfree(recv_tok.value);
 
                 if (maj_status == GSS_S_COMPLETE) {
                         /* If mutual state flag is not true, kex fails */
@@ -126,15 +157,21 @@ kexgss_client(Kex *kex) {
                                     send_tok.length);
                         }
                         packet_send();
+                        gss_release_buffer(&min_status, &send_tok);
 
                         /* If we've sent them data, they should reply */
-                
-                        type = packet_read();
+                        do {    
+                                type = packet_read();
+                                if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
+                                        debug("Received KEXGSS_HOSTKEY");
+                                        if (serverhostkey)
+                                                fatal("Server host key received more than once");
+                                        serverhostkey = 
+                                            packet_get_string(&slen);
+                                }
+                        } while (type == SSH2_MSG_KEXGSS_HOSTKEY);
+
                         switch (type) {
-                        case SSH2_MSG_KEXGSS_HOSTKEY:
-                                debug("Received KEXGSS_HOSTKEY");
-                                serverhostkey = packet_get_string(&slen);
-                                break;
                         case SSH2_MSG_KEXGSS_CONTINUE:
                                 debug("Received GSSAPI_CONTINUE");
                                 if (maj_status == GSS_S_COMPLETE) 
@@ -144,8 +181,8 @@ kexgss_client(Kex *kex) {
                                 break;
                         case SSH2_MSG_KEXGSS_COMPLETE:
                                 debug("Received GSSAPI_COMPLETE");
-                                packet_get_bignum2(dh_server_pub);
-                                msg_tok.value = packet_get_string(&strlen);
+                                packet_get_bignum2(dh_server_pub);
+                                msg_tok.value =  packet_get_string(&strlen);
                                 msg_tok.length = strlen; 
 
                                 /* Is there a token included? */
@@ -156,10 +193,10 @@ kexgss_client(Kex *kex) {
                                         /* If we're already complete - protocol error */
                                         if (maj_status == GSS_S_COMPLETE)
                                                 packet_disconnect("Protocol error: received token when complete");
-                                } else {
-                                        /* No token included */
-                                        if (maj_status != GSS_S_COMPLETE)
-                                                packet_disconnect("Protocol error: did not receive final token");
+                                        } else {
+                                                /* No token included */
+                                                if (maj_status != GSS_S_COMPLETE)
+                                                        packet_disconnect("Protocol error: did not receive final token");
                                 }
                                 break;
                         case SSH2_MSG_KEXGSS_ERROR:
@@ -168,7 +205,7 @@ kexgss_client(Kex *kex) {
                                 min_status = packet_get_int();
                                 msg = packet_get_string(NULL);
                                 lang = packet_get_string(NULL);
-                                fprintf(stderr,"GSSAPI Error: \n%s",msg);
+                                fatal("GSSAPI Error: \n%s",msg);
                         default:
                                 packet_disconnect("Protocol error: didn't expect packet type %d",
                                 type);
@@ -181,12 +218,12 @@ kexgss_client(Kex *kex) {
                 }
         } while (maj_status & GSS_S_CONTINUE_NEEDED);
 
-        /* 
+        /* 
          * We _must_ have received a COMPLETE message in reply from the 
-         * server, which will have set dh_server_pub and msg_tok 
+         * server, which will have set dh_server_pub and msg_tok 
          */
 
-        if (type!=SSH2_MSG_KEXGSS_COMPLETE)
+        if (type != SSH2_MSG_KEXGSS_COMPLETE)
                 fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
 
         /* Check f in range [1, p-1] */
@@ -203,28 +240,52 @@ kexgss_client(Kex *kex) {
         memset(kbuf, 0, klen);
         xfree(kbuf);
 
-        /* The GSS hash is identical to the DH one */
-        hash = kex_dh_hash( kex->client_version_string, 
-            kex->server_version_string,
-            buffer_ptr(&kex->my), buffer_len(&kex->my),
-            buffer_ptr(&kex->peer), buffer_len(&kex->peer),
-            serverhostkey, slen, /* server host key */
-            dh->pub_key,        /* e */
-            dh_server_pub,      /* f */
-            shared_secret       /* K */
-        );
-        
+        if (gex) {
+                kexgex_hash(
+                    kex->evp_md,
+                    kex->client_version_string,
+                    kex->server_version_string,
+                    buffer_ptr(&kex->my), buffer_len(&kex->my),
+                    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+                    serverhostkey, slen,
+                    min, nbits, max,
+                    dh->p, dh->g,
+                    dh->pub_key,
+                    dh_server_pub,
+                    shared_secret,
+                    &hash, &hashlen
+                );
+        } else {
+                /* The GSS hash is identical to the DH one */
+                kex_dh_hash( kex->client_version_string, 
+                    kex->server_version_string,
+                    buffer_ptr(&kex->my), buffer_len(&kex->my),
+                    buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+                    serverhostkey, slen, /* server host key */
+                    dh->pub_key,        /* e */
+                    dh_server_pub,      /* f */
+                    shared_secret,      /* K */
+                    &hash, &hashlen
+                );
+        }
+
         gssbuf.value = hash;
-        gssbuf.length = 20;
+        gssbuf.length = hashlen;
 
         /* Verify that the hash matches the MIC we just got. */
         if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
                 packet_disconnect("Hash's MIC didn't verify");
-        
+
+        xfree(msg_tok.value);
+
         DH_free(dh);
+        if (serverhostkey)
+                xfree(serverhostkey);
+        BN_clear_free(dh_server_pub);
+
         /* save session id */
         if (kex->session_id == NULL) {
-                kex->session_id_len = 20;
+                kex->session_id_len = hashlen;
                 kex->session_id = xmalloc(kex->session_id_len);
                 memcpy(kex->session_id, hash, kex->session_id_len);
         }
@@ -234,7 +295,7 @@ kexgss_client(Kex *kex) {
         else
                 ssh_gssapi_delete_ctx(&ctxt);
 
-        kex_derive_keys(kex, hash, shared_secret);
+        kex_derive_keys(kex, hash, hashlen, shared_secret);
         BN_clear_free(shared_secret);
         kex_finish(kex);
 }