/*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
#ifdef GSSAPI
+#include "includes.h"
+
#include <openssl/crypto.h>
#include <openssl/bn.h>
+#include <string.h>
+
#include "xmalloc.h"
#include "buffer.h"
-#include "bufaux.h"
+#include "ssh2.h"
+#include "key.h"
+#include "cipher.h"
#include "kex.h"
#include "log.h"
#include "packet.h"
#include "dh.h"
-#include "ssh2.h"
-#include "ssh-gss.h"
-#include "canohost.h"
+#include "ssh-gss.h"
void
-kexgss_client(Kex *kex)
-{
- gss_buffer_desc gssbuf,send_tok,recv_tok, msg_tok, *token_ptr;
+kexgss_client(Kex *kex) {
+ 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;
+ u_char *empty = "";
char *msg;
char *lang;
int type = 0;
int first = 1;
- int slen = 0, strlen;
-
- /* Initialise our GSSAPI world */
+ int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
+
+ /* Initialise our GSSAPI world */
ssh_gssapi_build_ctx(&ctxt);
- if (ssh_gssapi_client_id_kex(ctxt,kex->name)==NULL) {
+ if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
+ == GSS_C_NO_OID)
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 (kex->gss_client &&
+ ssh_gssapi_client_identity(ctxt, kex->gss_client))
+ fatal("Couldn't acquire client credentials");
+
+ switch (kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ dh = dh_new_group1();
+ break;
+ case KEX_GSS_GRP14_SHA1:
+ dh = dh_new_group14();
+ break;
+ case KEX_GSS_GEX_SHA1:
+ debug("Doing group exchange\n");
+ nbits = dh_estimate(kex->we_need * 8);
+ 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);
+ break;
+ default:
+ fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
}
- /* 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 */
- dh_server_pub = BN_new();
- if (dh_server_pub == NULL) {
- fatal("dh_server_pub == NULL");
- }
-
+ dh_server_pub = BN_new();
+ if (dh_server_pub == NULL)
+ fatal("dh_server_pub == NULL");
+
token_ptr = GSS_C_NO_BUFFER;
do {
debug("Calling gss_init_sec_context");
- maj_status=ssh_gssapi_init_ctx(ctxt,
- kex->options.gss_deleg_creds,
- token_ptr,&send_tok,
- &ret_flags);
+ maj_status = ssh_gssapi_init_ctx(ctxt,
+ kex->gss_deleg_creds, token_ptr, &send_tok,
+ &ret_flags);
if (GSS_ERROR(maj_status)) {
- if (send_tok.length!=0) {
- /* Hmmm - not sure about this */
+ if (send_tok.length != 0) {
packet_start(SSH2_MSG_KEXGSS_CONTINUE);
packet_put_string(send_tok.value,
- send_tok.length);
- }
+ send_tok.length);
+ }
fatal("gss_init_context failed");
}
/* 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 */
- if (!(ret_flags & GSS_C_MUTUAL_FLAG)) {
+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
fatal("Mutual authentication failed");
- }
+
/* If integ avail flag is not true kex fails */
- if (!(ret_flags & GSS_C_INTEG_FLAG)) {
+ if (!(ret_flags & GSS_C_INTEG_FLAG))
fatal("Integrity check failed");
- }
}
-
- /* If we have data to send, then the last message that we
- * received cannot have been a 'complete'. */
- if (send_tok.length !=0) {
+
+ /*
+ * If we have data to send, then the last message that we
+ * received cannot have been a 'complete'.
+ */
+ if (send_tok.length != 0) {
if (first) {
packet_start(SSH2_MSG_KEXGSS_INIT);
packet_put_string(send_tok.value,
- send_tok.length);
+ send_tok.length);
packet_put_bignum2(dh->pub_key);
- first=0;
+ first = 0;
} else {
packet_start(SSH2_MSG_KEXGSS_CONTINUE);
packet_put_string(send_tok.value,
- send_tok.length);
+ send_tok.length);
}
packet_send();
- packet_write_wait();
+ gss_release_buffer(&min_status, &send_tok);
+
+ /* If we've sent them data, they should reply */
+ 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);
-
- /* If we've sent them data, they'd better be polite
- * and reply. */
-
- type = packet_read();
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)
fatal("GSSAPI Continue received from server when complete");
- recv_tok.value=packet_get_string(&strlen);
- recv_tok.length=strlen; /* int vs. size_t */
+ recv_tok.value = packet_get_string(&strlen);
+ recv_tok.length = strlen;
break;
case SSH2_MSG_KEXGSS_COMPLETE:
debug("Received GSSAPI_COMPLETE");
- packet_get_bignum2(dh_server_pub);
- msg_tok.value=packet_get_string(&strlen);
- msg_tok.length=strlen; /* int vs. size_t */
+ packet_get_bignum2(dh_server_pub);
+ msg_tok.value = packet_get_string(&strlen);
+ msg_tok.length = strlen;
/* Is there a token included? */
if (packet_get_char()) {
recv_tok.value=
packet_get_string(&strlen);
- recv_tok.length=strlen; /*int/size_t*/
+ recv_tok.length = strlen;
/* 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:
debug("Received Error");
- maj_status=packet_get_int();
- min_status=packet_get_int();
- msg=packet_get_string(NULL);
- lang=packet_get_string(NULL);
- fprintf(stderr,"GSSAPI Error: \n%s",msg);
+ maj_status = packet_get_int();
+ min_status = packet_get_int();
+ msg = packet_get_string(NULL);
+ lang = packet_get_string(NULL);
+ fatal("GSSAPI Error: \n%.400s",msg);
default:
packet_disconnect("Protocol error: didn't expect packet type %d",
type);
}
- token_ptr=&recv_tok;
+ token_ptr = &recv_tok;
} else {
/* No data, and not complete */
- if (maj_status!=GSS_S_COMPLETE) {
+ if (maj_status != GSS_S_COMPLETE)
fatal("Not complete, and no token output");
- }
}
- } 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 */
-
- if (type!=SSH2_MSG_KEXGSS_COMPLETE)
- fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
-
+ } 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
+ */
+
+ 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] */
- if (!dh_pub_is_valid(dh, dh_server_pub))
- packet_disconnect("bad server public DH value");
-
- /* compute K=f^x mod p */
- klen = DH_size(dh);
- kbuf = xmalloc(klen);
- kout = DH_compute_key(kbuf, dh_server_pub, dh);
-
- shared_secret = BN_new();
- BN_bin2bn(kbuf,kout, shared_secret);
- 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 */
- );
-
- gssbuf.value=hash;
- gssbuf.length=20;
-
- /* Verify that H matches the token we just got. */
- if ((maj_status = gss_verify_mic(&min_status,
- ctxt->context,
- &gssbuf,
- &msg_tok,
- NULL))) {
+ if (!dh_pub_is_valid(dh, dh_server_pub))
+ packet_disconnect("bad server public DH value");
+
+ /* compute K=f^x mod p */
+ klen = DH_size(dh);
+ kbuf = xmalloc(klen);
+ kout = DH_compute_key(kbuf, dh_server_pub, dh);
+ if (kout < 0)
+ fatal("DH_compute_key: failed");
+
+ shared_secret = BN_new();
+ if (shared_secret == NULL)
+ fatal("kexgss_client: BN_new failed");
+ if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
+ fatal("kexdh_client: BN_bin2bn failed");
+
+ memset(kbuf, 0, klen);
+ xfree(kbuf);
+
+ switch (kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ case KEX_GSS_GRP14_SHA1:
+ 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 ? serverhostkey : empty), slen,
+ dh->pub_key, /* e */
+ dh_server_pub, /* f */
+ shared_secret, /* K */
+ &hash, &hashlen
+ );
+ break;
+ case KEX_GSS_GEX_SHA1:
+ 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 ? serverhostkey : empty), slen,
+ min, nbits, max,
+ dh->p, dh->g,
+ dh->pub_key,
+ dh_server_pub,
+ shared_secret,
+ &hash, &hashlen
+ );
+ break;
+ default:
+ fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+ }
+
+ gssbuf.value = hash;
+ 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");
- }
-
- DH_free(dh);
- ssh_gssapi_delete_ctx(&ctxt);
- /* save session id */
- if (kex->session_id == NULL) {
- kex->session_id_len = 20;
- kex->session_id = xmalloc(kex->session_id_len);
- memcpy(kex->session_id, hash, kex->session_id_len);
- }
-
- kex_derive_keys(kex, hash, shared_secret);
+
+ 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 = hashlen;
+ kex->session_id = xmalloc(kex->session_id_len);
+ memcpy(kex->session_id, hash, kex->session_id_len);
+ }
+
+ if (kex->gss_deleg_creds)
+ ssh_gssapi_credentials_updated(ctxt);
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = ctxt;
+ else
+ ssh_gssapi_delete_ctx(&ctxt);
+
+ kex_derive_keys(kex, hash, hashlen, shared_secret);
BN_clear_free(shared_secret);
- kex_finish(kex);
+ kex_finish(kex);
}
#endif /* GSSAPI */
andersk / gssapi-openssh.git / blobdiff