/* Allows a remotely initiated security context between the
application and a remote peer to be established, using krb5.
Assumes context_handle is valid. */
OM_uint32
gss_krb5_accept_sec_context (OM_uint32 * minor_status,
gss_ctx_id_t * context_handle,
const gss_cred_id_t acceptor_cred_handle,
const gss_buffer_t input_token_buffer,
const gss_channel_bindings_t input_chan_bindings,
gss_name_t * src_name,
gss_OID * mech_type,
gss_buffer_t output_token,
OM_uint32 * ret_flags,
OM_uint32 * time_rec,
gss_cred_id_t * delegated_cred_handle)
{
gss_buffer_desc data;
char *in;
size_t inlen;
gss_ctx_id_t cx;
_gss_krb5_ctx_t cxk5;
_gss_krb5_cred_t crk5;
int rc;
if (minor_status)
*minor_status = 0;
if (ret_flags)
*ret_flags = 0;
if (!acceptor_cred_handle)
/* XXX support GSS_C_NO_CREDENTIAL: acquire_cred() default server */
return GSS_S_NO_CRED;
if (*context_handle)
return GSS_S_FAILURE;
crk5 = acceptor_cred_handle->krb5;
cx = calloc (sizeof (*cx), 1);
if (!cx)
{
if (minor_status)
*minor_status = ENOMEM;
return GSS_S_FAILURE;
}
cxk5 = calloc (sizeof (*cxk5), 1);
if (!cxk5)
{
free (cx);
if (minor_status)
*minor_status = ENOMEM;
return GSS_S_FAILURE;
}
cx->mech = GSS_KRB5;
cx->krb5 = cxk5;
/* XXX cx->peer?? */
*context_handle = cx;
cxk5->sh = crk5->sh;
cxk5->key = crk5->key;
cxk5->acceptor = 1;
rc = shishi_ap (cxk5->sh, &cxk5->ap);
if (rc != SHISHI_OK)
return GSS_S_FAILURE;
rc = gss_decapsulate_token (input_token_buffer, GSS_KRB5, &in, &inlen);
if (!rc)
return GSS_S_BAD_MIC;
if (inlen < TOK_LEN)
return GSS_S_BAD_MIC;
if (memcmp (in, TOK_AP_REQ, TOK_LEN) != 0)
return GSS_S_BAD_MIC;
rc = shishi_ap_req_der_set (cxk5->ap, in + TOK_LEN, inlen - TOK_LEN);
if (rc != SHISHI_OK)
return GSS_S_FAILURE;
rc = shishi_ap_req_process (cxk5->ap, crk5->key);
if (rc != SHISHI_OK)
{
if (minor_status)
*minor_status = GSS_KRB5_S_G_VALIDATE_FAILED;
return GSS_S_FAILURE;
}
rc = shishi_authenticator_seqnumber_get (cxk5->sh,
shishi_ap_authenticator (cxk5->ap),
&cxk5->initseqnr);
if (rc != SHISHI_OK)
return GSS_S_FAILURE;
rc = _gss_krb5_checksum_parse (minor_status,
context_handle,
input_chan_bindings);
if (rc != GSS_S_COMPLETE)
return GSS_S_FAILURE;
cxk5->tkt = shishi_ap_tkt (cxk5->ap);
cxk5->key = shishi_ap_key (cxk5->ap);
if (shishi_apreq_mutual_required_p (crk5->sh, shishi_ap_req (cxk5->ap)))
{
Shishi_asn1 aprep;
rc = shishi_ap_rep_asn1 (cxk5->ap, &aprep);
if (rc != SHISHI_OK)
{
printf ("Error creating AP-REP: %s\n", shishi_strerror (rc));
return GSS_S_FAILURE;
}
rc = shishi_encapreppart_seqnumber_get (cxk5->sh,
shishi_ap_encapreppart (cxk5->
ap),
&cxk5->acceptseqnr);
if (rc != SHISHI_OK)
{
/* A strict 1964 implementation would return
GSS_S_DEFECTIVE_TOKEN here. gssapi-cfx permit absent
sequence number, though. */
cxk5->acceptseqnr = 0;
}
{
char *der;
size_t len;
rc = shishi_asn1_to_der (crk5->sh, aprep, &der, &len);
if (rc != SHISHI_OK)
{
printf ("Error der encoding aprep: %s\n", shishi_strerror (rc));
return GSS_S_FAILURE;
}
data.value = der;
data.length = len;
}
rc = gss_encapsulate_token_prefix (&data, TOK_AP_REP, TOK_LEN,
GSS_KRB5, output_token);
if (!rc)
return GSS_S_FAILURE;
if (ret_flags)
*ret_flags = GSS_C_MUTUAL_FLAG;
}
else
{
output_token->value = NULL;
output_token->length = 0;
}
if (src_name)
{
gss_name_t p;
p = malloc (sizeof (*p));
if (!p)
{
if (minor_status)
*minor_status = ENOMEM;
return GSS_S_FAILURE;
}
rc = shishi_encticketpart_client (cxk5->sh,
shishi_tkt_encticketpart (cxk5->tkt),
&p->value, &p->length);
if (rc != SHISHI_OK)
return GSS_S_FAILURE;
p->type = GSS_KRB5_NT_PRINCIPAL_NAME;
*src_name = p;
}
/* PROT_READY is not mentioned in 1964/gssapi-cfx but we support
it anyway. */
if (ret_flags)
*ret_flags |= GSS_C_PROT_READY_FLAG;
if (minor_status)
*minor_status = 0;
return GSS_S_COMPLETE;
}
static Shishi_ap *
auth (Shishi * h, int verbose, const char *cname, const char *sname)
{
Shishi_key *key;
Shishi_ap *ap;
Shishi_asn1 apreq;
char *buf;
size_t buflen;
int rc;
printf ("Client: %s\n", cname);
printf ("Server: %s\n", sname);
/* Get key for the server. */
key = shishi_hostkeys_for_server (h, sname);
if (!key)
{
printf ("could not find key: %s\n", shishi_error (h));
return NULL;
}
if (verbose)
shishi_key_print (h, stderr, key);
/* Read Authentication request from client */
printf ("Waiting for client to authenticate itself...\n");
rc = shishi_apreq_parse (h, stdin, &apreq);
if (rc != SHISHI_OK)
{
printf ("could not read AP-REQ: %s\n", shishi_strerror (rc));
return NULL;
}
/* Create Authentication context */
rc = shishi_ap (h, &ap);
if (rc != SHISHI_OK)
{
printf ("Could not create AP: %s\n", shishi_strerror (rc));
return NULL;
}
/* Store request in context */
shishi_ap_req_set (ap, apreq);
/* Process authentication request */
rc = shishi_ap_req_process (ap, key);
if (rc != SHISHI_OK)
{
printf ("Could not process AP-REQ: %s\n", shishi_strerror (rc));
return NULL;
}
if (verbose)
shishi_authenticator_print (h, stderr, shishi_ap_authenticator (ap));
rc = shishi_authenticator_client (h, shishi_ap_authenticator (ap),
&buf, &buflen);
printf ("Client name (from authenticator): %.*s\n", (int) buflen, buf);
free (buf);
rc = shishi_encticketpart_clientrealm
(h, shishi_tkt_encticketpart (shishi_ap_tkt (ap)), &buf, &buflen);
printf ("Client name (from encticketpart): %.*s\n", (int) buflen, buf);
free (buf);
rc = shishi_ticket_server (h, shishi_tkt_ticket (shishi_ap_tkt (ap)),
&buf, &buflen);
printf ("Server name (from ticket): %.*s\n", (int) buflen, buf);
free (buf);
/* User is authenticated. */
printf ("User authenticated.\n");
/* Authenticate ourself to client, if request */
if (shishi_apreq_mutual_required_p (h, apreq))
{
Shishi_asn1 aprep;
printf ("Mutual authentication required.\n");
rc = shishi_ap_rep_asn1 (ap, &aprep);
if (rc != SHISHI_OK)
{
printf ("Error creating AP-REP: %s\n", shishi_strerror (rc));
return NULL;
}
if (verbose)
shishi_encapreppart_print (h, stderr, shishi_ap_encapreppart (ap));
shishi_aprep_print (h, stdout, aprep);
/* We are authenticated to client */
}
return ap;
}
/* authentication, server side */
int
get_auth (int infd, krb5_context *ctx, krb5_auth_context *actx,
krb5_keyblock **key, const char **err_msg,
int *protoversion, int *cksumtype,
char **cksum, size_t *cksumlen, char *srvname)
{
char *out;
size_t outlen;
char *buf;
int buflen;
int len;
int rc;
int error;
/* KERBEROS 5 SENDAUTH MESSAGE */
char krb5sendauth[] = "KRB5_SENDAUTH_V1.0";
/* PROTOCOL VERSION */
char krb5kcmd1[] = "KCMDV0.1";
char krb5kcmd2[] = "KCMDV0.2";
char *servername, *server = NULL, *realm = NULL;
*err_msg = NULL;
/* Get key for the server. */
# if 0
/*
* XXX: Taken straight from the version for libshishi.
* XXX: No adaptions yet.
*/
rc = shishi_init_server (handle);
if (rc != SHISHI_OK)
return rc;
if (srvname && *srvname)
{
rc = shishi_parse_name (*handle, srvname, &server, &realm);
if (rc != SHISHI_OK)
{
*err_msg = shishi_strerror (rc);
return rc;
}
}
if (server && *server)
{
char *p;
servername = malloc (sizeof (SERVICE) + strlen (server) + 2);
if (!servername)
{
*err_msg = "Not enough memory";
return SHISHI_TOO_SMALL_BUFFER;
}
p = strchr (server, '/');
if (p && (p != server))
sprintf (servername, "%s", server); /* Non-empty prefix. */
else
sprintf (servername, "%s/%s", SERVICE,
server + (p ? 1 : 0)); /* Remove initial slash. */
}
else
servername = shishi_server_for_local_service (*handle, SERVICE);
if (realm && *realm)
shishi_realm_default_set (*handle, realm);
free (server);
free (realm);
/* Enable use of `~/.k5login'. */
if (shishi_check_version ("1.0.2")) /* Faulty in version 1.0.1. */
{
rc = shishi_cfg_authorizationtype_set (*handle, "k5login basic");
if (rc != SHISHI_OK)
{
*err_msg = shishi_error (*handle);
return rc;
}
}
key = shishi_hostkeys_for_serverrealm (*handle, servername,
shishi_realm_default (*handle));
free (servername);
if (!key)
{
*err_msg = shishi_error (*handle);
return SHISHI_INVALID_KEY;
}
/* Read Kerberos 5 sendauth message */
rc = read (infd, &len, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error reading message size";
return SHISHI_IO_ERROR;
}
buflen = ntohl (len);
buf = malloc (buflen);
if (!buf)
{
*err_msg = "Not enough memory";
return SHISHI_TOO_SMALL_BUFFER;
}
rc = read (infd, buf, buflen);
if (rc != buflen)
{
*err_msg = "Error reading authentication message";
return SHISHI_IO_ERROR;
}
len = strlen (krb5sendauth);
rc = strncmp (buf, krb5sendauth, buflen >= len ? len : buflen);
if (rc)
{
*err_msg = "Invalid authentication type";
/* Authentication type is wrong. */
write (infd, "\001", 1);
return SHISHI_VERIFY_FAILED;
}
free (buf);
/* Read protocol version */
rc = read (infd, &len, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error reading protocol message size";
return SHISHI_IO_ERROR;
}
buflen = ntohl (len);
buf = malloc (buflen);
if (!buf)
{
*err_msg = "Not enough memory";
return SHISHI_TOO_SMALL_BUFFER;
}
rc = read (infd, buf, buflen);
if (rc != buflen)
{
*err_msg = "Error reading protocol message";
return SHISHI_IO_ERROR;
}
len = strlen (krb5kcmd1);
rc = strncmp (buf, krb5kcmd1, buflen >= len ? len : buflen);
if (rc)
{
len = strlen (krb5kcmd2);
rc = strncmp (buf, krb5kcmd2, buflen >= len ? len : buflen);
if (rc)
{
*err_msg = "Protocol version not supported";
/* Protocol version is wrong. */
write (infd, "\002", 1);
return SHISHI_VERIFY_FAILED;
}
*protoversion = 2;
}
else
*protoversion = 1;
free (buf);
/* Authentication type is ok */
write (infd, "\0", 1);
/* Read Authentication request from client */
rc = read (infd, &len, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error reading authentication request size";
return SHISHI_IO_ERROR;
}
buflen = ntohl (len);
buf = malloc (buflen);
if (!buf)
{
*err_msg = "Not enough memory";
return SHISHI_TOO_SMALL_BUFFER;
}
rc = read (infd, buf, buflen);
if (rc != buflen)
{
*err_msg = "Error reading authentication request";
return SHISHI_IO_ERROR;
}
/* Create Authentication context */
rc = shishi_ap_nosubkey (*handle, ap);
if (rc != SHISHI_OK)
return rc;
/* Store request in context */
rc = shishi_ap_req_der_set (*ap, buf, buflen);
if (rc != SHISHI_OK)
return rc;
free (buf);
/* Process authentication request */
rc = shishi_ap_req_process (*ap, key);
if (rc != SHISHI_OK)
return rc;
# ifdef ENCRYPTION
/* extract subkey if present from ap exchange for secure connection */
if (*protoversion == 2)
{
*enckey = NULL;
shishi_authenticator_get_subkey (*handle,
shishi_ap_authenticator (*ap), enckey);
}
# endif
/* Get authenticator checksum */
rc = shishi_authenticator_cksum (*handle,
shishi_ap_authenticator (*ap),
cksumtype, cksum, cksumlen);
if (rc != SHISHI_OK)
return rc;
/* User is authenticated. */
error = 0;
write (infd, &error, sizeof (int));
/* Authenticate ourself to client, if requested. */
if (shishi_apreq_mutual_required_p (*handle, shishi_ap_req (*ap)))
{
int len;
rc = shishi_ap_rep_der (*ap, &out, &outlen);
if (rc != SHISHI_OK)
return rc;
len = outlen;
len = htonl (len);
rc = write (infd, &len, sizeof (len));
if (rc != sizeof (int))
{
*err_msg = "Error sending AP-REP";
free (out);
return SHISHI_IO_ERROR;
}
rc = write (infd, out, ntohl (len));
if (rc != (int) ntohl (len))
{
*err_msg = "Error sending AP-REP";
free (out);
return SHISHI_IO_ERROR;
}
free (out);
/* We are authenticated to client */
}
# ifdef ENCRYPTION
if (*protoversion == 1)
{
Shishi_tkt *tkt;
tkt = shishi_ap_tkt (*ap);
if (tkt == NULL)
{
*err_msg = "Could not get tkt from AP-REQ";
return SHISHI_INVALID_TICKET;
}
rc = shishi_encticketpart_get_key (*handle,
shishi_tkt_encticketpart (tkt),
enckey);
if (rc != SHISHI_OK)
return rc;
}
# endif /* ENCRYPTION */
return 0;
# else
return -1;
# endif
}
int
get_auth (int infd, Shishi ** handle, Shishi_ap ** ap,
Shishi_key ** enckey, const char **err_msg, int *protoversion,
int *cksumtype, char **cksum, int *cksumlen)
{
Shishi_key *key;
char *out;
int outlen;
char *buf;
int buflen;
int len;
int rc;
int i;
int error;
/* KERBEROS 5 SENDAUTH MESSAGE */
char krb5sendauth[] = "KRB5_SENDAUTH_V1.0";
/* PROTOCOL VERSION */
char krb5kcmd1[] = "KCMDV0.1";
char krb5kcmd2[] = "KCMDV0.2";
int auth_correct = 0;
char *servername;
*err_msg = NULL;
/* Get key for the server. */
if (!shishi_check_version (SHISHI_VERSION))
{
*err_msg =
"shishi_check_version() failed: header file incompatible with shared library.";
return 1;
}
rc = shishi_init_server (handle);
if (rc != SHISHI_OK)
return rc;
servername = shishi_server_for_local_service (*handle, SERVICE);
key = shishi_hostkeys_for_server (*handle, servername);
if (!key)
{
*err_msg = shishi_error (*handle);
return 1;
}
/* Read Kerberos 5 sendauth message */
rc = read (infd, &len, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error reading message size";
return 1;
}
buflen = ntohl (len);
buf = malloc (buflen);
if (!buf)
{
*err_msg = "Not enough memory";
return 1;
}
rc = read (infd, buf, buflen);
if (rc != buflen)
{
*err_msg = "Error reading authentication message";
return 1;
}
len = strlen (krb5sendauth);
rc = strncmp (buf, krb5sendauth, buflen >= len ? len : buflen);
if (rc)
{
*err_msg = "Invalid authentication type";
return 1;
}
free (buf);
/* Read protocol version */
rc = read (infd, &len, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error reading protocol message size";
return 1;
}
buflen = ntohl (len);
buf = malloc (buflen);
if (!buf)
{
*err_msg = "Not enough memory";
return 1;
}
rc = read (infd, buf, buflen);
if (rc != buflen)
{
*err_msg = "Error reading protocol message";
return 1;
}
len = strlen (krb5kcmd1);
rc = strncmp (buf, krb5kcmd1, buflen >= len ? len : buflen);
if (rc)
{
len = strlen (krb5kcmd2);
rc = strncmp (buf, krb5kcmd2, buflen >= len ? len : buflen);
if (rc)
{
*err_msg = "Protocol version not supported";
return 1;
}
*protoversion = 2;
}
else
*protoversion = 1;
free (buf);
/* Authentication type is ok */
write (infd, "\0", 1);
/* Read Authentication request from client */
rc = read (infd, &len, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error reading authentication request size";
return 1;
}
buflen = ntohl (len);
buf = malloc (buflen);
if (!buf)
{
*err_msg = "Not enough memory";
return 1;
}
rc = read (infd, buf, buflen);
if (rc != buflen)
{
*err_msg = "Error reading authentication request";
return 1;
}
/* Create Authentication context */
rc = shishi_ap_nosubkey (*handle, ap);
if (rc != SHISHI_OK)
return rc;
/* Store request in context */
shishi_ap_req_der_set (*ap, buf, buflen);
if (rc != SHISHI_OK)
return rc;
free (buf);
/* Process authentication request */
rc = shishi_ap_req_process (*ap, key);
if (rc != SHISHI_OK)
return rc;
# ifdef ENCRYPTION
/* extract subkey if present from ap exchange for secure connection */
if (*protoversion == 2)
{
*enckey = NULL;
shishi_authenticator_get_subkey (*handle,
shishi_ap_authenticator (*ap), enckey);
}
# endif
/* Get authenticator checksum */
rc = shishi_authenticator_cksum (*handle,
shishi_ap_authenticator (*ap),
cksumtype, cksum, cksumlen);
if (rc != SHISHI_OK)
return rc;
/* User is authenticated. */
error = 0;
write (infd, &error, sizeof (int));
/* Authenticate ourself to client, if request */
if (shishi_apreq_mutual_required_p (*handle, shishi_ap_req (*ap)))
{
rc = shishi_ap_rep_der (*ap, &out, &outlen);
if (rc != SHISHI_OK)
return rc;
outlen = htonl (outlen);
rc = write (infd, &outlen, sizeof (int));
if (rc != sizeof (int))
{
*err_msg = "Error sending AP-REP";
free (out);
return 1;
}
rc = write (infd, out, ntohl (outlen));
if (rc != ntohl (outlen))
{
*err_msg = "Error sending AP-REP";
free (out);
return 1;
}
free (out);
/* We are authenticated to client */
}
# ifdef ENCRYPTION
if (*protoversion == 1)
{
Shishi_tkt *tkt;
tkt = shishi_ap_tkt (*ap);
if (tkt == NULL)
{
*err_msg = "Could not get tkt from AP-REQ";
return 1;
}
rc = shishi_encticketpart_get_key (*handle,
shishi_tkt_encticketpart (tkt),
enckey);
if (rc != SHISHI_OK)
return rc;
}
# endif
return SHISHI_OK;
}
