/*
 * Copyright 1994 by OpenVision Technologies, Inc.
 * 
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of OpenVision not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. OpenVision makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 * 
 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#if !defined(lint) && !defined(__CODECENTER__)
static char *rcsid = "$Header$";
#endif

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <gssapi/gssapi_generic.h>
#include "gss-misc.h"

void usage()
{
     fprintf(stderr, "Usage: gss-client [-port port] [-d] host service \
msg\n");
     exit(1);
}

/*
 * Function: connect_to_server
 *
 * Purpose: Opens a TCP connection to the name host and port.
 *
 * Arguments:
 *
 * 	host		(r) the target host name
 * 	port		(r) the target port, in host byte order
 *
 * Returns: the established socket file desciptor, or -1 on failure
 *
 * Effects:
 *
 * The host name is resolved with gethostbyname(), and the socket is
 * opened and connected.  If an error occurs, an error message is
 * displayed and -1 is returned.
 */
int connect_to_server(host, port)
     char *host;
     u_short port;
{
     struct sockaddr_in saddr;
     struct hostent *hp;
     int s;
     
     if ((hp = gethostbyname(host)) == NULL) {
	  fprintf(stderr, "Unknown host: %s\n", host);
	  return -1;
     }
     
     saddr.sin_family = hp->h_addrtype;
     memcpy((char *)&saddr.sin_addr, hp->h_addr, hp->h_length);
     saddr.sin_port = htons(port);

     if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
	  perror("creating socket");
	  return -1;
     }
     if (connect(s, (struct sockaddr *)&saddr, sizeof(saddr)) < 0) {
	  perror("connecting to server");
	  (void) close(s);
	  return -1;
     }
     return s;
}

/*
 * Function: client_establish_context
 *
 * Purpose: establishes a GSS-API context with a specified service and
 * returns the context handle
 *
 * Arguments:
 *
 * 	s		(r) an established TCP connection to the service
 * 	service_name	(r) the ASCII service name of the service
 * 	context		(w) the established GSS-API context
 *	ret_flags	(w) the returned flags from init_sec_context
 *
 * Returns: 0 on success, -1 on failure
 *
 * Effects:
 * 
 * service_name is imported as a GSS-API name and a GSS-API context is
 * established with the corresponding service; the service should be
 * listening on the TCP connection s.  The default GSS-API mechanism
 * is used, and mutual authentication and replay detection are
 * requested.
 * 
 * If successful, the context handle is returned in context.  If
 * unsuccessful, the GSS-API error messages are displayed on stderr
 * and -1 is returned.
 */
int client_establish_context(s, service_name, deleg_flag,
			     gss_context, ret_flags)
     int s;
     char *service_name;
     OM_uint32 deleg_flag;
     gss_ctx_id_t *gss_context;
     OM_uint32 *ret_flags;
{
     gss_buffer_desc send_tok, recv_tok, *token_ptr;
     gss_name_t target_name;
     OM_uint32 maj_stat, min_stat;

     /*
      * Import the name into target_name.  Use send_tok to save
      * local variable space.
      */
     send_tok.value = service_name;
     send_tok.length = strlen(service_name) + 1;
     maj_stat = gss_import_name(&min_stat, &send_tok,
				(gss_OID) gss_nt_service_name, &target_name);
     if (maj_stat != GSS_S_COMPLETE) {
	  display_status("parsing name", maj_stat, min_stat);
	  return -1;
     }
     
     /*
      * Perform the context-establishement loop.
      *
      * On each pass through the loop, token_ptr points to the token
      * to send to the server (or GSS_C_NO_BUFFER on the first pass).
      * Every generated token is stored in send_tok which is then
      * transmitted to the server; every received token is stored in
      * recv_tok, which token_ptr is then set to, to be processed by
      * the next call to gss_init_sec_context.
      * 
      * GSS-API guarantees that send_tok's length will be non-zero
      * if and only if the server is expecting another token from us,
      * and that gss_init_sec_context returns GSS_S_CONTINUE_NEEDED if
      * and only if the server has another token to send us.
      */
     
     token_ptr = GSS_C_NO_BUFFER;
     *gss_context = GSS_C_NO_CONTEXT;

     do {
	  maj_stat =
	       gss_init_sec_context(&min_stat,
				    GSS_C_NO_CREDENTIAL,
				    gss_context,
				    target_name,
				    GSS_C_NULL_OID,
				    GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG |
							deleg_flag,
				    0,
				    NULL,	/* no channel bindings */
				    token_ptr,
				    NULL,	/* ignore mech type */
				    &send_tok,
				    ret_flags,
				    NULL);	/* ignore time_rec */

	  if (token_ptr != GSS_C_NO_BUFFER)
	       (void) gss_release_buffer(&min_stat, &recv_tok);

	  if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
	       display_status("initializing context", maj_stat, min_stat);
	       (void) gss_release_name(&min_stat, &target_name);
	       return -1;
	  }

	  if (send_tok.length != 0) {
	       printf("Sending init_sec_context token (size=%d)...",
		     send_tok.length);
	       if (send_token(s, &send_tok) < 0) {
		    (void) gss_release_buffer(&min_stat, &send_tok);
		    (void) gss_release_name(&min_stat, &target_name);
		    return -1;
	       }
	  }
	  (void) gss_release_buffer(&min_stat, &send_tok);
	  
	  if (maj_stat == GSS_S_CONTINUE_NEEDED) {
	       printf("continue needed...");
	       if (recv_token(s, &recv_tok) < 0) {
		    (void) gss_release_name(&min_stat, &target_name);
		    return -1;
	       }
	       token_ptr = &recv_tok;
	  }
	  printf("\n");
     } while (maj_stat == GSS_S_CONTINUE_NEEDED);

     (void) gss_release_name(&min_stat, &target_name);
     return 0;
}

void read_file(file_name, in_buf)
    char		*file_name;
    gss_buffer_t	in_buf;
{
    int fd, bytes_in, count;
    struct stat stat_buf;
    
    if ((fd = open(file_name, O_RDONLY, 0)) < 0) {
	perror("open");
	fprintf(stderr, "Couldn't open file %s\n", file_name);
	exit(1);
    }
    if (fstat(fd, &stat_buf) < 0) {
	perror("fstat");
	exit(1);
    }
    in_buf->length = stat_buf.st_size;
    in_buf->value = malloc(in_buf->length);
    if (in_buf->value == 0) {
	fprintf(stderr, "Couldn't allocate %d byte buffer for reading file\n",
		in_buf->length);
	exit(1);
    }
    memset(in_buf->value, 0, in_buf->length);
    for (bytes_in = 0; bytes_in < in_buf->length; bytes_in += count) {
	count = read(fd, in_buf->value, in_buf->length);
	if (count < 0) {
	    perror("read");
	    exit(1);
	}
	if (count == 0)
	    break;
    }
    if (bytes_in != count)
	fprintf(stderr, "Warning, only read in %d bytes, expected %d\n",
		bytes_in, count);
}

/*
 * Function: call_server
 *
 * Purpose: Call the "sign" service.
 *
 * Arguments:
 *
 * 	host		(r) the host providing the service
 * 	port		(r) the port to connect to on host
 * 	service_name	(r) the GSS-API service name to authenticate to	
 * 	msg		(r) the message to have "signed"
 *
 * Returns: 0 on success, -1 on failure
 *
 * Effects:
 * 
 * call_server opens a TCP connection to <host:port> and establishes a
 * GSS-API context with service_name over the connection.  It then
 * seals msg in a GSS-API token with gss_seal, sends it to the server,
 * reads back a GSS-API signature block for msg from the server, and
 * verifies it with gss_verify.  -1 is returned if any step fails,
 * otherwise 0 is returned.
 */
int call_server(host, port, service_name, deleg_flag, msg, use_file)
     char *host;
     u_short port;
     char *service_name;
     OM_uint32 deleg_flag;
     char *msg;
     int use_file;
{
     gss_ctx_id_t context;
     gss_buffer_desc in_buf, out_buf;
     int s, state;
     OM_uint32 ret_flags;
     OM_uint32 maj_stat, min_stat;
     gss_name_t		src_name, targ_name;
     gss_buffer_desc	sname, tname;
     OM_uint32		lifetime;
     gss_OID		mechanism, name_type;
     int		is_local;
     OM_uint32		context_flags;
     int		is_open;
     gss_qop_t		qop_state;
     gss_OID_set	mech_names;
     gss_buffer_desc	oid_name;
     size_t	i;

     /* Open connection */
     if ((s = connect_to_server(host, port)) < 0)
	  return -1;

     /* Establish context */
     if (client_establish_context(s, service_name, deleg_flag, &context,
				  &ret_flags) < 0) {
	  (void) close(s);
	  return -1;
     }

     /* display the flags */
     display_ctx_flags(ret_flags);

     /* Get context information */
     maj_stat = gss_inquire_context(&min_stat, context,
				    &src_name, &targ_name, &lifetime,
				    &mechanism, &context_flags,
				    &is_local,
				    &is_open);
     if (maj_stat != GSS_S_COMPLETE) {
	 display_status("inquiring context", maj_stat, min_stat);
	 return -1;
     }

     maj_stat = gss_display_name(&min_stat, src_name, &sname,
				 &name_type);
     if (maj_stat != GSS_S_COMPLETE) {
	 display_status("displaying source name", maj_stat, min_stat);
	 return -1;
     }
     maj_stat = gss_display_name(&min_stat, targ_name, &tname,
				 (gss_OID *) NULL);
     if (maj_stat != GSS_S_COMPLETE) {
	 display_status("displaying target name", maj_stat, min_stat);
	 return -1;
     }
     fprintf(stderr, "\"%.*s\" to \"%.*s\", lifetime %d, flags %x, %s, %s\n",
	     (int) sname.length, (char *) sname.value,
	     (int) tname.length, (char *) tname.value, lifetime,
	     context_flags,
	     (is_local) ? "locally initiated" : "remotely initiated",
	     (is_open) ? "open" : "closed");

     (void) gss_release_name(&min_stat, &src_name);
     (void) gss_release_name(&min_stat, &targ_name);
     (void) gss_release_buffer(&min_stat, &sname);
     (void) gss_release_buffer(&min_stat, &tname);

     maj_stat = gss_oid_to_str(&min_stat,
			       name_type,
			       &oid_name);
     if (maj_stat != GSS_S_COMPLETE) {
	 display_status("converting oid->string", maj_stat, min_stat);
	 return -1;
     }
     fprintf(stderr, "Name type of source name is %.*s.\n",
	     (int) oid_name.length, (char *) oid_name.value);
     (void) gss_release_buffer(&min_stat, &oid_name);

     /* Now get the names supported by the mechanism */
     maj_stat = gss_inquire_names_for_mech(&min_stat,
					   mechanism,
					   &mech_names);
     if (maj_stat != GSS_S_COMPLETE) {
	 display_status("inquiring mech names", maj_stat, min_stat);
	 return -1;
     }

     maj_stat = gss_oid_to_str(&min_stat,
			       mechanism,
			       &oid_name);
     if (maj_stat != GSS_S_COMPLETE) {
	 display_status("converting oid->string", maj_stat, min_stat);
	 return -1;
     }
     fprintf(stderr, "Mechanism %.*s supports %d names\n",
	     (int) oid_name.length, (char *) oid_name.value,
	     mech_names->count);
     (void) gss_release_buffer(&min_stat, &oid_name);

     for (i=0; i<mech_names->count; i++) {
	 maj_stat = gss_oid_to_str(&min_stat,
				   &mech_names->elements[i],
				   &oid_name);
	 if (maj_stat != GSS_S_COMPLETE) {
	     display_status("converting oid->string", maj_stat, min_stat);
	     return -1;
	 }
	 fprintf(stderr, "  %d: %.*s\n", i,
		 (int) oid_name.length, (char *) oid_name.value);

	 (void) gss_release_buffer(&min_stat, &oid_name);
     }
     (void) gss_release_oid_set(&min_stat, &mech_names);

     if (use_file) {
	 read_file(msg, &in_buf);
     } else {
	 /* Seal the message */
	 in_buf.value = msg;
	 in_buf.length = strlen(msg) + 1;
     }

     maj_stat = gss_wrap(&min_stat, context, 1, GSS_C_QOP_DEFAULT,
			 &in_buf, &state, &out_buf);
     if (maj_stat != GSS_S_COMPLETE) {
	  display_status("sealing message", maj_stat, min_stat);
	  (void) close(s);
	  (void) gss_delete_sec_context(&min_stat, &context, GSS_C_NO_BUFFER);
	  return -1;
     } else if (! state) {
	  fprintf(stderr, "Warning!  Message not encrypted.\n");
     }

     /* Send to server */
     if (send_token(s, &out_buf) < 0) {
	  (void) close(s);
	  (void) gss_delete_sec_context(&min_stat, &context, GSS_C_NO_BUFFER);
	  return -1;
     }
     (void) gss_release_buffer(&min_stat, &out_buf);

     /* Read signature block into out_buf */
     if (recv_token(s, &out_buf) < 0) {
	  (void) close(s);
	  (void) gss_delete_sec_context(&min_stat, &context, GSS_C_NO_BUFFER);
	  return -1;
     }

     /* Verify signature block */
     maj_stat = gss_verify_mic(&min_stat, context, &in_buf,
			       &out_buf, &qop_state);
     if (maj_stat != GSS_S_COMPLETE) {
	  display_status("verifying signature", maj_stat, min_stat);
	  (void) close(s);
	  (void) gss_delete_sec_context(&min_stat, &context, GSS_C_NO_BUFFER);
	  return -1;
     }
     (void) gss_release_buffer(&min_stat, &out_buf);

     if (use_file)
	 free(in_buf.value);

     printf("Signature verified.\n");

     /* Delete context */
     maj_stat = gss_delete_sec_context(&min_stat, &context, &out_buf);
     if (maj_stat != GSS_S_COMPLETE) {
	  display_status("deleting context", maj_stat, min_stat);
	  (void) close(s);
	  (void) gss_delete_sec_context(&min_stat, &context, GSS_C_NO_BUFFER);
	  return -1;
     }

     (void) gss_release_buffer(&min_stat, &out_buf);
     (void) close(s);
     return 0;
}

int main(argc, argv)
     int argc;
     char **argv;
{
     char *service_name, *server_host, *msg;
     u_short port = 4444;
     int use_file = 0;
     OM_uint32 deleg_flag = 0;
     
     display_file = stdout;

     /* Parse arguments. */
     argc--; argv++;
     while (argc) {
	  if (strcmp(*argv, "-port") == 0) {
	       argc--; argv++;
	       if (!argc) usage();
	       port = atoi(*argv);
	  } else if (strcmp(*argv, "-d") == 0) {
	       deleg_flag = GSS_C_DELEG_FLAG;
	  } else if (strcmp(*argv, "-f") == 0) {
	       use_file = 1;
	  } else 
	       break;
	  argc--; argv++;
     }
     if (argc != 3)
	  usage();

     server_host = *argv++;
     service_name = *argv++;
     msg = *argv++;

     if (call_server(server_host, port, service_name,
		     deleg_flag, msg, use_file) < 0)
	  exit(1);

     return 0;
}