JavaScript is required to for searching.
Skip Navigation Links
Exit Print View
Developer's Guide to Oracle Solaris 10 Security     Oracle Solaris 10 1/13 Information Library
search filter icon
search icon

Document Information

Preface

1.  Oracle Solaris Security for Developers (Overview)

2.  Developing Privileged Applications

3.  Writing PAM Applications and Services

4.  Writing Applications That Use GSS-API

5.  GSS-API Client Example

6.  GSS-API Server Example

7.  Writing Applications That Use SASL

8.  Introduction to the Oracle Solaris Cryptographic Framework

9.  Writing User-Level Cryptographic Applications and Providers

10.  Using the Smart Card Framework

A.  Sample C-Based GSS-API Programs

Client-Side Application

Server-Side Application

Miscellaneous GSS-API Sample Functions

B.  GSS-API Reference

C.  Specifying an OID

D.  Source Code for SASL Example

E.  SASL Reference Tables

F.  Packaging and Signing Cryptographic Providers

Glossary

Index

Client-Side Application

The source code for the client-side program, gss_client, is provided in the following example.

Example A-1 Complete Listing of gss-client.c Sample Program

/*
 * 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: /cvs/krbdev/krb5/src/appl/gss-sample/gss-client.c,\
v 1.16 1998/10/30 02:52:03 marc Exp $";
#endif

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.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.h>
#include <gssapi/gssapi_ext.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 descriptor, 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, sizeof(saddr.sin_addr));
     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, oid,
                             gss_context, ret_flags)
     int s;
     char *service_name;
     gss_OID oid;
     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, init_sec_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_C_NT_HOSTBASED_SERVICE, &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(&init_sec_min_stat,
                                    GSS_C_NO_CREDENTIAL,
                                    gss_context,
                                    target_name,
                                    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 (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_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
               display_status("initializing context", maj_stat,
                              init_sec_min_stat);
               (void) gss_release_name(&min_stat, &target_name);
               if (*gss_context == GSS_C_NO_CONTEXT)
                       gss_delete_sec_context(&min_stat, gss_context,
                                              GSS_C_NO_BUFFER);
               return -1;
          }
          
          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;

    if (in_buf->length == 0) {
        in_buf->value = NULL;
        return;
    }

    if ((in_buf->value = malloc(in_buf->length)) == 0) {
        fprintf(stderr, \
            "Couldn't allocate %d byte buffer for reading file\n",
            in_buf->length);
        exit(1);
    }

    /* this code used to check for incomplete reads, but you can't get
       an incomplete read on any file for which fstat() is meaningful */

    count = read(fd, in_buf->value, in_buf->length);
    if (count < 0) {
        perror("read");
        exit(1);
    }
    if (count < in_buf->length)
        fprintf(stderr, "Warning, only read in %d bytes, expected %d\n",
                count, in_buf->length);
}

/*
 * 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, oid, service_name, deleg_flag, msg, use_file)
     char *host;
     u_short port;
     gss_OID oid;
     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, oid,
         &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);
     }

     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;
}

static void parse_oid(char *mechanism, gss_OID *oid)
{
    char        *mechstr = 0, *cp;
    gss_buffer_desc tok;
    OM_uint32 maj_stat, min_stat;
    
    if (isdigit(mechanism[0])) {
        mechstr = malloc(strlen(mechanism)+5);
        if (!mechstr) {
            printf("Couldn't allocate mechanism scratch!\n");
            return;
        }
        sprintf(mechstr, "{ %s }", mechanism);
        for (cp = mechstr; *cp; cp++)
            if (*cp == '.')
                *cp = ' ';
        tok.value = mechstr;
    } else
        tok.value = mechanism;
    tok.length = strlen(tok.value);
    maj_stat = gss_str_to_oid(&min_stat, &tok, oid);
    if (maj_stat != GSS_S_COMPLETE) {
        display_status("str_to_oid", maj_stat, min_stat);
        return;
    }
    if (mechstr)
        free(mechstr);
}

int main(argc, argv)
     int argc;
     char **argv;
{
     char *service_name, *server_host, *msg;
     char *mechanism = 0;
     u_short port = 4444;
     int use_file = 0;
     OM_uint32 deleg_flag = 0, min_stat;
     gss_OID oid = GSS_C_NULL_OID;
     
     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, "-mech") == 0) {
               argc--; argv++;
               if (!argc) usage();
               mechanism = *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 (mechanism)
         parse_oid(mechanism, &oid);

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

     if (oid != GSS_C_NULL_OID)
         (void) gss_release_oid(&min_stat, &oid);
         
     return 0;
}