The following is the source code for the server-side program,gss_server.
/* * 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-server.c, \ v 1.21 1998/12/22 \04:10:08 tytso Exp $";#endif#include <stdio.h>#include <sys/types.h>#include <sys/socket.h>#include <sys/time.h>#include <netinet/in.h>#include <unistd.h>#include <stdlib.h>#include <ctype.h>#include <gssapi/gssapi.h>#include <gssapi/gssapi_ext.h>#include <gss-misc.h>#include <string.h>void usage(){ fprintf(stderr, "Usage: gss-server [-port port] [-verbose]\n"); fprintf(stderr, " [-inetd] [-logfile file] [service_name]\n"); exit(1);}FILE *log;int verbose = 0;/* * Function: server_acquire_creds * * Purpose: imports a service name and acquires credentials for it * * Arguments: * * service_name (r) the ASCII service name * server_creds (w) the GSS-API service credentials * * Returns: 0 on success, -1 on failure * * Effects: * * The service name is imported with gss_import_name, and service * credentials are acquired with gss_acquire_cred. If either operation * fails, an error message is displayed and -1 is returned; otherwise, * 0 is returned. */int server_acquire_creds(service_name, server_creds) char *service_name; gss_cred_id_t *server_creds;{ gss_buffer_desc name_buf; gss_name_t server_name; OM_uint32 maj_stat, min_stat; name_buf.value = service_name; name_buf.length = strlen(name_buf.value) + 1; maj_stat = gss_import_name(&min_stat, &name_buf, (gss_OID) GSS_C_NT_HOSTBASED_SERVICE, &server_name); if (maj_stat != GSS_S_COMPLETE) { display_status("importing name", maj_stat, min_stat); return -1; } maj_stat = gss_acquire_cred(&min_stat, server_name, 0, GSS_C_NULL_OID_SET, GSS_C_ACCEPT, server_creds, NULL, NULL); if (maj_stat != GSS_S_COMPLETE) { display_status("acquiring credentials", maj_stat, min_stat); return -1; } (void) gss_release_name(&min_stat, &server_name); return 0;}/* * Function: server_establish_context * * Purpose: establishes a GSS-API context as a specified service with * an incoming client, and returns the context handle and associated * client name * * Arguments: * * s (r) an established TCP connection to the client * service_creds (r) server credentials, from gss_acquire_cred * context (w) the established GSS-API context * client_name (w) the client's ASCII name * * Returns: 0 on success, -1 on failure * * Effects: * * Any valid client request is accepted. If a context is established, * its handle is returned in context and the client name is returned * in client_name and 0 is returned. If unsuccessful, an error * message is displayed and -1 is returned. */int server_establish_context(s, server_creds, context, client_name, \ ret_flags) int s; gss_cred_id_t server_creds; gss_ctx_id_t *context; gss_buffer_t client_name; OM_uint32 *ret_flags;{ gss_buffer_desc send_tok, recv_tok; gss_name_t client; gss_OID doid; OM_uint32 maj_stat, min_stat, acc_sec_min_stat; gss_buffer_desc oid_name; *context = GSS_C_NO_CONTEXT; do { if (recv_token(s, &recv_tok) < 0) return -1; if (verbose && log) { fprintf(log, "Received token (size=%d): \n", recv_tok.length); print_token(&recv_tok); } maj_stat = gss_accept_sec_context(&acc_sec_min_stat, context, server_creds, &recv_tok, GSS_C_NO_CHANNEL_BINDINGS, &client, &doid, &send_tok, ret_flags, NULL, /* ignore time_rec */ NULL); /* ignore del_cred_handle */ (void) gss_release_buffer(&min_stat, &recv_tok); if (send_tok.length != 0) { if (verbose && log) { fprintf(log, "Sending accept_sec_context token (size=%d):\n", send_tok.length); print_token(&send_tok); } if (send_token(s, &send_tok) < 0) { fprintf(log, "failure sending token\n"); return -1; } (void) gss_release_buffer(&min_stat, &send_tok); } if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) { display_status("accepting context", maj_stat, acc_sec_min_stat); if (*context == GSS_C_NO_CONTEXT) gss_delete_sec_context(&min_stat, context, GSS_C_NO_BUFFER); return -1; } if (verbose && log) { if (maj_stat == GSS_S_CONTINUE_NEEDED) fprintf(log, "continue needed...\n"); else fprintf(log, "\n"); fflush(log); } } while (maj_stat == GSS_S_CONTINUE_NEEDED); /* display the flags */ display_ctx_flags(*ret_flags); if (verbose && log) { maj_stat = gss_oid_to_str(&min_stat, doid, &oid_name); if (maj_stat != GSS_S_COMPLETE) { display_status("converting oid->string", maj_stat, min_stat); return -1; } fprintf(log, "Accepted connection using mechanism OID %.*s.\n", (int) oid_name.length, (char *) oid_name.value); (void) gss_release_buffer(&min_stat, &oid_name); } maj_stat = gss_display_name(&min_stat, client, client_name, &doid); if (maj_stat != GSS_S_COMPLETE) { display_status("displaying name", maj_stat, min_stat); return -1; } maj_stat = gss_release_name(&min_stat, &client); if (maj_stat != GSS_S_COMPLETE) { display_status("releasing name", maj_stat, min_stat); return -1; } return 0;}/* * Function: create_socket * * Purpose: Opens a listening TCP socket. * * Arguments: * * port (r) the port number on which to listen * * Returns: the listening socket file descriptor, or -1 on failure * * Effects: * * A listening socket on the specified port is created and returned. * On error, an error message is displayed and -1 is returned. */int create_socket(port) u_short port;{ struct sockaddr_in saddr; int s; int on = 1; saddr.sin_family = AF_INET; saddr.sin_port = htons(port); saddr.sin_addr.s_addr = INADDR_ANY; if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) { perror("creating socket"); return -1; } /* Let the socket be reused right away */ (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on)); if (bind(s, (struct sockaddr *) &saddr, sizeof(saddr)) < 0) { perror("binding socket"); (void) close(s); return -1; } if (listen(s, 5) < 0) { perror("listening on socket"); (void) close(s); return -1; } return s;}static float timeval_subtract(tv1, tv2) struct timeval *tv1, *tv2;{ return ((tv1->tv_sec - tv2->tv_sec) + ((float) (tv1->tv_usec - tv2->tv_usec)) / 1000000);}/* * Yes, yes, this isn't the best place for doing this test. * DO NOT REMOVE THIS UNTIL A BETTER TEST HAS BEEN WRITTEN, THOUGH. * -TYT */int test_import_export_context(context) gss_ctx_id_t *context;{ OM_uint32 min_stat, maj_stat; gss_buffer_desc context_token, copied_token; struct timeval tm1, tm2; /* * Attempt to save and then restore the context. */ gettimeofday(&tm1, (struct timezone *)0); maj_stat = gss_export_sec_context(&min_stat, context, \ &context_token); if (maj_stat != GSS_S_COMPLETE) { display_status("exporting context", maj_stat, min_stat); return 1; } gettimeofday(&tm2, (struct timezone *)0); if (verbose && log) fprintf(log, "Exported context: %d bytes, %7.4f seconds\n", context_token.length, timeval_subtract(&tm2, &tm1)); copied_token.length = context_token.length; copied_token.value = malloc(context_token.length); if (copied_token.value == 0) { fprintf(log, "Couldn't allocate memory to copy context \ token.\n"); return 1; } memcpy(copied_token.value, context_token.value, \ copied_token.length); maj_stat = gss_import_sec_context(&min_stat, &copied_token, \ context); if (maj_stat != GSS_S_COMPLETE) { display_status("importing context", maj_stat, min_stat); return 1; } free(copied_token.value); gettimeofday(&tm1, (struct timezone *)0); if (verbose && log) fprintf(log, "Importing context: %7.4f seconds\n", timeval_subtract(&tm1, &tm2)); (void) gss_release_buffer(&min_stat, &context_token); return 0;}/* * Function: sign_server * * Purpose: Performs the "sign" service. * * Arguments: * * s (r) a TCP socket on which a connection has been * accept()ed * service_name (r) the ASCII name of the GSS-API service to * establish a context as * * Returns: -1 on error * * Effects: * * sign_server establishes a context, and performs a single sign request. * * A sign request is a single GSS-API sealed token. The token is * unsealed and a signature block, produced with gss_sign, is returned * to the sender. The context is then destroyed and the connection * closed. * * If any error occurs, -1 is returned. */int sign_server(s, server_creds) int s; gss_cred_id_t server_creds;{ gss_buffer_desc client_name, xmit_buf, msg_buf; gss_ctx_id_t context; OM_uint32 maj_stat, min_stat; int i, conf_state, ret_flags; char *cp; /* Establish a context with the client */ if (server_establish_context(s, server_creds, &context, &client_name, &ret_flags) < 0) return(-1); printf("Accepted connection: \"%.*s\"\n", (int) client_name.length, (char *) client_name.value); (void) gss_release_buffer(&min_stat, &client_name); for (i=0; i < 3; i++) if (test_import_export_context(&context)) return -1; /* Receive the sealed message token */ if (recv_token(s, &xmit_buf) < 0) return(-1); if (verbose && log) { fprintf(log, "Sealed message token:\n"); print_token(&xmit_buf); } maj_stat = gss_unwrap(&min_stat, context, &xmit_buf, &msg_buf, &conf_state, (gss_qop_t *) NULL); if (maj_stat != GSS_S_COMPLETE) { display_status("unsealing message", maj_stat, min_stat); return(-1); } else if (! conf_state) { fprintf(stderr, "Warning! Message not encrypted.\n"); } (void) gss_release_buffer(&min_stat, &xmit_buf); fprintf(log, "Received message: "); cp = msg_buf.value; if ((isprint(cp[0]) || isspace(cp[0])) && (isprint(cp[1]) || isspace(cp[1]))) { fprintf(log, "\"%.*s\"\n", msg_buf.length, msg_buf.value); } else { printf("\n"); print_token(&msg_buf); } /* Produce a signature block for the message */ maj_stat = gss_get_mic(&min_stat, context, GSS_C_QOP_DEFAULT, &msg_buf, &xmit_buf); if (maj_stat != GSS_S_COMPLETE) { display_status("signing message", maj_stat, min_stat); return(-1); } (void) gss_release_buffer(&min_stat, &msg_buf); /* Send the signature block to the client */ if (send_token(s, &xmit_buf) < 0) return(-1); (void) gss_release_buffer(&min_stat, &xmit_buf); /* Delete context */ maj_stat = gss_delete_sec_context(&min_stat, &context, NULL); if (maj_stat != GSS_S_COMPLETE) { display_status("deleting context", maj_stat, min_stat); return(-1); } fflush(log); return(0);}intmain(argc, argv) int argc; char **argv;{ char *service_name; gss_cred_id_t server_creds; OM_uint32 min_stat; u_short port = 4444; int s; int once = 0; int do_inetd = 0; log = stdout; display_file = stdout; argc--; argv++; while (argc) { if (strcmp(*argv, "-port") == 0) { argc--; argv++; if (!argc) usage(); port = atoi(*argv); } else if (strcmp(*argv, "-verbose") == 0) { verbose = 1; } else if (strcmp(*argv, "-once") == 0) { once = 1; } else if (strcmp(*argv, "-inetd") == 0) { do_inetd = 1; } else if (strcmp(*argv, "-logfile") == 0) { argc--; argv++; if (!argc) usage(); log = fopen(*argv, "a"); display_file = log; if (!log) { perror(*argv); exit(1); } } else break; argc--; argv++; } if (argc != 1) usage(); if ((*argv)[0] == '-') usage(); service_name = *argv; if (server_acquire_creds(service_name, &server_creds) < 0) return -1; if (do_inetd) { close(1); close(2); sign_server(0, server_creds); close(0); } else { int stmp; if ((stmp = create_socket(port)) >= 0) { do { /* Accept a TCP connection */ if ((s = accept(stmp, NULL, 0)) < 0) { perror("accepting connection"); continue; } /* this return value is not checked, because there's not really anything to do if it fails */ sign_server(s, server_creds); close(s); } while (!once); close(stmp); } } (void) gss_release_cred(&min_stat, &server_creds); /*NOTREACHED*/ (void) close(s); return 0;}