/*	$OpenBSD: ksrvutil.c,v 1.6 1999/05/23 17:19:24 aaron Exp $	*/
/* $KTH: ksrvutil.c,v 1.39 1997/05/02 14:28:52 assar Exp $ */

/* 
 *  Copyright (C) 1989 by the Massachusetts Institute of Technology
 *
 *  Export of this software from the United States of America is assumed
 *  to require a specific license from the United States Government.
 *  It is the responsibility of any person or organization contemplating
 *  export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 *
 */

/*
 * list and update contents of srvtab files
 */

/*
 * ksrvutil
 * list and update the contents of srvtab files
 */

#include "kadm_locl.h"

#include "ksrvutil.h"

#ifdef NOENCRYPTION
#define read_long_pw_string placebo_read_pw_string
#else /* NOENCRYPTION */
#define read_long_pw_string des_read_pw_string
#endif /* NOENCRYPTION */

#define SRVTAB_MODE 0600	/* rw------- */
#define PAD "  "
#define VNO_HEADER "Version"
#define VNO_FORMAT "%4d   "
#define KEY_HEADER "       Key       " /* 17 characters long */
#define PRINC_HEADER "  Principal\n"
#define PRINC_FORMAT "%s"

char u_name[ANAME_SZ];
char u_inst[INST_SZ];
char u_realm[REALM_SZ];

char progname[] = "ksrvutil";

int destroyp = FALSE;		/* Should the ticket file be destroyed? */

static unsigned short
get_mode(char *filename)
{
    struct stat statbuf;
    unsigned short mode;

    memset(&statbuf, 0, sizeof(statbuf));
    
    if (stat(filename, &statbuf) < 0) 
	mode = SRVTAB_MODE;
    else
	mode = statbuf.st_mode;

    return(mode);
}

static void
copy_keyfile(char *keyfile, char *backup_keyfile)
{
    int keyfile_fd;
    int backup_keyfile_fd;
    int keyfile_mode;
    char buf[BUFSIZ];		/* for copying keyfiles */
    int rcount;			/* for copying keyfiles */
    int try_again;
    
    memset(buf, 0, sizeof(buf));
    
    do {
	try_again = FALSE;
	if ((keyfile_fd = open(keyfile, O_RDONLY, 0)) < 0) {
	    if (errno != ENOENT)
		err (1, "read %s", keyfile);
	    else {
		try_again = TRUE;
		if ((keyfile_fd = 
		     open(keyfile, 
			  O_WRONLY | O_TRUNC | O_CREAT, SRVTAB_MODE)) < 0)
		    err(1, "create %s", keyfile);
		else
		    if (close(keyfile_fd) < 0)
			err (1, "close %s", keyfile);
	    }
	}
    } while(try_again);

    keyfile_mode = get_mode(keyfile);

    if ((backup_keyfile_fd = 
	 open(backup_keyfile, O_WRONLY | O_TRUNC | O_CREAT, 
	      keyfile_mode)) < 0)
	err (1, "write %s", backup_keyfile);
    do {
	if ((rcount = read(keyfile_fd, buf, sizeof(buf))) < 0)
	    err (1, "read %s", keyfile);
	if (rcount && (write(backup_keyfile_fd, buf, rcount) != rcount))
	    err (1, "write %s", backup_keyfile);
    } while (rcount);
    if (close(backup_keyfile_fd) < 0)
	err(1, "close %s", backup_keyfile);
    if (close(keyfile_fd) < 0)
	err(1, "close %s", keyfile);
}

void
leave(char *str, int x)
{
    if (str)
	fprintf(stderr, "%s\n", str);
    if (destroyp)
	 dest_tkt();
    exit(x);
}

void
safe_read_stdin(char *prompt, char *buf, size_t size)
{
    printf("%s", prompt);
    fflush(stdout);
    memset(buf, 0, size);
    if (read(0, buf, size - 1) < 0) {
	warn("read stdin");
	leave(NULL, 1);
    }
    buf[strlen(buf)-1] = 0;
}

void
safe_write(char *filename, int fd, void *buf, size_t len)
{
    if (write(fd, buf, len) != len) {
	warn("write %s", filename);
	close(fd);
	leave("In progress srvtab in this file.", 1);
    }
}

static int
yes_no(char *string, int dflt)
{
  char ynbuf[5];
  
  printf("%s (y,n) [%c]", string, dflt?'y':'n');
  for (;;) {
    safe_read_stdin("", ynbuf, sizeof(ynbuf));
    
    if ((ynbuf[0] == 'n') || (ynbuf[0] == 'N'))
      return(0);
    else if ((ynbuf[0] == 'y') || (ynbuf[0] == 'Y'))
      return(1);
    else if(ynbuf[0] == 0)
      return dflt;
    else {
      printf("Please enter 'y' or 'n': ");
      fflush(stdout);
    }
  }
}

int yn(char *string)
{
  return yes_no(string, 1);
}

int ny(char *string)
{
  return yes_no(string, 0);
}

static void
append_srvtab(char *filename, int fd, char *sname, char *sinst, char *srealm, unsigned char key_vno, unsigned char *key)
{
  /* Add one to append null */
    safe_write(filename, fd, sname, strlen(sname) + 1);
    safe_write(filename, fd, sinst, strlen(sinst) + 1);
    safe_write(filename, fd, srealm, strlen(srealm) + 1);
    safe_write(filename, fd, &key_vno, 1);
    safe_write(filename, fd, key, sizeof(des_cblock));
    fsync(fd);
}    

static void
print_key(unsigned char *key)
{
    int i;

    for (i = 0; i < 4; i++)
	printf("%02x", key[i]);
    printf(" ");
    for (i = 4; i < 8; i++)
	printf("%02x", key[i]);
}

static void
print_name(char *name, char *inst, char *realm)
{
    printf("%s", krb_unparse_name_long(name, inst, realm));
}

static int
get_svc_new_key(des_cblock *new_key, char *sname, char *sinst,
		char *srealm, char *keyfile)
{
    int status = KADM_SUCCESS;

    if (((status = krb_get_svc_in_tkt(sname, sinst, srealm, PWSERV_NAME,
				      KADM_SINST, 1, keyfile)) == KSUCCESS) &&
	((status = kadm_init_link(PWSERV_NAME, KRB_MASTER, srealm)) == 
	 KADM_SUCCESS)) {
#ifdef NOENCRYPTION
	memset(new_key, 0, sizeof(des_cblock));
	(*new_key)[0] = (unsigned char) 1;
#else /* NOENCRYPTION */
	des_new_random_key(new_key);
#endif /* NOENCRYPTION */
	return(KADM_SUCCESS);
    }
    
    return(status);
}

static void
get_key_from_password(des_cblock (*key), char *cellname)
{
    char password[MAX_KPW_LEN];	/* storage for the password */

    if (read_long_pw_string(password, sizeof(password)-1, "Password: ", 1))
	leave("Error reading password.", 1);

#ifdef NOENCRYPTION
    memset(key, 0, sizeof(des_cblock));
    (*key)[0] = (unsigned char) 1;
#else /* NOENCRYPTION */
    if (strlen(cellname) == 0)
      des_string_to_key(password, key);
    else
      afs_string_to_key(password, cellname, key);
#endif /* NOENCRYPTION */
    memset(password, 0, sizeof(password));
}    

static void
usage(void)
{
    fprintf(stderr, "Usage: ksrvutil [-f keyfile] [-i] [-k] ");
    fprintf(stderr, "[-p principal] [-r realm] ");
    fprintf(stderr, "[-c AFS cellname] ");
    fprintf(stderr, "{list | change | add | get}\n");
    fprintf(stderr, "   -i causes the program to ask for ");
    fprintf(stderr, "confirmation before changing keys.\n");
    fprintf(stderr, "   -k causes the key to printed for list or ");
    fprintf(stderr, "change.\n");
    exit(1);
}

int
main(int argc, char **argv)
{
    char sname[ANAME_SZ];	/* name of service */
    char sinst[INST_SZ];	/* instance of service */
    char srealm[REALM_SZ];	/* realm of service */
    unsigned char key_vno;	/* key version number */
    int status;			/* general purpose error status */
    des_cblock new_key;
    des_cblock old_key;
    char change_tkt[MAXPATHLEN]; /* Ticket to use for key change */
    char keyfile[MAXPATHLEN];	/* Original keyfile */
    char work_keyfile[MAXPATHLEN]; /* Working copy of keyfile */
    char backup_keyfile[MAXPATHLEN]; /* Backup copy of keyfile */
    unsigned short keyfile_mode; /* Protections on keyfile */
    int work_keyfile_fd = -1;	/* Initialize so that */
    int backup_keyfile_fd = -1;	/* compiler doesn't complain */
    char local_realm[REALM_SZ];	/* local kerberos realm */
    char cellname[1024];         /* AFS cell name */
    int c;
    int interactive = FALSE;
    int list = FALSE;
    int change = FALSE;
    int add = FALSE;
    int get = FALSE;
    int key = FALSE;		/* do we show keys? */
    int arg_entered = FALSE;
    int change_this_key = FALSE;
    char databuf[BUFSIZ];
    int first_printed = FALSE;	/* have we printed the first item? */
    
    memset(sname, 0, sizeof(sname));
    memset(sinst, 0, sizeof(sinst));
    memset(srealm, 0, sizeof(srealm));
    	  
    memset(change_tkt, 0, sizeof(change_tkt));
    memset(keyfile, 0, sizeof(keyfile));
    memset(work_keyfile, 0, sizeof(work_keyfile));
    memset(backup_keyfile, 0, sizeof(backup_keyfile));
    memset(local_realm, 0, sizeof(local_realm));
    memset(cellname, 0, sizeof(cellname));
    
    if (krb_get_default_principal(u_name, u_inst, u_realm) < 0)
	errx (1, "could not get default principal");

    /* This is used only as a default for adding keys */
    if (krb_get_lrealm(local_realm, 1) != KSUCCESS) {
	strncpy(local_realm, KRB_REALM, REALM_SZ - 1);
	local_realm[REALM_SZ - 1] = '\0';
    }
    
    while((c = getopt(argc, argv, "ikc:f:p:r:")) != -1) {
	 switch (c) {
	      case 'i':
	      interactive++;
	      break;
	      case 'k':
	      key++;
	      break;
	      case 'c':
	      strcpy(cellname, optarg);
	      break;
	      case 'f':
	      strcpy(keyfile, optarg);
	      break;
	      case 'p':
	      if((status = kname_parse (u_name, u_inst, u_realm, optarg)) !=
		 KSUCCESS)
		  errx (1, "principal %s: %s", optarg,
			krb_get_err_text(status));
	      break;
	      case 'r':
	      strcpy(u_realm, optarg);
	      break;
	      case '?':
	      usage();
	 }
    }
    if (optind >= argc)
	 usage();
    if (*u_realm == '\0')
	 strcpy (u_realm, local_realm);
    if (strcmp(argv[optind], "list") == 0) {
	 if (arg_entered)
	      usage();
	 else {
	      arg_entered++;
	      list++;
	 }
    }
    else if (strcmp(argv[optind], "change") == 0) {
	 if (arg_entered)
	      usage();
	 else {
	      arg_entered++;
	      change++;
	 }
    }
    else if (strcmp(argv[optind], "add") == 0) {
	 if (arg_entered)
	      usage();
	 else {
	      arg_entered++;
	      add++;
	 }
    }
    else if (strcmp(argv[optind], "get") == 0) {
	 if (arg_entered)
	      usage();
	 else {
	      arg_entered++;
	      get++;
	 }
    }
    else
	 usage();
    ++optind;
    
    if (!arg_entered)
	usage();

    if (!keyfile[0])
	strcpy(keyfile, KEYFILE);
    
    strcpy(work_keyfile, keyfile);
    strcpy(backup_keyfile, keyfile);
    
    if (change || add || get) {
	strcat(work_keyfile, ".work");
	strcat(backup_keyfile, ".old");
	
	copy_keyfile(keyfile, backup_keyfile);
    }
    
    if (add || get)
	copy_keyfile(backup_keyfile, work_keyfile);

    keyfile_mode = get_mode(keyfile);

    if (change || list)
	if ((backup_keyfile_fd = open(backup_keyfile, O_RDONLY, 0)) < 0)
	    err (1, "open %s", backup_keyfile);

    if (change) {
	if ((work_keyfile_fd = 
	     open(work_keyfile, O_WRONLY | O_CREAT | O_TRUNC, 
		  SRVTAB_MODE)) < 0)
	    err (1, "creat %s", work_keyfile);
    }
    else if (add) {
	if ((work_keyfile_fd =
	     open(work_keyfile, O_APPEND | O_WRONLY, SRVTAB_MODE)) < 0)
	    err (1, "open with append %s", work_keyfile );
    }
    else if (get) {
	if ((work_keyfile_fd =
	     open(work_keyfile, O_RDWR | O_CREAT, SRVTAB_MODE)) < 0)
	    err (1, "open for writing %s", work_keyfile);
    }
    
    if (change || list) {
	while ((getst(backup_keyfile_fd, sname, SNAME_SZ) > 0) &&
	       (getst(backup_keyfile_fd, sinst, INST_SZ) > 0) &&
	       (getst(backup_keyfile_fd, srealm, REALM_SZ) > 0) &&
	       (read(backup_keyfile_fd, &key_vno, 1) > 0) &&
	       (read(backup_keyfile_fd, old_key, sizeof(old_key)) > 0)) {
	    if (list) {
		if (!first_printed) {
		    printf(VNO_HEADER);
		    printf(PAD);
		    if (key) {
			printf(KEY_HEADER);
			printf(PAD);
		    }
		    printf(PRINC_HEADER);
		    first_printed = 1;
		}
		printf(VNO_FORMAT, key_vno);
		printf(PAD);
		if (key) {
		    print_key(old_key);
		    printf(PAD);
		}
		print_name(sname, sinst, srealm);
		printf("\n");
	    }
	    else if (change) {
		snprintf(change_tkt, sizeof(change_tkt),
			 TKT_ROOT "_ksrvutil.%u",
			 (unsigned)getpid());
		krb_set_tkt_string(change_tkt);
		destroyp = TRUE;

		printf("\nPrincipal: ");
		print_name(sname, sinst, srealm);
		printf("; version %d\n", key_vno);
		if (interactive)
		    change_this_key = yn("Change this key?");
		else if (change)
		    change_this_key = 1;
		else
		    change_this_key = 0;
		
		if (change_this_key)
		    printf("Changing to version %d.\n", key_vno + 1);
		else if (change)
		    printf("Not changing this key.\n");
		
		if (change_this_key) {
		    /*
		     * This is not a good choice of seed when/if the
		     * key has been compromised so we also use a
		     * random sequence number!
		     */
		    des_init_random_number_generator(&old_key);
#if 0 /* kth-krb has own addidtions to libdes */
		    {
		        des_cblock seqnum;
			des_generate_random_block(&seqnum);
			des_set_sequence_number((unsigned char *)&seqnum);
		    }
#endif
		    /* 
		     * Pick a new key and determine whether or not
		     * it is safe to change
		     */
		    if ((status = 
			 get_svc_new_key(&new_key, sname, sinst, 
					 srealm, keyfile)) == KADM_SUCCESS)
			key_vno++;
		    else {
		        memcpy(new_key, old_key, sizeof(new_key));
			warnx ("Key NOT changed: %s\n",
			       krb_get_err_text(status));
			change_this_key = FALSE;
		    }
		}
		else 
		    memcpy(new_key, old_key, sizeof(new_key));
		append_srvtab(work_keyfile, work_keyfile_fd, 
			      sname, sinst, srealm, key_vno, new_key);
		if (key && change_this_key) {
		    printf("Old key: ");
		    print_key(old_key);
		    printf("; new key: ");
		    print_key(new_key);
		    printf("\n");
		}
		if (change_this_key) {
		    if ((status = kadm_change_pw(new_key)) == KADM_SUCCESS) {
			printf("Key changed.\n");
			dest_tkt();
		    }
		    else {
			com_err(progname, status, 
				" attempting to change password.");
			dest_tkt();
			/* XXX This knows the format of a keyfile */
			if (lseek(work_keyfile_fd, -9, SEEK_CUR) >= 0) {
			    key_vno--;
			    safe_write(work_keyfile,
				       work_keyfile_fd, &key_vno, 1);
			    safe_write(work_keyfile, work_keyfile_fd,
				       old_key, sizeof(des_cblock));
			    fsync(work_keyfile_fd);
			    fprintf(stderr,"Key NOT changed.\n");
			} else {
			    warn ("Unable to revert keyfile");
			    leave("", 1);
			}
		    }
		}
	    }
	    memset(old_key, 0, sizeof(des_cblock));
	    memset(new_key, 0, sizeof(des_cblock));
	}
    }
    else if (add) {
	do {
	    do {
		safe_read_stdin("Name: ", databuf, sizeof(databuf));
		strncpy(sname, databuf, sizeof(sname) - 1);
		sname[sizeof(sname) - 1] = '\0';
		if (strchr(sname, '.') != 0) {
		  strncpy(sinst, strchr(sname, '.') + 1, sizeof(sinst) - 1);
		  sinst[sizeof(sinst) - 1] = '\0';
		  *(strchr(sname, '.')) = 0;
		} else {
		  safe_read_stdin("Instance: ", databuf, sizeof(databuf));
		  strncpy(sinst, databuf, sizeof(sinst) - 1);
		  sinst[sizeof(sinst) - 1] = '\0';
		}
		safe_read_stdin("Realm: ", databuf, sizeof(databuf));
		strncpy(srealm, databuf, sizeof(srealm) - 1);
		srealm[sizeof(srealm) - 1] = '\0';
		safe_read_stdin("Version number: ", databuf, sizeof(databuf));
		key_vno = atoi(databuf);
		if (key_vno == 0)
		    key_vno = 1; /* Version numbers are never 0 */
		if (!srealm[0]) {
		    strncpy(srealm, local_realm, sizeof(srealm) - 1);
		    srealm[sizeof(srealm) - 1] = '\0';
		}
		printf("New principal: ");
		print_name(sname, sinst, srealm);
		printf("; version %d\n", key_vno);
	    } while (!yn("Is this correct?"));
	    get_key_from_password(&new_key, cellname);
	    if (key) {
		printf("Key: ");
		print_key(new_key);
		printf("\n");
	    }
	    append_srvtab(work_keyfile, work_keyfile_fd, 
			  sname, sinst, srealm, key_vno, new_key);
	    printf("Key successfully added.\n");
	} while (yn("Would you like to add another key?"));
    }
    else if (get) {
        ksrvutil_get(work_keyfile_fd, work_keyfile,
		     argc - optind, argv + optind);
    }

    if (change || list) 
	if (close(backup_keyfile_fd) < 0)
	    warn ("close %s", backup_keyfile);
    
    if (change || add || get) {
	if (close(work_keyfile_fd) < 0)
	    err (1, "close %s", work_keyfile);
	if (rename(work_keyfile, keyfile) < 0)
	    err (1, "rename(%s, %s)", work_keyfile, keyfile);
	chmod(backup_keyfile, keyfile_mode);
	chmod(keyfile, keyfile_mode);
	printf("Old keyfile in %s.\n", backup_keyfile);
    }
    return 0;
}