/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * kadmin/ktutil/ktutil_funcs.c
 *
 *(C) Copyright 1995, 1996 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   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.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * 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.
 *
 * Utility functions for ktutil.
 */

#include "k5-int.h"
#include "ktutil.h"
#ifdef KRB5_KRB4_COMPAT
#include "kerberosIV/krb.h"
#include <stdio.h>
#endif
#include <string.h>
#include <ctype.h>
#include <libintl.h>

/*
 * Free a kt_list
 */
krb5_error_code ktutil_free_kt_list(context, list)
    krb5_context context;
    krb5_kt_list list;
{
    krb5_kt_list lp, prev;
    krb5_error_code retval = 0;

    for (lp = list; lp;) {
        retval = krb5_kt_free_entry(context, lp->entry);
        free((char *)lp->entry);
        if (retval)
            break;
        prev = lp;
        lp = lp->next;
        free((char *)prev);
    }
    return retval;
}

/*
 * Delete a numbered entry in a kt_list.  Takes a pointer to a kt_list
 * in case head gets deleted.
 */
krb5_error_code ktutil_delete(context, list, idx)
    krb5_context context;
    krb5_kt_list *list;
    int idx;
{
    krb5_kt_list lp, prev;
    int i;

    for (lp = *list, i = 1; lp; prev = lp, lp = lp->next, i++) {
        if (i == idx) {
            if (i == 1)
                *list = lp->next;
            else
                prev->next = lp->next;
            lp->next = NULL;
            return ktutil_free_kt_list(context, lp);
        }
    }
    return EINVAL;
}

/*
 * Create a new keytab entry and add it to the keytab list.
 * Based on the value of use_pass, either prompt the user for a
 * password or key.  If the keytab list is NULL, allocate a new
 * one first.
 */
krb5_error_code ktutil_add(context, list, princ_str, kvno,
                           enctype_str, use_pass)
    krb5_context context;
    krb5_kt_list *list;
    char *princ_str;
    krb5_kvno kvno;
    char *enctype_str;
    int use_pass;
{
    krb5_keytab_entry *entry;
    krb5_kt_list lp = NULL, prev = NULL;
    krb5_principal princ;
    krb5_enctype enctype;
    krb5_timestamp now;
    krb5_error_code retval;
    krb5_data password, salt;
    krb5_keyblock key;
    char buf[BUFSIZ];
    char promptstr[1024];

    char *cp;
    int i, tmp;
    unsigned int pwsize = BUFSIZ;

    retval = krb5_parse_name(context, princ_str, &princ);
    if (retval)
        return retval;
    /* now unparse in order to get the default realm appended
       to princ_str, if no realm was specified */
    retval = krb5_unparse_name(context, princ, &princ_str);
    if (retval)
        return retval;
    retval = krb5_string_to_enctype(enctype_str, &enctype);
    if (retval)
        return KRB5_BAD_ENCTYPE;
    retval = krb5_timeofday(context, &now);
    if (retval)
        return retval;

    if (*list) {
        /* point lp at the tail of the list */
        for (lp = *list; lp->next; lp = lp->next);
    }
    entry = (krb5_keytab_entry *) malloc(sizeof(krb5_keytab_entry));
    if (!entry) {
        return ENOMEM;
    }
    memset((char *) entry, 0, sizeof(*entry));

    if (!lp) {          /* if list is empty, start one */
        lp = (krb5_kt_list) malloc(sizeof(*lp));
        if (!lp) {
            return ENOMEM;
        }
    } else {
        lp->next = (krb5_kt_list) malloc(sizeof(*lp));
        if (!lp->next) {
            return ENOMEM;
        }
        prev = lp;
        lp = lp->next;
    }
    lp->next = NULL;
    lp->entry = entry;

    if (use_pass) {
        password.length = pwsize;
        password.data = (char *) malloc(pwsize);
        if (!password.data) {
            retval = ENOMEM;
            goto cleanup;
        }

        (void) snprintf(promptstr, sizeof(promptstr),
                gettext("Password for %.1000s"), princ_str);
        retval = krb5_read_password(context, promptstr, NULL, password.data,
                                    &password.length);
        if (retval)
            goto cleanup;
        retval = krb5_principal2salt(context, princ, &salt);
        if (retval)
            goto cleanup;
        retval = krb5_c_string_to_key(context, enctype, &password,
                                      &salt, &key);
        if (retval)
            goto cleanup;
        memset(password.data, 0, password.length);
        password.length = 0;
        memcpy(&lp->entry->key, &key, sizeof(krb5_keyblock));
    } else {
        printf(gettext("Key for %s (hex): "), princ_str);
        fgets(buf, BUFSIZ, stdin);
        /*
         * We need to get rid of the trailing '\n' from fgets.
         * If we have an even number of hex digits (as we should),
         * write a '\0' over the '\n'.  If for some reason we have
         * an odd number of hex digits, force an even number of hex
         * digits by writing a '0' into the last position (the string
         * will still be null-terminated).
         */
        buf[strlen(buf) - 1] = strlen(buf) % 2 ? '\0' : '0';
        if (strlen(buf) == 0) {
            fprintf(stderr, "addent: %s", gettext("Error reading key.\n"));
            retval = 0;
            goto cleanup;
        }

        lp->entry->key.enctype = enctype;
        lp->entry->key.contents = (krb5_octet *) malloc((strlen(buf) + 1) / 2);
        if (!lp->entry->key.contents) {
            retval = ENOMEM;
            goto cleanup;
        }

        i = 0;
        for (cp = buf; *cp; cp += 2) {
            if (!isxdigit((int) cp[0]) || !isxdigit((int) cp[1])) {
                fprintf(stderr, "addent: %s",
                        gettext("Illegal character in key.\n"));
                retval = 0;
                goto cleanup;
            }
            sscanf(cp, "%02x", &tmp);
            lp->entry->key.contents[i++] = (krb5_octet) tmp;
        }
        lp->entry->key.length = i;
    }
    lp->entry->principal = princ;
    lp->entry->vno = kvno;
    lp->entry->timestamp = now;

    if (!*list)
        *list = lp;

    return 0;

 cleanup:
    if (prev)
        prev->next = NULL;
    ktutil_free_kt_list(context, lp);
    return retval;
}

/*
 * Read in a keytab and append it to list.  If list starts as NULL,
 * allocate a new one if necessary.
 */
krb5_error_code ktutil_read_keytab(context, name, list)
    krb5_context context;
    char *name;
    krb5_kt_list *list;
{
    krb5_kt_list lp = NULL, tail = NULL, back = NULL;
    krb5_keytab kt;
    krb5_keytab_entry *entry;
    krb5_kt_cursor cursor;
    krb5_error_code retval = 0;

    if (*list) {
        /* point lp at the tail of the list */
        for (lp = *list; lp->next; lp = lp->next);
        back = lp;
    }
    retval = krb5_kt_resolve(context, name, &kt);
    if (retval)
        return retval;
    retval = krb5_kt_start_seq_get(context, kt, &cursor);
    if (retval)
        goto close_kt;
    for (;;) {
        entry = (krb5_keytab_entry *)malloc(sizeof (krb5_keytab_entry));
        if (!entry) {
            retval = ENOMEM;
            break;
        }
        memset((char *)entry, 0, sizeof (*entry));
        retval = krb5_kt_next_entry(context, kt, entry, &cursor);
        if (retval)
            break;

        if (!lp) {              /* if list is empty, start one */
            lp = (krb5_kt_list)malloc(sizeof (*lp));
            if (!lp) {
                retval = ENOMEM;
                break;
            }
        } else {
            lp->next = (krb5_kt_list)malloc(sizeof (*lp));
            if (!lp->next) {
                retval = ENOMEM;
                break;
            }
            lp = lp->next;
        }
        if (!tail)
            tail = lp;
        lp->next = NULL;
        lp->entry = entry;
    }
    if (entry)
        free((char *)entry);
    if (retval) {
        if (retval == KRB5_KT_END)
            retval = 0;
        else {
            ktutil_free_kt_list(context, tail);
            tail = NULL;
            if (back)
                back->next = NULL;
        }
    }
    if (!*list)
        *list = tail;
    krb5_kt_end_seq_get(context, kt, &cursor);
 close_kt:
    krb5_kt_close(context, kt);
    return retval;
}

/*
 * Takes a kt_list and writes it to the named keytab.
 */
krb5_error_code ktutil_write_keytab(context, list, name)
    krb5_context context;
    krb5_kt_list list;
    char *name;
{
    krb5_kt_list lp;
    krb5_keytab kt;
    char ktname[MAXPATHLEN+sizeof("WRFILE:")+1];
    krb5_error_code retval = 0;

    strcpy(ktname, "WRFILE:");
    if (strlen (name) >= MAXPATHLEN)
        return ENAMETOOLONG;
    strncat (ktname, name, MAXPATHLEN);
    retval = krb5_kt_resolve(context, ktname, &kt);
    if (retval)
        return retval;
    for (lp = list; lp; lp = lp->next) {
        retval = krb5_kt_add_entry(context, kt, lp->entry);
        if (retval)
            break;
    }
    krb5_kt_close(context, kt);
    return retval;
}

#ifdef KRB5_KRB4_COMPAT
/*
 * getstr() takes a file pointer, a string and a count.  It reads from
 * the file until either it has read "count" characters, or until it
 * reads a null byte.  When finished, what has been read exists in the
 * given string "s".  If "count" characters were actually read, the
 * last is changed to a null, so the returned string is always null-
 * terminated.  getstr() returns the number of characters read,
 * including the null terminator.
 */

static int getstr(fp, s, n)
    FILE *fp;
    register char *s;
    int n;
{
    register int count = n;
    while (fread(s, 1, 1, fp) > 0 && --count)
        if (*s++ == '\0')
            return (n - count);
    *s = '\0';
    return (n - count);
}

/*
 * Read in a named krb4 srvtab and append to list.  Allocate new list
 * if needed.
 */
krb5_error_code ktutil_read_srvtab(context, name, list)
    krb5_context context;
    char *name;
    krb5_kt_list *list;
{
    krb5_kt_list lp = NULL, tail = NULL, back = NULL;
    krb5_keytab_entry *entry;
    krb5_error_code retval = 0;
    char sname[SNAME_SZ];       /* name of service */
    char sinst[INST_SZ];        /* instance of service */
    char srealm[REALM_SZ];      /* realm of service */
    unsigned char kvno;         /* key version number */
    des_cblock key;
    FILE *fp;

    if (*list) {
        /* point lp at the tail of the list */
        for (lp = *list; lp->next; lp = lp->next);
        back = lp;
    }
    fp = fopen(name, "r");
    if (!fp)
        return EIO;
    for (;;) {
        entry = (krb5_keytab_entry *)malloc(sizeof (krb5_keytab_entry));
        if (!entry) {
            retval = ENOMEM;
            break;
        }
        memset((char *)entry, 0, sizeof (*entry));
        memset(sname, 0, sizeof (sname));
        memset(sinst, 0, sizeof (sinst));
        memset(srealm, 0, sizeof (srealm));
        if (!(getstr(fp, sname, SNAME_SZ) > 0 &&
              getstr(fp, sinst, INST_SZ) > 0 &&
              getstr(fp, srealm, REALM_SZ) > 0 &&
              fread(&kvno, 1, 1, fp) > 0 &&
              fread((char *)key, sizeof (key), 1, fp) > 0))
            break;
        entry->magic = KV5M_KEYTAB_ENTRY;
        entry->timestamp = 0;   /* XXX */
        entry->vno = kvno;
        retval = krb5_425_conv_principal(context,
                                         sname, sinst, srealm,
                                         &entry->principal);
        if (retval)
            break;
        entry->key.magic = KV5M_KEYBLOCK;
        entry->key.enctype = ENCTYPE_DES_CBC_CRC;
        entry->key.length = sizeof (key);
        entry->key.contents = (krb5_octet *)malloc(sizeof (key));
        if (!entry->key.contents) {
            retval = ENOMEM;
            break;
        }
        memcpy((char *)entry->key.contents, (char *)key, sizeof (key));
        if (!lp) {              /* if list is empty, start one */
            lp = (krb5_kt_list)malloc(sizeof (*lp));
            if (!lp) {
                retval = ENOMEM;
                break;
            }
        } else {
            lp->next = (krb5_kt_list)malloc(sizeof (*lp));
            if (!lp->next) {
                retval = ENOMEM;
                break;
            }
            lp = lp->next;
        }
        lp->next = NULL;
        lp->entry = entry;
        if (!tail)
            tail = lp;
    }
    if (entry) {
        if (entry->magic == KV5M_KEYTAB_ENTRY)
            krb5_kt_free_entry(context, entry);
        free((char *)entry);
    }
    if (retval) {
        ktutil_free_kt_list(context, tail);
        tail = NULL;
        if (back)
            back->next = NULL;
    }
    if (!*list)
        *list = tail;
    fclose(fp);
    return retval;
}

/*
 * Writes a kt_list out to a krb4 srvtab file.  Note that it first
 * prunes the kt_list so that it won't contain any keys that are not
 * the most recent, and ignores keys that are not ENCTYPE_DES.
 */
krb5_error_code ktutil_write_srvtab(context, list, name)
    krb5_context context;
    krb5_kt_list list;
    char *name;
{
    krb5_kt_list lp, lp1, prev, pruned = NULL;
    krb5_error_code retval = 0;
    FILE *fp;
    char sname[SNAME_SZ];
    char sinst[INST_SZ];
    char srealm[REALM_SZ];

    /* First do heinous stuff to prune the list. */
    for (lp = list; lp; lp = lp->next) {
        if ((lp->entry->key.enctype != ENCTYPE_DES_CBC_CRC) &&
            (lp->entry->key.enctype != ENCTYPE_DES_CBC_MD5) &&
            (lp->entry->key.enctype != ENCTYPE_DES_CBC_MD4) &&
            (lp->entry->key.enctype != ENCTYPE_DES_CBC_RAW))
            continue;

        for (lp1 = pruned; lp1; prev = lp1, lp1 = lp1->next) {
            /* Hunt for the current principal in the pruned list */
            if (krb5_principal_compare(context,
                                       lp->entry->principal,
                                       lp1->entry->principal))
                    break;
        }
        if (!lp1) {             /* need to add entry to tail of pruned list */
            if (!pruned) {
                pruned = (krb5_kt_list) malloc(sizeof (*pruned));
                if (!pruned)
                    return ENOMEM;
                memset((char *) pruned, 0, sizeof(*pruned));
                lp1 = pruned;
            } else {
                prev->next
                    = (krb5_kt_list) malloc(sizeof (*pruned));
                if (!prev->next) {
                    retval = ENOMEM;
                    goto free_pruned;
                }
                memset((char *) prev->next, 0, sizeof(*pruned));
                lp1 = prev->next;
            }
            lp1->entry = lp->entry;
        } else {
            /* This heuristic should be roughly the same as in the
               keytab-reading code in libkrb5.  */
            int offset = 0;
            if (lp1->entry->vno > 240 || lp->entry->vno > 240) {
                offset = 128;
            }
#define M(X) (((X) + offset) % 256)
            if (M(lp1->entry->vno) < M(lp->entry->vno))
                /* Check if lp->entry is newer kvno; if so, update */
                lp1->entry = lp->entry;
        }
    }
    umask(0077); /*Changing umask for all of ktutil is OK
                  * We don't ever write out anything that should use
                  * default umask.*/
    fp = fopen(name, "w");
    if (!fp) {
        retval = EIO;
        goto free_pruned;
    }
    for (lp = pruned; lp; lp = lp->next) {
        unsigned char  kvno;
        kvno = (unsigned char) lp->entry->vno;
        retval = krb5_524_conv_principal(context,
                                         lp->entry->principal,
                                         sname, sinst, srealm);
        if (retval)
            break;
        fwrite(sname, strlen(sname) + 1, 1, fp);
        fwrite(sinst, strlen(sinst) + 1, 1, fp);
        fwrite(srealm, strlen(srealm) + 1, 1, fp);
        fwrite((char *)&kvno, 1, 1, fp);
        fwrite((char *)lp->entry->key.contents,
               sizeof (des_cblock), 1, fp);
    }
    fclose(fp);
 free_pruned:
    /*
     * Loop over and free the pruned list; don't use free_kt_list
     * because that kills the entries.
     */
    for (lp = pruned; lp;) {
        prev = lp;
        lp = lp->next;
        free((char *)prev);
    }
    return retval;
}
#endif /* KRB5_KRB4_COMPAT */