lib/krb5/keytab_memory.c

   1 /*
   2  * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35
  36 /* memory operations -------------------------------------------- */
  37
  38 struct mkt_data {
  39     krb5_keytab_entry *entries;
  40     int num_entries;
  41     char *name;
  42     int refcount;
  43     struct mkt_data *next;
  44 };
  45
  46 /* this mutex protects mkt_head, ->refcount, and ->next
  47  * content is not protected (name is static and need no protection)
  48  */
  49 static HEIMDAL_MUTEX mkt_mutex = HEIMDAL_MUTEX_INITIALIZER;
  50 static struct mkt_data *mkt_head;
  51
  52
  53 static krb5_error_code KRB5_CALLCONV
  54 mkt_resolve(krb5_context context, const char *name, krb5_keytab id)
  55 {
  56     struct mkt_data *d;
  57
  58     HEIMDAL_MUTEX_lock(&mkt_mutex);
  59
  60     for (d = mkt_head; d != NULL; d = d->next)
  61         if (strcmp(d->name, name) == 0)
  62             break;
  63     if (d) {
  64         if (d->refcount < 1)
  65             krb5_abortx(context, "Double close on memory keytab, "
  66                         "refcount < 1 %d", d->refcount);
  67         d->refcount++;
  68         id->data = d;
  69         HEIMDAL_MUTEX_unlock(&mkt_mutex);
  70         return 0;
  71     }
  72
  73     d = calloc(1, sizeof(*d));
  74     if(d == NULL) {
  75         HEIMDAL_MUTEX_unlock(&mkt_mutex);
  76         return krb5_enomem(context);
  77     }
  78     d->name = strdup(name);
  79     if (d->name == NULL) {
  80         HEIMDAL_MUTEX_unlock(&mkt_mutex);
  81         free(d);
  82         return krb5_enomem(context);
  83     }
  84     d->entries = NULL;
  85     d->num_entries = 0;
  86     d->refcount = 1;
  87     d->next = mkt_head;
  88     mkt_head = d;
  89     HEIMDAL_MUTEX_unlock(&mkt_mutex);
  90     id->data = d;
  91     return 0;
  92 }
  93
  94 static krb5_error_code KRB5_CALLCONV
  95 mkt_close(krb5_context context, krb5_keytab id)
  96 {
  97     struct mkt_data *d = id->data, **dp;
  98     int i;
  99
 100     HEIMDAL_MUTEX_lock(&mkt_mutex);
 101     if (d->refcount < 1)
 102         krb5_abortx(context,
 103                     "krb5 internal error, memory keytab refcount < 1 on close");
 104
 105     if (--d->refcount > 0) {
 106         HEIMDAL_MUTEX_unlock(&mkt_mutex);
 107         return 0;
 108     }
 109     for (dp = &mkt_head; *dp != NULL; dp = &(*dp)->next) {
 110         if (*dp == d) {
 111             *dp = d->next;
 112             break;
 113         }
 114     }
 115     HEIMDAL_MUTEX_unlock(&mkt_mutex);
 116
 117     free(d->name);
 118     for(i = 0; i < d->num_entries; i++)
 119         krb5_kt_free_entry(context, &d->entries[i]);
 120     free(d->entries);
 121     free(d);
 122     return 0;
 123 }
 124
 125 static krb5_error_code KRB5_CALLCONV
 126 mkt_get_name(krb5_context context,
 127              krb5_keytab id,
 128              char *name,
 129              size_t namesize)
 130 {
 131     struct mkt_data *d = id->data;
 132     strlcpy(name, d->name, namesize);
 133     return 0;
 134 }
 135
 136 static krb5_error_code KRB5_CALLCONV
 137 mkt_start_seq_get(krb5_context context,
 138                   krb5_keytab id,
 139                   krb5_kt_cursor *c)
 140 {
 141     /* XXX */
 142     c->fd = 0;
 143     return 0;
 144 }
 145
 146 static krb5_error_code KRB5_CALLCONV
 147 mkt_next_entry(krb5_context context,
 148                krb5_keytab id,
 149                krb5_keytab_entry *entry,
 150                krb5_kt_cursor *c)
 151 {
 152     struct mkt_data *d = id->data;
 153     if(c->fd >= d->num_entries)
 154         return KRB5_KT_END;
 155     return krb5_kt_copy_entry_contents(context, &d->entries[c->fd++], entry);
 156 }
 157
 158 static krb5_error_code KRB5_CALLCONV
 159 mkt_end_seq_get(krb5_context context,
 160                 krb5_keytab id,
 161                 krb5_kt_cursor *cursor)
 162 {
 163     return 0;
 164 }
 165
 166 static krb5_error_code KRB5_CALLCONV
 167 mkt_add_entry(krb5_context context,
 168               krb5_keytab id,
 169               krb5_keytab_entry *entry)
 170 {
 171     struct mkt_data *d = id->data;
 172     krb5_keytab_entry *tmp;
 173     tmp = realloc(d->entries, (d->num_entries + 1) * sizeof(*d->entries));
 174     if (tmp == NULL)
 175         return krb5_enomem(context);
 176     d->entries = tmp;
 177     return krb5_kt_copy_entry_contents(context, entry,
 178                                        &d->entries[d->num_entries++]);
 179 }
 180
 181 static krb5_error_code KRB5_CALLCONV
 182 mkt_remove_entry(krb5_context context,
 183                  krb5_keytab id,
 184                  krb5_keytab_entry *entry)
 185 {
 186     struct mkt_data *d = id->data;
 187     krb5_keytab_entry *e, *end;
 188     int found = 0;
 189
 190     if (d->num_entries == 0) {
 191         krb5_clear_error_message(context);
 192         return KRB5_KT_NOTFOUND;
 193     }
 194
 195     /* do this backwards to minimize copying */
 196     for(end = d->entries + d->num_entries, e = end - 1; e >= d->entries; e--) {
 197         if(krb5_kt_compare(context, e, entry->principal,
 198                            entry->vno, entry->keyblock.keytype)) {
 199             krb5_kt_free_entry(context, e);
 200             memmove(e, e + 1, (end - e - 1) * sizeof(*e));
 201             memset(end - 1, 0, sizeof(*end));
 202             d->num_entries--;
 203             end--;
 204             found = 1;
 205         }
 206     }
 207     if (!found) {
 208         krb5_clear_error_message (context);
 209         return KRB5_KT_NOTFOUND;
 210     }
 211     e = realloc(d->entries, d->num_entries * sizeof(*d->entries));
 212     if(e != NULL || d->num_entries == 0)
 213         d->entries = e;
 214     return 0;
 215 }
 216
 217 const krb5_kt_ops krb5_mkt_ops = {
 218     "MEMORY",
 219     mkt_resolve,
 220     mkt_get_name,
 221     mkt_close,
 222     NULL, /* destroy */
 223     NULL, /* get */
 224     mkt_start_seq_get,
 225     mkt_next_entry,
 226     mkt_end_seq_get,
 227     mkt_add_entry,
 228     mkt_remove_entry,
 229     NULL,
 230     0
 231 };