[u/mdw/catacomb] / key-misc.c

/* -*-c-*-
 *
 * $Id: key-misc.c,v 1.4 2004/04/08 01:02:49 mdw Exp $
 *
 * Simple key management
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: key-misc.c,v $
 * Revision 1.4  2004/04/08 01:02:49  mdw
 * key-binary.c
 *
 * Revision 1.3  2001/06/22 19:39:12  mdw
 * New interface to find out whether a key has expired.  Also, a bug fix
 * to @key_bytag@ so that it finds expired keys correctly.
 *
 * Revision 1.2  2000/02/12 18:21:02  mdw
 * Overhaul of key management (again).
 *
 * Revision 1.1  1999/12/22 15:47:48  mdw
 * Major key-management revision.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <mLib/bits.h>
#include <mLib/hash.h>
#include <mLib/sub.h>
#include <mLib/sym.h>

#include "key.h"

/*----- Useful macros -----------------------------------------------------*/

#define KEY_WRITE(f) do {                                               \
     if (!(f)->f & KF_WRITE)                                            \
       return (KERR_READONLY);                                          \
   } while (0)

#define KEY_MODIFY(f) do { (f)->f |= KF_MODIFIED; } while (0)

#define KEY_LOAD(n) ((n) * 2)

/*----- Iteration and iterators -------------------------------------------*/

/* --- @key_mkiter@ --- *
 *
 * Arguments:   @key_iter *i@ = pointer to iterator object
 *              @key_file *f@ = pointer to file structure
 *
 * Returns:     ---
 *
 * Use:         Initializes a key iterator.  The keys are returned by
 *              @key_next@.
 */

void key_mkiter(key_iter *i, key_file *f)
{
  HASH_MKITER(&i->i, &f->byid);
  i->t = time(0);
}

/* --- @key_next@ --- *
 *
 * Arguments:   @key_iter *i@ = pointer to iterator object
 *
 * Returns:     Pointer to next key, or null.
 *
 * Use:         Returns the next key in some arbitrary sequence.
 */

key *key_next(key_iter *i)
{
  hash_base *b;
  key *k;
  do {
    HASH_NEXT(&i->i, b);
    k = (key *)b;
  } while (k && KEY_EXPIRED(i->t, k->exp) && KEY_EXPIRED(i->t, k->del));
  return (k);
}

/*----- Lookup ------------------------------------------------------------*/

/* --- @key_bytype@ --- *
 *
 * Arguments:   @key_file *f@ = key file we want a key from
 *              @const char *type@ = type string for desired key
 *
 * Returns:     Pointer to the best key to use, or null.
 *
 * Use:         Looks up a key by its type.  Returns the key with the latest
 *              expiry time.  This function will not return an expired key.
 */

key *key_bytype(key_file *f, const char *type)
{
  time_t now = time(0);
  key *k;
  key_ref *kr;

  if ((kr = sym_find(&f->bytype, type, -1, 0, 0)) == 0)
    return (0);
  for (k = kr->k; k && KEY_EXPIRED(now, k->exp); k = k->next)
    ;
  return (k);
}

/* --- @key_byid@ --- *
 *
 * Arguments:   @key_file *f@ = key file to find a key from
 *              @uint32 id@ = id to look for
 *
 * Returns:     Key with matching id.
 *
 * Use:         Returns a key given its id.  This function will return an
 *              expired key, but not a deleted one.
 */

key *key_byid(key_file *f, uint32 id)
{
  time_t t = time(0);
  hash_base **bin, *b;

  bin = HASH_BIN(&f->byid, id);
  for (b = *bin; b; b = b->next) {
    if (b->hash == id) {
      key *k = (key *)b;
      if (KEY_EXPIRED(t, k->exp) && KEY_EXPIRED(t, k->del))
        return (0);
      return (k);
    }
  }
  return (0);
}

/* --- @key_bytag@ --- *
 *
 * Arguments:   @key_file *f@ = key file to find a key from
 *              @const char *tag@ = pointer to tag string
 *
 * Returns:     Key with matching id or tag.
 *
 * Use:         Returns a key given its tag or id.  This function will return
 *              an expired key, but not a deleted one.
 */

key *key_bytag(key_file *f, const char *tag)
{
  time_t t = time(0);
  char *p;
  uint32 id;
  key_ref *kr = sym_find(&f->bytag, tag, -1, 0, 0);

  if (kr && !(KEY_EXPIRED(t, kr->k->exp) && KEY_EXPIRED(t, kr->k->del)))
    return (kr->k);
  id = strtoul(tag, &p, 16);
  if (!*p)
    return (key_byid(f, id));
  return (key_bytype(f, tag));
}

/* --- @key_qtag@ --- *
 *
 * Arguments:   @key_file *f@ = key file to find a key from
 *              @const char *tag@ = pointer to tag string
 *              @dstr *d@ = pointer to string for full tag name
 *              @key **k@ = where to store the key pointer
 *              @key_data **kd@ = where to store the key data pointer
 *
 * Returns:     Zero if OK, nonzero if it failed.
 *
 * Use:         Performs a full lookup on a qualified tag name.  The tag is
 *              qualified by the names of subkeys, separated by dots.  Hence,
 *              a qualified tag is ID|TAG[.TAG...].  The various result
 *              pointers can be null to indicate that the result isn't
 *              interesting. 
 */

int key_qtag(key_file *f, const char *tag, dstr *d, key **k, key_data **kd)
{
  dstr dd = DSTR_INIT;
  const char *q;
  key *kk;
  key_data *kkd;

  /* --- Find the end of the base tag --- */

  if ((q = strchr(tag, '.')) == 0)
    DPUTS(&dd, tag);
  else {
    DPUTM(&dd, tag, q - tag);
    DPUTZ(&dd);
    q++;
  }

  /* --- Look up the key tag --- */

  if ((kk = key_bytag(f, dd.buf)) == 0) {
    dstr_destroy(&dd);
    return (-1);
  }

  /* --- Set the various initial bits of result up --- */

  if (d)
    key_fulltag(kk, d);
  if (k)
    *k = kk;
  kkd = &kk->k;

  /* --- Now dig through the rest of the tag --- */

  while (q && *q) {

    /* --- Stick on the next bit of the fullqtag --- */

    DRESET(&dd);
    while (*q && *q != '.') {
      DPUTC(&dd, *q);
      q++;
    }
    DPUTZ(&dd);
    if (d) {
      DPUTC(d, '.');
      DPUTD(d, &dd);
    }

    /* --- Look up the subkey --- */

    if (kkd->e != KENC_STRUCT) {
      kkd = 0;
      break;
    }
    if ((kkd = key_structfind(kkd, dd.buf)) == 0)
      break;
  }

  /* --- Return the results --- */

  if (!kkd)
    return (-1);
  dstr_destroy(&dd);
  if (kd)
    *kd = kkd;
  return (0);
}

/*----- Miscellaneous functions -------------------------------------------*/

/* --- @key_delete@ --- *
 *
 * Arguments:   @key_file *f@ = pointer to file block
 *              @key *k@ = key to delete
 *
 * Returns:     Error code (one of the @KERR@ constants).
 *
 * Use:         Removes the given key from the list.  The key file must be
 *              writable.  (Due to the horridness of the data structures,
 *              deleted keys aren't actually removed, just marked so that
 *              they can't be looked up or iterated over.  One upshot of
 *              this is that they don't get written back to the file when
 *              it's closed.)
 */

int key_delete(key_file *f, key *k)
{
  KEY_WRITE(f);
  k->exp = KEXP_EXPIRE;
  k->del = KEXP_EXPIRE;
  KEY_MODIFY(f);
  return (0);
}

/* --- @key_expired@ --- *
 *
 * Arguments:   @key *k@ = pointer to key block
 *
 * Returns:     Zero if the key is OK, nonzero if it's expired.
 */

int key_expired(key *k)
{
  time_t now = time(0);
  return (KEY_EXPIRED(now, k->exp) || KEY_EXPIRED(now, k->del));
}

/* --- @key_expire@ --- *
 *
 * Arguments:   @key_file *f@ = pointer to file block
 *              @key *k@ = pointer to key block
 *
 * Returns:     Error code (one of the @KERR@ constants).
 *
 * Use:         Immediately marks the key as expired.  It may be removed
 *              immediately, if it is no longer required, and will be removed
 *              by a tidy operation when it is no longer required.  The key
 *              file must be writable.
 */

int key_expire(key_file *f, key *k)
{
  KEY_WRITE(f);
  k->exp = KEXP_EXPIRE;
  if (k->del == KEXP_FOREVER)
    k->del = KEXP_EXPIRE;
  KEY_MODIFY(f);
  return (0);
}

/* --- @key_used@ --- *
 *
 * Arguments:   @key_file *f@ = pointer to key file
 *              @key *k@ = pointer to key block
 *              @time_t t@ = when key can be removed
 *
 * Returns:     Zero if OK, nonzero on failure.
 *
 * Use:         Marks a key as being required until a given time.  Even
 *              though the key may expire before then (and won't be returned
 *              by type after that time), it will still be available when
 *              requested explicitly by id.  The key file must be writable.
 *
 *              The only (current) reason for failure is attempting to use
 *              a key which can expire for something which can't.
 */

int key_used(key_file *f, key *k, time_t t)
{
  KEY_WRITE(f);
  if (t == KEXP_FOREVER) {
    if (k->exp != KEXP_FOREVER)
      return (KERR_WILLEXPIRE);
  } else if (k->del >= t)
    return (0);

  k->del = t;
  KEY_MODIFY(f);
  return (0);
}

/* --- @key_fingerprint@ --- *
 *
 * Arguments:   @key *k@ = the key to fingerprint
 *              @ghash *h@ = the hash to use
 *              @const key_filter *kf@ = filter to apply
 *
 * Returns:     Nonzero if the key slightly matched the filter.
 *
 * Use:         Updates the hash context with the key contents.
 */

static int abyname(const void *a, const void *b) {
  key_attr *const *x = a, *const *y = b;
  return (strcmp(SYM_NAME(*x), SYM_NAME(*y)));
}

int key_fingerprint(key *k, ghash *h, const key_filter *kf)
{
  dstr d = DSTR_INIT;
  int rc = 0;
  key_attr *a, **v;
  size_t n, i, len;
  octet b[2];
  sym_iter ai;

  if (!key_encode(&k->k, &d, kf))
    goto done;
  rc = 1;
  GH_HASH(h, d.buf, d.len);
  for (n = 0, sym_mkiter(&ai, &k->a); (a = sym_next(&ai)) != 0; n++);
  if (n) {
    v = xmalloc(n * sizeof(*v));
    for (i = 0, sym_mkiter(&ai, &k->a); (a = sym_next(&ai)) != 0; i++)
      v[i] = a;
    qsort(v, n, sizeof(*v), abyname);
    len = strlen(k->type); STORE8(b, len);
    GH_HASH(h, b, 1); GH_HASH(h, k->type, len);
    for (i = 0; i < n; i++) {
      a = v[i];
      len = strlen(SYM_NAME(a)); STORE8(b, len);
      GH_HASH(h, b, 1); GH_HASH(h, SYM_NAME(a), len);
      len = strlen(a->p); STORE16(b, len);
      GH_HASH(h, b, 2); GH_HASH(h, a->p, len);
    }
    xfree(v);
  }    
done:
  dstr_destroy(&d);
  return (rc);
}

/*----- That's all, folks -------------------------------------------------*/