path: root/daemon/ldap.c

/* TODO: Include attribution for ideas, and code from mod_auth_digest */

#define _XOPEN_SOURCE

#include "usuals.h"
#include "httpauthd.h"
#include "hash.h"
#include "defaults.h"
#include "digest.h"
#include "basic.h"
#include "md5.h"
#include "sha1.h"

#include <sys/time.h>
#include <unistd.h>
#include <syslog.h>

/* LDAP library */
#include <ldap.h>

unsigned char g_ldap_secret[DIGEST_SECRET_LEN];

/* -------------------------------------------------------------------------------
 * Defaults and Constants
 */

#define BASIC_ESTABLISHED  (void*)1

/* TODO: We need to support more password types */
#define LDAP_PW_CLEAR    0
#define LDAP_PW_CRYPT    1
#define LDAP_PW_MD5      2
#define LDAP_PW_SHA      3
#define LDAP_PW_UNKNOWN -1

typedef struct ldap_pw_type
{
  const char* name;
  int type;
}
ldap_pw_type_t;

static const ldap_pw_type_t kLDAPPWTypes[] =
{
  { "cleartext", LDAP_PW_CLEAR },
  { "crypt", LDAP_PW_CRYPT },
  { "md5", LDAP_PW_MD5 },
  { "sha", LDAP_PW_SHA }
};


/* -------------------------------------------------------------------------------
 * Structures
 */

/* Our hanler context */
typedef struct ldap_context
{
  /* Settings ---------------------------------------------------------- */
  const char* servers;      /* Servers to authenticate against (required) */
  const char* filter;       /* Filter (either this or dnmap must be set) */
  const char* base;         /* Base for the filter */
  const char* pw_attr;      /* The clear password attribute */
  const char* ha1_attr;     /* Password for an encrypted Digest H(A1) */
  const char* user;         /* User to bind as */
  const char* password;     /* Password to bind with */
  const char* dnmap;        /* For mapping users to dns */
  int port;                 /* Port to connect to LDAP server on */
  int scope;                /* Scope for filter */

  int dobind;               /* Bind to do simple authentication */
  int ldap_max;             /* Number of open connections allowed */
  int ldap_timeout;         /* Maximum amount of time to dedicate to an ldap query */

  ha_options_t* opts;       /* Options from httpauthd.c */

  /* Context ----------------------------------------------------------- */
  hash_t* cache;            /* Some cached records or basic */

  LDAP** pool;            /* Pool of available connections */
  int pool_mark;          /* Amount of connections allocated */
}
ldap_context_t;


/* The defaults for the context */
static const ldap_context_t ldap_defaults =
{
  NULL,               /* servers */
  NULL,               /* filter */
  NULL,               /* base */
  "userPassword",     /* pw_attr */
  NULL,               /* ha1_attr */
  NULL,               /* user */
  NULL,               /* password */
  NULL,               /* dnmap */
  389,                /* port */
  LDAP_SCOPE_SUBTREE, /* scope */
  1,                  /* dobind */
  10,                 /* ldap_max */
  30,                 /* ldap_timeout */
  NULL,               /* cache */
  NULL,               /* pool */
  0                   /* pool_mark */
};


/* -------------------------------------------------------------------------------
 * Internal Functions
 */

static void free_hash_object(void* arg, void* val)
{
  if(val && val != BASIC_ESTABLISHED)
    free(val);
}

static int report_ldap(const char* msg, int code)
{
  ASSERT(code != LDAP_SUCCESS);

  switch(code)
  {
  case LDAP_NO_MEMORY:
    ha_messagex(LOG_CRIT, "out of memory");
    return HA_CRITERROR;

  default:
    if(!msg)
      msg = "error";

    ha_messagex(LOG_ERR, "ldap: %s: %s", msg, ldap_err2string(code));
    return HA_FAILED;
  };
}

static digest_record_t* get_cached_digest(ldap_context_t* ctx, unsigned char* nonce)
{
  digest_record_t* rec;

  ASSERT(ctx && nonce);

  if(ctx->opts->cache_max == 0)
    return NULL;

  ha_lock(NULL);

    rec = (digest_record_t*)hash_get(ctx->cache, nonce);

    /* Just in case it's a basic :) */
    if(rec && rec != BASIC_ESTABLISHED)
      hash_rem(ctx->cache, nonce);

  ha_unlock(NULL);

  ASSERT(!rec || memcmp(nonce, rec->nonce, DIGEST_NONCE_LEN) == 0);
  return rec;
}

static int have_cached_basic(ldap_context_t* ctx, unsigned char* key)
{
  int ret = 0;

  ASSERT(ctx && key);

  ha_lock(NULL);

    ret = (hash_get(ctx->cache, key) == BASIC_ESTABLISHED);

  ha_unlock(NULL);

  return ret;
}

static int save_cached_digest(ldap_context_t* ctx, digest_record_t* rec)
{
  int r;

  ASSERT(ctx && rec);

  if(ctx->opts->cache_max == 0)
  {
    free_hash_object(NULL, rec);
    return HA_FALSE;
  }

  ha_lock(NULL);

    while(hash_count(ctx->cache) >= ctx->opts->cache_max)
      hash_bump(ctx->cache);

    r = hash_set(ctx->cache, rec->nonce, rec);

  ha_unlock(NULL);

  if(!r)
  {
    ha_messagex(LOG_CRIT, "out of memory");
    return HA_CRITERROR;
  }

  return HA_OK;
}

static int add_cached_basic(ldap_context_t* ctx, unsigned char* key)
{
  int r;

  ASSERT(ctx && key);

  if(ctx->opts->cache_max == 0)
    return HA_FALSE;

  ha_lock(NULL);

    while(hash_count(ctx->cache) >= ctx->opts->cache_max)
      hash_bump(ctx->cache);

    r = hash_set(ctx->cache, key, BASIC_ESTABLISHED);

  ha_unlock(NULL);

  if(!r)
  {
    ha_messagex(LOG_CRIT, "out of memory");
    return HA_CRITERROR;
  }

  return HA_OK;
}

static const char* substitute_params(ldap_context_t* ctx, ha_buffer_t* buf,
                                     const char* user, const char* str)
{
  const char* t;

  ASSERT(ctx && buf && user && str);
  /* TODO: We need to be escaping the user and realm properly */
  /* This starts a new block to join */
  ha_bufcpy(buf, "");

  while(str[0])
  {
    t = strchr(str, '%');
    if(!t)
    {
      ha_bufjoin(buf);
      ha_bufcpy(buf, str);
      break;
    }

    ha_bufjoin(buf);
    ha_bufncpy(buf, str, t - str);

    t++;

    switch(t[0])
    {
    case 'u':
      ha_bufjoin(buf);
      ha_bufcpy(buf, user);
      t++;
      break;

    case 'r':
      ha_bufjoin(buf);
      ha_bufcpy(buf, ctx->opts->realm);
      t++;
      break;

    case '%':
      ha_bufjoin(buf);
      ha_bufcpy(buf, "%");
      t++;
      break;
    };

    str = t;
  }

  return ha_bufdata(buf);
}

static const char* make_password_md5(ha_buffer_t* buf, const char* clearpw)
{
  md5_ctx_t md5;
  unsigned char digest[MD5_LEN];

  ASSERT(buf && clearpw);

  md5_init(&md5);
  md5_update(&md5, clearpw, strlen(clearpw));
  md5_final(digest, &md5);

  return ha_bufenc64(buf, digest, MD5_LEN);
}

static const char* make_password_sha(ha_buffer_t* buf, const char* clearpw)
{
  sha1_ctx_t sha;
  unsigned char digest[SHA1_LEN];

  ASSERT(buf && clearpw);

  sha1_init(&sha);
  sha1_update(&sha, clearpw, strlen(clearpw));
  sha1_final(digest, &sha);

  return ha_bufenc64(buf, digest, SHA1_LEN);
}

static int parse_ldap_password(const char** password)
{
  const char* pw;
  const char* scheme;
  int i;

  ASSERT(password && *password);

  pw = *password;

  /* zero length passwords are clear */
  if(strlen(pw) == 0)
    return LDAP_PW_CLEAR;

  /* passwords without a scheme are clear */
  if(pw[0] != '{')
    return LDAP_PW_CLEAR;

  pw++;
  scheme = pw;

  while(*pw && (isalpha(*pw) || isdigit(*pw) || *pw == '-'))
    pw++;

  /* scheme should end in a brace */
  if(*pw != '}')
    return LDAP_PW_CLEAR;

  *password = pw + 1;

  /* find a scheme in our map */
  for(i = 0; i < countof(kLDAPPWTypes); i++)
  {
    if(strncasecmp(kLDAPPWTypes[i].name, scheme, pw - scheme) == 0)
      return kLDAPPWTypes[i].type;
  }

  return LDAP_PW_UNKNOWN;
}

static const char* find_cleartext_password(ha_buffer_t* buf, const char** pws)
{
  ASSERT(buf);

  for(; pws && *pws; pws++)
  {
    const char* pw = *pws;

    if(parse_ldap_password(&pw) == LDAP_PW_CLEAR)
      return pw;
  }

  return NULL;
}

static int parse_ldap_ha1(ha_buffer_t* buf, struct berval* bv, unsigned char* ha1)
{
  ASSERT(buf && bv && ha1);
  size_t len;
  void* d;

  /* Raw binary */
  if(bv->bv_len == MD5_LEN)
  {
    ha_messagex(LOG_DEBUG, "ldap: found ha1 in raw binary format");
    memcpy(ha1, bv->bv_val, MD5_LEN);
    return HA_OK;
  }

  /* Hex encoded */
  else if(bv->bv_len == (MD5_LEN * 2))
  {
    len = MD5_LEN;
    d = ha_bufdechex(buf, bv->bv_val, &len);

    if(d && len == MD5_LEN)
    {
      ha_messagex(LOG_DEBUG, "ldap: found ha1 in hex encoded format");
      memcpy(ha1, d, MD5_LEN);
      return HA_OK;
    }
  }

  /* B64 Encoded */
  else
  {
    len = MD5_LEN;
    d = ha_bufdec64(buf, bv->bv_val, &len);

    if(d && len == MD5_LEN)
    {
      ha_messagex(LOG_DEBUG, "ldap: found ha1 in b64 encoded format");
      memcpy(ha1, ha_bufdata(buf), MD5_LEN);
      return HA_OK;
    }
  }

  return ha_buferr(buf) ? HA_CRITERROR : HA_FALSE;
}

static int validate_ldap_password(ldap_context_t* ctx, LDAP* ld, LDAPMessage* entry,
                                  ha_buffer_t* buf, const char* user, const char* clearpw)
{
  char** pws;
  char** t;
  const char* pw;
  const char* p;
  int type;
  int res = HA_FALSE;
  int unknown = 0;

  ASSERT(entry && ld && ctx && clearpw);

  ASSERT(ctx->pw_attr);
  pws = ldap_get_values(ld, entry, ctx->pw_attr);

  if(pws)
  {
    for(t = pws ; *t; t++)
    {
      pw = *t;
      type = parse_ldap_password(&pw);

      switch(type)
      {
      case LDAP_PW_CLEAR:
        p = clearpw;
        break;

      case LDAP_PW_MD5:
        p = make_password_md5(buf, clearpw);
        break;

      case LDAP_PW_CRYPT:

        /* Not sure if crypt is thread safe */
        ha_lock(NULL);
          p = crypt(clearpw, pw);
        ha_unlock(NULL);
        break;

      case LDAP_PW_SHA:
        p = make_password_sha(buf, clearpw);
        break;

      case LDAP_PW_UNKNOWN:
        unknown = 1;
        continue;

      default:
        /* Not reached */
        ASSERT(0);
      };

      if(!p)
      {
        res = HA_CRITERROR;
        break;
      }

      if(strcmp(pw, p) == 0)
      {
        ha_messagex(LOG_DEBUG, "ldap: successful validate against password");
        res = HA_OK;
        break;
      }
    }

    ldap_value_free(pws);
  }

  if(res == HA_FALSE && unknown)
    ha_messagex(LOG_ERR, "ldap: server does not contain any compatible passwords for user: %s", user);

  return res;
}

static int validate_ldap_ha1(ldap_context_t* ctx, LDAP* ld, LDAPMessage* entry,
                             ha_buffer_t* buf, const char* user, const char* clearpw)
{
  struct berval** ha1s;
  struct berval** b;
  unsigned char key[MD5_LEN];
  unsigned char k[MD5_LEN];
  int r, first = 1;
  int res = HA_FALSE;

  ASSERT(ctx && ld && entry && buf && user && clearpw);

  if(!ctx->ha1_attr)
    return HA_FALSE;

  ha1s = ldap_get_values_len(ld, entry, ctx->ha1_attr);

  if(ha1s)
  {
    digest_makeha1(key, user, ctx->opts->realm, clearpw);

    for(b = ha1s ; *b; b++)
    {
      r = parse_ldap_ha1(buf, *b, k);
      if(r < 0)
      {
        res = r;
        break;
      }

      if(r == HA_FALSE)
      {
        if(first)
          ha_messagex(LOG_ERR, "ldap: server contains invalid HA1 digest hash for user: %s", user);

        first = 0;
        continue;
      }

      if(memcmp(key, k, MD5_LEN) == 0)
      {
        ha_messagex(LOG_DEBUG, "ldap: successful validate against ha1");
        res = HA_OK;
        break;
      }
    }

    ldap_value_free_len(ha1s);
  }

  return res;
}

static LDAP* get_ldap_connection(ldap_context_t* ctx)
{
  LDAP* ld;
  int i, r;

  ASSERT(ctx);

  for(i = 0; i < ctx->ldap_max; i++)
  {
    /* An open connection in the pool */
    if(ctx->pool[i])
    {
      ha_messagex(LOG_DEBUG, "ldap: using cached connection");
      ld = ctx->pool[i];
      ctx->pool[i] = NULL;
      return ld;
    }
  }

  if(ctx->pool_mark >= ctx->ldap_max)
  {
    ha_messagex(LOG_ERR, "ldap: too many open connections");
    return NULL;
  }

  ld = ldap_init(ctx->servers, ctx->port);
  if(!ld)
  {
    ha_message(LOG_ERR, "ldap: couldn't initialize connection");
    return NULL;
  }

  if(ctx->user || ctx->password)
  {
    r = ldap_simple_bind_s(ld, ctx->user ? ctx->user : "",
                           ctx->password ? ctx->password : "");
    if(r != LDAP_SUCCESS)
    {
      report_ldap("ldap: couldn't bind to LDAP server", r);
      ldap_unbind_s(ld);
      return NULL;
    }
  }

  ctx->pool_mark++;
  ha_messagex(LOG_DEBUG, "ldap: opened new connection (total %d)", ctx->pool_mark);
  return ld;
}

static void save_ldap_connection(ldap_context_t* ctx, LDAP* ld)
{
  int i, e;

  ASSERT(ctx);

  if(!ld)
    return;

  ldap_get_option(ld, LDAP_OPT_ERROR_NUMBER, &e);

  /* Make sure it's worth saving */
  switch(e)
  {
  case LDAP_SERVER_DOWN:
  case LDAP_LOCAL_ERROR:
  case LDAP_NO_MEMORY:
    break;

  default:
    for(i = 0; i < ctx->ldap_max; i++)
    {
      /* An open connection in the pool */
      if(!ctx->pool[i])
      {
        ha_messagex(LOG_DEBUG, "ldap: caching connection for later use");
        ctx->pool[i] = ld;
        ld = NULL;
        break;
      }
    }

    break;
  };

  if(ld != NULL)
  {
    ldap_unbind_s(ld);
    ctx->pool_mark--;
    ha_messagex(LOG_DEBUG, "ldap: discarding connection (total %d)", ctx->pool_mark);
  }
}

static int retrieve_user_entry(ldap_context_t* ctx, ha_buffer_t* buf, LDAP* ld,
                               const char* user, const char** dn,
                               LDAPMessage** entry, LDAPMessage** result)
{
  struct timeval tv;
  const char* filter;
  const char* attrs[3];
  const char* base;
  int scope;
  int r;

  ASSERT(ctx && buf && ld && user && dn && entry && result);

  if(ctx->filter)
  {
    /* Filters can also have %u and %r */
    filter = substitute_params(ctx, buf, user, ctx->filter);
    if(!filter)
      return HA_CRITERROR;
  }
  else
  {
    filter = "(objectClass=*)";
  }

  attrs[0] = ctx->dobind ? NULL : ctx->pw_attr;
  attrs[1] = ctx->dobind ? NULL : ctx->ha1_attr;
  attrs[2] = NULL;

  tv.tv_sec = ctx->ldap_timeout;
  tv.tv_usec = 0;

  base = *dn ? *dn : ctx->base;
  scope = *dn ? LDAP_SCOPE_BASE : ctx->scope;

  ha_messagex(LOG_DEBUG, "ldap: performing search: [ base: %s / scope: %d / filter: %s ]",
              base, scope, filter);

  r = ldap_search_st(ld, base, scope, filter, (char**)attrs, 0, &tv, result);

  if(r != LDAP_SUCCESS)
  {
    if(r == LDAP_NO_SUCH_OBJECT)
    {
      ha_messagex(LOG_WARNING, "ldap: user not found in LDAP: %s", user);
      return HA_FALSE;
    }

    return report_ldap("couldn't search LDAP server", r);
  }


  /* Only one result should exist */
  switch(r = ldap_count_entries(ld, *result))
  {
  case 1:
    *entry = ldap_first_entry(ld, *result);
    if(!(*dn))
    {
      *dn = ldap_get_dn(ld, *entry);
      ha_messagex(LOG_DEBUG, "ldap: found entry for user: %s", *dn);
    }
    return HA_OK;

  case 0:
    ha_messagex(LOG_WARNING, "ldap: user not found in LDAP: %s", user);
    break;

  default:
    ha_messagex(LOG_WARNING, "ldap: more than one user found for filter: %s", filter);
    break;
  };

  return HA_FALSE;
}

static int complete_digest_ha1(ldap_context_t* ctx, digest_record_t* rec,
                               ha_buffer_t* buf, const char* user)
{
  LDAP* ld = NULL;                /* freed in finally */
  LDAPMessage* results = NULL;    /* freed in finally */
  LDAPMessage* entry = NULL;      /* no need to free */
  struct berval** ha1s = NULL;    /* freed manually */
  char** pws;
  int ret = HA_FALSE;
  const char* dn = NULL;
  int r;

  ASSERT(ctx && rec && buf && user);

  ld = get_ldap_connection(ctx);
  if(!ld)
  {
    ret = HA_FAILED;
    goto finally;
  }

  /*
   * Discover the DN of the user. If there's a DN map string
   * then we can do this really quickly here without querying
   * the LDAP tree
   */
  if(ctx->dnmap)
  {
    /* The map can have %u and %r to denote user and realm */
    dn = substitute_params(ctx, buf, user, ctx->dnmap);
    if(!dn)
    {
      ret = HA_CRITERROR;
      goto finally;
    }

    ha_messagex(LOG_INFO, "ldap: mapped %s to %s", user, dn);
  }

  /* Okay now we contact the LDAP server. */
  r = retrieve_user_entry(ctx, buf, ld, user, &dn, &entry, &results);
  if(r != HA_OK)
  {
    ret = r;
    goto finally;
  }

  /* Figure out the users ha1 */
  if(ctx->ha1_attr)
    ha1s = ldap_get_values_len(ld, entry, ctx->ha1_attr);

  if(ha1s)
  {
    if(*ha1s)
    {
      ret = parse_ldap_ha1(buf, *ha1s, rec->ha1);
      if(ret != HA_OK)
      {
        if(ret == HA_FALSE)
          ha_messagex(LOG_ERR, "ldap: server contains invalid HA1 for user: %s", user);
      }
    }

    ha_messagex(LOG_DEBUG, "ldap: using HA1 from ldap");
    ldap_value_free_len(ha1s);
    goto finally;
  }

  /* If no ha1 set or none found, use password and make a HA1 */
  pws = ldap_get_values(ld, entry, ctx->pw_attr);

  if(pws)
  {
    /* Find a cleartext password */
    const char* t = find_cleartext_password(buf, (const char**)pws);

    if(t)
    {
      digest_makeha1(rec->ha1, user, ctx->opts->realm, t);
      ret = HA_OK;
    }

    ldap_value_free(pws);

    if(ret == HA_OK)
    {
      ha_messagex(LOG_DEBUG, "ldap: using clear password from ldap");
      goto finally;
    }
  }

  ha_messagex(LOG_ERR, "ldap: server contains no clear password or HA1 for user: %s", user);

finally:

  if(ld)
    save_ldap_connection(ctx, ld);

  if(results)
    ldap_msgfree(results);

  return ret;
}

static int basic_ldap_response(ldap_context_t* ctx, const char* header,
                               ha_response_t* resp, ha_buffer_t* buf)
{
  basic_header_t basic;
  LDAP* ld = NULL;
  LDAPMessage* entry = NULL;
  LDAPMessage* results = NULL;
  const char* dn = NULL;
  int ret = HA_FALSE;
  int found = 0;
  int r;

  ASSERT(buf && header && resp && buf);

  if((r = basic_parse(header, buf, &basic)) < 0)
    return r;

  /* Past this point we don't return directly */

  /* Check and see if this connection is in the cache */
  if(have_cached_basic(ctx, basic.key))
  {
    ha_messagex(LOG_NOTICE, "ldap: validated basic user against cache: %s",
                basic.user);
    found = 1;
    ret = HA_OK;
    goto finally;
  }

  /* If we have a user name and password */
  if(!basic.user || !basic.user[0] ||
     !basic.password || !basic.password[0])
  {
    ha_messagex(LOG_NOTICE, "ldap: no valid basic auth info");
    goto finally;
  }


  ld = get_ldap_connection(ctx);
  if(!ld)
  {
    ret = HA_FAILED;
    goto finally;
  }


  /*
   * Discover the DN of the user. If there's a DN map string
   * then we can do this really quickly here without querying
   * the LDAP tree
   */
  if(ctx->dnmap)
  {
    /* The map can have %u and %r to denote user and realm */
    dn = substitute_params(ctx, buf, basic.user, ctx->dnmap);
    if(!dn)
    {
      ret = HA_CRITERROR;
      goto finally;
    }

    ha_messagex(LOG_INFO, "ldap: mapped %s to %s", basic.user, dn);
  }


  /**
   * Okay now we contact the LDAP server. There are many ways
   * this is used for different authentication modes:
   *
   * - If a dn has been mapped above, this can apply a
   *   configured filter to narrow things down.
   * - If no dn has been mapped, then this maps out a dn
   *   by using the single object the filter returns.
   * - If not in 'dobind' mode we also retrieve the password
   *   here.
   *
   * All this results in only one query to the LDAP server,
   * except for the case of dobind without a dnmap.
   */

  if(!ctx->dobind || !dn || ctx->filter)
  {
    r = retrieve_user_entry(ctx, buf, ld, basic.user, &dn, &entry, &results);
    if(r != HA_OK)
    {
      ret = r;
      goto finally;
    }
  }


  /* Now if in bind mode we try to bind as that user */
  if(ctx->dobind)
  {
    ASSERT(dn);

    r = ldap_simple_bind_s(ld, dn, basic.password);
    if(r != LDAP_SUCCESS)
    {
      if(r == LDAP_INVALID_CREDENTIALS)
        ha_messagex(LOG_WARNING, "ldap: basic authentication (via bind) failed for user: %s",
                      basic.user);

      else
        report_ldap("couldn't bind to LDAP server", r);

      goto finally;
    }

    /* It worked! */
    ha_messagex(LOG_NOTICE, "ldap: validated basic user using bind: %s", basic.user);
    found = 1;
  }


  /* Otherwise we compare the password attribute */
  else
  {
    ret = validate_ldap_password(ctx, ld, entry, buf, basic.user, basic.password);
    if(ret == HA_FALSE)
      ret = validate_ldap_ha1(ctx, ld, entry, buf, basic.user, basic.password);

    if(ret == HA_OK)
    {
      ha_messagex(LOG_NOTICE, "ldap: validated basic user password/ha1: %s", basic.user);
      found = 1;
    }

    else
    {
      ha_messagex(LOG_WARNING, "ldap: invalid, unreadable or unrecognized password for user: %s", basic.user);
    }
  }


finally:

  if(ld)
    save_ldap_connection(ctx, ld);

  if(results)
    ldap_msgfree(results);

  if(found && ret >= 0)
  {
    resp->code = HA_SERVER_ACCEPT;
    resp->detail = basic.user;

    /* We put this connection into the successful connections */
    ret = add_cached_basic(ctx, basic.key);
  }

  return ret;
}

static int digest_ldap_challenge(ldap_context_t* ctx, ha_response_t* resp,
                                 ha_buffer_t* buf, int stale)
{
  unsigned char nonce[DIGEST_NONCE_LEN];
  const char* nonce_str;
  const char* header;

  ASSERT(ctx && resp && buf);

#ifdef _DEBUG
  if(ctx->opts->digest_debugnonce)
  {
    nonce_str = ctx->opts->digest_debugnonce;
    ha_messagex(LOG_WARNING, "simple: using debug nonce. security non-existant.");
  }
  else
#endif
  {
    unsigned char nonce[DIGEST_NONCE_LEN];
    digest_makenonce(nonce, g_ldap_secret, NULL);

    nonce_str = ha_bufenchex(buf, nonce, DIGEST_NONCE_LEN);
    if(!nonce_str)
      return HA_CRITERROR;
  }

  /* Now generate a message to send */
  header = digest_challenge(buf, nonce_str, ctx->opts->realm,
                            ctx->opts->digest_domains, stale);

  if(!header)
    return HA_CRITERROR;

  /* And append it nicely */
  resp->code = HA_SERVER_DECLINE;
  ha_addheader(resp, "WWW-Authenticate", header);

  ha_messagex(LOG_DEBUG, "ldap: created digest challenge with nonce: %s", nonce_str);
  return HA_OK;
}

static int digest_ldap_response(ldap_context_t* ctx, const char* header,
                                const char* method, const char* uri,
                               ha_response_t* resp, ha_buffer_t* buf)
{
  unsigned char nonce[DIGEST_NONCE_LEN];
  digest_header_t dg;
  digest_record_t* rec = NULL;
  const char* t;
  time_t expiry;
  int ret = HA_FALSE;
  int stale = 0;
  int r;

  ASSERT(ctx && header && method && uri && resp && buf);

  /* We use this below to send a default response */
  resp->code = -1;

  if((r = digest_parse(header, buf, &dg, nonce)) < 0)
    return r;

#ifdef _DEBUG
  if(ctx->opts->digest_debugnonce)
  {
    if(dg.nonce && strcmp(dg.nonce, ctx->opts->digest_debugnonce) != 0)
    {
      ret = HA_FALSE;
      resp->code = HA_SERVER_BADREQ;
      ha_messagex(LOG_WARNING, "ldap: digest response contains invalid nonce");
      goto finally;
    }

    /* Do a rough hash into the real nonce, for use as a key */
    md5_string(nonce, ctx->opts->digest_debugnonce);

    /* Debug nonce's never expire */
    expiry = time(NULL);
  }
  else
#endif
  {
    r = digest_checknonce(nonce, g_ldap_secret, &expiry);
    if(r != HA_OK)
    {
      if(r == HA_FALSE)
      {
        resp->code = HA_SERVER_BADREQ;
        ha_messagex(LOG_WARNING, "ldap: digest response contains invalid nonce");
      }

      goto finally;
    }
  }

  rec = get_cached_digest(ctx, nonce);

  /* Check to see if we're stale */
  if((expiry + ctx->opts->cache_timeout) <= time(NULL))
  {
    ha_messagex(LOG_INFO, "ldap: nonce expired, sending stale challenge: %s",
                dg.username);

    stale = 1;
    goto finally;
  }

  if(!rec)
  {
    ha_messagex(LOG_INFO, "ldap: no record in cache, creating one: %s", dg.username);

    /*
     * If we're valid but don't have a record in the
     * cache then complete the record properly.
     */

    rec = digest_makerec(nonce, dg.username);
    if(!rec)
    {
      ret = HA_CRITERROR;
      goto finally;
    }

    r = complete_digest_ha1(ctx, rec, buf, dg.username);
    if(r != HA_OK)
    {
      ret = r;
      goto finally;
    }
  }

  /* Increment our nonce count */
  rec->nc++;

  ret = digest_check(ctx->opts->realm, method,
                     ctx->opts->digest_ignoreuri ? NULL : uri, buf, &dg, rec);

  if(ret == HA_BADREQ)
  {
    ret = HA_FALSE;
    resp->code = HA_SERVER_BADREQ;
  }

  else if(ret == HA_OK)
  {
    resp->code = HA_SERVER_ACCEPT;
    resp->detail = dg.username;

    /* Figure out if we need a new nonce */
    if((expiry + (ctx->opts->cache_timeout -
                  (ctx->opts->cache_timeout / 8))) < time(NULL))
    {
      ha_messagex(LOG_INFO, "ldap: nonce almost expired, creating new one: %s",
                  dg.username);

      digest_makenonce(nonce, g_ldap_secret, NULL);
      stale = 1;
    }

    t = digest_respond(buf, &dg, rec, stale ? nonce : NULL);
    if(!t)
    {
      ret = HA_CRITERROR;
      goto finally;
    }

    if(t[0])
      ha_addheader(resp, "Authentication-Info", t);

    ha_messagex(LOG_NOTICE, "ldap: validated digest user: %s", dg.username);

    /* Put the connection into the cache */
    if((r = save_cached_digest(ctx, rec)) < 0)
      ret = r;

    rec = NULL;
  }

finally:

  /* If the record wasn't stored away then free it */
  if(rec)
    free(rec);

  /* If nobody above responded then challenge the client again */
  if(resp->code == -1)
    return digest_ldap_challenge(ctx, resp, buf, stale);

  return ret;
}


/* -------------------------------------------------------------------------------
 * Handler Functions
 */

int ldap_config(ha_context_t* context, const char* name, const char* value)
{
  ldap_context_t* ctx = (ldap_context_t*)(context->data);

  ASSERT(name && value && value[0]);

  if(strcmp(name, "ldapservers") == 0)
  {
    ctx->servers = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldapfilter") == 0)
  {
    ctx->filter = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldapbase") == 0)
  {
    ctx->base = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldappwattr") == 0)
  {
    ctx->pw_attr = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldapha1attr") == 0)
  {
    ctx->ha1_attr = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldapuser") == 0)
  {
    ctx->user = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldappassword") == 0)
  {
    ctx->password = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldapdnmap") == 0)
  {
    ctx->dnmap = value;
    return HA_OK;
  }

  else if(strcmp(name, "ldapscope") == 0)
  {
    if(strcmp(value, "sub") == 0 || strcmp(value, "subtree") == 0)
      ctx->scope = LDAP_SCOPE_SUBTREE;
    else if(strcmp(value, "base") == 0)
      ctx->scope = LDAP_SCOPE_BASE;
    else if(strcmp(value, "one") == 0 || strcmp(value, "onelevel") == 0)
      ctx->scope = LDAP_SCOPE_ONELEVEL;

    else
    {
      ha_messagex(LOG_ERR, "invalid value for '%s' (must be 'sub', 'base' or 'one')", name);
      return HA_FAILED;
    }

    return HA_OK;
  }

  else if(strcmp(name, "ldapdobind") == 0)
  {
    return ha_confbool(name, value, &(ctx->dobind));
  }

  else if(strcmp(name, "ldapmax") == 0)
  {
    return ha_confint(name, value, 1, 256, &(ctx->ldap_max));
  }

  else if(strcmp(name, "ldaptimeout") == 0)
  {
    return ha_confint(name, value, 0, 86400, &(ctx->ldap_timeout));
  }

  return HA_FALSE;
}

int ldap_inithand(ha_context_t* context)
{
  /* Global initialization */
  if(!context)
  {
    ha_messagex(LOG_DEBUG, "ldap: generating secret");
    return ha_genrandom(g_ldap_secret, DIGEST_SECRET_LEN);
  }


  /* Context specific initialization */
  else
  {
    ldap_context_t* ctx = (ldap_context_t*)(context->data);

    ASSERT(ctx);

    /* Make sure there are some types of authentication we can do */
    if(!(context->opts.types & (HA_TYPE_BASIC | HA_TYPE_DIGEST)))
    {
      ha_messagex(LOG_ERR, "ldap: module configured, but does not implement any "
                           "configured authentication type.");
      return HA_FAILED;
    }

    /* Check for mandatory configuration */
    if(!ctx->servers)
    {
      ha_messagex(LOG_ERR, "ldap: configuration incomplete. "
                           "Must have LDAPServers.");
      return HA_FAILED;
    }

    if(!ctx->dnmap && (!ctx->filter || !ctx->base))
    {
      ha_messagex(LOG_ERR, "ldap: configuration incomplete. "
                           "When not using LDAPDNMap must specify LDAPBase and LDAPFilter.");
      return HA_FAILED;
    }

    /* The cache for digest records and basic */
    if(!(ctx->cache = hash_create(MD5_LEN, free_hash_object, NULL)))
    {
      ha_messagex(LOG_CRIT, "out of memory");
      return HA_CRITERROR;
    }

    ASSERT(!ctx->pool);
    ASSERT(ctx->ldap_max > 0);

    /*
     * Our connection pool. It's the size of our maximum
     * amount of pending connections as that's the max
     * we'd be able to use at a time anyway.
     */
    ctx->pool = (LDAP**)malloc(sizeof(LDAP*) * ctx->ldap_max);
    if(!ctx->pool)
    {
      ha_messagex(LOG_CRIT, "out of memory");
      return HA_CRITERROR;
    }

    memset(ctx->pool, 0, sizeof(LDAP*) * ctx->ldap_max);

    /* Copy some settings over for easy access */
    ctx->opts = &(context->opts);

    ha_messagex(LOG_INFO, "ldap: initialized handler");
  }

  return HA_OK;
}

void ldap_destroy(ha_context_t* context)
{
  int i;

  if(!context)
    return;

  /* Note: We don't need to be thread safe here anymore */
  ldap_context_t* ctx = (ldap_context_t*)(context->data);

  ASSERT(ctx);

  if(ctx->cache)
    hash_free(ctx->cache);

  if(ctx->pool)
  {
    /* Close any connections we have open */
    for(i = 0; i < ctx->ldap_max; i++)
    {
      if(ctx->pool[i])
        ldap_unbind_s(ctx->pool[i]);
    }

    /* And free the connection pool */
    free(ctx->pool);
  }

  ha_messagex(LOG_INFO, "ldap: uninitialized handler");
}

int ldap_process(ha_context_t* context, ha_request_t* req,
                 ha_response_t* resp, ha_buffer_t* buf)
{
  ldap_context_t* ctx = (ldap_context_t*)context->data;
  time_t t = time(NULL);
  const char* header = NULL;
  int ret, r;

  ASSERT(req && resp && buf);
  ASSERT(req->args[AUTH_ARG_METHOD]);
  ASSERT(req->args[AUTH_ARG_URI]);

  ha_lock(NULL);

    /* Purge out stale connection stuff. */
    r = hash_purge(ctx->cache, t - ctx->opts->cache_timeout);

  ha_unlock(NULL);

  if(r > 0)
    ha_messagex(LOG_DEBUG, "ldap: purged cache records: %d", r);

  /* We use this below to detect whether to send a default response */
  resp->code = -1;


  /* Check the headers and see if we got a response thingy */
  if(context->opts.types & HA_TYPE_DIGEST)
  {
    header = ha_getheader(req, "Authorization", HA_PREFIX_DIGEST);
    if(header)
    {
      ha_messagex(LOG_DEBUG, "ldap: processing basic auth header");
      ret = digest_ldap_response(ctx, header, req->args[AUTH_ARG_METHOD],
                                 req->args[AUTH_ARG_URI], resp, buf);
      if(ret < 0)
        return ret;
    }
  }

  /* Or a basic authentication */
  if(!header && context->opts.types & HA_TYPE_BASIC)
  {
    header = ha_getheader(req, "Authorization", HA_PREFIX_BASIC);
    if(header)
    {
      ha_messagex(LOG_DEBUG, "ldap: processing digest auth header");
      ret = basic_ldap_response(ctx, header, resp, buf);
      if(ret < 0)
        return ret;
    }
  }


  /* Send a default response if that's what we need */
  if(resp->code == -1)
  {
    resp->code = HA_SERVER_DECLINE;

    if(context->opts.types & HA_TYPE_BASIC)
    {
      ha_bufmcat(buf, "BASIC realm=\"", ctx->opts->realm , "\"", NULL);

      if(ha_buferr(buf))
        return HA_CRITERROR;

      ha_addheader(resp, "WWW-Authenticate", ha_bufdata(buf));
      ha_messagex(LOG_DEBUG, "ldap: sent basic auth request");
    }

    if(context->opts.types & HA_TYPE_DIGEST)
    {
      ret = digest_ldap_challenge(ctx, resp, buf, 0);
      if(ret < 0)
        return ret;
    }
  }

  return ret;
}


/* -------------------------------------------------------------------------------
 * Handler Definition
 */

ha_handler_t ldap_handler =
{
  "LDAP",                  /* The type */
  ldap_inithand,         /* Initialization function */
  ldap_destroy,            /* Uninitialization routine */
  ldap_config,             /* Config routine */
  ldap_process,            /* Processing routine */
  &ldap_defaults,          /* The context defaults */
  sizeof(ldap_context_t)
};