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src/subversion/subversion/svnserve/serve.c  view on Meta::CPAN

{
  authz_baton_t *sb = baton;

  return authz_check_access(allowed, path, svn_authz_read,
                            sb->server, sb->conn, pool);
}

/* If authz is enabled in the specified BATON, return a read authorization
   function. Otherwise, return NULL. */
static svn_repos_authz_func_t authz_check_access_cb_func(server_baton_t *baton)
{
  if (baton->authzdb)
     return authz_check_access_cb;
  return NULL;
}

/* Set *ALLOWED to TRUE if the REQUIRED access to PATH is granted,
 * according to the state in BATON.  Use POOL for temporary
 * allocations only.  ROOT is not used.  Implements the
 * svn_repos_authz_callback_t interface.
 */
static svn_error_t *authz_commit_cb(svn_repos_authz_access_t required,
                                    svn_boolean_t *allowed,
                                    svn_fs_root_t *root,
                                    const char *path,
                                    void *baton,
                                    apr_pool_t *pool)
{
  authz_baton_t *sb = baton;

  return authz_check_access(allowed, path, required,
                            sb->server, sb->conn, pool);
}


enum access_type get_access(server_baton_t *b, enum authn_type auth)
{
  const char *var = (auth == AUTHENTICATED) ? SVN_CONFIG_OPTION_AUTH_ACCESS :
    SVN_CONFIG_OPTION_ANON_ACCESS;
  const char *val, *def = (auth == AUTHENTICATED) ? "write" : "read";
  enum access_type result;

  svn_config_get(b->cfg, &val, SVN_CONFIG_SECTION_GENERAL, var, def);
  result = (strcmp(val, "write") == 0 ? WRITE_ACCESS :
            strcmp(val, "read") == 0 ? READ_ACCESS : NO_ACCESS);
  return (result == WRITE_ACCESS && b->read_only) ? READ_ACCESS : result;
}

static enum access_type current_access(server_baton_t *b)
{
  return get_access(b, (b->user) ? AUTHENTICATED : UNAUTHENTICATED);
}

/* Send authentication mechs for ACCESS_TYPE to the client.  If NEEDS_USERNAME
   is true, don't send anonymous mech even if that would give the desired
   access. */
static svn_error_t *send_mechs(svn_ra_svn_conn_t *conn, apr_pool_t *pool,
                               server_baton_t *b, enum access_type required,
                               svn_boolean_t needs_username)
{
  if (!needs_username && get_access(b, UNAUTHENTICATED) >= required)
    SVN_ERR(svn_ra_svn__write_word(conn, pool, "ANONYMOUS"));
  if (b->tunnel_user && get_access(b, AUTHENTICATED) >= required)
    SVN_ERR(svn_ra_svn__write_word(conn, pool, "EXTERNAL"));
  if (b->pwdb && get_access(b, AUTHENTICATED) >= required)
    SVN_ERR(svn_ra_svn__write_word(conn, pool, "CRAM-MD5"));
  return SVN_NO_ERROR;
}

/* Context for cleanup handler. */
struct cleanup_fs_access_baton
{
  svn_fs_t *fs;
  apr_pool_t *pool;
};

/* Pool cleanup handler.  Make sure fs's access_t points to NULL when
   the command pool is destroyed. */
static apr_status_t cleanup_fs_access(void *data)
{
  svn_error_t *serr;
  struct cleanup_fs_access_baton *baton = data;

  serr = svn_fs_set_access(baton->fs, NULL);
  if (serr)
    {
      apr_status_t apr_err = serr->apr_err;
      svn_error_clear(serr);
      return apr_err;
    }

  return APR_SUCCESS;
}


/* Create an svn_fs_access_t in POOL for USER and associate it with
   B's filesystem.  Also, register a cleanup handler with POOL which
   de-associates the svn_fs_access_t from B's filesystem. */
static svn_error_t *
create_fs_access(server_baton_t *b, apr_pool_t *pool)
{
  svn_fs_access_t *fs_access;
  struct cleanup_fs_access_baton *cleanup_baton;

  if (!b->user)
    return SVN_NO_ERROR;

  SVN_ERR(svn_fs_create_access(&fs_access, b->user, pool));
  SVN_ERR(svn_fs_set_access(b->fs, fs_access));

  cleanup_baton = apr_pcalloc(pool, sizeof(*cleanup_baton));
  cleanup_baton->pool = pool;
  cleanup_baton->fs = b->fs;
  apr_pool_cleanup_register(pool, cleanup_baton, cleanup_fs_access,
                            apr_pool_cleanup_null);

  return SVN_NO_ERROR;
}

/* Authenticate, once the client has chosen a mechanism and possibly
 * sent an initial mechanism token.  On success, set *success to true
 * and b->user to the authenticated username (or NULL for anonymous).
 * On authentication failure, report failure to the client and set
 * *success to FALSE.  On communications failure, return an error.
 * If NEEDS_USERNAME is TRUE, don't allow anonymous authentication. */
static svn_error_t *auth(svn_ra_svn_conn_t *conn, apr_pool_t *pool,
                         const char *mech, const char *mecharg,
                         server_baton_t *b, enum access_type required,
                         svn_boolean_t needs_username,
                         svn_boolean_t *success)
{
  const char *user;
  *success = FALSE;

  if (get_access(b, AUTHENTICATED) >= required
      && b->tunnel_user && strcmp(mech, "EXTERNAL") == 0)
    {
      if (*mecharg && strcmp(mecharg, b->tunnel_user) != 0)
        return svn_ra_svn__write_tuple(conn, pool, "w(c)", "failure",
                                       "Requested username does not match");
      b->user = b->tunnel_user;
      SVN_ERR(svn_ra_svn__write_tuple(conn, pool, "w()", "success"));
      *success = TRUE;
      return SVN_NO_ERROR;
    }

  if (get_access(b, UNAUTHENTICATED) >= required
      && strcmp(mech, "ANONYMOUS") == 0 && ! needs_username)
    {
      SVN_ERR(svn_ra_svn__write_tuple(conn, pool, "w()", "success"));
      *success = TRUE;
      return SVN_NO_ERROR;
    }

  if (get_access(b, AUTHENTICATED) >= required
      && b->pwdb && strcmp(mech, "CRAM-MD5") == 0)
    {
      SVN_ERR(svn_ra_svn_cram_server(conn, pool, b->pwdb, &user, success));
      b->user = apr_pstrdup(b->pool, user);
      return SVN_NO_ERROR;
    }

  return svn_ra_svn__write_tuple(conn, pool, "w(c)", "failure",
                                "Must authenticate with listed mechanism");
}

/* Perform an authentication request using the built-in SASL implementation. */
static svn_error_t *
internal_auth_request(svn_ra_svn_conn_t *conn, apr_pool_t *pool,
                      server_baton_t *b, enum access_type required,
                      svn_boolean_t needs_username)
{
  svn_boolean_t success;
  const char *mech, *mecharg;

  SVN_ERR(svn_ra_svn__write_tuple(conn, pool, "w((!", "success"));
  SVN_ERR(send_mechs(conn, pool, b, required, needs_username));
  SVN_ERR(svn_ra_svn__write_tuple(conn, pool, "!)c)", b->realm));
  do
    {
      SVN_ERR(svn_ra_svn__read_tuple(conn, pool, "w(?c)", &mech, &mecharg));
      if (!*mech)
        break;
      SVN_ERR(auth(conn, pool, mech, mecharg, b, required, needs_username,
                   &success));
    }
  while (!success);
  return SVN_NO_ERROR;
}

/* Perform an authentication request in order to get an access level of
 * REQUIRED or higher.  Since the client may escape the authentication
 * exchange, the caller should check current_access(b) to see if
 * authentication succeeded. */
static svn_error_t *auth_request(svn_ra_svn_conn_t *conn, apr_pool_t *pool,
                                 server_baton_t *b, enum access_type required,
                                 svn_boolean_t needs_username)
{
#ifdef SVN_HAVE_SASL
  if (b->use_sasl)
    return cyrus_auth_request(conn, pool, b, required, needs_username);
#endif

  return internal_auth_request(conn, pool, b, required, needs_username);
}

/* Send a trivial auth notification on CONN which lists no mechanisms,
 * indicating that authentication is unnecessary.  Usually called in
 * response to invocation of a svnserve command.
 */
static svn_error_t *trivial_auth_request(svn_ra_svn_conn_t *conn,
                                         apr_pool_t *pool, server_baton_t *b)
{
  return svn_ra_svn__write_cmd_response(conn, pool, "()c", "");
}