diff --git a/lib/common/crmcommon_private.h b/lib/common/crmcommon_private.h
index dbf924f2bb..3020be377c 100644
--- a/lib/common/crmcommon_private.h
+++ b/lib/common/crmcommon_private.h
@@ -1,327 +1,286 @@
 /*
  * Copyright 2018-2023 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
  * This source code is licensed under the GNU Lesser General Public License
  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
  */
 
 #ifndef CRMCOMMON_PRIVATE__H
 #  define CRMCOMMON_PRIVATE__H
 
 /* This header is for the sole use of libcrmcommon, so that functions can be
  * declared with G_GNUC_INTERNAL for efficiency.
  */
 
 #include <stdint.h>         // uint8_t, uint32_t
 #include <stdbool.h>        // bool
 #include <sys/types.h>      // size_t
 #include <glib.h>           // GList
 #include <libxml/tree.h>    // xmlNode, xmlAttr
 #include <qb/qbipcc.h>      // struct qb_ipc_response_header
 
 // Decent chunk size for processing large amounts of data
 #define PCMK__BUFFER_SIZE 4096
 
 #if defined(PCMK__UNIT_TESTING)
 #undef G_GNUC_INTERNAL
 #define G_GNUC_INTERNAL
 #endif
 
 /* When deleting portions of an XML tree, we keep a record so we can know later
  * (e.g. when checking differences) that something was deleted.
  */
 typedef struct pcmk__deleted_xml_s {
         char *path;
         int position;
 } pcmk__deleted_xml_t;
 
 typedef struct xml_node_private_s {
         long check;
         uint32_t flags;
 } xml_node_private_t;
 
 typedef struct xml_doc_private_s {
         long check;
         uint32_t flags;
         char *user;
         GList *acls;
         GList *deleted_objs; // List of pcmk__deleted_xml_t
 } xml_doc_private_t;
 
 #define pcmk__set_xml_flags(xml_priv, flags_to_set) do {                    \
         (xml_priv)->flags = pcmk__set_flags_as(__func__, __LINE__,          \
             LOG_NEVER, "XML", "XML node", (xml_priv)->flags,                \
             (flags_to_set), #flags_to_set);                                 \
     } while (0)
 
 #define pcmk__clear_xml_flags(xml_priv, flags_to_clear) do {                \
         (xml_priv)->flags = pcmk__clear_flags_as(__func__, __LINE__,        \
             LOG_NEVER, "XML", "XML node", (xml_priv)->flags,                \
             (flags_to_clear), #flags_to_clear);                             \
     } while (0)
 
 G_GNUC_INTERNAL
 void pcmk__xml2text(xmlNodePtr data, uint32_t options, GString *buffer,
                     int depth);
 
 G_GNUC_INTERNAL
 bool pcmk__tracking_xml_changes(xmlNode *xml, bool lazy);
 
 G_GNUC_INTERNAL
 void pcmk__mark_xml_created(xmlNode *xml);
 
 G_GNUC_INTERNAL
 int pcmk__xml_position(const xmlNode *xml,
                        enum xml_private_flags ignore_if_set);
 
 G_GNUC_INTERNAL
 xmlNode *pcmk__xml_match(const xmlNode *haystack, const xmlNode *needle,
                          bool exact);
 
 G_GNUC_INTERNAL
 void pcmk__xml_update(xmlNode *parent, xmlNode *target, xmlNode *update,
                       bool as_diff);
 
 G_GNUC_INTERNAL
 xmlNode *pcmk__xc_match(const xmlNode *root, const xmlNode *search_comment,
                         bool exact);
 
 G_GNUC_INTERNAL
 void pcmk__xc_update(xmlNode *parent, xmlNode *target, xmlNode *update);
 
 G_GNUC_INTERNAL
 void pcmk__free_acls(GList *acls);
 
 G_GNUC_INTERNAL
 void pcmk__unpack_acl(xmlNode *source, xmlNode *target, const char *user);
 
 G_GNUC_INTERNAL
 bool pcmk__is_user_in_group(const char *user, const char *group);
 
 G_GNUC_INTERNAL
 void pcmk__apply_acl(xmlNode *xml);
 
 G_GNUC_INTERNAL
 void pcmk__apply_creation_acl(xmlNode *xml, bool check_top);
 
 G_GNUC_INTERNAL
 void pcmk__mark_xml_attr_dirty(xmlAttr *a);
 
 G_GNUC_INTERNAL
 bool pcmk__xa_filterable(const char *name);
 
 G_GNUC_INTERNAL
 void pcmk__log_xmllib_err(void *ctx, const char *fmt, ...)
 G_GNUC_PRINTF(2, 3);
 
 G_GNUC_INTERNAL
 void pcmk__mark_xml_node_dirty(xmlNode *xml);
 
 G_GNUC_INTERNAL
 bool pcmk__marked_as_deleted(xmlAttrPtr a, void *user_data);
 
 G_GNUC_INTERNAL
 void pcmk__dump_xml_attr(const xmlAttr *attr, GString *buffer);
 
 /*
  * IPC
  */
 
 #define PCMK__IPC_VERSION 1
 
 #define PCMK__CONTROLD_API_MAJOR "1"
 #define PCMK__CONTROLD_API_MINOR "0"
 
 // IPC behavior that varies by daemon
 typedef struct pcmk__ipc_methods_s {
     /*!
      * \internal
      * \brief Allocate any private data needed by daemon IPC
      *
      * \param[in,out] api  IPC API connection
      *
      * \return Standard Pacemaker return code
      */
     int (*new_data)(pcmk_ipc_api_t *api);
 
     /*!
      * \internal
      * \brief Free any private data used by daemon IPC
      *
      * \param[in,out] api_data  Data allocated by new_data() method
      */
     void (*free_data)(void *api_data);
 
     /*!
      * \internal
      * \brief Perform daemon-specific handling after successful connection
      *
      * Some daemons require clients to register before sending any other
      * commands. The controller requires a CRM_OP_HELLO (with no reply), and
      * the CIB manager, executor, and fencer require a CRM_OP_REGISTER (with a
      * reply). Ideally this would be consistent across all daemons, but for now
      * this allows each to do its own authorization.
      *
      * \param[in,out] api  IPC API connection
      *
      * \return Standard Pacemaker return code
      */
     int (*post_connect)(pcmk_ipc_api_t *api);
 
     /*!
      * \internal
      * \brief Check whether an IPC request results in a reply
      *
      * \param[in,out] api      IPC API connection
      * \param[in,out] request  IPC request XML
      *
      * \return true if request would result in an IPC reply, false otherwise
      */
     bool (*reply_expected)(pcmk_ipc_api_t *api, xmlNode *request);
 
     /*!
      * \internal
      * \brief Perform daemon-specific handling of an IPC message
      *
      * \param[in,out] api  IPC API connection
      * \param[in,out] msg  Message read from IPC connection
      *
      * \return true if more IPC reply messages should be expected
      */
     bool (*dispatch)(pcmk_ipc_api_t *api, xmlNode *msg);
 
     /*!
      * \internal
      * \brief Perform daemon-specific handling of an IPC disconnect
      *
      * \param[in,out] api  IPC API connection
      */
     void (*post_disconnect)(pcmk_ipc_api_t *api);
 } pcmk__ipc_methods_t;
 
 // Implementation of pcmk_ipc_api_t
 struct pcmk_ipc_api_s {
     enum pcmk_ipc_server server;          // Daemon this IPC API instance is for
     enum pcmk_ipc_dispatch dispatch_type; // How replies should be dispatched
     size_t ipc_size_max;                  // maximum IPC buffer size
     crm_ipc_t *ipc;                       // IPC connection
     mainloop_io_t *mainloop_io;     // If using mainloop, I/O source for IPC
     bool free_on_disconnect;        // Whether disconnect should free object
     pcmk_ipc_callback_t cb;         // Caller-registered callback (if any)
     void *user_data;                // Caller-registered data (if any)
     void *api_data;                 // For daemon-specific use
     pcmk__ipc_methods_t *cmds;      // Behavior that varies by daemon
 };
 
 typedef struct pcmk__ipc_header_s {
     struct qb_ipc_response_header qb;
     uint32_t size_uncompressed;
     uint32_t size_compressed;
     uint32_t flags;
     uint8_t version;
 } pcmk__ipc_header_t;
 
 G_GNUC_INTERNAL
 int pcmk__send_ipc_request(pcmk_ipc_api_t *api, xmlNode *request);
 
 G_GNUC_INTERNAL
 void pcmk__call_ipc_callback(pcmk_ipc_api_t *api,
                              enum pcmk_ipc_event event_type,
                              crm_exit_t status, void *event_data);
 
 G_GNUC_INTERNAL
 unsigned int pcmk__ipc_buffer_size(unsigned int max);
 
 G_GNUC_INTERNAL
 bool pcmk__valid_ipc_header(const pcmk__ipc_header_t *header);
 
 G_GNUC_INTERNAL
 pcmk__ipc_methods_t *pcmk__attrd_api_methods(void);
 
 G_GNUC_INTERNAL
 pcmk__ipc_methods_t *pcmk__controld_api_methods(void);
 
 G_GNUC_INTERNAL
 pcmk__ipc_methods_t *pcmk__pacemakerd_api_methods(void);
 
 G_GNUC_INTERNAL
 pcmk__ipc_methods_t *pcmk__schedulerd_api_methods(void);
 
 
 /*
  * Logging
  */
 
 //! XML is newly created
 #define PCMK__XML_PREFIX_CREATED "++"
 
 //! XML has been deleted
 #define PCMK__XML_PREFIX_DELETED "--"
 
 //! XML has been modified
 #define PCMK__XML_PREFIX_MODIFIED "+ "
 
 //! XML has been moved
 #define PCMK__XML_PREFIX_MOVED "+~"
 
-/*!
- * \brief Check the authenticity of the IPC socket peer process
- *
- * If everything goes well, peer's authenticity is verified by the means
- * of comparing against provided referential UID and GID (either satisfies),
- * and the result of this check can be deduced from the return value.
- * As an exception, detected UID of 0 ("root") satisfies arbitrary
- * provided referential daemon's credentials.
- *
- * \param[in]  qb_ipc  libqb client connection if available
- * \param[in]  sock    IPC related, connected Unix socket to check peer of
- * \param[in]  refuid  referential UID to check against
- * \param[in]  refgid  referential GID to check against
- * \param[out] gotpid  to optionally store obtained PID of the peer
- *                     (not available on FreeBSD, special value of 1
- *                     used instead, and the caller is required to
- *                     special case this value respectively)
- * \param[out] gotuid  to optionally store obtained UID of the peer
- * \param[out] gotgid  to optionally store obtained GID of the peer
- *
- * \return Standard Pacemaker return code
- *         ie: 0 if it the connection is authentic
- *         pcmk_rc_ipc_unauthorized if the connection is not authentic,
- *         standard errors.
- *
- * \note While this function is tolerant on what constitutes authorized
- *       IPC daemon process (its effective user matches UID=0 or \p refuid,
- *       or at least its group matches \p refgid), either or both (in case
- *       of UID=0) mismatches on the expected credentials of such peer
- *       process \e shall be investigated at the caller when value of 1
- *       gets returned there, since higher-than-expected privileges in
- *       respect to the expected/intended credentials possibly violate
- *       the least privilege principle and may pose an additional risk
- *       (i.e. such accidental inconsistency shall be eventually fixed).
- */
-int pcmk__crm_ipc_is_authentic_process(qb_ipcc_connection_t *qb_ipc, int sock,
-                                       uid_t refuid, gid_t refgid,
-                                       pid_t *gotpid, uid_t *gotuid,
-                                       gid_t *gotgid);
-
-
 /*
  * Output
  */
 G_GNUC_INTERNAL
 int pcmk__bare_output_new(pcmk__output_t **out, const char *fmt_name,
                           const char *filename, char **argv);
 
 G_GNUC_INTERNAL
 void pcmk__register_patchset_messages(pcmk__output_t *out);
 
 
 /*
  * Utils
  */
 #define PCMK__PW_BUFFER_LEN 500
 
 
 #endif  // CRMCOMMON_PRIVATE__H
diff --git a/lib/common/ipc_client.c b/lib/common/ipc_client.c
index e3002fde29..3ef5c127b4 100644
--- a/lib/common/ipc_client.c
+++ b/lib/common/ipc_client.c
@@ -1,1574 +1,1596 @@
 /*
  * Copyright 2004-2023 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
  * This source code is licensed under the GNU Lesser General Public License
  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
  */
 
 #include <crm_internal.h>
 
 #if defined(HAVE_UCRED) || defined(HAVE_SOCKPEERCRED)
 #  ifdef HAVE_UCRED
 #    ifndef _GNU_SOURCE
 #      define _GNU_SOURCE
 #    endif
 #  endif
 #  include <sys/socket.h>
 #elif defined(HAVE_GETPEERUCRED)
 #  include <ucred.h>
 #endif
 
 #include <stdio.h>
 #include <sys/types.h>
 #include <errno.h>
 #include <bzlib.h>
 
 #include <crm/crm.h>   /* indirectly: pcmk_err_generic */
 #include <crm/msg_xml.h>
 #include <crm/common/ipc.h>
 #include <crm/common/ipc_internal.h>
 #include "crmcommon_private.h"
 
+static int is_ipc_provider_expected(qb_ipcc_connection_t *qb_ipc, int sock,
+                                    uid_t refuid, gid_t refgid, pid_t *gotpid,
+                                    uid_t *gotuid, gid_t *gotgid);
+
 /*!
  * \brief Create a new object for using Pacemaker daemon IPC
  *
  * \param[out] api     Where to store new IPC object
  * \param[in]  server  Which Pacemaker daemon the object is for
  *
  * \return Standard Pacemaker result code
  *
  * \note The caller is responsible for freeing *api using pcmk_free_ipc_api().
  * \note This is intended to supersede crm_ipc_new() but currently only
  *       supports the controller, pacemakerd, and schedulerd IPC API.
  */
 int
 pcmk_new_ipc_api(pcmk_ipc_api_t **api, enum pcmk_ipc_server server)
 {
     if (api == NULL) {
         return EINVAL;
     }
 
     *api = calloc(1, sizeof(pcmk_ipc_api_t));
     if (*api == NULL) {
         return errno;
     }
 
     (*api)->server = server;
     if (pcmk_ipc_name(*api, false) == NULL) {
         pcmk_free_ipc_api(*api);
         *api = NULL;
         return EOPNOTSUPP;
     }
 
     (*api)->ipc_size_max = 0;
 
     // Set server methods and max_size (if not default)
     switch (server) {
         case pcmk_ipc_attrd:
             (*api)->cmds = pcmk__attrd_api_methods();
             break;
 
         case pcmk_ipc_based:
             (*api)->ipc_size_max = 512 * 1024; // 512KB
             break;
 
         case pcmk_ipc_controld:
             (*api)->cmds = pcmk__controld_api_methods();
             break;
 
         case pcmk_ipc_execd:
             break;
 
         case pcmk_ipc_fenced:
             break;
 
         case pcmk_ipc_pacemakerd:
             (*api)->cmds = pcmk__pacemakerd_api_methods();
             break;
 
         case pcmk_ipc_schedulerd:
             (*api)->cmds = pcmk__schedulerd_api_methods();
             // @TODO max_size could vary by client, maybe take as argument?
             (*api)->ipc_size_max = 5 * 1024 * 1024; // 5MB
             break;
     }
     if ((*api)->cmds == NULL) {
         pcmk_free_ipc_api(*api);
         *api = NULL;
         return ENOMEM;
     }
 
     (*api)->ipc = crm_ipc_new(pcmk_ipc_name(*api, false),
                               (*api)->ipc_size_max);
     if ((*api)->ipc == NULL) {
         pcmk_free_ipc_api(*api);
         *api = NULL;
         return ENOMEM;
     }
 
     // If daemon API has its own data to track, allocate it
     if ((*api)->cmds->new_data != NULL) {
         if ((*api)->cmds->new_data(*api) != pcmk_rc_ok) {
             pcmk_free_ipc_api(*api);
             *api = NULL;
             return ENOMEM;
         }
     }
     crm_trace("Created %s API IPC object", pcmk_ipc_name(*api, true));
     return pcmk_rc_ok;
 }
 
 static void
 free_daemon_specific_data(pcmk_ipc_api_t *api)
 {
     if ((api != NULL) && (api->cmds != NULL)) {
         if ((api->cmds->free_data != NULL) && (api->api_data != NULL)) {
             api->cmds->free_data(api->api_data);
             api->api_data = NULL;
         }
         free(api->cmds);
         api->cmds = NULL;
     }
 }
 
 /*!
  * \internal
  * \brief Call an IPC API event callback, if one is registed
  *
  * \param[in,out] api         IPC API connection
  * \param[in]     event_type  The type of event that occurred
  * \param[in]     status      Event status
  * \param[in,out] event_data  Event-specific data
  */
 void
 pcmk__call_ipc_callback(pcmk_ipc_api_t *api, enum pcmk_ipc_event event_type,
                         crm_exit_t status, void *event_data)
 {
     if ((api != NULL) && (api->cb != NULL)) {
         api->cb(api, event_type, status, event_data, api->user_data);
     }
 }
 
 /*!
  * \internal
  * \brief Clean up after an IPC disconnect
  *
  * \param[in,out] user_data  IPC API connection that disconnected
  *
  * \note This function can be used as a main loop IPC destroy callback.
  */
 static void
 ipc_post_disconnect(gpointer user_data)
 {
     pcmk_ipc_api_t *api = user_data;
 
     crm_info("Disconnected from %s IPC API", pcmk_ipc_name(api, true));
 
     // Perform any daemon-specific handling needed
     if ((api->cmds != NULL) && (api->cmds->post_disconnect != NULL)) {
         api->cmds->post_disconnect(api);
     }
 
     // Call client's registered event callback
     pcmk__call_ipc_callback(api, pcmk_ipc_event_disconnect, CRM_EX_DISCONNECT,
                             NULL);
 
     /* If this is being called from a running main loop, mainloop_gio_destroy()
      * will free ipc and mainloop_io immediately after calling this function.
      * If this is called from a stopped main loop, these will leak, so the best
      * practice is to close the connection before stopping the main loop.
      */
     api->ipc = NULL;
     api->mainloop_io = NULL;
 
     if (api->free_on_disconnect) {
         /* pcmk_free_ipc_api() has already been called, but did not free api
          * or api->cmds because this function needed them. Do that now.
          */
         free_daemon_specific_data(api);
         crm_trace("Freeing IPC API object after disconnect");
         free(api);
     }
 }
 
 /*!
  * \brief Free the contents of an IPC API object
  *
  * \param[in,out] api  IPC API object to free
  */
 void
 pcmk_free_ipc_api(pcmk_ipc_api_t *api)
 {
     bool free_on_disconnect = false;
 
     if (api == NULL) {
         return;
     }
     crm_debug("Releasing %s IPC API", pcmk_ipc_name(api, true));
 
     if (api->ipc != NULL) {
         if (api->mainloop_io != NULL) {
             /* We need to keep the api pointer itself around, because it is the
              * user data for the IPC client destroy callback. That will be
              * triggered by the pcmk_disconnect_ipc() call below, but it might
              * happen later in the main loop (if still running).
              *
              * This flag tells the destroy callback to free the object. It can't
              * do that unconditionally, because the application might call this
              * function after a disconnect that happened by other means.
              */
             free_on_disconnect = api->free_on_disconnect = true;
         }
         pcmk_disconnect_ipc(api); // Frees api if free_on_disconnect is true
     }
     if (!free_on_disconnect) {
         free_daemon_specific_data(api);
         crm_trace("Freeing IPC API object");
         free(api);
     }
 }
 
 /*!
  * \brief Get the IPC name used with an IPC API connection
  *
  * \param[in] api      IPC API connection
  * \param[in] for_log  If true, return human-friendly name instead of IPC name
  *
  * \return IPC API's human-friendly or connection name, or if none is available,
  *         "Pacemaker" if for_log is true and NULL if for_log is false
  */
 const char *
 pcmk_ipc_name(const pcmk_ipc_api_t *api, bool for_log)
 {
     if (api == NULL) {
         return for_log? "Pacemaker" : NULL;
     }
     switch (api->server) {
         case pcmk_ipc_attrd:
             return for_log? "attribute manager" : T_ATTRD;
 
         case pcmk_ipc_based:
             return for_log? "CIB manager" : NULL /* PCMK__SERVER_BASED_RW */;
 
         case pcmk_ipc_controld:
             return for_log? "controller" : CRM_SYSTEM_CRMD;
 
         case pcmk_ipc_execd:
             return for_log? "executor" : NULL /* CRM_SYSTEM_LRMD */;
 
         case pcmk_ipc_fenced:
             return for_log? "fencer" : NULL /* "stonith-ng" */;
 
         case pcmk_ipc_pacemakerd:
             return for_log? "launcher" : CRM_SYSTEM_MCP;
 
         case pcmk_ipc_schedulerd:
             return for_log? "scheduler" : CRM_SYSTEM_PENGINE;
 
         default:
             return for_log? "Pacemaker" : NULL;
     }
 }
 
 /*!
  * \brief Check whether an IPC API connection is active
  *
  * \param[in,out] api  IPC API connection
  *
  * \return true if IPC is connected, false otherwise
  */
 bool
 pcmk_ipc_is_connected(pcmk_ipc_api_t *api)
 {
     return (api != NULL) && crm_ipc_connected(api->ipc);
 }
 
 /*!
  * \internal
  * \brief Call the daemon-specific API's dispatch function
  *
  * Perform daemon-specific handling of IPC reply dispatch. It is the daemon
  * method's responsibility to call the client's registered event callback, as
  * well as allocate and free any event data.
  *
  * \param[in,out] api      IPC API connection
  * \param[in,out] message  IPC reply XML to dispatch
  */
 static bool
 call_api_dispatch(pcmk_ipc_api_t *api, xmlNode *message)
 {
     crm_log_xml_trace(message, "ipc-received");
     if ((api->cmds != NULL) && (api->cmds->dispatch != NULL)) {
         return api->cmds->dispatch(api, message);
     }
 
     return false;
 }
 
 /*!
  * \internal
  * \brief Dispatch previously read IPC data
  *
  * \param[in]     buffer  Data read from IPC
  * \param[in,out] api     IPC object
  *
  * \return Standard Pacemaker return code.  In particular:
  *
  * pcmk_rc_ok: There are no more messages expected from the server.  Quit
  *             reading.
  * EINPROGRESS: There are more messages expected from the server.  Keep reading.
  *
  * All other values indicate an error.
  */
 static int
 dispatch_ipc_data(const char *buffer, pcmk_ipc_api_t *api)
 {
     bool more = false;
     xmlNode *msg;
 
     if (buffer == NULL) {
         crm_warn("Empty message received from %s IPC",
                  pcmk_ipc_name(api, true));
         return ENOMSG;
     }
 
     msg = string2xml(buffer);
     if (msg == NULL) {
         crm_warn("Malformed message received from %s IPC",
                  pcmk_ipc_name(api, true));
         return EPROTO;
     }
 
     more = call_api_dispatch(api, msg);
     free_xml(msg);
 
     if (more) {
         return EINPROGRESS;
     } else {
         return pcmk_rc_ok;
     }
 }
 
 /*!
  * \internal
  * \brief Dispatch data read from IPC source
  *
  * \param[in]     buffer     Data read from IPC
  * \param[in]     length     Number of bytes of data in buffer (ignored)
  * \param[in,out] user_data  IPC object
  *
  * \return Always 0 (meaning connection is still required)
  *
  * \note This function can be used as a main loop IPC dispatch callback.
  */
 static int
 dispatch_ipc_source_data(const char *buffer, ssize_t length, gpointer user_data)
 {
     pcmk_ipc_api_t *api = user_data;
 
     CRM_CHECK(api != NULL, return 0);
     dispatch_ipc_data(buffer, api);
     return 0;
 }
 
 /*!
  * \brief Check whether an IPC connection has data available (without main loop)
  *
  * \param[in]  api         IPC API connection
  * \param[in]  timeout_ms  If less than 0, poll indefinitely; if 0, poll once
  *                         and return immediately; otherwise, poll for up to
  *                         this many milliseconds
  *
  * \return Standard Pacemaker return code
  *
  * \note Callers of pcmk_connect_ipc() using pcmk_ipc_dispatch_poll should call
  *       this function to check whether IPC data is available. Return values of
  *       interest include pcmk_rc_ok meaning data is available, and EAGAIN
  *       meaning no data is available; all other values indicate errors.
  * \todo This does not allow the caller to poll multiple file descriptors at
  *       once. If there is demand for that, we could add a wrapper for
  *       crm_ipc_get_fd(api->ipc), so the caller can call poll() themselves.
  */
 int
 pcmk_poll_ipc(const pcmk_ipc_api_t *api, int timeout_ms)
 {
     int rc;
     struct pollfd pollfd = { 0, };
 
     if ((api == NULL) || (api->dispatch_type != pcmk_ipc_dispatch_poll)) {
         return EINVAL;
     }
     pollfd.fd = crm_ipc_get_fd(api->ipc);
     pollfd.events = POLLIN;
     rc = poll(&pollfd, 1, timeout_ms);
     if (rc < 0) {
         /* Some UNIX systems return negative and set EAGAIN for failure to
          * allocate memory; standardize the return code in that case
          */
         return (errno == EAGAIN)? ENOMEM : errno;
     } else if (rc == 0) {
         return EAGAIN;
     }
     return pcmk_rc_ok;
 }
 
 /*!
  * \brief Dispatch available messages on an IPC connection (without main loop)
  *
  * \param[in,out] api  IPC API connection
  *
  * \return Standard Pacemaker return code
  *
  * \note Callers of pcmk_connect_ipc() using pcmk_ipc_dispatch_poll should call
  *       this function when IPC data is available.
  */
 void
 pcmk_dispatch_ipc(pcmk_ipc_api_t *api)
 {
     if (api == NULL) {
         return;
     }
     while (crm_ipc_ready(api->ipc) > 0) {
         if (crm_ipc_read(api->ipc) > 0) {
             dispatch_ipc_data(crm_ipc_buffer(api->ipc), api);
         }
     }
 }
 
 // \return Standard Pacemaker return code
 static int
 connect_with_main_loop(pcmk_ipc_api_t *api)
 {
     int rc;
 
     struct ipc_client_callbacks callbacks = {
         .dispatch = dispatch_ipc_source_data,
         .destroy = ipc_post_disconnect,
     };
 
     rc = pcmk__add_mainloop_ipc(api->ipc, G_PRIORITY_DEFAULT, api,
                                 &callbacks, &(api->mainloop_io));
     if (rc != pcmk_rc_ok) {
         return rc;
     }
     crm_debug("Connected to %s IPC (attached to main loop)",
               pcmk_ipc_name(api, true));
     /* After this point, api->mainloop_io owns api->ipc, so api->ipc
      * should not be explicitly freed.
      */
     return pcmk_rc_ok;
 }
 
 // \return Standard Pacemaker return code
 static int
 connect_without_main_loop(pcmk_ipc_api_t *api)
 {
     int rc;
 
     if (!crm_ipc_connect(api->ipc)) {
         rc = errno;
         crm_ipc_close(api->ipc);
         return rc;
     }
     crm_debug("Connected to %s IPC (without main loop)",
               pcmk_ipc_name(api, true));
     return pcmk_rc_ok;
 }
 
 /*!
  * \brief Connect to a Pacemaker daemon via IPC
  *
  * \param[in,out] api            IPC API instance
  * \param[in]     dispatch_type  How IPC replies should be dispatched
  *
  * \return Standard Pacemaker return code
  */
 int
 pcmk_connect_ipc(pcmk_ipc_api_t *api, enum pcmk_ipc_dispatch dispatch_type)
 {
     const int n_attempts = 2;
     int rc = pcmk_rc_ok;
 
     if (api == NULL) {
         crm_err("Cannot connect to uninitialized API object");
         return EINVAL;
     }
 
     if (api->ipc == NULL) {
         api->ipc = crm_ipc_new(pcmk_ipc_name(api, false),
                                   api->ipc_size_max);
         if (api->ipc == NULL) {
             crm_err("Failed to re-create IPC API");
             return ENOMEM;
         }
     }
 
     if (crm_ipc_connected(api->ipc)) {
         crm_trace("Already connected to %s IPC API", pcmk_ipc_name(api, true));
         return pcmk_rc_ok;
     }
 
     api->dispatch_type = dispatch_type;
 
     for (int i = 0; i < n_attempts; i++) {
         switch (dispatch_type) {
             case pcmk_ipc_dispatch_main:
                 rc = connect_with_main_loop(api);
                 break;
 
             case pcmk_ipc_dispatch_sync:
             case pcmk_ipc_dispatch_poll:
                 rc = connect_without_main_loop(api);
                 break;
         }
 
         if (rc != EAGAIN) {
             break;
         }
 
         /* EAGAIN may occur due to interruption by a signal or due to some
          * transient issue. Try one more time to be more resilient.
          */
         if (i < (n_attempts - 1)) {
             crm_trace("Connection to %s IPC API failed with EAGAIN, retrying",
                       pcmk_ipc_name(api, true));
         }
     }
 
     if (rc != pcmk_rc_ok) {
         return rc;
     }
 
     if ((api->cmds != NULL) && (api->cmds->post_connect != NULL)) {
         rc = api->cmds->post_connect(api);
         if (rc != pcmk_rc_ok) {
             crm_ipc_close(api->ipc);
         }
     }
     return rc;
 }
 
 /*!
  * \brief Disconnect an IPC API instance
  *
  * \param[in,out] api  IPC API connection
  *
  * \return Standard Pacemaker return code
  *
  * \note If the connection is attached to a main loop, this function should be
  *       called before quitting the main loop, to ensure that all memory is
  *       freed.
  */
 void
 pcmk_disconnect_ipc(pcmk_ipc_api_t *api)
 {
     if ((api == NULL) || (api->ipc == NULL)) {
         return;
     }
     switch (api->dispatch_type) {
         case pcmk_ipc_dispatch_main:
             {
                 mainloop_io_t *mainloop_io = api->mainloop_io;
 
                 // Make sure no code with access to api can use these again
                 api->mainloop_io = NULL;
                 api->ipc = NULL;
 
                 mainloop_del_ipc_client(mainloop_io);
                 // After this point api might have already been freed
             }
             break;
 
         case pcmk_ipc_dispatch_poll:
         case pcmk_ipc_dispatch_sync:
             {
                 crm_ipc_t *ipc = api->ipc;
 
                 // Make sure no code with access to api can use ipc again
                 api->ipc = NULL;
 
                 // This should always be the case already, but to be safe
                 api->free_on_disconnect = false;
 
                 crm_ipc_close(ipc);
                 crm_ipc_destroy(ipc);
                 ipc_post_disconnect(api);
             }
             break;
     }
 }
 
 /*!
  * \brief Register a callback for IPC API events
  *
  * \param[in,out] api       IPC API connection
  * \param[in]     callback  Callback to register
  * \param[in]     userdata  Caller data to pass to callback
  *
  * \note This function may be called multiple times to update the callback
  *       and/or user data. The caller remains responsible for freeing
  *       userdata in any case (after the IPC is disconnected, if the
  *       user data is still registered with the IPC).
  */
 void
 pcmk_register_ipc_callback(pcmk_ipc_api_t *api, pcmk_ipc_callback_t cb,
                            void *user_data)
 {
     if (api == NULL) {
         return;
     }
     api->cb = cb;
     api->user_data = user_data;
 }
 
 /*!
  * \internal
  * \brief Send an XML request across an IPC API connection
  *
  * \param[in,out] api      IPC API connection
  * \param[in,out] request  XML request to send
  *
  * \return Standard Pacemaker return code
  *
  * \note Daemon-specific IPC API functions should call this function to send
  *       requests, because it handles different dispatch types appropriately.
  */
 int
 pcmk__send_ipc_request(pcmk_ipc_api_t *api, xmlNode *request)
 {
     int rc;
     xmlNode *reply = NULL;
     enum crm_ipc_flags flags = crm_ipc_flags_none;
 
     if ((api == NULL) || (api->ipc == NULL) || (request == NULL)) {
         return EINVAL;
     }
     crm_log_xml_trace(request, "ipc-sent");
 
     // Synchronous dispatch requires waiting for a reply
     if ((api->dispatch_type == pcmk_ipc_dispatch_sync)
         && (api->cmds != NULL)
         && (api->cmds->reply_expected != NULL)
         && (api->cmds->reply_expected(api, request))) {
         flags = crm_ipc_client_response;
     }
 
     // The 0 here means a default timeout of 5 seconds
     rc = crm_ipc_send(api->ipc, request, flags, 0, &reply);
 
     if (rc < 0) {
         return pcmk_legacy2rc(rc);
     } else if (rc == 0) {
         return ENODATA;
     }
 
     // With synchronous dispatch, we dispatch any reply now
     if (reply != NULL) {
         bool more = call_api_dispatch(api, reply);
 
         free_xml(reply);
 
         while (more) {
             rc = crm_ipc_read(api->ipc);
 
             if (rc == -EAGAIN) {
                 continue;
             } else if (rc == -ENOMSG || rc == pcmk_ok) {
                 return pcmk_rc_ok;
             } else if (rc < 0) {
                 return -rc;
             }
 
             rc = dispatch_ipc_data(crm_ipc_buffer(api->ipc), api);
 
             if (rc == pcmk_rc_ok) {
                 more = false;
             } else if (rc == EINPROGRESS) {
                 more = true;
             } else {
                 continue;
             }
         }
     }
     return pcmk_rc_ok;
 }
 
 /*!
  * \internal
  * \brief Create the XML for an IPC request to purge a node from the peer cache
  *
  * \param[in]  api        IPC API connection
  * \param[in]  node_name  If not NULL, name of node to purge
  * \param[in]  nodeid     If not 0, node ID of node to purge
  *
  * \return Newly allocated IPC request XML
  *
  * \note The controller, fencer, and pacemakerd use the same request syntax, but
  *       the attribute manager uses a different one. The CIB manager doesn't
  *       have any syntax for it. The executor and scheduler don't connect to the
  *       cluster layer and thus don't have or need any syntax for it.
  *
  * \todo Modify the attribute manager to accept the common syntax (as well
  *       as its current one, for compatibility with older clients). Modify
  *       the CIB manager to accept and honor the common syntax. Modify the
  *       executor and scheduler to accept the syntax (immediately returning
  *       success), just for consistency. Modify this function to use the
  *       common syntax with all daemons if their version supports it.
  */
 static xmlNode *
 create_purge_node_request(const pcmk_ipc_api_t *api, const char *node_name,
                           uint32_t nodeid)
 {
     xmlNode *request = NULL;
     const char *client = crm_system_name? crm_system_name : "client";
 
     switch (api->server) {
         case pcmk_ipc_attrd:
             request = create_xml_node(NULL, __func__);
             crm_xml_add(request, F_TYPE, T_ATTRD);
             crm_xml_add(request, F_ORIG, crm_system_name);
             crm_xml_add(request, PCMK__XA_TASK, PCMK__ATTRD_CMD_PEER_REMOVE);
             pcmk__xe_add_node(request, node_name, nodeid);
             break;
 
         case pcmk_ipc_controld:
         case pcmk_ipc_fenced:
         case pcmk_ipc_pacemakerd:
             request = create_request(CRM_OP_RM_NODE_CACHE, NULL, NULL,
                                      pcmk_ipc_name(api, false), client, NULL);
             if (nodeid > 0) {
                 crm_xml_set_id(request, "%lu", (unsigned long) nodeid);
             }
             crm_xml_add(request, XML_ATTR_UNAME, node_name);
             break;
 
         case pcmk_ipc_based:
         case pcmk_ipc_execd:
         case pcmk_ipc_schedulerd:
             break;
     }
     return request;
 }
 
 /*!
  * \brief Ask a Pacemaker daemon to purge a node from its peer cache
  *
  * \param[in,out] api        IPC API connection
  * \param[in]     node_name  If not NULL, name of node to purge
  * \param[in]     nodeid     If not 0, node ID of node to purge
  *
  * \return Standard Pacemaker return code
  *
  * \note At least one of node_name or nodeid must be specified.
  */
 int
 pcmk_ipc_purge_node(pcmk_ipc_api_t *api, const char *node_name, uint32_t nodeid)
 {
     int rc = 0;
     xmlNode *request = NULL;
 
     if (api == NULL) {
         return EINVAL;
     }
     if ((node_name == NULL) && (nodeid == 0)) {
         return EINVAL;
     }
 
     request = create_purge_node_request(api, node_name, nodeid);
     if (request == NULL) {
         return EOPNOTSUPP;
     }
     rc = pcmk__send_ipc_request(api, request);
     free_xml(request);
 
     crm_debug("%s peer cache purge of node %s[%lu]: rc=%d",
               pcmk_ipc_name(api, true), node_name, (unsigned long) nodeid, rc);
     return rc;
 }
 
 /*
  * Generic IPC API (to eventually be deprecated as public API and made internal)
  */
 
 struct crm_ipc_s {
     struct pollfd pfd;
     unsigned int max_buf_size; // maximum bytes we can send or receive over IPC
     unsigned int buf_size;     // size of allocated buffer
     int msg_size;
     int need_reply;
     char *buffer;
     char *server_name;          // server IPC name being connected to
     qb_ipcc_connection_t *ipc;
 };
 
 /*!
  * \brief Create a new (legacy) object for using Pacemaker daemon IPC
  *
  * \param[in] name      IPC system name to connect to
  * \param[in] max_size  Use a maximum IPC buffer size of at least this size
  *
  * \return Newly allocated IPC object on success, NULL otherwise
  *
  * \note The caller is responsible for freeing the result using
  *       crm_ipc_destroy().
  * \note This should be considered deprecated for use with daemons supported by
  *       pcmk_new_ipc_api().
  */
 crm_ipc_t *
 crm_ipc_new(const char *name, size_t max_size)
 {
     crm_ipc_t *client = NULL;
 
     client = calloc(1, sizeof(crm_ipc_t));
     if (client == NULL) {
         crm_err("Could not create IPC connection: %s", strerror(errno));
         return NULL;
     }
 
     client->server_name = strdup(name);
     if (client->server_name == NULL) {
         crm_err("Could not create %s IPC connection: %s",
                 name, strerror(errno));
         free(client);
         return NULL;
     }
     client->buf_size = pcmk__ipc_buffer_size(max_size);
     client->buffer = malloc(client->buf_size);
     if (client->buffer == NULL) {
         crm_err("Could not create %s IPC connection: %s",
                 name, strerror(errno));
         free(client->server_name);
         free(client);
         return NULL;
     }
 
     /* Clients initiating connection pick the max buf size */
     client->max_buf_size = client->buf_size;
 
     client->pfd.fd = -1;
     client->pfd.events = POLLIN;
     client->pfd.revents = 0;
 
     return client;
 }
 
 /*!
  * \brief Establish an IPC connection to a Pacemaker component
  *
  * \param[in,out] client  Connection instance obtained from crm_ipc_new()
  *
  * \return true on success, false otherwise (in which case errno will be set;
  *         specifically, in case of discovering the remote side is not
  *         authentic, its value is set to ECONNABORTED).
  */
 bool
 crm_ipc_connect(crm_ipc_t *client)
 {
     uid_t cl_uid = 0;
     gid_t cl_gid = 0;
     pid_t found_pid = 0; uid_t found_uid = 0; gid_t found_gid = 0;
     int rv;
 
     if (client == NULL) {
         errno = EINVAL;
         return false;
     }
 
     client->need_reply = FALSE;
     client->ipc = qb_ipcc_connect(client->server_name, client->buf_size);
 
     if (client->ipc == NULL) {
         crm_debug("Could not establish %s IPC connection: %s (%d)",
                   client->server_name, pcmk_rc_str(errno), errno);
         return false;
     }
 
     client->pfd.fd = crm_ipc_get_fd(client);
     if (client->pfd.fd < 0) {
         rv = errno;
         /* message already omitted */
         crm_ipc_close(client);
         errno = rv;
         return false;
     }
 
     rv = pcmk_daemon_user(&cl_uid, &cl_gid);
     if (rv < 0) {
         /* message already omitted */
         crm_ipc_close(client);
         errno = -rv;
         return false;
     }
 
-    if ((rv = pcmk__crm_ipc_is_authentic_process(client->ipc, client->pfd.fd, cl_uid, cl_gid,
-                                                  &found_pid, &found_uid,
-                                                  &found_gid)) == pcmk_rc_ipc_unauthorized) {
+    rv = is_ipc_provider_expected(client->ipc, client->pfd.fd, cl_uid, cl_gid,
+                                  &found_pid, &found_uid, &found_gid);
+    if (rv == pcmk_rc_ipc_unauthorized) {
         crm_err("%s IPC provider authentication failed: process %lld has "
                 "uid %lld (expected %lld) and gid %lld (expected %lld)",
                 client->server_name,
                 (long long) PCMK__SPECIAL_PID_AS_0(found_pid),
                 (long long) found_uid, (long long) cl_uid,
                 (long long) found_gid, (long long) cl_gid);
         crm_ipc_close(client);
         errno = ECONNABORTED;
         return false;
 
     } else if (rv != pcmk_rc_ok) {
         crm_perror(LOG_ERR, "Could not verify authenticity of %s IPC provider",
                    client->server_name);
         crm_ipc_close(client);
         if (rv > 0) {
             errno = rv;
         } else {
             errno = ENOTCONN;
         }
         return false;
     }
 
     client->max_buf_size = qb_ipcc_get_buffer_size(client->ipc);
     if (client->max_buf_size > client->buf_size) {
         free(client->buffer);
         client->buffer = calloc(1, client->max_buf_size);
         client->buf_size = client->max_buf_size;
     }
     return true;
 }
 
 void
 crm_ipc_close(crm_ipc_t * client)
 {
     if (client) {
         if (client->ipc) {
             qb_ipcc_connection_t *ipc = client->ipc;
 
             client->ipc = NULL;
             qb_ipcc_disconnect(ipc);
         }
     }
 }
 
 void
 crm_ipc_destroy(crm_ipc_t * client)
 {
     if (client) {
         if (client->ipc && qb_ipcc_is_connected(client->ipc)) {
             crm_notice("Destroying active %s IPC connection",
                        client->server_name);
             /* The next line is basically unsafe
              *
              * If this connection was attached to mainloop and mainloop is active,
              *   the 'disconnected' callback will end up back here and we'll end
              *   up free'ing the memory twice - something that can still happen
              *   even without this if we destroy a connection and it closes before
              *   we call exit
              */
             /* crm_ipc_close(client); */
         } else {
             crm_trace("Destroying inactive %s IPC connection",
                       client->server_name);
         }
         free(client->buffer);
         free(client->server_name);
         free(client);
     }
 }
 
 int
 crm_ipc_get_fd(crm_ipc_t * client)
 {
     int fd = 0;
 
     if (client && client->ipc && (qb_ipcc_fd_get(client->ipc, &fd) == 0)) {
         return fd;
     }
     errno = EINVAL;
     crm_perror(LOG_ERR, "Could not obtain file descriptor for %s IPC",
                (client? client->server_name : "unspecified"));
     return -errno;
 }
 
 bool
 crm_ipc_connected(crm_ipc_t * client)
 {
     bool rc = FALSE;
 
     if (client == NULL) {
         crm_trace("No client");
         return FALSE;
 
     } else if (client->ipc == NULL) {
         crm_trace("No connection");
         return FALSE;
 
     } else if (client->pfd.fd < 0) {
         crm_trace("Bad descriptor");
         return FALSE;
     }
 
     rc = qb_ipcc_is_connected(client->ipc);
     if (rc == FALSE) {
         client->pfd.fd = -EINVAL;
     }
     return rc;
 }
 
 /*!
  * \brief Check whether an IPC connection is ready to be read
  *
  * \param[in,out] client  Connection to check
  *
  * \return Positive value if ready to be read, 0 if not ready, -errno on error
  */
 int
 crm_ipc_ready(crm_ipc_t *client)
 {
     int rc;
 
     CRM_ASSERT(client != NULL);
 
     if (!crm_ipc_connected(client)) {
         return -ENOTCONN;
     }
 
     client->pfd.revents = 0;
     rc = poll(&(client->pfd), 1, 0);
     return (rc < 0)? -errno : rc;
 }
 
 // \return Standard Pacemaker return code
 static int
 crm_ipc_decompress(crm_ipc_t * client)
 {
     pcmk__ipc_header_t *header = (pcmk__ipc_header_t *)(void*)client->buffer;
 
     if (header->size_compressed) {
         int rc = 0;
         unsigned int size_u = 1 + header->size_uncompressed;
         /* never let buf size fall below our max size required for ipc reads. */
         unsigned int new_buf_size = QB_MAX((sizeof(pcmk__ipc_header_t) + size_u), client->max_buf_size);
         char *uncompressed = calloc(1, new_buf_size);
 
         crm_trace("Decompressing message data %u bytes into %u bytes",
                  header->size_compressed, size_u);
 
         rc = BZ2_bzBuffToBuffDecompress(uncompressed + sizeof(pcmk__ipc_header_t), &size_u,
                                         client->buffer + sizeof(pcmk__ipc_header_t), header->size_compressed, 1, 0);
 
         if (rc != BZ_OK) {
             crm_err("Decompression failed: %s " CRM_XS " bzerror=%d",
                     bz2_strerror(rc), rc);
             free(uncompressed);
             return EILSEQ;
         }
 
         /*
          * This assert no longer holds true.  For an identical msg, some clients may
          * require compression, and others may not. If that same msg (event) is sent
          * to multiple clients, it could result in some clients receiving a compressed
          * msg even though compression was not explicitly required for them.
          *
          * CRM_ASSERT((header->size_uncompressed + sizeof(pcmk__ipc_header_t)) >= ipc_buffer_max);
          */
         CRM_ASSERT(size_u == header->size_uncompressed);
 
         memcpy(uncompressed, client->buffer, sizeof(pcmk__ipc_header_t));       /* Preserve the header */
         header = (pcmk__ipc_header_t *)(void*)uncompressed;
 
         free(client->buffer);
         client->buf_size = new_buf_size;
         client->buffer = uncompressed;
     }
 
     CRM_ASSERT(client->buffer[sizeof(pcmk__ipc_header_t) + header->size_uncompressed - 1] == 0);
     return pcmk_rc_ok;
 }
 
 long
 crm_ipc_read(crm_ipc_t * client)
 {
     pcmk__ipc_header_t *header = NULL;
 
     CRM_ASSERT(client != NULL);
     CRM_ASSERT(client->ipc != NULL);
     CRM_ASSERT(client->buffer != NULL);
 
     client->buffer[0] = 0;
     client->msg_size = qb_ipcc_event_recv(client->ipc, client->buffer,
                                           client->buf_size, 0);
     if (client->msg_size >= 0) {
         int rc = crm_ipc_decompress(client);
 
         if (rc != pcmk_rc_ok) {
             return pcmk_rc2legacy(rc);
         }
 
         header = (pcmk__ipc_header_t *)(void*)client->buffer;
         if (!pcmk__valid_ipc_header(header)) {
             return -EBADMSG;
         }
 
         crm_trace("Received %s IPC event %d size=%u rc=%d text='%.100s'",
                   client->server_name, header->qb.id, header->qb.size,
                   client->msg_size,
                   client->buffer + sizeof(pcmk__ipc_header_t));
 
     } else {
         crm_trace("No message received from %s IPC: %s",
                   client->server_name, pcmk_strerror(client->msg_size));
 
         if (client->msg_size == -EAGAIN) {
             return -EAGAIN;
         }
     }
 
     if (!crm_ipc_connected(client) || client->msg_size == -ENOTCONN) {
         crm_err("Connection to %s IPC failed", client->server_name);
     }
 
     if (header) {
         /* Data excluding the header */
         return header->size_uncompressed;
     }
     return -ENOMSG;
 }
 
 const char *
 crm_ipc_buffer(crm_ipc_t * client)
 {
     CRM_ASSERT(client != NULL);
     return client->buffer + sizeof(pcmk__ipc_header_t);
 }
 
 uint32_t
 crm_ipc_buffer_flags(crm_ipc_t * client)
 {
     pcmk__ipc_header_t *header = NULL;
 
     CRM_ASSERT(client != NULL);
     if (client->buffer == NULL) {
         return 0;
     }
 
     header = (pcmk__ipc_header_t *)(void*)client->buffer;
     return header->flags;
 }
 
 const char *
 crm_ipc_name(crm_ipc_t * client)
 {
     CRM_ASSERT(client != NULL);
     return client->server_name;
 }
 
 // \return Standard Pacemaker return code
 static int
 internal_ipc_get_reply(crm_ipc_t *client, int request_id, int ms_timeout,
                        ssize_t *bytes)
 {
     time_t timeout = time(NULL) + 1 + (ms_timeout / 1000);
     int rc = pcmk_rc_ok;
 
     /* get the reply */
     crm_trace("Waiting on reply to %s IPC message %d",
               client->server_name, request_id);
     do {
 
         *bytes = qb_ipcc_recv(client->ipc, client->buffer, client->buf_size, 1000);
         if (*bytes > 0) {
             pcmk__ipc_header_t *hdr = NULL;
 
             rc = crm_ipc_decompress(client);
             if (rc != pcmk_rc_ok) {
                 return rc;
             }
 
             hdr = (pcmk__ipc_header_t *)(void*)client->buffer;
             if (hdr->qb.id == request_id) {
                 /* Got it */
                 break;
             } else if (hdr->qb.id < request_id) {
                 xmlNode *bad = string2xml(crm_ipc_buffer(client));
 
                 crm_err("Discarding old reply %d (need %d)", hdr->qb.id, request_id);
                 crm_log_xml_notice(bad, "OldIpcReply");
 
             } else {
                 xmlNode *bad = string2xml(crm_ipc_buffer(client));
 
                 crm_err("Discarding newer reply %d (need %d)", hdr->qb.id, request_id);
                 crm_log_xml_notice(bad, "ImpossibleReply");
                 CRM_ASSERT(hdr->qb.id <= request_id);
             }
         } else if (!crm_ipc_connected(client)) {
             crm_err("%s IPC provider disconnected while waiting for message %d",
                     client->server_name, request_id);
             break;
         }
 
     } while (time(NULL) < timeout);
 
     if (*bytes < 0) {
         rc = (int) -*bytes; // System errno
     }
     return rc;
 }
 
 /*!
  * \brief Send an IPC XML message
  *
  * \param[in,out] client      Connection to IPC server
  * \param[in,out] message     XML message to send
  * \param[in]     flags       Bitmask of crm_ipc_flags
  * \param[in]     ms_timeout  Give up if not sent within this much time
  *                            (5 seconds if 0, or no timeout if negative)
  * \param[out]    reply       Reply from server (or NULL if none)
  *
  * \return Negative errno on error, otherwise size of reply received in bytes
  *         if reply was needed, otherwise number of bytes sent
  */
 int
 crm_ipc_send(crm_ipc_t * client, xmlNode * message, enum crm_ipc_flags flags, int32_t ms_timeout,
              xmlNode ** reply)
 {
     int rc = 0;
     ssize_t qb_rc = 0;
     ssize_t bytes = 0;
     struct iovec *iov;
     static uint32_t id = 0;
     static int factor = 8;
     pcmk__ipc_header_t *header;
 
     if (client == NULL) {
         crm_notice("Can't send IPC request without connection (bug?): %.100s",
                    message);
         return -ENOTCONN;
 
     } else if (!crm_ipc_connected(client)) {
         /* Don't even bother */
         crm_notice("Can't send %s IPC requests: Connection closed",
                    client->server_name);
         return -ENOTCONN;
     }
 
     if (ms_timeout == 0) {
         ms_timeout = 5000;
     }
 
     if (client->need_reply) {
         qb_rc = qb_ipcc_recv(client->ipc, client->buffer, client->buf_size, ms_timeout);
         if (qb_rc < 0) {
             crm_warn("Sending %s IPC disabled until pending reply received",
                      client->server_name);
             return -EALREADY;
 
         } else {
             crm_notice("Sending %s IPC re-enabled after pending reply received",
                        client->server_name);
             client->need_reply = FALSE;
         }
     }
 
     id++;
     CRM_LOG_ASSERT(id != 0); /* Crude wrap-around detection */
     rc = pcmk__ipc_prepare_iov(id, message, client->max_buf_size, &iov, &bytes);
     if (rc != pcmk_rc_ok) {
         crm_warn("Couldn't prepare %s IPC request: %s " CRM_XS " rc=%d",
                  client->server_name, pcmk_rc_str(rc), rc);
         return pcmk_rc2legacy(rc);
     }
 
     header = iov[0].iov_base;
     pcmk__set_ipc_flags(header->flags, client->server_name, flags);
 
     if (pcmk_is_set(flags, crm_ipc_proxied)) {
         /* Don't look for a synchronous response */
         pcmk__clear_ipc_flags(flags, "client", crm_ipc_client_response);
     }
 
     if(header->size_compressed) {
         if(factor < 10 && (client->max_buf_size / 10) < (bytes / factor)) {
             crm_notice("Compressed message exceeds %d0%% of configured IPC "
                        "limit (%u bytes); consider setting PCMK_ipc_buffer to "
                        "%u or higher",
                        factor, client->max_buf_size, 2 * client->max_buf_size);
             factor++;
         }
     }
 
     crm_trace("Sending %s IPC request %d of %u bytes using %dms timeout",
               client->server_name, header->qb.id, header->qb.size, ms_timeout);
 
     if ((ms_timeout > 0) || !pcmk_is_set(flags, crm_ipc_client_response)) {
 
         time_t timeout = time(NULL) + 1 + (ms_timeout / 1000);
 
         do {
             /* @TODO Is this check really needed? Won't qb_ipcc_sendv() return
              * an error if it's not connected?
              */
             if (!crm_ipc_connected(client)) {
                 goto send_cleanup;
             }
 
             qb_rc = qb_ipcc_sendv(client->ipc, iov, 2);
         } while ((qb_rc == -EAGAIN) && (time(NULL) < timeout));
 
         rc = (int) qb_rc; // Negative of system errno, or bytes sent
         if (qb_rc <= 0) {
             goto send_cleanup;
 
         } else if (!pcmk_is_set(flags, crm_ipc_client_response)) {
             crm_trace("Not waiting for reply to %s IPC request %d",
                       client->server_name, header->qb.id);
             goto send_cleanup;
         }
 
         rc = internal_ipc_get_reply(client, header->qb.id, ms_timeout, &bytes);
         if (rc != pcmk_rc_ok) {
             /* We didn't get the reply in time, so disable future sends for now.
              * The only alternative would be to close the connection since we
              * don't know how to detect and discard out-of-sequence replies.
              *
              * @TODO Implement out-of-sequence detection
              */
             client->need_reply = TRUE;
         }
         rc = (int) bytes; // Negative system errno, or size of reply received
 
     } else {
         // No timeout, and client response needed
         do {
             qb_rc = qb_ipcc_sendv_recv(client->ipc, iov, 2, client->buffer,
                                        client->buf_size, -1);
         } while ((qb_rc == -EAGAIN) && crm_ipc_connected(client));
         rc = (int) qb_rc; // Negative system errno, or size of reply received
     }
 
     if (rc > 0) {
         pcmk__ipc_header_t *hdr = (pcmk__ipc_header_t *)(void*)client->buffer;
 
         crm_trace("Received %d-byte reply %d to %s IPC %d: %.100s",
                   rc, hdr->qb.id, client->server_name, header->qb.id,
                   crm_ipc_buffer(client));
 
         if (reply) {
             *reply = string2xml(crm_ipc_buffer(client));
         }
 
     } else {
         crm_trace("No reply to %s IPC %d: rc=%d",
                   client->server_name, header->qb.id, rc);
     }
 
   send_cleanup:
     if (!crm_ipc_connected(client)) {
         crm_notice("Couldn't send %s IPC request %d: Connection closed "
                    CRM_XS " rc=%d", client->server_name, header->qb.id, rc);
 
     } else if (rc == -ETIMEDOUT) {
         crm_warn("%s IPC request %d failed: %s after %dms " CRM_XS " rc=%d",
                  client->server_name, header->qb.id, pcmk_strerror(rc),
                  ms_timeout, rc);
         crm_write_blackbox(0, NULL);
 
     } else if (rc <= 0) {
         crm_warn("%s IPC request %d failed: %s " CRM_XS " rc=%d",
                  client->server_name, header->qb.id,
                  ((rc == 0)? "No bytes sent" : pcmk_strerror(rc)), rc);
     }
 
     pcmk_free_ipc_event(iov);
     return rc;
 }
 
-int
-pcmk__crm_ipc_is_authentic_process(qb_ipcc_connection_t *qb_ipc, int sock, uid_t refuid, gid_t refgid,
-                                   pid_t *gotpid, uid_t *gotuid, gid_t *gotgid)
+/*!
+ * \brief Ensure an IPC provider has expected user or group
+ *
+ * \param[in]  qb_ipc  libqb client connection if available
+ * \param[in]  sock    Connected Unix socket for IPC
+ * \param[in]  refuid  Expected user ID
+ * \param[in]  refgid  Expected group ID
+ * \param[out] gotpid  If not NULL, where to store provider's actual process ID
+ *                     (or 1 on platforms where ID is not available)
+ * \param[out] gotuid  If not NULL, where to store provider's actual user ID
+ * \param[out] gotgid  If not NULL, where to store provider's actual group ID
+ *
+ * \return Standard Pacemaker return code
+ * \note An actual user ID of 0 (root) will always be considered authorized,
+ *       regardless of the expected values provided. The caller can use the
+ *       output arguments to be stricter than this function.
+ */
+static int
+is_ipc_provider_expected(qb_ipcc_connection_t *qb_ipc, int sock,
+                         uid_t refuid, gid_t refgid,
+                         pid_t *gotpid, uid_t *gotuid, gid_t *gotgid)
 {
     int ret = 0;
     pid_t found_pid = 0; uid_t found_uid = 0; gid_t found_gid = 0;
 #if defined(HAVE_UCRED)
     struct ucred ucred;
     socklen_t ucred_len = sizeof(ucred);
 #endif
 
 #ifdef HAVE_QB_IPCC_AUTH_GET
     if (qb_ipc && !qb_ipcc_auth_get(qb_ipc, &found_pid, &found_uid, &found_gid)) {
         goto do_checks;
     }
 #endif
 
 #if defined(HAVE_UCRED)
     if (!getsockopt(sock, SOL_SOCKET, SO_PEERCRED,
                     &ucred, &ucred_len)
                 && ucred_len == sizeof(ucred)) {
         found_pid = ucred.pid; found_uid = ucred.uid; found_gid = ucred.gid;
 
 #elif defined(HAVE_SOCKPEERCRED)
     struct sockpeercred sockpeercred;
     socklen_t sockpeercred_len = sizeof(sockpeercred);
 
     if (!getsockopt(sock, SOL_SOCKET, SO_PEERCRED,
                     &sockpeercred, &sockpeercred_len)
                 && sockpeercred_len == sizeof(sockpeercred_len)) {
         found_pid = sockpeercred.pid;
         found_uid = sockpeercred.uid; found_gid = sockpeercred.gid;
 
 #elif defined(HAVE_GETPEEREID)
     if (!getpeereid(sock, &found_uid, &found_gid)) {
         found_pid = PCMK__SPECIAL_PID;  /* cannot obtain PID (FreeBSD) */
 
 #elif defined(HAVE_GETPEERUCRED)
     ucred_t *ucred;
     if (!getpeerucred(sock, &ucred)) {
         errno = 0;
         found_pid = ucred_getpid(ucred);
         found_uid = ucred_geteuid(ucred); found_gid = ucred_getegid(ucred);
         ret = -errno;
         ucred_free(ucred);
         if (ret) {
             return (ret < 0) ? ret : -pcmk_err_generic;
         }
 
 #else
 #  error "No way to authenticate a Unix socket peer"
     errno = 0;
     if (0) {
 #endif
 #ifdef HAVE_QB_IPCC_AUTH_GET
     do_checks:
 #endif
         if (gotpid != NULL) {
             *gotpid = found_pid;
         }
         if (gotuid != NULL) {
             *gotuid = found_uid;
         }
         if (gotgid != NULL) {
             *gotgid = found_gid;
         }
         if (found_uid == 0 || found_uid == refuid || found_gid == refgid) {
 		ret = 0;
         } else {
                 ret = pcmk_rc_ipc_unauthorized;
         }
     } else {
         ret = (errno > 0) ? errno : pcmk_rc_error;
     }
     return ret;
 }
 
 int
 crm_ipc_is_authentic_process(int sock, uid_t refuid, gid_t refgid,
                              pid_t *gotpid, uid_t *gotuid, gid_t *gotgid)
 {
-    int ret  = pcmk__crm_ipc_is_authentic_process(NULL, sock, refuid, refgid,
-                                                  gotpid, gotuid, gotgid);
+    int ret = is_ipc_provider_expected(NULL, sock, refuid, refgid,
+                                       gotpid, gotuid, gotgid);
 
     /* The old function had some very odd return codes*/
     if (ret == 0) {
         return 1;
     } else if (ret == pcmk_rc_ipc_unauthorized) {
         return 0;
     } else {
         return pcmk_rc2legacy(ret);
     }
 }
 
 int
 pcmk__ipc_is_authentic_process_active(const char *name, uid_t refuid,
                                       gid_t refgid, pid_t *gotpid)
 {
     static char last_asked_name[PATH_MAX / 2] = "";  /* log spam prevention */
     int fd;
     int rc = pcmk_rc_ipc_unresponsive;
     int auth_rc = 0;
     int32_t qb_rc;
     pid_t found_pid = 0; uid_t found_uid = 0; gid_t found_gid = 0;
     qb_ipcc_connection_t *c;
 #ifdef HAVE_QB_IPCC_CONNECT_ASYNC
     struct pollfd pollfd = { 0, };
     int poll_rc;
 
     c = qb_ipcc_connect_async(name, 0,
                               &(pollfd.fd));
 #else
     c = qb_ipcc_connect(name, 0);
 #endif
     if (c == NULL) {
         crm_info("Could not connect to %s IPC: %s", name, strerror(errno));
         rc = pcmk_rc_ipc_unresponsive;
         goto bail;
     }
 #ifdef HAVE_QB_IPCC_CONNECT_ASYNC
     pollfd.events = POLLIN;
     do {
         poll_rc = poll(&pollfd, 1, 2000);
     } while ((poll_rc == -1) && (errno == EINTR));
     if ((poll_rc <= 0) || (qb_ipcc_connect_continue(c) != 0)) {
         crm_info("Could not connect to %s IPC: %s", name,
                  (poll_rc == 0)?"timeout":strerror(errno));
         rc = pcmk_rc_ipc_unresponsive;
         if (poll_rc > 0) {
             c = NULL; // qb_ipcc_connect_continue cleaned up for us
         }
         goto bail;
     }
 #endif
 
     qb_rc = qb_ipcc_fd_get(c, &fd);
     if (qb_rc != 0) {
         rc = (int) -qb_rc; // System errno
         crm_err("Could not get fd from %s IPC: %s " CRM_XS " rc=%d",
                 name, pcmk_rc_str(rc), rc);
         goto bail;
     }
 
-    auth_rc = pcmk__crm_ipc_is_authentic_process(c, fd, refuid, refgid, &found_pid,
-                                                 &found_uid, &found_gid);
+    auth_rc = is_ipc_provider_expected(c, fd, refuid, refgid,
+                                       &found_pid, &found_uid, &found_gid);
     if (auth_rc == pcmk_rc_ipc_unauthorized) {
         crm_err("Daemon (IPC %s) effectively blocked with unauthorized"
                 " process %lld (uid: %lld, gid: %lld)",
                 name, (long long) PCMK__SPECIAL_PID_AS_0(found_pid),
                 (long long) found_uid, (long long) found_gid);
         rc = pcmk_rc_ipc_unauthorized;
         goto bail;
     }
 
     if (auth_rc != pcmk_rc_ok) {
         rc = auth_rc;
         crm_err("Could not get peer credentials from %s IPC: %s "
                 CRM_XS " rc=%d", name, pcmk_rc_str(rc), rc);
         goto bail;
     }
 
     if (gotpid != NULL) {
         *gotpid = found_pid;
     }
 
     rc = pcmk_rc_ok;
     if ((found_uid != refuid || found_gid != refgid)
             && strncmp(last_asked_name, name, sizeof(last_asked_name))) {
         if ((found_uid == 0) && (refuid != 0)) {
             crm_warn("Daemon (IPC %s) runs as root, whereas the expected"
                      " credentials are %lld:%lld, hazard of violating"
                      " the least privilege principle",
                      name, (long long) refuid, (long long) refgid);
         } else {
             crm_notice("Daemon (IPC %s) runs as %lld:%lld, whereas the"
                        " expected credentials are %lld:%lld, which may"
                        " mean a different set of privileges than expected",
                        name, (long long) found_uid, (long long) found_gid,
                        (long long) refuid, (long long) refgid);
         }
         memccpy(last_asked_name, name, '\0', sizeof(last_asked_name));
     }
 
 bail:
     if (c != NULL) {
         qb_ipcc_disconnect(c);
     }
     return rc;
 }