diff --git a/lib/common/digest.c b/lib/common/digest.c
index 5d02d9cd3d..0884f5642b 100644
--- a/lib/common/digest.c
+++ b/lib/common/digest.c
@@ -1,359 +1,383 @@
/*
* Copyright 2015-2024 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>
#include <stdbool.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <glib.h> // GString, etc.
#include <gnutls/crypto.h> // gnutls_hash_fast(), gnutls_hash_get_len()
#include <gnutls/gnutls.h> // gnutls_strerror()
#include <crm/crm.h>
#include <crm/common/xml.h>
#include "crmcommon_private.h"
#define BEST_EFFORT_STATUS 0
+/*
+ * Pacemaker uses digests (MD5 hashes) of stringified XML to detect changes in
+ * the CIB as a whole, a particular resource's agent parameters, and the device
+ * parameters last used to unfence a particular node.
+ *
+ * "v2" digests hash pcmk__xml_string() directly, while less efficient "v1"
+ * digests do the same with a prefixed space, suffixed newline, and optional
+ * pre-sorting.
+ *
+ * On-disk CIB digests use v1 without sorting.
+ *
+ * Operation digests use v1 with sorting, and are stored in a resource's
+ * operation history in the CIB status section. They come in three flavors:
+ * - a digest of (nearly) all resource parameters and options, used to detect
+ * any resource configuration change;
+ * - a digest of resource parameters marked as nonreloadable, used to decide
+ * whether a reload or full restart is needed after a configuration change;
+ * - and a digest of resource parameters not marked as private, used in
+ * simulations where private parameters have been removed from the input.
+ *
+ * Unfencing digests are set as node attributes, and are used to require
+ * that nodes be unfenced again after a device's configuration changes.
+ */
+
/*!
* \internal
* \brief Dump XML in a format used with v1 digests
*
* \param[in] xml Root of XML to dump
*
* \return Newly allocated buffer containing dumped XML
*/
static GString *
dump_xml_for_digest(xmlNodePtr xml)
{
GString *buffer = g_string_sized_new(1024);
/* for compatibility with the old result which is used for v1 digests */
g_string_append_c(buffer, ' ');
pcmk__xml_string(xml, 0, buffer, 0);
g_string_append_c(buffer, '\n');
return buffer;
}
/*!
* \internal
* \brief Calculate and return v1 digest of XML tree
*
* \param[in] input Root of XML to digest
*
* \return Newly allocated string containing digest
*
* \note Example return value: "c048eae664dba840e1d2060f00299e9d"
*/
static char *
calculate_xml_digest_v1(xmlNode *input)
{
GString *buffer = dump_xml_for_digest(input);
char *digest = NULL;
// buffer->len > 2 for initial space and trailing newline
CRM_CHECK(buffer->len > 2,
g_string_free(buffer, TRUE);
return NULL);
digest = crm_md5sum((const char *) buffer->str);
crm_log_xml_trace(input, "digest:source");
g_string_free(buffer, TRUE);
return digest;
}
/*!
* \internal
* \brief Calculate and return the digest of a CIB, suitable for storing on disk
*
* \param[in] input Root of XML to digest
*
* \return Newly allocated string containing digest
*/
char *
pcmk__digest_on_disk_cib(xmlNode *input)
{
/* Always use the v1 format for on-disk digests.
* * Switching to v2 affects even full-restart upgrades, so it would be a
* compatibility nightmare.
* * We only use this once at startup. All other invocations are in a
* separate child process.
*/
return calculate_xml_digest_v1(input);
}
/*!
* \internal
* \brief Calculate and return digest of an operation XML element
*
* The digest is invariant to changes in the order of XML attributes, provided
* that \p input has no children.
*
* \param[in] input Root of XML to digest
*
* \return Newly allocated string containing digest
*/
char *
pcmk__digest_operation(xmlNode *input)
{
/* Switching to v2 digests would likely cause restarts during rolling
* upgrades.
*
* @TODO Confirm this. Switch to v2 if safe, or drop this TODO otherwise.
*/
xmlNode *sorted = pcmk__xml_copy(NULL, input);
char *digest = NULL;
pcmk__xe_sort_attrs(sorted);
digest = calculate_xml_digest_v1(sorted);
pcmk__xml_free(sorted);
return digest;
}
/*!
* \internal
* \brief Calculate and return the digest of an XML tree
*
* \param[in] xml XML tree to digest
* \param[in] filter Whether to filter certain XML attributes
*
* \return Newly allocated string containing digest
*/
char *
pcmk__digest_xml(xmlNode *xml, bool filter)
{
/* @TODO Filtering accounts for significant CPU usage. Consider removing if
* possible.
*/
char *digest = NULL;
GString *buf = g_string_sized_new(1024);
pcmk__xml_string(xml, (filter? pcmk__xml_fmt_filtered : 0), buf, 0);
digest = crm_md5sum(buf->str);
pcmk__if_tracing(
{
char *trace_file = crm_strdup_printf("%s/digest-%s",
pcmk__get_tmpdir(), digest);
crm_trace("Saving %s.%s.%s to %s",
crm_element_value(xml, PCMK_XA_ADMIN_EPOCH),
crm_element_value(xml, PCMK_XA_EPOCH),
crm_element_value(xml, PCMK_XA_NUM_UPDATES),
trace_file);
save_xml_to_file(xml, "digest input", trace_file);
free(trace_file);
},
{}
);
g_string_free(buf, TRUE);
return digest;
}
/*!
* \internal
* \brief Check whether calculated digest of given XML matches expected digest
*
* \param[in] input Root of XML tree to digest
* \param[in] expected Expected digest in on-disk format
*
* \return true if digests match, false on mismatch or error
*/
bool
pcmk__verify_digest(xmlNode *input, const char *expected)
{
char *calculated = NULL;
bool passed;
if (input != NULL) {
calculated = pcmk__digest_on_disk_cib(input);
if (calculated == NULL) {
crm_perror(LOG_ERR, "Could not calculate digest for comparison");
return false;
}
}
passed = pcmk__str_eq(expected, calculated, pcmk__str_casei);
if (passed) {
crm_trace("Digest comparison passed: %s", calculated);
} else {
crm_err("Digest comparison failed: expected %s, calculated %s",
expected, calculated);
}
free(calculated);
return passed;
}
/*!
* \internal
* \brief Check whether an XML attribute should be excluded from CIB digests
*
* \param[in] name XML attribute name
*
* \return true if XML attribute should be excluded from CIB digest calculation
*/
bool
pcmk__xa_filterable(const char *name)
{
static const char *filter[] = {
PCMK_XA_CRM_DEBUG_ORIGIN,
PCMK_XA_CIB_LAST_WRITTEN,
PCMK_XA_UPDATE_ORIGIN,
PCMK_XA_UPDATE_CLIENT,
PCMK_XA_UPDATE_USER,
};
for (int i = 0; i < PCMK__NELEM(filter); i++) {
if (strcmp(name, filter[i]) == 0) {
return true;
}
}
return false;
}
char *
crm_md5sum(const char *buffer)
{
char *digest = NULL;
gchar *raw_digest = NULL;
if (buffer == NULL) {
return NULL;
}
raw_digest = g_compute_checksum_for_string(G_CHECKSUM_MD5, buffer, -1);
if (raw_digest == NULL) {
crm_err("Failed to calculate hash");
return NULL;
}
digest = pcmk__str_copy(raw_digest);
g_free(raw_digest);
crm_trace("Digest %s.", digest);
return digest;
}
// Return true if a is an attribute that should be filtered
static bool
should_filter_for_digest(xmlAttrPtr a, void *user_data)
{
if (strncmp((const char *) a->name, CRM_META "_",
sizeof(CRM_META " ") - 1) == 0) {
return true;
}
return pcmk__str_any_of((const char *) a->name,
PCMK_XA_ID,
PCMK_XA_CRM_FEATURE_SET,
PCMK__XA_OP_DIGEST,
PCMK__META_ON_NODE,
PCMK__META_ON_NODE_UUID,
"pcmk_external_ip",
NULL);
}
/*!
* \internal
* \brief Remove XML attributes not needed for operation digest
*
* \param[in,out] param_set XML with operation parameters
*/
void
pcmk__filter_op_for_digest(xmlNode *param_set)
{
char *key = NULL;
char *timeout = NULL;
guint interval_ms = 0;
if (param_set == NULL) {
return;
}
/* Timeout is useful for recurring operation digests, so grab it before
* removing meta-attributes
*/
key = crm_meta_name(PCMK_META_INTERVAL);
if (crm_element_value_ms(param_set, key, &interval_ms) != pcmk_ok) {
interval_ms = 0;
}
free(key);
key = NULL;
if (interval_ms != 0) {
key = crm_meta_name(PCMK_META_TIMEOUT);
timeout = crm_element_value_copy(param_set, key);
}
// Remove all CRM_meta_* attributes and certain other attributes
pcmk__xe_remove_matching_attrs(param_set, should_filter_for_digest, NULL);
// Add timeout back for recurring operation digests
if (timeout != NULL) {
crm_xml_add(param_set, key, timeout);
}
free(timeout);
free(key);
}
// Deprecated functions kept only for backward API compatibility
// LCOV_EXCL_START
#include <crm/common/xml_compat.h>
#include <crm/common/xml_element_compat.h>
char *
calculate_on_disk_digest(xmlNode *input)
{
return calculate_xml_digest_v1(input);
}
char *
calculate_operation_digest(xmlNode *input, const char *version)
{
xmlNode *sorted = sorted_xml(input, NULL, true);
char *digest = calculate_xml_digest_v1(sorted);
pcmk__xml_free(sorted);
return digest;
}
char *
calculate_xml_versioned_digest(xmlNode *input, gboolean sort,
gboolean do_filter, const char *version)
{
if ((version == NULL) || (compare_version("3.0.5", version) > 0)) {
xmlNode *sorted = NULL;
char *digest = NULL;
if (sort) {
xmlNode *sorted = sorted_xml(input, NULL, true);
input = sorted;
}
crm_trace("Using v1 digest algorithm for %s",
pcmk__s(version, "unknown feature set"));
digest = calculate_xml_digest_v1(input);
pcmk__xml_free(sorted);
return digest;
}
crm_trace("Using v2 digest algorithm for %s", version);
return pcmk__digest_xml(input, do_filter);
}
// LCOV_EXCL_STOP
// End deprecated API