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 #include #include #include #include #include #include // GString, etc. #include // gnutls_hash_fast(), gnutls_hash_get_len() #include // gnutls_strerror() #include #include #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 #include 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