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pcmk_acl.c
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/*
* Copyright 2004-2024 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 <stdio.h>
#include <sys/types.h>
#include <pwd.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xpath.h>
#include <libxslt/transform.h>
#include <libxslt/variables.h>
#include <libxslt/xsltutils.h>
#include <crm/crm.h>
#include <crm/common/xml.h>
#include <crm/common/xml_internal.h>
#include <crm/common/internal.h>
#include <pacemaker-internal.h>
#define ACL_NS_PREFIX "http://clusterlabs.org/ns/pacemaker/access/"
#define ACL_NS_Q_PREFIX "pcmk-access-"
#define ACL_NS_Q_WRITABLE (const xmlChar *) ACL_NS_Q_PREFIX "writable"
#define ACL_NS_Q_READABLE (const xmlChar *) ACL_NS_Q_PREFIX "readable"
#define ACL_NS_Q_DENIED (const xmlChar *) ACL_NS_Q_PREFIX "denied"
static const xmlChar *NS_WRITABLE = (const xmlChar *) ACL_NS_PREFIX "writable";
static const xmlChar *NS_READABLE = (const xmlChar *) ACL_NS_PREFIX "readable";
static const xmlChar *NS_DENIED = (const xmlChar *) ACL_NS_PREFIX "denied";
/*!
* \brief This function takes a node and marks it with the namespace
* given in the ns parameter.
*
* \param[in,out] i_node
* \param[in] ns
* \param[in,out] ret
* \param[in,out] ns_recycle_writable
* \param[in,out] ns_recycle_readable
* \param[in,out] ns_recycle_denied
*/
static void
pcmk__acl_mark_node_with_namespace(xmlNode *i_node, const xmlChar *ns, int *ret,
xmlNs **ns_recycle_writable,
xmlNs **ns_recycle_readable,
xmlNs **ns_recycle_denied)
{
if (ns == NS_WRITABLE)
{
if (*ns_recycle_writable == NULL)
{
*ns_recycle_writable = xmlNewNs(xmlDocGetRootElement(i_node->doc),
NS_WRITABLE, ACL_NS_Q_WRITABLE);
}
xmlSetNs(i_node, *ns_recycle_writable);
*ret = pcmk_rc_ok;
}
else if (ns == NS_READABLE)
{
if (*ns_recycle_readable == NULL)
{
*ns_recycle_readable = xmlNewNs(xmlDocGetRootElement(i_node->doc),
NS_READABLE, ACL_NS_Q_READABLE);
}
xmlSetNs(i_node, *ns_recycle_readable);
*ret = pcmk_rc_ok;
}
else if (ns == NS_DENIED)
{
if (*ns_recycle_denied == NULL)
{
*ns_recycle_denied = xmlNewNs(xmlDocGetRootElement(i_node->doc),
NS_DENIED, ACL_NS_Q_DENIED);
};
xmlSetNs(i_node, *ns_recycle_denied);
*ret = pcmk_rc_ok;
}
}
/*!
* \brief Annotate a given XML element or property and its siblings with
* XML namespaces to indicate ACL permissions
*
* \param[in,out] xml_modify XML to annotate
*
* \return A standard Pacemaker return code
* Namely:
* - pcmk_rc_ok upon success,
* - pcmk_rc_already if ACLs were not applicable,
* - pcmk_rc_schema_validation if the validation schema version
* is unsupported (see note), or
* - EINVAL or ENOMEM as appropriate;
*
* \note This function is recursive
*/
static int
annotate_with_siblings(xmlNode *xml_modify)
{
static xmlNs *ns_recycle_writable = NULL,
*ns_recycle_readable = NULL,
*ns_recycle_denied = NULL;
static const xmlDoc *prev_doc = NULL;
xmlNode *i_node = NULL;
const xmlChar *ns;
int ret = EINVAL; // nodes have not been processed yet
if (prev_doc == NULL || prev_doc != xml_modify->doc) {
prev_doc = xml_modify->doc;
ns_recycle_writable = ns_recycle_readable = ns_recycle_denied = NULL;
}
for (i_node = xml_modify; i_node != NULL; i_node = i_node->next) {
switch (i_node->type) {
case XML_ELEMENT_NODE:
pcmk__set_xml_doc_flag(i_node, pcmk__xf_tracking);
if (!pcmk__check_acl(i_node, NULL, pcmk__xf_acl_read)) {
ns = NS_DENIED;
} else if (!pcmk__check_acl(i_node, NULL, pcmk__xf_acl_write)) {
ns = NS_READABLE;
} else {
ns = NS_WRITABLE;
}
pcmk__acl_mark_node_with_namespace(i_node, ns, &ret,
&ns_recycle_writable,
&ns_recycle_readable,
&ns_recycle_denied);
// @TODO Could replace recursion with iteration to save stack
if (i_node->properties != NULL) {
/* This is not entirely clear, but relies on the very same
* class-hierarchy emulation that libxml2 has firmly baked
* in its API/ABI
*/
ret |= annotate_with_siblings((xmlNodePtr)
i_node->properties);
}
if (i_node->children != NULL) {
ret |= annotate_with_siblings(i_node->children);
}
break;
case XML_ATTRIBUTE_NODE:
// We can utilize that parent has already been assigned the ns
if (!pcmk__check_acl(i_node->parent,
(const char *) i_node->name,
pcmk__xf_acl_read)) {
ns = NS_DENIED;
} else if (!pcmk__check_acl(i_node,
(const char *) i_node->name,
pcmk__xf_acl_write)) {
ns = NS_READABLE;
} else {
ns = NS_WRITABLE;
}
pcmk__acl_mark_node_with_namespace(i_node, ns, &ret,
&ns_recycle_writable,
&ns_recycle_readable,
&ns_recycle_denied);
break;
case XML_COMMENT_NODE:
// We can utilize that parent has already been assigned the ns
if (!pcmk__check_acl(i_node->parent,
(const char *) i_node->name,
pcmk__xf_acl_read)) {
ns = NS_DENIED;
} else if (!pcmk__check_acl(i_node->parent,
(const char *) i_node->name,
pcmk__xf_acl_write)) {
ns = NS_READABLE;
} else {
ns = NS_WRITABLE;
}
pcmk__acl_mark_node_with_namespace(i_node, ns, &ret,
&ns_recycle_writable,
&ns_recycle_readable,
&ns_recycle_denied);
break;
default:
break;
}
}
return ret;
}
int
pcmk__acl_annotate_permissions(const char *cred, const xmlDoc *cib_doc,
xmlDoc **acl_evaled_doc)
{
int ret;
xmlNode *target, *comment;
const char *validation;
CRM_CHECK(cred != NULL, return EINVAL);
CRM_CHECK(cib_doc != NULL, return EINVAL);
CRM_CHECK(acl_evaled_doc != NULL, return EINVAL);
/* avoid trivial accidental XML injection */
if (strpbrk(cred, "<>&") != NULL) {
return EINVAL;
}
if (!pcmk_acl_required(cred)) {
/* nothing to evaluate */
return pcmk_rc_already;
}
// @COMPAT xmlDocGetRootElement() requires non-const in libxml2 < 2.9.2
validation = crm_element_value(xmlDocGetRootElement((xmlDoc *) cib_doc),
PCMK_XA_VALIDATE_WITH);
if (pcmk__cmp_schemas_by_name(PCMK__COMPAT_ACL_2_MIN_INCL,
validation) > 0) {
return pcmk_rc_schema_validation;
}
target = pcmk__xml_copy(NULL, xmlDocGetRootElement((xmlDoc *) cib_doc));
if (target == NULL) {
return EINVAL;
}
pcmk__enable_acl(target, target, cred);
ret = annotate_with_siblings(target);
if (ret == pcmk_rc_ok) {
char *credentials = crm_strdup_printf("ACLs as evaluated for user %s",
cred);
comment = xmlNewDocComment(target->doc, (pcmkXmlStr) credentials);
free(credentials);
if (comment == NULL) {
xmlFreeNode(target);
return EINVAL;
}
xmlAddPrevSibling(xmlDocGetRootElement(target->doc), comment);
*acl_evaled_doc = target->doc;
return pcmk_rc_ok;
} else {
xmlFreeNode(target);
return ret; //for now, it should be some kind of error
}
}
int
pcmk__acl_evaled_render(xmlDoc *annotated_doc, enum pcmk__acl_render_how how,
xmlChar **doc_txt_ptr)
{
xmlDoc *xslt_doc;
xsltStylesheet *xslt;
xsltTransformContext *xslt_ctxt;
xmlDoc *res;
char *sfile;
static const char *params_namespace[] = {
"accessrendercfg:c-writable", ACL_NS_Q_PREFIX "writable:",
"accessrendercfg:c-readable", ACL_NS_Q_PREFIX "readable:",
"accessrendercfg:c-denied", ACL_NS_Q_PREFIX "denied:",
"accessrendercfg:c-reset", "",
"accessrender:extra-spacing", "no",
"accessrender:self-reproducing-prefix", ACL_NS_Q_PREFIX,
NULL
}, *params_useansi[] = {
/* start with hard-coded defaults, then adapt per the template ones */
"accessrendercfg:c-writable", "\x1b[32m",
"accessrendercfg:c-readable", "\x1b[34m",
"accessrendercfg:c-denied", "\x1b[31m",
"accessrendercfg:c-reset", "\x1b[0m",
"accessrender:extra-spacing", "no",
"accessrender:self-reproducing-prefix", ACL_NS_Q_PREFIX,
NULL
}, *params_noansi[] = {
"accessrendercfg:c-writable", "vvv---[ WRITABLE ]---vvv",
"accessrendercfg:c-readable", "vvv---[ READABLE ]---vvv",
"accessrendercfg:c-denied", "vvv---[ ~DENIED~ ]---vvv",
"accessrendercfg:c-reset", "",
"accessrender:extra-spacing", "yes",
"accessrender:self-reproducing-prefix", "",
NULL
};
const char **params;
int rc = pcmk_rc_ok;
xmlParserCtxtPtr parser_ctxt;
/* unfortunately, the input (coming from CIB originally) was parsed with
blanks ignored, and since the output is a conversion of XML to text
format (we would be covered otherwise thanks to implicit
pretty-printing), we need to dump the tree to string output first,
only to subsequently reparse it -- this time with blanks honoured */
xmlChar *annotated_dump;
int dump_size;
CRM_ASSERT(how != pcmk__acl_render_none);
// Color is the default render mode for terminals; text is default otherwise
if (how == pcmk__acl_render_default) {
if (isatty(STDOUT_FILENO)) {
how = pcmk__acl_render_color;
} else {
how = pcmk__acl_render_text;
}
}
xmlDocDumpFormatMemory(annotated_doc, &annotated_dump, &dump_size, 1);
res = xmlReadDoc(annotated_dump, "on-the-fly-access-render", NULL,
XML_PARSE_NONET);
CRM_ASSERT(res != NULL);
xmlFree(annotated_dump);
xmlFreeDoc(annotated_doc);
annotated_doc = res;
sfile = pcmk__xml_artefact_path(pcmk__xml_artefact_ns_base_xslt,
"access-render-2");
parser_ctxt = xmlNewParserCtxt();
CRM_ASSERT(sfile != NULL);
pcmk__mem_assert(parser_ctxt);
xslt_doc = xmlCtxtReadFile(parser_ctxt, sfile, NULL, XML_PARSE_NONET);
xslt = xsltParseStylesheetDoc(xslt_doc); /* acquires xslt_doc! */
if (xslt == NULL) {
crm_crit("Problem in parsing %s", sfile);
rc = EINVAL;
goto done;
}
xmlFreeParserCtxt(parser_ctxt);
xslt_ctxt = xsltNewTransformContext(xslt, annotated_doc);
pcmk__mem_assert(xslt_ctxt);
switch (how) {
case pcmk__acl_render_namespace:
params = params_namespace;
break;
case pcmk__acl_render_text:
params = params_noansi;
break;
default:
/* pcmk__acl_render_color is the only remaining option.
* The compiler complains about params possibly uninitialized if we
* don't use default here.
*/
params = params_useansi;
break;
}
xsltQuoteUserParams(xslt_ctxt, params);
res = xsltApplyStylesheetUser(xslt, annotated_doc, NULL,
NULL, NULL, xslt_ctxt);
xmlFreeDoc(annotated_doc);
annotated_doc = NULL;
xsltFreeTransformContext(xslt_ctxt);
xslt_ctxt = NULL;
if (how == pcmk__acl_render_color && params != params_useansi) {
char **param_i = (char **) params;
do {
free(*param_i);
} while (*param_i++ != NULL);
free(params);
}
if (res == NULL) {
rc = EINVAL;
} else {
int doc_txt_len;
int temp = xsltSaveResultToString(doc_txt_ptr, &doc_txt_len, res, xslt);
xmlFreeDoc(res);
if (temp != 0) {
rc = EINVAL;
}
}
done:
if (xslt != NULL) {
xsltFreeStylesheet(xslt);
}
free(sfile);
return rc;
}

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