mirror of
https://git.postgresql.org/git/postgresql.git
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529 lines
12 KiB
C
529 lines
12 KiB
C
/* -------------------------------------------------------------------------
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*
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* contrib/sepgsql/label.c
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*
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* Routines to support SELinux labels (security context)
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*
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* Copyright (c) 2010-2011, PostgreSQL Global Development Group
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*
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* -------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "access/genam.h"
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#include "catalog/catalog.h"
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#include "catalog/dependency.h"
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#include "catalog/indexing.h"
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#include "catalog/pg_attribute.h"
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#include "catalog/pg_class.h"
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#include "catalog/pg_namespace.h"
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#include "catalog/pg_proc.h"
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#include "commands/dbcommands.h"
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#include "commands/seclabel.h"
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#include "libpq/libpq-be.h"
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#include "miscadmin.h"
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#include "utils/builtins.h"
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#include "utils/fmgroids.h"
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#include "utils/lsyscache.h"
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#include "utils/rel.h"
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#include "utils/tqual.h"
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#include "sepgsql.h"
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#include <selinux/label.h>
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/*
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* client_label
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*
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* security label of the client process
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*/
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static char *client_label = NULL;
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char *
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sepgsql_get_client_label(void)
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{
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return client_label;
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}
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char *
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sepgsql_set_client_label(char *new_label)
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{
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char *old_label = client_label;
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client_label = new_label;
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return old_label;
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}
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/*
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* sepgsql_get_label
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*
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* It returns a security context of the specified database object.
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* If unlabeled or incorrectly labeled, the system "unlabeled" label
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* shall be returned.
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*/
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char *
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sepgsql_get_label(Oid classId, Oid objectId, int32 subId)
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{
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ObjectAddress object;
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char *label;
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object.classId = classId;
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object.objectId = objectId;
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object.objectSubId = subId;
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label = GetSecurityLabel(&object, SEPGSQL_LABEL_TAG);
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if (!label || security_check_context_raw((security_context_t) label))
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{
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security_context_t unlabeled;
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if (security_get_initial_context_raw("unlabeled", &unlabeled) < 0)
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("SELinux: failed to get initial security label: %m")));
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PG_TRY();
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{
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label = pstrdup(unlabeled);
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}
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PG_CATCH();
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{
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freecon(unlabeled);
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PG_RE_THROW();
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}
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PG_END_TRY();
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freecon(unlabeled);
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}
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return label;
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}
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/*
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* sepgsql_object_relabel
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*
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* An entrypoint of SECURITY LABEL statement
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*/
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void
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sepgsql_object_relabel(const ObjectAddress *object, const char *seclabel)
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{
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/*
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* validate format of the supplied security label, if it is security
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* context of selinux.
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*/
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if (seclabel &&
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security_check_context_raw((security_context_t) seclabel) < 0)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_NAME),
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errmsg("SELinux: invalid security label: \"%s\"", seclabel)));
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/*
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* Do actual permission checks for each object classes
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*/
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switch (object->classId)
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{
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case NamespaceRelationId:
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sepgsql_schema_relabel(object->objectId, seclabel);
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break;
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case RelationRelationId:
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if (object->objectSubId == 0)
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sepgsql_relation_relabel(object->objectId,
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seclabel);
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else
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sepgsql_attribute_relabel(object->objectId,
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object->objectSubId,
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seclabel);
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break;
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case ProcedureRelationId:
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sepgsql_proc_relabel(object->objectId, seclabel);
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break;
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default:
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elog(ERROR, "unsupported object type: %u", object->classId);
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break;
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}
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}
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/*
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* TEXT sepgsql_getcon(VOID)
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*
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* It returns the security label of the client.
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*/
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PG_FUNCTION_INFO_V1(sepgsql_getcon);
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Datum
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sepgsql_getcon(PG_FUNCTION_ARGS)
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{
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char *client_label;
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if (!sepgsql_is_enabled())
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PG_RETURN_NULL();
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client_label = sepgsql_get_client_label();
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PG_RETURN_TEXT_P(cstring_to_text(client_label));
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}
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/*
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* TEXT sepgsql_mcstrans_in(TEXT)
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*
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* It translate the given qualified MLS/MCS range into raw format
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* when mcstrans daemon is working.
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*/
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PG_FUNCTION_INFO_V1(sepgsql_mcstrans_in);
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Datum
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sepgsql_mcstrans_in(PG_FUNCTION_ARGS)
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{
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text *label = PG_GETARG_TEXT_P(0);
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char *raw_label;
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char *result;
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if (!sepgsql_is_enabled())
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ereport(ERROR,
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(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
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errmsg("sepgsql is not enabled")));
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if (selinux_trans_to_raw_context(text_to_cstring(label),
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&raw_label) < 0)
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("SELinux: could not translate security label: %m")));
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PG_TRY();
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{
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result = pstrdup(raw_label);
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}
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PG_CATCH();
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{
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freecon(raw_label);
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PG_RE_THROW();
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}
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PG_END_TRY();
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freecon(raw_label);
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PG_RETURN_TEXT_P(cstring_to_text(result));
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}
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/*
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* TEXT sepgsql_mcstrans_out(TEXT)
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*
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* It translate the given raw MLS/MCS range into qualified format
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* when mcstrans daemon is working.
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*/
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PG_FUNCTION_INFO_V1(sepgsql_mcstrans_out);
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Datum
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sepgsql_mcstrans_out(PG_FUNCTION_ARGS)
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{
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text *label = PG_GETARG_TEXT_P(0);
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char *qual_label;
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char *result;
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if (!sepgsql_is_enabled())
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ereport(ERROR,
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(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
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errmsg("sepgsql is not currently enabled")));
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if (selinux_raw_to_trans_context(text_to_cstring(label),
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&qual_label) < 0)
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("SELinux: could not translate security label: %m")));
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PG_TRY();
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{
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result = pstrdup(qual_label);
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}
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PG_CATCH();
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{
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freecon(qual_label);
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PG_RE_THROW();
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}
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PG_END_TRY();
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freecon(qual_label);
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PG_RETURN_TEXT_P(cstring_to_text(result));
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}
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/*
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* quote_object_names
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*
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* It tries to quote the supplied identifiers
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*/
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static char *
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quote_object_name(const char *src1, const char *src2,
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const char *src3, const char *src4)
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{
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StringInfoData result;
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const char *temp;
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initStringInfo(&result);
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if (src1)
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{
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temp = quote_identifier(src1);
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appendStringInfo(&result, "%s", temp);
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if (src1 != temp)
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pfree((void *) temp);
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}
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if (src2)
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{
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temp = quote_identifier(src2);
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appendStringInfo(&result, ".%s", temp);
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if (src2 != temp)
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pfree((void *) temp);
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}
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if (src3)
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{
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temp = quote_identifier(src3);
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appendStringInfo(&result, ".%s", temp);
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if (src3 != temp)
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pfree((void *) temp);
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}
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if (src4)
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{
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temp = quote_identifier(src4);
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appendStringInfo(&result, ".%s", temp);
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if (src4 != temp)
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pfree((void *) temp);
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}
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return result.data;
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}
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/*
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* exec_object_restorecon
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*
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* This routine is a helper called by sepgsql_restorecon; it set up
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* initial security labels of database objects within the supplied
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* catalog OID.
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*/
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static void
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exec_object_restorecon(struct selabel_handle * sehnd, Oid catalogId)
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{
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Relation rel;
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SysScanDesc sscan;
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HeapTuple tuple;
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char *database_name = get_database_name(MyDatabaseId);
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char *namespace_name;
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Oid namespace_id;
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char *relation_name;
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/*
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* Open the target catalog. We don't want to allow writable accesses by
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* other session during initial labeling.
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*/
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rel = heap_open(catalogId, AccessShareLock);
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sscan = systable_beginscan(rel, InvalidOid, false,
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SnapshotNow, 0, NULL);
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while (HeapTupleIsValid(tuple = systable_getnext(sscan)))
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{
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Form_pg_namespace nspForm;
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Form_pg_class relForm;
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Form_pg_attribute attForm;
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Form_pg_proc proForm;
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char *objname;
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int objtype = 1234;
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ObjectAddress object;
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security_context_t context;
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/*
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* The way to determine object name depends on object classes. So, any
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* branches set up `objtype', `objname' and `object' here.
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*/
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switch (catalogId)
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{
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case NamespaceRelationId:
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nspForm = (Form_pg_namespace) GETSTRUCT(tuple);
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objtype = SELABEL_DB_SCHEMA;
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objname = quote_object_name(database_name,
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NameStr(nspForm->nspname),
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NULL, NULL);
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object.classId = NamespaceRelationId;
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object.objectId = HeapTupleGetOid(tuple);
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object.objectSubId = 0;
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break;
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case RelationRelationId:
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relForm = (Form_pg_class) GETSTRUCT(tuple);
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if (relForm->relkind == RELKIND_RELATION)
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objtype = SELABEL_DB_TABLE;
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else if (relForm->relkind == RELKIND_SEQUENCE)
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objtype = SELABEL_DB_SEQUENCE;
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else if (relForm->relkind == RELKIND_VIEW)
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objtype = SELABEL_DB_VIEW;
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else
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continue; /* no need to assign security label */
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namespace_name = get_namespace_name(relForm->relnamespace);
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objname = quote_object_name(database_name,
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namespace_name,
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NameStr(relForm->relname),
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NULL);
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pfree(namespace_name);
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object.classId = RelationRelationId;
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object.objectId = HeapTupleGetOid(tuple);
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object.objectSubId = 0;
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break;
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case AttributeRelationId:
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attForm = (Form_pg_attribute) GETSTRUCT(tuple);
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if (get_rel_relkind(attForm->attrelid) != RELKIND_RELATION)
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continue; /* no need to assign security label */
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objtype = SELABEL_DB_COLUMN;
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namespace_id = get_rel_namespace(attForm->attrelid);
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namespace_name = get_namespace_name(namespace_id);
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relation_name = get_rel_name(attForm->attrelid);
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objname = quote_object_name(database_name,
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namespace_name,
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relation_name,
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NameStr(attForm->attname));
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pfree(namespace_name);
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pfree(relation_name);
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object.classId = RelationRelationId;
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object.objectId = attForm->attrelid;
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object.objectSubId = attForm->attnum;
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break;
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case ProcedureRelationId:
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proForm = (Form_pg_proc) GETSTRUCT(tuple);
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objtype = SELABEL_DB_PROCEDURE;
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namespace_name = get_namespace_name(proForm->pronamespace);
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objname = quote_object_name(database_name,
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namespace_name,
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NameStr(proForm->proname),
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NULL);
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pfree(namespace_name);
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object.classId = ProcedureRelationId;
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object.objectId = HeapTupleGetOid(tuple);
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object.objectSubId = 0;
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break;
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default:
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elog(ERROR, "unexpected catalog id: %u", catalogId);
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objname = NULL; /* for compiler quiet */
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break;
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}
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if (selabel_lookup_raw(sehnd, &context, objname, objtype) == 0)
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{
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PG_TRY();
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{
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/*
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* Check SELinux permission to relabel the fetched object,
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* then do the actual relabeling.
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*/
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sepgsql_object_relabel(&object, context);
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SetSecurityLabel(&object, SEPGSQL_LABEL_TAG, context);
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}
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PG_CATCH();
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{
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freecon(context);
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PG_RE_THROW();
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}
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PG_END_TRY();
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freecon(context);
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}
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else if (errno == ENOENT)
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ereport(WARNING,
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(errmsg("SELinux: no initial label assigned for %s (type=%d), skipping",
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objname, objtype)));
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else
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("SELinux: could not determine initial security label for %s (type=%d): %m", objname, objtype)));
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pfree(objname);
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}
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systable_endscan(sscan);
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heap_close(rel, NoLock);
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}
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/*
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* BOOL sepgsql_restorecon(TEXT specfile)
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*
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* This function tries to assign initial security labels on all the object
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* within the current database, according to the system setting.
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* It is typically invoked by sepgsql-install script just after initdb, to
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* assign initial security labels.
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*
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* If @specfile is not NULL, it uses explicitly specified specfile, instead
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* of the system default.
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*/
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PG_FUNCTION_INFO_V1(sepgsql_restorecon);
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Datum
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sepgsql_restorecon(PG_FUNCTION_ARGS)
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{
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struct selabel_handle *sehnd;
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struct selinux_opt seopts;
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/*
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* SELinux has to be enabled on the running platform.
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*/
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if (!sepgsql_is_enabled())
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ereport(ERROR,
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(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
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errmsg("sepgsql is not currently enabled")));
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/*
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* Check DAC permission. Only superuser can set up initial security
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* labels, like root-user in filesystems
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*/
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("SELinux: must be superuser to restore initial contexts")));
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/*
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* Open selabel_lookup(3) stuff. It provides a set of mapping between an
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* initial security label and object class/name due to the system setting.
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*/
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if (PG_ARGISNULL(0))
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{
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seopts.type = SELABEL_OPT_UNUSED;
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seopts.value = NULL;
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}
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else
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{
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seopts.type = SELABEL_OPT_PATH;
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seopts.value = TextDatumGetCString(PG_GETARG_DATUM(0));
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}
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sehnd = selabel_open(SELABEL_CTX_DB, &seopts, 1);
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if (!sehnd)
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("SELinux: failed to initialize labeling handle: %m")));
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PG_TRY();
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{
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/*
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* Right now, we have no support labeling on the shared database
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* objects, such as database, role, or tablespace.
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*/
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exec_object_restorecon(sehnd, NamespaceRelationId);
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exec_object_restorecon(sehnd, RelationRelationId);
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exec_object_restorecon(sehnd, AttributeRelationId);
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exec_object_restorecon(sehnd, ProcedureRelationId);
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}
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PG_CATCH();
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{
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selabel_close(sehnd);
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PG_RE_THROW();
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}
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PG_END_TRY();
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selabel_close(sehnd);
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PG_RETURN_BOOL(true);
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}
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