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When using the following functions, users could see various types of errors of the type "cache lookup failed for OID XXX" with elog(), that can only be used for internal errors: * pg_describe_object() * pg_identify_object() * pg_identify_object_as_address() The set of APIs managing object addresses for all object types are made smarter by gaining a new argument "missing_ok" that allows any caller to control if an error is raised or not on an undefined object. The SQL functions listed above are changed to handle the case where an object is missing. Regression tests are added for all object types for the cases where these are undefined. Before this commit, these cases failed with cache lookup errors, and now they basically return NULL (minus the name of the object type requested). Author: Michael Paquier Reviewed-by: Aleksander Alekseev, Dmitry Dolgov, Daniel Gustafsson, Álvaro Herrera, Kyotaro Horiguchi Discussion: https://postgr.es/m/CAB7nPqSZxrSmdHK-rny7z8mi=EAFXJ5J-0RbzDw6aus=wB5azQ@mail.gmail.com
363 lines
9.1 KiB
C
363 lines
9.1 KiB
C
/* -------------------------------------------------------------------------
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*
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* contrib/sepgsql/dml.c
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*
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* Routines to handle DML permission checks
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*
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* Copyright (c) 2010-2020, 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/htup_details.h"
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#include "access/sysattr.h"
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#include "access/tupdesc.h"
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#include "catalog/catalog.h"
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#include "catalog/dependency.h"
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#include "catalog/heap.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_inherits.h"
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#include "commands/seclabel.h"
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#include "commands/tablecmds.h"
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#include "executor/executor.h"
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#include "nodes/bitmapset.h"
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#include "sepgsql.h"
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#include "utils/lsyscache.h"
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#include "utils/syscache.h"
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/*
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* fixup_whole_row_references
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*
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* When user references a whole-row Var, it is equivalent to referencing
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* all the user columns (not system columns). So, we need to fix up the
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* given bitmapset, if it contains a whole-row reference.
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*/
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static Bitmapset *
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fixup_whole_row_references(Oid relOid, Bitmapset *columns)
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{
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Bitmapset *result;
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HeapTuple tuple;
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AttrNumber natts;
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AttrNumber attno;
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int index;
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/* if no whole-row references, nothing to do */
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index = InvalidAttrNumber - FirstLowInvalidHeapAttributeNumber;
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if (!bms_is_member(index, columns))
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return columns;
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/* obtain number of attributes */
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tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relOid));
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if (!HeapTupleIsValid(tuple))
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elog(ERROR, "cache lookup failed for relation %u", relOid);
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natts = ((Form_pg_class) GETSTRUCT(tuple))->relnatts;
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ReleaseSysCache(tuple);
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/* remove bit 0 from column set, add in all the non-dropped columns */
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result = bms_copy(columns);
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result = bms_del_member(result, index);
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for (attno = 1; attno <= natts; attno++)
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{
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tuple = SearchSysCache2(ATTNUM,
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ObjectIdGetDatum(relOid),
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Int16GetDatum(attno));
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if (!HeapTupleIsValid(tuple))
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continue; /* unexpected case, should we error? */
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if (!((Form_pg_attribute) GETSTRUCT(tuple))->attisdropped)
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{
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index = attno - FirstLowInvalidHeapAttributeNumber;
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result = bms_add_member(result, index);
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}
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ReleaseSysCache(tuple);
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}
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return result;
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}
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/*
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* fixup_inherited_columns
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*
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* When user is querying on a table with children, it implicitly accesses
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* child tables also. So, we also need to check security label of child
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* tables and columns, but here is no guarantee attribute numbers are
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* same between the parent and children.
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* It returns a bitmapset which contains attribute number of the child
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* table based on the given bitmapset of the parent.
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*/
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static Bitmapset *
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fixup_inherited_columns(Oid parentId, Oid childId, Bitmapset *columns)
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{
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Bitmapset *result = NULL;
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int index;
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/*
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* obviously, no need to do anything here
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*/
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if (parentId == childId)
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return columns;
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index = -1;
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while ((index = bms_next_member(columns, index)) >= 0)
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{
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/* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
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AttrNumber attno = index + FirstLowInvalidHeapAttributeNumber;
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char *attname;
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/*
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* whole-row-reference shall be fixed-up later
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*/
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if (attno == InvalidAttrNumber)
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{
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result = bms_add_member(result, index);
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continue;
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}
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attname = get_attname(parentId, attno, false);
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attno = get_attnum(childId, attname);
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if (attno == InvalidAttrNumber)
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elog(ERROR, "cache lookup failed for attribute %s of relation %u",
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attname, childId);
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result = bms_add_member(result,
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attno - FirstLowInvalidHeapAttributeNumber);
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pfree(attname);
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}
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return result;
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}
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/*
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* check_relation_privileges
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*
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* It actually checks required permissions on a certain relation
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* and its columns.
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*/
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static bool
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check_relation_privileges(Oid relOid,
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Bitmapset *selected,
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Bitmapset *inserted,
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Bitmapset *updated,
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uint32 required,
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bool abort_on_violation)
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{
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ObjectAddress object;
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char *audit_name;
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Bitmapset *columns;
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int index;
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char relkind = get_rel_relkind(relOid);
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bool result = true;
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/*
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* Hardwired Policies: SE-PostgreSQL enforces - clients cannot modify
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* system catalogs using DMLs - clients cannot reference/modify toast
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* relations using DMLs
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*/
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if (sepgsql_getenforce() > 0)
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{
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if ((required & (SEPG_DB_TABLE__UPDATE |
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SEPG_DB_TABLE__INSERT |
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SEPG_DB_TABLE__DELETE)) != 0 &&
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IsCatalogRelationOid(relOid))
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("SELinux: hardwired security policy violation")));
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if (relkind == RELKIND_TOASTVALUE)
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("SELinux: hardwired security policy violation")));
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}
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/*
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* Check permissions on the relation
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*/
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object.classId = RelationRelationId;
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object.objectId = relOid;
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object.objectSubId = 0;
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audit_name = getObjectIdentity(&object, false);
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switch (relkind)
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{
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case RELKIND_RELATION:
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case RELKIND_PARTITIONED_TABLE:
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result = sepgsql_avc_check_perms(&object,
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SEPG_CLASS_DB_TABLE,
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required,
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audit_name,
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abort_on_violation);
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break;
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case RELKIND_SEQUENCE:
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Assert((required & ~SEPG_DB_TABLE__SELECT) == 0);
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if (required & SEPG_DB_TABLE__SELECT)
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result = sepgsql_avc_check_perms(&object,
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SEPG_CLASS_DB_SEQUENCE,
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SEPG_DB_SEQUENCE__GET_VALUE,
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audit_name,
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abort_on_violation);
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break;
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case RELKIND_VIEW:
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result = sepgsql_avc_check_perms(&object,
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SEPG_CLASS_DB_VIEW,
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SEPG_DB_VIEW__EXPAND,
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audit_name,
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abort_on_violation);
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break;
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default:
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/* nothing to be checked */
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break;
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}
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pfree(audit_name);
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/*
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* Only columns owned by relations shall be checked
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*/
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if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE)
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return true;
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/*
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* Check permissions on the columns
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*/
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selected = fixup_whole_row_references(relOid, selected);
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inserted = fixup_whole_row_references(relOid, inserted);
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updated = fixup_whole_row_references(relOid, updated);
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columns = bms_union(selected, bms_union(inserted, updated));
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while ((index = bms_first_member(columns)) >= 0)
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{
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AttrNumber attnum;
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uint32 column_perms = 0;
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if (bms_is_member(index, selected))
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column_perms |= SEPG_DB_COLUMN__SELECT;
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if (bms_is_member(index, inserted))
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{
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if (required & SEPG_DB_TABLE__INSERT)
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column_perms |= SEPG_DB_COLUMN__INSERT;
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}
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if (bms_is_member(index, updated))
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{
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if (required & SEPG_DB_TABLE__UPDATE)
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column_perms |= SEPG_DB_COLUMN__UPDATE;
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}
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if (column_perms == 0)
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continue;
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/* obtain column's permission */
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attnum = index + FirstLowInvalidHeapAttributeNumber;
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object.classId = RelationRelationId;
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object.objectId = relOid;
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object.objectSubId = attnum;
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audit_name = getObjectDescription(&object, false);
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result = sepgsql_avc_check_perms(&object,
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SEPG_CLASS_DB_COLUMN,
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column_perms,
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audit_name,
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abort_on_violation);
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pfree(audit_name);
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if (!result)
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return result;
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}
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return true;
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}
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/*
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* sepgsql_dml_privileges
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*
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* Entrypoint of the DML permission checks
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*/
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bool
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sepgsql_dml_privileges(List *rangeTabls, bool abort_on_violation)
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{
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ListCell *lr;
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foreach(lr, rangeTabls)
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{
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RangeTblEntry *rte = lfirst(lr);
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uint32 required = 0;
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List *tableIds;
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ListCell *li;
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/*
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* Only regular relations shall be checked
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*/
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if (rte->rtekind != RTE_RELATION)
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continue;
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/*
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* Find out required permissions
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*/
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if (rte->requiredPerms & ACL_SELECT)
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required |= SEPG_DB_TABLE__SELECT;
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if (rte->requiredPerms & ACL_INSERT)
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required |= SEPG_DB_TABLE__INSERT;
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if (rte->requiredPerms & ACL_UPDATE)
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{
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if (!bms_is_empty(rte->updatedCols))
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required |= SEPG_DB_TABLE__UPDATE;
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else
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required |= SEPG_DB_TABLE__LOCK;
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}
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if (rte->requiredPerms & ACL_DELETE)
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required |= SEPG_DB_TABLE__DELETE;
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/*
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* Skip, if nothing to be checked
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*/
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if (required == 0)
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continue;
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/*
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* If this RangeTblEntry is also supposed to reference inherited
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* tables, we need to check security label of the child tables. So, we
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* expand rte->relid into list of OIDs of inheritance hierarchy, then
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* checker routine will be invoked for each relations.
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*/
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if (!rte->inh)
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tableIds = list_make1_oid(rte->relid);
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else
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tableIds = find_all_inheritors(rte->relid, NoLock, NULL);
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foreach(li, tableIds)
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{
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Oid tableOid = lfirst_oid(li);
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Bitmapset *selectedCols;
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Bitmapset *insertedCols;
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Bitmapset *updatedCols;
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/*
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* child table has different attribute numbers, so we need to fix
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* up them.
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*/
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selectedCols = fixup_inherited_columns(rte->relid, tableOid,
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rte->selectedCols);
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insertedCols = fixup_inherited_columns(rte->relid, tableOid,
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rte->insertedCols);
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updatedCols = fixup_inherited_columns(rte->relid, tableOid,
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rte->updatedCols);
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/*
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* check permissions on individual tables
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*/
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if (!check_relation_privileges(tableOid,
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selectedCols,
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insertedCols,
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updatedCols,
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required, abort_on_violation))
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return false;
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}
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list_free(tableIds);
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}
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return true;
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}
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