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Rework query relation permission checking

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Currently, information about the permissions to be checked on relations
mentioned in a query is stored in their range table entries.  So the
executor must scan the entire range table looking for relations that
need to have permissions checked.  This can make the permission checking
part of the executor initialization needlessly expensive when many
inheritance children are present in the range range.  While the
permissions need not be checked on the individual child relations, the
executor still must visit every range table entry to filter them out.

This commit moves the permission checking information out of the range
table entries into a new plan node called RTEPermissionInfo.  Every
top-level (inheritance "root") RTE_RELATION entry in the range table
gets one and a list of those is maintained alongside the range table.
This new list is initialized by the parser when initializing the range
table.  The rewriter can add more entries to it as rules/views are
expanded.  Finally, the planner combines the lists of the individual
subqueries into one flat list that is passed to the executor for
checking.

To make it quick to find the RTEPermissionInfo entry belonging to a
given relation, RangeTblEntry gets a new Index field 'perminfoindex'
that stores the corresponding RTEPermissionInfo's index in the query's
list of the latter.

ExecutorCheckPerms_hook has gained another List * argument; the
signature is now:
typedef bool (*ExecutorCheckPerms_hook_type) (List *rangeTable,
					      List *rtePermInfos,
					      bool ereport_on_violation);
The first argument is no longer used by any in-core uses of the hook,
but we leave it in place because there may be other implementations that
do.  Implementations should likely scan the rtePermInfos list to
determine which operations to allow or deny.

Author: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/CA+HiwqGjJDmUhDSfv-U2qhKJjt9ST7Xh9JXC_irsAQ1TAUsJYg@mail.gmail.com
This commit is contained in:
Alvaro Herrera
2022-12-06 16:09:24 +01:00
parent b5bbaf08ed
commit a61b1f7482
47 changed files with 954 additions and 534 deletions
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42
contrib/sepgsql/dml.c
View File

@ -23,6 +23,7 @@
#include "commands/tablecmds.h"
#include "executor/executor.h"
#include "nodes/bitmapset.h"
#include "parser/parsetree.h"
#include "sepgsql.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
@ -277,38 +278,33 @@ check_relation_privileges(Oid relOid,
* Entrypoint of the DML permission checks
*/
bool
sepgsql_dml_privileges(List *rangeTabls, bool abort_on_violation)
sepgsql_dml_privileges(List *rangeTbls, List *rteperminfos,
bool abort_on_violation)
{
ListCell *lr;
foreach(lr, rangeTabls)
foreach(lr, rteperminfos)
{
RangeTblEntry *rte = lfirst(lr);
RTEPermissionInfo *perminfo = lfirst_node(RTEPermissionInfo, lr);
uint32 required = 0;
List *tableIds;
ListCell *li;
/*
* Only regular relations shall be checked
*/
if (rte->rtekind != RTE_RELATION)
continue;
/*
* Find out required permissions
*/
if (rte->requiredPerms & ACL_SELECT)
if (perminfo->requiredPerms & ACL_SELECT)
required |= SEPG_DB_TABLE__SELECT;
if (rte->requiredPerms & ACL_INSERT)
if (perminfo->requiredPerms & ACL_INSERT)
required |= SEPG_DB_TABLE__INSERT;
if (rte->requiredPerms & ACL_UPDATE)
if (perminfo->requiredPerms & ACL_UPDATE)
{
if (!bms_is_empty(rte->updatedCols))
if (!bms_is_empty(perminfo->updatedCols))
required |= SEPG_DB_TABLE__UPDATE;
else
required |= SEPG_DB_TABLE__LOCK;
}
if (rte->requiredPerms & ACL_DELETE)
if (perminfo->requiredPerms & ACL_DELETE)
required |= SEPG_DB_TABLE__DELETE;
/*
@ -323,10 +319,10 @@ sepgsql_dml_privileges(List *rangeTabls, bool abort_on_violation)
* expand rte->relid into list of OIDs of inheritance hierarchy, then
* checker routine will be invoked for each relations.
*/
if (!rte->inh)
tableIds = list_make1_oid(rte->relid);
if (!perminfo->inh)
tableIds = list_make1_oid(perminfo->relid);
else
tableIds = find_all_inheritors(rte->relid, NoLock, NULL);
tableIds = find_all_inheritors(perminfo->relid, NoLock, NULL);
foreach(li, tableIds)
{
@ -339,12 +335,12 @@ sepgsql_dml_privileges(List *rangeTabls, bool abort_on_violation)
* child table has different attribute numbers, so we need to fix
* up them.
*/
selectedCols = fixup_inherited_columns(rte->relid, tableOid,
rte->selectedCols);
insertedCols = fixup_inherited_columns(rte->relid, tableOid,
rte->insertedCols);
updatedCols = fixup_inherited_columns(rte->relid, tableOid,
rte->updatedCols);
selectedCols = fixup_inherited_columns(perminfo->relid, tableOid,
perminfo->selectedCols);
insertedCols = fixup_inherited_columns(perminfo->relid, tableOid,
perminfo->insertedCols);
updatedCols = fixup_inherited_columns(perminfo->relid, tableOid,
perminfo->updatedCols);
/*
* check permissions on individual tables