postgresql/src/backend/commands/seclabel.c

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/* -------------------------------------------------------------------------
*
* seclabel.c
* routines to support security label feature.
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/htup_details.h"
#include "access/relation.h"
#include "access/table.h"
#include "catalog/catalog.h"
#include "catalog/indexing.h"
#include "catalog/pg_seclabel.h"
#include "catalog/pg_shseclabel.h"
#include "commands/seclabel.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/memutils.h"
#include "utils/rel.h"
typedef struct
{
const char *provider_name;
check_object_relabel_type hook;
} LabelProvider;
static List *label_provider_list = NIL;
static bool
SecLabelSupportsObjectType(ObjectType objtype)
{
switch (objtype)
{
case OBJECT_AGGREGATE:
case OBJECT_COLUMN:
case OBJECT_DATABASE:
case OBJECT_DOMAIN:
case OBJECT_EVENT_TRIGGER:
case OBJECT_FOREIGN_TABLE:
case OBJECT_FUNCTION:
case OBJECT_LANGUAGE:
case OBJECT_LARGEOBJECT:
case OBJECT_MATVIEW:
case OBJECT_PROCEDURE:
case OBJECT_PUBLICATION:
case OBJECT_ROLE:
case OBJECT_ROUTINE:
case OBJECT_SCHEMA:
case OBJECT_SEQUENCE:
case OBJECT_SUBSCRIPTION:
case OBJECT_TABLE:
case OBJECT_TABLESPACE:
case OBJECT_TYPE:
case OBJECT_VIEW:
return true;
case OBJECT_ACCESS_METHOD:
case OBJECT_AMOP:
case OBJECT_AMPROC:
case OBJECT_ATTRIBUTE:
case OBJECT_CAST:
case OBJECT_COLLATION:
case OBJECT_CONVERSION:
case OBJECT_DEFAULT:
case OBJECT_DEFACL:
case OBJECT_DOMCONSTRAINT:
case OBJECT_EXTENSION:
case OBJECT_FDW:
case OBJECT_FOREIGN_SERVER:
case OBJECT_INDEX:
case OBJECT_OPCLASS:
case OBJECT_OPERATOR:
case OBJECT_OPFAMILY:
case OBJECT_PARAMETER_ACL:
case OBJECT_POLICY:
case OBJECT_PUBLICATION_NAMESPACE:
case OBJECT_PUBLICATION_REL:
case OBJECT_RULE:
case OBJECT_STATISTIC_EXT:
case OBJECT_TABCONSTRAINT:
case OBJECT_TRANSFORM:
case OBJECT_TRIGGER:
case OBJECT_TSCONFIGURATION:
case OBJECT_TSDICTIONARY:
case OBJECT_TSPARSER:
case OBJECT_TSTEMPLATE:
case OBJECT_USER_MAPPING:
return false;
/*
* There's intentionally no default: case here; we want the
* compiler to warn if a new ObjectType hasn't been handled above.
*/
}
/* Shouldn't get here, but if we do, say "no support" */
return false;
}
/*
* ExecSecLabelStmt --
*
* Apply a security label to a database object.
*
* Returns the ObjectAddress of the object to which the policy was applied.
*/
ObjectAddress
ExecSecLabelStmt(SecLabelStmt *stmt)
{
LabelProvider *provider = NULL;
ObjectAddress address;
Relation relation;
ListCell *lc;
/*
* Find the named label provider, or if none specified, check whether
* there's exactly one, and if so use it.
*/
if (stmt->provider == NULL)
{
if (label_provider_list == NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("no security label providers have been loaded")));
Represent Lists as expansible arrays, not chains of cons-cells. Originally, Postgres Lists were a more or less exact reimplementation of Lisp lists, which consist of chains of separately-allocated cons cells, each having a value and a next-cell link. We'd hacked that once before (commit d0b4399d8) to add a separate List header, but the data was still in cons cells. That makes some operations -- notably list_nth() -- O(N), and it's bulky because of the next-cell pointers and per-cell palloc overhead, and it's very cache-unfriendly if the cons cells end up scattered around rather than being adjacent. In this rewrite, we still have List headers, but the data is in a resizable array of values, with no next-cell links. Now we need at most two palloc's per List, and often only one, since we can allocate some values in the same palloc call as the List header. (Of course, extending an existing List may require repalloc's to enlarge the array. But this involves just O(log N) allocations not O(N).) Of course this is not without downsides. The key difficulty is that addition or deletion of a list entry may now cause other entries to move, which it did not before. For example, that breaks foreach() and sister macros, which historically used a pointer to the current cons-cell as loop state. We can repair those macros transparently by making their actual loop state be an integer list index; the exposed "ListCell *" pointer is no longer state carried across loop iterations, but is just a derived value. (In practice, modern compilers can optimize things back to having just one loop state value, at least for simple cases with inline loop bodies.) In principle, this is a semantics change for cases where the loop body inserts or deletes list entries ahead of the current loop index; but I found no such cases in the Postgres code. The change is not at all transparent for code that doesn't use foreach() but chases lists "by hand" using lnext(). The largest share of such code in the backend is in loops that were maintaining "prev" and "next" variables in addition to the current-cell pointer, in order to delete list cells efficiently using list_delete_cell(). However, we no longer need a previous-cell pointer to delete a list cell efficiently. Keeping a next-cell pointer doesn't work, as explained above, but we can improve matters by changing such code to use a regular foreach() loop and then using the new macro foreach_delete_current() to delete the current cell. (This macro knows how to update the associated foreach loop's state so that no cells will be missed in the traversal.) There remains a nontrivial risk of code assuming that a ListCell * pointer will remain good over an operation that could now move the list contents. To help catch such errors, list.c can be compiled with a new define symbol DEBUG_LIST_MEMORY_USAGE that forcibly moves list contents whenever that could possibly happen. This makes list operations significantly more expensive so it's not normally turned on (though it is on by default if USE_VALGRIND is on). There are two notable API differences from the previous code: * lnext() now requires the List's header pointer in addition to the current cell's address. * list_delete_cell() no longer requires a previous-cell argument. These changes are somewhat unfortunate, but on the other hand code using either function needs inspection to see if it is assuming anything it shouldn't, so it's not all bad. Programmers should be aware of these significant performance changes: * list_nth() and related functions are now O(1); so there's no major access-speed difference between a list and an array. * Inserting or deleting a list element now takes time proportional to the distance to the end of the list, due to moving the array elements. (However, it typically *doesn't* require palloc or pfree, so except in long lists it's probably still faster than before.) Notably, lcons() used to be about the same cost as lappend(), but that's no longer true if the list is long. Code that uses lcons() and list_delete_first() to maintain a stack might usefully be rewritten to push and pop at the end of the list rather than the beginning. * There are now list_insert_nth...() and list_delete_nth...() functions that add or remove a list cell identified by index. These have the data-movement penalty explained above, but there's no search penalty. * list_concat() and variants now copy the second list's data into storage belonging to the first list, so there is no longer any sharing of cells between the input lists. The second argument is now declared "const List *" to reflect that it isn't changed. This patch just does the minimum needed to get the new implementation in place and fix bugs exposed by the regression tests. As suggested by the foregoing, there's a fair amount of followup work remaining to do. Also, the ENABLE_LIST_COMPAT macros are finally removed in this commit. Code using those should have been gone a dozen years ago. Patch by me; thanks to David Rowley, Jesper Pedersen, and others for review. Discussion: https://postgr.es/m/11587.1550975080@sss.pgh.pa.us
2019-07-15 19:41:58 +02:00
if (list_length(label_provider_list) != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("must specify provider when multiple security label providers have been loaded")));
provider = (LabelProvider *) linitial(label_provider_list);
}
else
{
foreach(lc, label_provider_list)
{
LabelProvider *lp = lfirst(lc);
if (strcmp(stmt->provider, lp->provider_name) == 0)
{
provider = lp;
break;
}
}
if (provider == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("security label provider \"%s\" is not loaded",
stmt->provider)));
}
if (!SecLabelSupportsObjectType(stmt->objtype))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("security labels are not supported for this type of object")));
/*
* Translate the parser representation which identifies this object into
* an ObjectAddress. get_object_address() will throw an error if the
* object does not exist, and will also acquire a lock on the target to
* guard against concurrent modifications.
*/
address = get_object_address(stmt->objtype, stmt->object,
&relation, ShareUpdateExclusiveLock, false);
/* Require ownership of the target object. */
check_object_ownership(GetUserId(), stmt->objtype, address,
stmt->object, relation);
/* Perform other integrity checks as needed. */
switch (stmt->objtype)
{
case OBJECT_COLUMN:
2011-04-10 17:42:00 +02:00
/*
* Allow security labels only on columns of tables, views,
* materialized views, composite types, and foreign tables (which
* are the only relkinds for which pg_dump will dump labels).
*/
if (relation->rd_rel->relkind != RELKIND_RELATION &&
relation->rd_rel->relkind != RELKIND_VIEW &&
relation->rd_rel->relkind != RELKIND_MATVIEW &&
relation->rd_rel->relkind != RELKIND_COMPOSITE_TYPE &&
Implement table partitioning. Table partitioning is like table inheritance and reuses much of the existing infrastructure, but there are some important differences. The parent is called a partitioned table and is always empty; it may not have indexes or non-inherited constraints, since those make no sense for a relation with no data of its own. The children are called partitions and contain all of the actual data. Each partition has an implicit partitioning constraint. Multiple inheritance is not allowed, and partitioning and inheritance can't be mixed. Partitions can't have extra columns and may not allow nulls unless the parent does. Tuples inserted into the parent are automatically routed to the correct partition, so tuple-routing ON INSERT triggers are not needed. Tuple routing isn't yet supported for partitions which are foreign tables, and it doesn't handle updates that cross partition boundaries. Currently, tables can be range-partitioned or list-partitioned. List partitioning is limited to a single column, but range partitioning can involve multiple columns. A partitioning "column" can be an expression. Because table partitioning is less general than table inheritance, it is hoped that it will be easier to reason about properties of partitions, and therefore that this will serve as a better foundation for a variety of possible optimizations, including query planner optimizations. The tuple routing based which this patch does based on the implicit partitioning constraints is an example of this, but it seems likely that many other useful optimizations are also possible. Amit Langote, reviewed and tested by Robert Haas, Ashutosh Bapat, Amit Kapila, Rajkumar Raghuwanshi, Corey Huinker, Jaime Casanova, Rushabh Lathia, Erik Rijkers, among others. Minor revisions by me.
2016-12-07 19:17:43 +01:00
relation->rd_rel->relkind != RELKIND_FOREIGN_TABLE &&
relation->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot set security label on relation \"%s\"",
RelationGetRelationName(relation)),
errdetail_relkind_not_supported(relation->rd_rel->relkind)));
break;
default:
break;
}
/* Provider gets control here, may throw ERROR to veto new label. */
provider->hook(&address, stmt->label);
/* Apply new label. */
SetSecurityLabel(&address, provider->provider_name, stmt->label);
/*
* If get_object_address() opened the relation for us, we close it to keep
* the reference count correct - but we retain any locks acquired by
* get_object_address() until commit time, to guard against concurrent
* activity.
*/
if (relation != NULL)
relation_close(relation, NoLock);
return address;
}
/*
* GetSharedSecurityLabel returns the security label for a shared object for
* a given provider, or NULL if there is no such label.
*/
static char *
GetSharedSecurityLabel(const ObjectAddress *object, const char *provider)
{
Relation pg_shseclabel;
ScanKeyData keys[3];
SysScanDesc scan;
HeapTuple tuple;
Datum datum;
bool isnull;
char *seclabel = NULL;
ScanKeyInit(&keys[0],
Anum_pg_shseclabel_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->objectId));
ScanKeyInit(&keys[1],
Anum_pg_shseclabel_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->classId));
ScanKeyInit(&keys[2],
Anum_pg_shseclabel_provider,
BTEqualStrategyNumber, F_TEXTEQ,
CStringGetTextDatum(provider));
pg_shseclabel = table_open(SharedSecLabelRelationId, AccessShareLock);
scan = systable_beginscan(pg_shseclabel, SharedSecLabelObjectIndexId,
criticalSharedRelcachesBuilt, NULL, 3, keys);
tuple = systable_getnext(scan);
if (HeapTupleIsValid(tuple))
{
datum = heap_getattr(tuple, Anum_pg_shseclabel_label,
RelationGetDescr(pg_shseclabel), &isnull);
if (!isnull)
seclabel = TextDatumGetCString(datum);
}
systable_endscan(scan);
table_close(pg_shseclabel, AccessShareLock);
return seclabel;
}
/*
* GetSecurityLabel returns the security label for a shared or database object
* for a given provider, or NULL if there is no such label.
*/
char *
GetSecurityLabel(const ObjectAddress *object, const char *provider)
{
Relation pg_seclabel;
ScanKeyData keys[4];
SysScanDesc scan;
HeapTuple tuple;
Datum datum;
bool isnull;
char *seclabel = NULL;
/* Shared objects have their own security label catalog. */
if (IsSharedRelation(object->classId))
return GetSharedSecurityLabel(object, provider);
/* Must be an unshared object, so examine pg_seclabel. */
ScanKeyInit(&keys[0],
Anum_pg_seclabel_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->objectId));
ScanKeyInit(&keys[1],
Anum_pg_seclabel_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->classId));
ScanKeyInit(&keys[2],
Anum_pg_seclabel_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(object->objectSubId));
ScanKeyInit(&keys[3],
Anum_pg_seclabel_provider,
BTEqualStrategyNumber, F_TEXTEQ,
CStringGetTextDatum(provider));
pg_seclabel = table_open(SecLabelRelationId, AccessShareLock);
scan = systable_beginscan(pg_seclabel, SecLabelObjectIndexId, true,
NULL, 4, keys);
tuple = systable_getnext(scan);
if (HeapTupleIsValid(tuple))
{
datum = heap_getattr(tuple, Anum_pg_seclabel_label,
RelationGetDescr(pg_seclabel), &isnull);
if (!isnull)
seclabel = TextDatumGetCString(datum);
}
systable_endscan(scan);
table_close(pg_seclabel, AccessShareLock);
return seclabel;
}
/*
* SetSharedSecurityLabel is a helper function of SetSecurityLabel to
* handle shared database objects.
*/
static void
SetSharedSecurityLabel(const ObjectAddress *object,
const char *provider, const char *label)
{
Relation pg_shseclabel;
ScanKeyData keys[4];
SysScanDesc scan;
HeapTuple oldtup;
HeapTuple newtup = NULL;
Datum values[Natts_pg_shseclabel];
bool nulls[Natts_pg_shseclabel];
bool replaces[Natts_pg_shseclabel];
/* Prepare to form or update a tuple, if necessary. */
memset(nulls, false, sizeof(nulls));
memset(replaces, false, sizeof(replaces));
values[Anum_pg_shseclabel_objoid - 1] = ObjectIdGetDatum(object->objectId);
values[Anum_pg_shseclabel_classoid - 1] = ObjectIdGetDatum(object->classId);
values[Anum_pg_shseclabel_provider - 1] = CStringGetTextDatum(provider);
if (label != NULL)
values[Anum_pg_shseclabel_label - 1] = CStringGetTextDatum(label);
/* Use the index to search for a matching old tuple */
ScanKeyInit(&keys[0],
Anum_pg_shseclabel_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->objectId));
ScanKeyInit(&keys[1],
Anum_pg_shseclabel_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->classId));
ScanKeyInit(&keys[2],
Anum_pg_shseclabel_provider,
BTEqualStrategyNumber, F_TEXTEQ,
CStringGetTextDatum(provider));
pg_shseclabel = table_open(SharedSecLabelRelationId, RowExclusiveLock);
scan = systable_beginscan(pg_shseclabel, SharedSecLabelObjectIndexId, true,
NULL, 3, keys);
oldtup = systable_getnext(scan);
if (HeapTupleIsValid(oldtup))
{
if (label == NULL)
CatalogTupleDelete(pg_shseclabel, &oldtup->t_self);
else
{
replaces[Anum_pg_shseclabel_label - 1] = true;
newtup = heap_modify_tuple(oldtup, RelationGetDescr(pg_shseclabel),
values, nulls, replaces);
CatalogTupleUpdate(pg_shseclabel, &oldtup->t_self, newtup);
}
}
systable_endscan(scan);
/* If we didn't find an old tuple, insert a new one */
if (newtup == NULL && label != NULL)
{
newtup = heap_form_tuple(RelationGetDescr(pg_shseclabel),
values, nulls);
CatalogTupleInsert(pg_shseclabel, newtup);
}
if (newtup != NULL)
heap_freetuple(newtup);
table_close(pg_shseclabel, RowExclusiveLock);
}
/*
* SetSecurityLabel attempts to set the security label for the specified
* provider on the specified object to the given value. NULL means that any
* existing label should be deleted.
*/
void
SetSecurityLabel(const ObjectAddress *object,
const char *provider, const char *label)
{
Relation pg_seclabel;
ScanKeyData keys[4];
SysScanDesc scan;
HeapTuple oldtup;
HeapTuple newtup = NULL;
Datum values[Natts_pg_seclabel];
bool nulls[Natts_pg_seclabel];
bool replaces[Natts_pg_seclabel];
/* Shared objects have their own security label catalog. */
if (IsSharedRelation(object->classId))
{
SetSharedSecurityLabel(object, provider, label);
return;
}
/* Prepare to form or update a tuple, if necessary. */
memset(nulls, false, sizeof(nulls));
memset(replaces, false, sizeof(replaces));
values[Anum_pg_seclabel_objoid - 1] = ObjectIdGetDatum(object->objectId);
values[Anum_pg_seclabel_classoid - 1] = ObjectIdGetDatum(object->classId);
values[Anum_pg_seclabel_objsubid - 1] = Int32GetDatum(object->objectSubId);
values[Anum_pg_seclabel_provider - 1] = CStringGetTextDatum(provider);
if (label != NULL)
values[Anum_pg_seclabel_label - 1] = CStringGetTextDatum(label);
/* Use the index to search for a matching old tuple */
ScanKeyInit(&keys[0],
Anum_pg_seclabel_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->objectId));
ScanKeyInit(&keys[1],
Anum_pg_seclabel_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->classId));
ScanKeyInit(&keys[2],
Anum_pg_seclabel_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(object->objectSubId));
ScanKeyInit(&keys[3],
Anum_pg_seclabel_provider,
BTEqualStrategyNumber, F_TEXTEQ,
CStringGetTextDatum(provider));
pg_seclabel = table_open(SecLabelRelationId, RowExclusiveLock);
scan = systable_beginscan(pg_seclabel, SecLabelObjectIndexId, true,
NULL, 4, keys);
oldtup = systable_getnext(scan);
if (HeapTupleIsValid(oldtup))
{
if (label == NULL)
CatalogTupleDelete(pg_seclabel, &oldtup->t_self);
else
{
replaces[Anum_pg_seclabel_label - 1] = true;
newtup = heap_modify_tuple(oldtup, RelationGetDescr(pg_seclabel),
values, nulls, replaces);
CatalogTupleUpdate(pg_seclabel, &oldtup->t_self, newtup);
}
}
systable_endscan(scan);
/* If we didn't find an old tuple, insert a new one */
if (newtup == NULL && label != NULL)
{
newtup = heap_form_tuple(RelationGetDescr(pg_seclabel),
values, nulls);
CatalogTupleInsert(pg_seclabel, newtup);
}
/* Update indexes, if necessary */
if (newtup != NULL)
heap_freetuple(newtup);
table_close(pg_seclabel, RowExclusiveLock);
}
/*
* DeleteSharedSecurityLabel is a helper function of DeleteSecurityLabel
* to handle shared database objects.
*/
void
DeleteSharedSecurityLabel(Oid objectId, Oid classId)
{
Relation pg_shseclabel;
ScanKeyData skey[2];
SysScanDesc scan;
HeapTuple oldtup;
ScanKeyInit(&skey[0],
Anum_pg_shseclabel_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(objectId));
ScanKeyInit(&skey[1],
Anum_pg_shseclabel_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(classId));
pg_shseclabel = table_open(SharedSecLabelRelationId, RowExclusiveLock);
scan = systable_beginscan(pg_shseclabel, SharedSecLabelObjectIndexId, true,
NULL, 2, skey);
while (HeapTupleIsValid(oldtup = systable_getnext(scan)))
CatalogTupleDelete(pg_shseclabel, &oldtup->t_self);
systable_endscan(scan);
table_close(pg_shseclabel, RowExclusiveLock);
}
/*
* DeleteSecurityLabel removes all security labels for an object (and any
* sub-objects, if applicable).
*/
void
DeleteSecurityLabel(const ObjectAddress *object)
{
Relation pg_seclabel;
ScanKeyData skey[3];
SysScanDesc scan;
HeapTuple oldtup;
int nkeys;
/* Shared objects have their own security label catalog. */
if (IsSharedRelation(object->classId))
{
Assert(object->objectSubId == 0);
DeleteSharedSecurityLabel(object->objectId, object->classId);
return;
}
ScanKeyInit(&skey[0],
Anum_pg_seclabel_objoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->objectId));
ScanKeyInit(&skey[1],
Anum_pg_seclabel_classoid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(object->classId));
if (object->objectSubId != 0)
{
ScanKeyInit(&skey[2],
Anum_pg_seclabel_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(object->objectSubId));
nkeys = 3;
}
else
nkeys = 2;
pg_seclabel = table_open(SecLabelRelationId, RowExclusiveLock);
scan = systable_beginscan(pg_seclabel, SecLabelObjectIndexId, true,
NULL, nkeys, skey);
while (HeapTupleIsValid(oldtup = systable_getnext(scan)))
CatalogTupleDelete(pg_seclabel, &oldtup->t_self);
systable_endscan(scan);
table_close(pg_seclabel, RowExclusiveLock);
}
void
register_label_provider(const char *provider_name, check_object_relabel_type hook)
{
LabelProvider *provider;
MemoryContext oldcxt;
oldcxt = MemoryContextSwitchTo(TopMemoryContext);
provider = palloc(sizeof(LabelProvider));
provider->provider_name = pstrdup(provider_name);
provider->hook = hook;
label_provider_list = lappend(label_provider_list, provider);
MemoryContextSwitchTo(oldcxt);
}