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sfrostsfrost
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Handle dependencies properly in ALTER POLICY
ALTER POLICY hadn't fully considered partial policy alternation (eg: change just the roles on the policy, or just change one of the expressions) when rebuilding the dependencies. Instead, it would happily remove all dependencies which existed for the policy and then only recreate the dependencies for the objects referred to in the specific ALTER POLICY command. Correct that by extracting and building the dependencies for all objects referenced by the policy, regardless of if they were provided as part of the ALTER POLICY command or were already in place as part of the pre-existing policy.
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‎src/backend/commands/policy.c

Lines changed: 97 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -766,20 +766,117 @@ AlterPolicy(AlterPolicyStmt *stmt)
766766
replaces[Anum_pg_policy_polroles - 1] = true;
767767
values[Anum_pg_policy_polroles - 1] = PointerGetDatum(role_ids);
768768
}
769+
else
770+
{
771+
Oid *roles;
772+
Datum roles_datum;
773+
bool attr_isnull;
774+
ArrayType *policy_roles;
775+
776+
/*
777+
* We need to pull the set of roles this policy applies to from
778+
* what's in the catalog, so that we can recreate the dependencies
779+
* correctly for the policy.
780+
*/
781+
782+
roles_datum = heap_getattr(policy_tuple, Anum_pg_policy_polroles,
783+
RelationGetDescr(pg_policy_rel),
784+
&attr_isnull);
785+
Assert(!attr_isnull);
786+
787+
policy_roles = DatumGetArrayTypePCopy(roles_datum);
788+
789+
roles = (Oid *) ARR_DATA_PTR(policy_roles);
790+
791+
nitems = ARR_DIMS(policy_roles)[0];
792+
793+
role_oids = (Datum *) palloc(nitems * sizeof(Datum));
794+
795+
for (i = 0; i < nitems; i++)
796+
role_oids[i] = ObjectIdGetDatum(roles[i]);
797+
}
769798

770799
if (qual != NULL)
771800
{
772801
replaces[Anum_pg_policy_polqual - 1] = true;
773802
values[Anum_pg_policy_polqual - 1]
774803
= CStringGetTextDatum(nodeToString(qual));
775804
}
805+
else
806+
{
807+
Datum value_datum;
808+
bool attr_isnull;
809+
810+
/*
811+
* We need to pull the USING expression and build the range table for
812+
* the policy from what's in the catalog, so that we can recreate
813+
* the dependencies correctly for the policy.
814+
*/
815+
816+
/* Check if the policy has a USING expr */
817+
value_datum = heap_getattr(policy_tuple, Anum_pg_policy_polqual,
818+
RelationGetDescr(pg_policy_rel),
819+
&attr_isnull);
820+
if (!attr_isnull)
821+
{
822+
char *qual_value;
823+
ParseState *qual_pstate = make_parsestate(NULL);
824+
825+
/* parsestate is built just to build the range table */
826+
qual_pstate = make_parsestate(NULL);
827+
828+
qual_value = TextDatumGetCString(value_datum);
829+
qual = stringToNode(qual_value);
830+
831+
/* Add this rel to the parsestate's rangetable, for dependencies */
832+
addRangeTableEntryForRelation(qual_pstate, target_table, NULL,
833+
false, false);
834+
835+
qual_parse_rtable = qual_pstate->p_rtable;
836+
free_parsestate(qual_pstate);
837+
}
838+
}
776839

777840
if (with_check_qual != NULL)
778841
{
779842
replaces[Anum_pg_policy_polwithcheck - 1] = true;
780843
values[Anum_pg_policy_polwithcheck - 1]
781844
= CStringGetTextDatum(nodeToString(with_check_qual));
782845
}
846+
else
847+
{
848+
Datum value_datum;
849+
bool attr_isnull;
850+
851+
/*
852+
* We need to pull the WITH CHECK expression and build the range table
853+
* for the policy from what's in the catalog, so that we can recreate
854+
* the dependencies correctly for the policy.
855+
*/
856+
857+
/* Check if the policy has a WITH CHECK expr */
858+
value_datum = heap_getattr(policy_tuple, Anum_pg_policy_polwithcheck,
859+
RelationGetDescr(pg_policy_rel),
860+
&attr_isnull);
861+
if (!attr_isnull)
862+
{
863+
char *with_check_value;
864+
ParseState *with_check_pstate = make_parsestate(NULL);
865+
866+
/* parsestate is built just to build the range table */
867+
with_check_pstate = make_parsestate(NULL);
868+
869+
with_check_value = TextDatumGetCString(value_datum);
870+
with_check_qual = stringToNode(with_check_value);
871+
872+
/* Add this rel to the parsestate's rangetable, for dependencies */
873+
addRangeTableEntryForRelation(with_check_pstate, target_table, NULL,
874+
false, false);
875+
876+
with_check_parse_rtable = with_check_pstate->p_rtable;
877+
free_parsestate(with_check_pstate);
878+
}
879+
}
783880

784881
new_tuple = heap_modify_tuple(policy_tuple,
785882
RelationGetDescr(pg_policy_rel),

‎src/test/regress/expected/rowsecurity.out

Lines changed: 43 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3246,6 +3246,49 @@ SET row_security = on;
32463246
UPDATE r1 SET a = 30 RETURNING *;
32473247
ERROR: new row violates row-level security policy for table "r1"
32483248
DROP TABLE r1;
3249+
-- Check dependency handling
3250+
RESET SESSION AUTHORIZATION;
3251+
CREATE TABLE dep1 (c1 int);
3252+
CREATE TABLE dep2 (c1 int);
3253+
CREATE POLICY dep_p1 ON dep1 TO rls_regress_user1 USING (c1 > (select max(dep2.c1) from dep2));
3254+
ALTER POLICY dep_p1 ON dep1 TO rls_regress_user1,rls_regress_user2;
3255+
-- Should return one
3256+
SELECT count(*) = 1 FROM pg_depend
3257+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
3258+
AND refobjid = (SELECT oid FROM pg_class WHERE relname = 'dep2');
3259+
?column?
3260+
----------
3261+
t
3262+
(1 row)
3263+
3264+
ALTER POLICY dep_p1 ON dep1 USING (true);
3265+
-- Should return one
3266+
SELECT count(*) = 1 FROM pg_shdepend
3267+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
3268+
AND refobjid = (SELECT oid FROM pg_authid WHERE rolname = 'rls_regress_user1');
3269+
?column?
3270+
----------
3271+
t
3272+
(1 row)
3273+
3274+
-- Should return one
3275+
SELECT count(*) = 1 FROM pg_shdepend
3276+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
3277+
AND refobjid = (SELECT oid FROM pg_authid WHERE rolname = 'rls_regress_user2');
3278+
?column?
3279+
----------
3280+
t
3281+
(1 row)
3282+
3283+
-- Should return zero
3284+
SELECT count(*) = 0 FROM pg_depend
3285+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
3286+
AND refobjid = (SELECT oid FROM pg_class WHERE relname = 'dep2');
3287+
?column?
3288+
----------
3289+
t
3290+
(1 row)
3291+
32493292
--
32503293
-- Clean up objects
32513294
--

‎src/test/regress/sql/rowsecurity.sql

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1490,6 +1490,37 @@ UPDATE r1 SET a = 30 RETURNING *;
14901490

14911491
DROP TABLE r1;
14921492

1493+
-- Check dependency handling
1494+
RESET SESSION AUTHORIZATION;
1495+
CREATE TABLE dep1 (c1 int);
1496+
CREATE TABLE dep2 (c1 int);
1497+
1498+
CREATE POLICY dep_p1 ON dep1 TO rls_regress_user1 USING (c1 > (select max(dep2.c1) from dep2));
1499+
ALTER POLICY dep_p1 ON dep1 TO rls_regress_user1,rls_regress_user2;
1500+
1501+
-- Should return one
1502+
SELECT count(*) = 1 FROM pg_depend
1503+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
1504+
AND refobjid = (SELECT oid FROM pg_class WHERE relname = 'dep2');
1505+
1506+
ALTER POLICY dep_p1 ON dep1 USING (true);
1507+
1508+
-- Should return one
1509+
SELECT count(*) = 1 FROM pg_shdepend
1510+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
1511+
AND refobjid = (SELECT oid FROM pg_authid WHERE rolname = 'rls_regress_user1');
1512+
1513+
-- Should return one
1514+
SELECT count(*) = 1 FROM pg_shdepend
1515+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
1516+
AND refobjid = (SELECT oid FROM pg_authid WHERE rolname = 'rls_regress_user2');
1517+
1518+
-- Should return zero
1519+
SELECT count(*) = 0 FROM pg_depend
1520+
WHERE objid = (SELECT oid FROM pg_policy WHERE polname = 'dep_p1')
1521+
AND refobjid = (SELECT oid FROM pg_class WHERE relname = 'dep2');
1522+
1523+
14931524
--
14941525
-- Clean up objects
14951526
--

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