database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-03 09:13:20 +03:00
Code Activity

Fix corner-case failures in has_foo_privilege() family of functions.

Browse Source 
The variants of these functions that take numeric inputs (OIDs or
column numbers) are supposed to return NULL rather than failing
on bad input; this rule reduces problems with snapshot skew when
queries apply the functions to all rows of a catalog.

has_column_privilege() had careless handling of the case where the
table OID didn't exist.  You might get something like this:
	select has_column_privilege(9999,'nosuchcol','select');
	ERROR:  column "nosuchcol" of relation "(null)" does not exist
or you might get a crash, depending on the platform's printf's response
to a null string pointer.

In addition, while applying the column-number variant to a dropped
column returned NULL as desired, applying the column-name variant
did not:
	select has_column_privilege('mytable','........pg.dropped.2........','select');
	ERROR:  column "........pg.dropped.2........" of relation "mytable" does not exist
It seems better to make this case return NULL as well.

Also, the OID-accepting variants of has_foreign_data_wrapper_privilege,
has_server_privilege, and has_tablespace_privilege didn't follow the
principle of returning NULL for nonexistent OIDs.  Superusers got TRUE,
everybody else got an error.

Per investigation of Jaime Casanova's report of a new crash in HEAD.
These behaviors have been like this for a long time, so back-patch to
all supported branches.

Patch by me; thanks to Stephen Frost for discussion and review

Discussion: https://postgr.es/m/CAJGNTeP=-6Gyqq5TN9OvYEydi7Fv1oGyYj650LGTnW44oAzYCg@mail.gmail.com
This commit is contained in:
Tom Lane
2018-10-02 11:54:13 -04:00
parent 2bedb0ec79
commit fd81fae67f
3 changed files with 159 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

89
src/backend/utils/adt/acl.c
View File

@@ -2450,8 +2450,12 @@ has_any_column_privilege_id_id(PG_FUNCTION_ARGS)
*
* The result is a boolean value: true if user has the indicated
* privilege, false if not. The variants that take a relation OID
* and an integer attnum return NULL (rather than throwing an error)
* if the column doesn't exist or is dropped.
* return NULL (rather than throwing an error) if that relation OID
* doesn't exist. Likewise, the variants that take an integer attnum
* return NULL (rather than throwing an error) if there is no such
* pg_attribute entry. All variants return NULL if an attisdropped
* column is selected. These rules are meant to avoid unnecessary
* failures in queries that scan pg_attribute.
*/
/*
@@ -2468,6 +2472,12 @@ column_privilege_check(Oid tableoid, AttrNumber attnum,
HeapTuple attTuple;
Form_pg_attribute attributeForm;
/*
* If convert_column_name failed, we can just return -1 immediately.
*/
if (attnum == InvalidAttrNumber)
return -1;
/*
* First check if we have the privilege at the table level. We check
* existence of the pg_class row before risking calling pg_class_aclcheck.
@@ -2829,21 +2839,59 @@ has_column_privilege_id_attnum(PG_FUNCTION_ARGS)
/*
* Given a table OID and a column name expressed as a string, look it up
* and return the column number
* and return the column number. Returns InvalidAttrNumber in cases
* where caller should return NULL instead of failing.
*/
static AttrNumber
convert_column_name(Oid tableoid, text *column)
{
AttrNumber attnum;
char *colname;
HeapTuple attTuple;
AttrNumber attnum;
colname = text_to_cstring(column);
attnum = get_attnum(tableoid, colname);
if (attnum == InvalidAttrNumber)
/*
* We don't use get_attnum() here because it will report that dropped
* columns don't exist. We need to treat dropped columns differently from
* nonexistent columns.
*/
attTuple = SearchSysCache2(ATTNAME,
ObjectIdGetDatum(tableoid),
CStringGetDatum(colname));
if (HeapTupleIsValid(attTuple))
{
Form_pg_attribute attributeForm;
attributeForm = (Form_pg_attribute) GETSTRUCT(attTuple);
/* We want to return NULL for dropped columns */
if (attributeForm->attisdropped)
attnum = InvalidAttrNumber;
else
attnum = attributeForm->attnum;
ReleaseSysCache(attTuple);
}
else
{
char *tablename = get_rel_name(tableoid);
/*
* If the table OID is bogus, or it's just been dropped, we'll get
* NULL back. In such cases we want has_column_privilege to return
* NULL too, so just return InvalidAttrNumber.
*/
if (tablename != NULL)
{
/* tableoid exists, colname does not, so throw error */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colname, get_rel_name(tableoid))));
colname, tablename)));
}
/* tableoid doesn't exist, so act like attisdropped case */
attnum = InvalidAttrNumber;
}
pfree(colname);
return attnum;
}
@@ -3147,6 +3195,9 @@ has_foreign_data_wrapper_privilege_name_id(PG_FUNCTION_ARGS)
roleid = get_role_oid_or_public(NameStr(*username));
mode = convert_foreign_data_wrapper_priv_string(priv_type_text);
if (!SearchSysCacheExists1(FOREIGNDATAWRAPPEROID, ObjectIdGetDatum(fdwid)))
PG_RETURN_NULL();
aclresult = pg_foreign_data_wrapper_aclcheck(fdwid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -3170,6 +3221,9 @@ has_foreign_data_wrapper_privilege_id(PG_FUNCTION_ARGS)
roleid = GetUserId();
mode = convert_foreign_data_wrapper_priv_string(priv_type_text);
if (!SearchSysCacheExists1(FOREIGNDATAWRAPPEROID, ObjectIdGetDatum(fdwid)))
PG_RETURN_NULL();
aclresult = pg_foreign_data_wrapper_aclcheck(fdwid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -3214,6 +3268,9 @@ has_foreign_data_wrapper_privilege_id_id(PG_FUNCTION_ARGS)
mode = convert_foreign_data_wrapper_priv_string(priv_type_text);
if (!SearchSysCacheExists1(FOREIGNDATAWRAPPEROID, ObjectIdGetDatum(fdwid)))
PG_RETURN_NULL();
aclresult = pg_foreign_data_wrapper_aclcheck(fdwid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -3913,6 +3970,9 @@ has_server_privilege_name_id(PG_FUNCTION_ARGS)
roleid = get_role_oid_or_public(NameStr(*username));
mode = convert_server_priv_string(priv_type_text);
if (!SearchSysCacheExists1(FOREIGNSERVEROID, ObjectIdGetDatum(serverid)))
PG_RETURN_NULL();
aclresult = pg_foreign_server_aclcheck(serverid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -3936,6 +3996,9 @@ has_server_privilege_id(PG_FUNCTION_ARGS)
roleid = GetUserId();
mode = convert_server_priv_string(priv_type_text);
if (!SearchSysCacheExists1(FOREIGNSERVEROID, ObjectIdGetDatum(serverid)))
PG_RETURN_NULL();
aclresult = pg_foreign_server_aclcheck(serverid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -3980,6 +4043,9 @@ has_server_privilege_id_id(PG_FUNCTION_ARGS)
mode = convert_server_priv_string(priv_type_text);
if (!SearchSysCacheExists1(FOREIGNSERVEROID, ObjectIdGetDatum(serverid)))
PG_RETURN_NULL();
aclresult = pg_foreign_server_aclcheck(serverid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -4095,6 +4161,9 @@ has_tablespace_privilege_name_id(PG_FUNCTION_ARGS)
roleid = get_role_oid_or_public(NameStr(*username));
mode = convert_tablespace_priv_string(priv_type_text);
if (!SearchSysCacheExists1(TABLESPACEOID, ObjectIdGetDatum(tablespaceoid)))
PG_RETURN_NULL();
aclresult = pg_tablespace_aclcheck(tablespaceoid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -4118,6 +4187,9 @@ has_tablespace_privilege_id(PG_FUNCTION_ARGS)
roleid = GetUserId();
mode = convert_tablespace_priv_string(priv_type_text);
if (!SearchSysCacheExists1(TABLESPACEOID, ObjectIdGetDatum(tablespaceoid)))
PG_RETURN_NULL();
aclresult = pg_tablespace_aclcheck(tablespaceoid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);
@@ -4162,6 +4234,9 @@ has_tablespace_privilege_id_id(PG_FUNCTION_ARGS)
mode = convert_tablespace_priv_string(priv_type_text);
if (!SearchSysCacheExists1(TABLESPACEOID, ObjectIdGetDatum(tablespaceoid)))
PG_RETURN_NULL();
aclresult = pg_tablespace_aclcheck(tablespaceoid, roleid, mode);
PG_RETURN_BOOL(aclresult == ACLCHECK_OK);

57
src/test/regress/expected/privileges.out
View File

@@ -1036,6 +1036,63 @@ from (select oid from pg_class where relname = 'atest1') as t1;
f
(1 row)
-- has_column_privilege function
-- bad-input checks (as non-super-user)
select has_column_privilege('pg_authid',NULL,'select');
has_column_privilege
----------------------
(1 row)
select has_column_privilege('pg_authid','nosuchcol','select');
ERROR: column "nosuchcol" of relation "pg_authid" does not exist
select has_column_privilege(9999,'nosuchcol','select');
has_column_privilege
----------------------
(1 row)
select has_column_privilege(9999,99::int2,'select');
has_column_privilege
----------------------
(1 row)
select has_column_privilege('pg_authid',99::int2,'select');
has_column_privilege
----------------------
(1 row)
select has_column_privilege(9999,99::int2,'select');
has_column_privilege
----------------------
(1 row)
create temp table mytable(f1 int, f2 int, f3 int);
alter table mytable drop column f2;
select has_column_privilege('mytable','f2','select');
ERROR: column "f2" of relation "mytable" does not exist
select has_column_privilege('mytable','........pg.dropped.2........','select');
has_column_privilege
----------------------
(1 row)
select has_column_privilege('mytable',2::int2,'select');
has_column_privilege
----------------------
t
(1 row)
revoke select on table mytable from regressuser3;
select has_column_privilege('mytable',2::int2,'select');
has_column_privilege
----------------------
(1 row)
-- Grant options
SET SESSION AUTHORIZATION regressuser1;
CREATE TABLE atest4 (a int);

17
src/test/regress/sql/privileges.sql
View File

@@ -657,6 +657,23 @@ from (select oid from pg_class where relname = 'atest1') as t1;
select has_table_privilege(t1.oid,'trigger')
from (select oid from pg_class where relname = 'atest1') as t1;
-- has_column_privilege function
-- bad-input checks (as non-super-user)
select has_column_privilege('pg_authid',NULL,'select');
select has_column_privilege('pg_authid','nosuchcol','select');
select has_column_privilege(9999,'nosuchcol','select');
select has_column_privilege(9999,99::int2,'select');
select has_column_privilege('pg_authid',99::int2,'select');
select has_column_privilege(9999,99::int2,'select');
create temp table mytable(f1 int, f2 int, f3 int);
alter table mytable drop column f2;
select has_column_privilege('mytable','f2','select');
select has_column_privilege('mytable','........pg.dropped.2........','select');
select has_column_privilege('mytable',2::int2,'select');
revoke select on table mytable from regressuser3;
select has_column_privilege('mytable',2::int2,'select');
-- Grant options