From 1aebfbea83c4a3e1a0aba4b0910135dc5a45666c Mon Sep 17 00:00:00 2001 From: Dean Rasheed Date: Mon, 6 May 2019 11:38:43 +0100 Subject: [PATCH] Fix security checks for selectivity estimation functions with RLS. In commit e2d4ef8de8, security checks were added to prevent user-supplied operators from running over data from pg_statistic unless the user has table or column privileges on the table, or the operator is leakproof. For a table with RLS, however, checking for table or column privileges is insufficient, since that does not guarantee that the user has permission to view all of the column's data. Fix this by also checking for securityQuals on the RTE, and insisting that the operator be leakproof if there are any. Thus the leakproofness check will only be skipped if there are no securityQuals and the user has table or column privileges on the table -- i.e., only if we know that the user has access to all the data in the column. Back-patch to 9.5 where RLS was added. Dean Rasheed, reviewed by Jonathan Katz and Stephen Frost. Security: CVE-2019-10130 --- src/backend/utils/adt/selfuncs.c | 21 +++++++++++++++------ src/test/regress/expected/rowsecurity.out | 21 +++++++++++++++++++++ src/test/regress/sql/rowsecurity.sql | 20 ++++++++++++++++++++ 3 files changed, 56 insertions(+), 6 deletions(-) diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index b4199131552..514612857ad 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -4597,9 +4597,13 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid, * For simplicity, we insist on the whole * table being selectable, rather than trying * to identify which column(s) the index - * depends on. + * depends on. Also require all rows to be + * selectable --- there must be no + * securityQuals from security barrier views + * or RLS policies. */ vardata->acl_ok = + rte->securityQuals == NIL && (pg_class_aclcheck(rte->relid, GetUserId(), ACL_SELECT) == ACLCHECK_OK); } @@ -4663,12 +4667,17 @@ examine_simple_variable(PlannerInfo *root, Var *var, if (HeapTupleIsValid(vardata->statsTuple)) { - /* check if user has permission to read this column */ + /* + * Check if user has permission to read this column. We require + * all rows to be accessible, so there must be no securityQuals + * from security barrier views or RLS policies. + */ vardata->acl_ok = - (pg_class_aclcheck(rte->relid, GetUserId(), - ACL_SELECT) == ACLCHECK_OK) || - (pg_attribute_aclcheck(rte->relid, var->varattno, GetUserId(), - ACL_SELECT) == ACLCHECK_OK); + rte->securityQuals == NIL && + ((pg_class_aclcheck(rte->relid, GetUserId(), + ACL_SELECT) == ACLCHECK_OK) || + (pg_attribute_aclcheck(rte->relid, var->varattno, GetUserId(), + ACL_SELECT) == ACLCHECK_OK)); } else { diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out index d764991d7b2..aa3b083ee3a 100644 --- a/src/test/regress/expected/rowsecurity.out +++ b/src/test/regress/expected/rowsecurity.out @@ -3937,6 +3937,27 @@ RESET SESSION AUTHORIZATION; DROP VIEW rls_view; DROP TABLE rls_tbl; DROP TABLE ref_tbl; +-- Leaky operator test +CREATE TABLE rls_tbl (a int); +INSERT INTO rls_tbl SELECT x/10 FROM generate_series(1, 100) x; +ANALYZE rls_tbl; +ALTER TABLE rls_tbl ENABLE ROW LEVEL SECURITY; +GRANT SELECT ON rls_tbl TO regress_rls_alice; +SET SESSION AUTHORIZATION regress_rls_alice; +CREATE FUNCTION op_leak(int, int) RETURNS bool + AS 'BEGIN RAISE NOTICE ''op_leak => %, %'', $1, $2; RETURN $1 < $2; END' + LANGUAGE plpgsql; +CREATE OPERATOR <<< (procedure = op_leak, leftarg = int, rightarg = int, + restrict = scalarltsel); +SELECT * FROM rls_tbl WHERE a <<< 1000; + a +--- +(0 rows) + +DROP OPERATOR <<< (int, int); +DROP FUNCTION op_leak(int, int); +RESET SESSION AUTHORIZATION; +DROP TABLE rls_tbl; -- -- Clean up objects -- diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql index df8fe11db1e..679733051ca 100644 --- a/src/test/regress/sql/rowsecurity.sql +++ b/src/test/regress/sql/rowsecurity.sql @@ -1790,6 +1790,26 @@ DROP VIEW rls_view; DROP TABLE rls_tbl; DROP TABLE ref_tbl; +-- Leaky operator test +CREATE TABLE rls_tbl (a int); +INSERT INTO rls_tbl SELECT x/10 FROM generate_series(1, 100) x; +ANALYZE rls_tbl; + +ALTER TABLE rls_tbl ENABLE ROW LEVEL SECURITY; +GRANT SELECT ON rls_tbl TO regress_rls_alice; + +SET SESSION AUTHORIZATION regress_rls_alice; +CREATE FUNCTION op_leak(int, int) RETURNS bool + AS 'BEGIN RAISE NOTICE ''op_leak => %, %'', $1, $2; RETURN $1 < $2; END' + LANGUAGE plpgsql; +CREATE OPERATOR <<< (procedure = op_leak, leftarg = int, rightarg = int, + restrict = scalarltsel); +SELECT * FROM rls_tbl WHERE a <<< 1000; +DROP OPERATOR <<< (int, int); +DROP FUNCTION op_leak(int, int); +RESET SESSION AUTHORIZATION; +DROP TABLE rls_tbl; + -- -- Clean up objects --