From dee0200f0276c0f9da930a2c926f90f5615f2d64 Mon Sep 17 00:00:00 2001 From: Stephen Frost Date: Mon, 3 Aug 2015 15:32:49 -0400 Subject: [PATCH] RLS: Keep deny policy when only restrictive exist Only remove the default deny policy when a permissive policy exists (either from the hook or defined by the user). If only restrictive policies exist then no rows will be visible, as restrictive policies shouldn't make rows visible. To address this requirement, a single "USING (true)" permissive policy can be created. Update the test_rls_hooks regression tests to create the necessary "USING (true)" permissive policy. Back-patch to 9.5 where RLS was added. Per discussion with Dean. --- src/backend/rewrite/rowsecurity.c | 14 ++++++++++---- .../test_rls_hooks/expected/test_rls_hooks.out | 7 +++++++ .../modules/test_rls_hooks/sql/test_rls_hooks.sql | 8 ++++++++ src/test/modules/test_rls_hooks/test_rls_hooks.c | 5 +++++ 4 files changed, 30 insertions(+), 4 deletions(-) diff --git a/src/backend/rewrite/rowsecurity.c b/src/backend/rewrite/rowsecurity.c index 562dbc90e9..5a81db3618 100644 --- a/src/backend/rewrite/rowsecurity.c +++ b/src/backend/rewrite/rowsecurity.c @@ -225,12 +225,18 @@ get_row_security_policies(Query *root, CmdType commandType, RangeTblEntry *rte, } /* - * If the only built-in policy is the default-deny one, and hook policies - * exist, then use the hook policies only and do not apply the + * If the only built-in policy is the default-deny one, and permissive hook + * policies exist, then use the hook policies only and do not apply the * default-deny policy. Otherwise, we will apply both sets below. + * + * Note that we do not remove the defaultDeny policy if only *restrictive* + * policies exist as restrictive policies should only ever be reducing what + * is visible. Therefore, at least one permissive policy must exist which + * allows records to be seen before restrictive policies can remove rows + * from that set. A single "true" policy can be created to address this + * requirement, if necessary. */ - if (defaultDeny && - (hook_policies_restrictive != NIL || hook_policies_permissive != NIL)) + if (defaultDeny && hook_policies_permissive != NIL) { rowsec_expr = NULL; rowsec_with_check_expr = NULL; diff --git a/src/test/modules/test_rls_hooks/expected/test_rls_hooks.out b/src/test/modules/test_rls_hooks/expected/test_rls_hooks.out index 3a7a4c329f..4587eb014b 100644 --- a/src/test/modules/test_rls_hooks/expected/test_rls_hooks.out +++ b/src/test/modules/test_rls_hooks/expected/test_rls_hooks.out @@ -13,6 +13,11 @@ CREATE TABLE rls_test_restrictive ( supervisor name, data integer ); +-- At least one permissive policy must exist, otherwise +-- the default deny policy will be applied. For +-- testing the only-restrictive-policies from the hook, +-- create a simple 'allow all' policy. +CREATE POLICY p1 ON rls_test_restrictive USING (true); -- initial test data INSERT INTO rls_test_restrictive VALUES ('r1','s1',1); INSERT INTO rls_test_restrictive VALUES ('r2','s2',2); @@ -109,6 +114,8 @@ RESET ROLE; -- Create "internal" policies, to check that the policies from -- the hooks are combined correctly. CREATE POLICY p1 ON rls_test_permissive USING (data % 2 = 0); +-- Remove the original allow-all policy +DROP POLICY p1 ON rls_test_restrictive; CREATE POLICY p1 ON rls_test_restrictive USING (data % 2 = 0); CREATE POLICY p1 ON rls_test_both USING (data % 2 = 0); SET ROLE r1; diff --git a/src/test/modules/test_rls_hooks/sql/test_rls_hooks.sql b/src/test/modules/test_rls_hooks/sql/test_rls_hooks.sql index ece4ab9dc9..3071213732 100644 --- a/src/test/modules/test_rls_hooks/sql/test_rls_hooks.sql +++ b/src/test/modules/test_rls_hooks/sql/test_rls_hooks.sql @@ -17,6 +17,12 @@ CREATE TABLE rls_test_restrictive ( data integer ); +-- At least one permissive policy must exist, otherwise +-- the default deny policy will be applied. For +-- testing the only-restrictive-policies from the hook, +-- create a simple 'allow all' policy. +CREATE POLICY p1 ON rls_test_restrictive USING (true); + -- initial test data INSERT INTO rls_test_restrictive VALUES ('r1','s1',1); INSERT INTO rls_test_restrictive VALUES ('r2','s2',2); @@ -101,6 +107,8 @@ RESET ROLE; -- the hooks are combined correctly. CREATE POLICY p1 ON rls_test_permissive USING (data % 2 = 0); +-- Remove the original allow-all policy +DROP POLICY p1 ON rls_test_restrictive; CREATE POLICY p1 ON rls_test_restrictive USING (data % 2 = 0); CREATE POLICY p1 ON rls_test_both USING (data % 2 = 0); diff --git a/src/test/modules/test_rls_hooks/test_rls_hooks.c b/src/test/modules/test_rls_hooks/test_rls_hooks.c index d76b17ae46..b96dbff954 100644 --- a/src/test/modules/test_rls_hooks/test_rls_hooks.c +++ b/src/test/modules/test_rls_hooks/test_rls_hooks.c @@ -119,6 +119,11 @@ test_rls_hooks_permissive(CmdType cmdtype, Relation relation) /* * Return restrictive policies to be added + * + * Note that a permissive policy must exist or the default-deny policy + * will be included and nothing will be visible. If no filtering should + * be done except for the restrictive policy, then a single "USING (true)" + * permissive policy can be used; see the regression tests. */ List * test_rls_hooks_restrictive(CmdType cmdtype, Relation relation)