From 2485a85e96db137f7962a2e702b99869957f0990 Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Mon, 6 May 2024 09:00:07 -0500 Subject: [PATCH] Fix privilege checks in pg_stats_ext and pg_stats_ext_exprs. The catalog view pg_stats_ext fails to consider privileges for expression statistics. The catalog view pg_stats_ext_exprs fails to consider privileges and row-level security policies. To fix, restrict the data in these views to table owners or roles that inherit privileges of the table owner. It may be possible to apply less restrictive privilege checks in some cases, but that is left as a future exercise. Furthermore, for pg_stats_ext_exprs, do not return data for tables with row-level security enabled, as is already done for pg_stats_ext. On the back-branches, a fix-CVE-2024-4317.sql script is provided that will install into the "share" directory. This file can be used to apply the fix to existing clusters. Bumps catversion on 'master' branch only. Reported-by: Lukas Fittl Reviewed-by: Noah Misch, Tomas Vondra, Tom Lane Security: CVE-2024-4317 Backpatch-through: 14 --- doc/src/sgml/catalogs.sgml | 3 +- doc/src/sgml/system-views.sgml | 4 +- src/backend/catalog/Makefile | 3 +- src/backend/catalog/fix-CVE-2024-4317.sql | 117 ++++++++++++++++++++++ src/backend/catalog/meson.build | 1 + src/backend/catalog/system_views.sql | 11 +- src/test/regress/expected/rules.out | 8 +- src/test/regress/expected/stats_ext.out | 43 ++++++++ src/test/regress/sql/stats_ext.sql | 27 +++++ 9 files changed, 200 insertions(+), 17 deletions(-) create mode 100644 src/backend/catalog/fix-CVE-2024-4317.sql diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index e1d9a67a96..21893b85dd 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -7733,8 +7733,7 @@ SCRAM-SHA-256$<iteration count>:&l is a publicly readable view on pg_statistic_ext_data (after joining with pg_statistic_ext) that only exposes - information about those tables and columns that are readable by the - current user. + information about tables the current user owns. diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml index b3be3ebe71..39815d5faf 100644 --- a/doc/src/sgml/system-views.sgml +++ b/doc/src/sgml/system-views.sgml @@ -3823,7 +3823,7 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx and pg_statistic_ext_data catalogs. This view allows access only to rows of pg_statistic_ext and pg_statistic_ext_data - that correspond to tables the user has permission to read, and therefore + that correspond to tables the user owns, and therefore it is safe to allow public read access to this view. @@ -4034,7 +4034,7 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx and pg_statistic_ext_data catalogs. This view allows access only to rows of pg_statistic_ext and pg_statistic_ext_data - that correspond to tables the user has permission to read, and therefore + that correspond to tables the user owns, and therefore it is safe to allow public read access to this view. diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile index a60107bf94..db0024a21b 100644 --- a/src/backend/catalog/Makefile +++ b/src/backend/catalog/Makefile @@ -130,13 +130,14 @@ install-data: bki-stamp installdirs $(INSTALL_DATA) $(srcdir)/system_views.sql '$(DESTDIR)$(datadir)/system_views.sql' $(INSTALL_DATA) $(srcdir)/information_schema.sql '$(DESTDIR)$(datadir)/information_schema.sql' $(INSTALL_DATA) $(srcdir)/sql_features.txt '$(DESTDIR)$(datadir)/sql_features.txt' + $(INSTALL_DATA) $(srcdir)/fix-CVE-2024-4317.sql '$(DESTDIR)$(datadir)/fix-CVE-2024-4317.sql' installdirs: $(MKDIR_P) '$(DESTDIR)$(datadir)' .PHONY: uninstall-data uninstall-data: - rm -f $(addprefix '$(DESTDIR)$(datadir)'/, postgres.bki system_constraints.sql system_functions.sql system_views.sql information_schema.sql sql_features.txt) + rm -f $(addprefix '$(DESTDIR)$(datadir)'/, postgres.bki system_constraints.sql system_functions.sql system_views.sql information_schema.sql sql_features.txt fix-CVE-2024-4317.sql) # postgres.bki, system_constraints.sql, and the generated headers are # in the distribution tarball, so they are not cleaned here. diff --git a/src/backend/catalog/fix-CVE-2024-4317.sql b/src/backend/catalog/fix-CVE-2024-4317.sql new file mode 100644 index 0000000000..b24eba9a35 --- /dev/null +++ b/src/backend/catalog/fix-CVE-2024-4317.sql @@ -0,0 +1,117 @@ +/* + * fix-CVE-2024-4317.sql + * + * Copyright (c) 2024, PostgreSQL Global Development Group + * + * src/backend/catalog/fix-CVE-2024-4317.sql + * + * This file should be run in every database in the cluster to address + * CVE-2024-4317. + */ + +SET search_path = pg_catalog; + +CREATE OR REPLACE VIEW pg_stats_ext WITH (security_barrier) AS + SELECT cn.nspname AS schemaname, + c.relname AS tablename, + sn.nspname AS statistics_schemaname, + s.stxname AS statistics_name, + pg_get_userbyid(s.stxowner) AS statistics_owner, + ( SELECT array_agg(a.attname ORDER BY a.attnum) + FROM unnest(s.stxkeys) k + JOIN pg_attribute a + ON (a.attrelid = s.stxrelid AND a.attnum = k) + ) AS attnames, + pg_get_statisticsobjdef_expressions(s.oid) as exprs, + s.stxkind AS kinds, + sd.stxdinherit AS inherited, + sd.stxdndistinct AS n_distinct, + sd.stxddependencies AS dependencies, + m.most_common_vals, + m.most_common_val_nulls, + m.most_common_freqs, + m.most_common_base_freqs + FROM pg_statistic_ext s JOIN pg_class c ON (c.oid = s.stxrelid) + JOIN pg_statistic_ext_data sd ON (s.oid = sd.stxoid) + LEFT JOIN pg_namespace cn ON (cn.oid = c.relnamespace) + LEFT JOIN pg_namespace sn ON (sn.oid = s.stxnamespace) + LEFT JOIN LATERAL + ( SELECT array_agg(values) AS most_common_vals, + array_agg(nulls) AS most_common_val_nulls, + array_agg(frequency) AS most_common_freqs, + array_agg(base_frequency) AS most_common_base_freqs + FROM pg_mcv_list_items(sd.stxdmcv) + ) m ON sd.stxdmcv IS NOT NULL + WHERE pg_has_role(c.relowner, 'USAGE') + AND (c.relrowsecurity = false OR NOT row_security_active(c.oid)); + +CREATE OR REPLACE VIEW pg_stats_ext_exprs WITH (security_barrier) AS + SELECT cn.nspname AS schemaname, + c.relname AS tablename, + sn.nspname AS statistics_schemaname, + s.stxname AS statistics_name, + pg_get_userbyid(s.stxowner) AS statistics_owner, + stat.expr, + sd.stxdinherit AS inherited, + (stat.a).stanullfrac AS null_frac, + (stat.a).stawidth AS avg_width, + (stat.a).stadistinct AS n_distinct, + (CASE + WHEN (stat.a).stakind1 = 1 THEN (stat.a).stavalues1 + WHEN (stat.a).stakind2 = 1 THEN (stat.a).stavalues2 + WHEN (stat.a).stakind3 = 1 THEN (stat.a).stavalues3 + WHEN (stat.a).stakind4 = 1 THEN (stat.a).stavalues4 + WHEN (stat.a).stakind5 = 1 THEN (stat.a).stavalues5 + END) AS most_common_vals, + (CASE + WHEN (stat.a).stakind1 = 1 THEN (stat.a).stanumbers1 + WHEN (stat.a).stakind2 = 1 THEN (stat.a).stanumbers2 + WHEN (stat.a).stakind3 = 1 THEN (stat.a).stanumbers3 + WHEN (stat.a).stakind4 = 1 THEN (stat.a).stanumbers4 + WHEN (stat.a).stakind5 = 1 THEN (stat.a).stanumbers5 + END) AS most_common_freqs, + (CASE + WHEN (stat.a).stakind1 = 2 THEN (stat.a).stavalues1 + WHEN (stat.a).stakind2 = 2 THEN (stat.a).stavalues2 + WHEN (stat.a).stakind3 = 2 THEN (stat.a).stavalues3 + WHEN (stat.a).stakind4 = 2 THEN (stat.a).stavalues4 + WHEN (stat.a).stakind5 = 2 THEN (stat.a).stavalues5 + END) AS histogram_bounds, + (CASE + WHEN (stat.a).stakind1 = 3 THEN (stat.a).stanumbers1[1] + WHEN (stat.a).stakind2 = 3 THEN (stat.a).stanumbers2[1] + WHEN (stat.a).stakind3 = 3 THEN (stat.a).stanumbers3[1] + WHEN (stat.a).stakind4 = 3 THEN (stat.a).stanumbers4[1] + WHEN (stat.a).stakind5 = 3 THEN (stat.a).stanumbers5[1] + END) correlation, + (CASE + WHEN (stat.a).stakind1 = 4 THEN (stat.a).stavalues1 + WHEN (stat.a).stakind2 = 4 THEN (stat.a).stavalues2 + WHEN (stat.a).stakind3 = 4 THEN (stat.a).stavalues3 + WHEN (stat.a).stakind4 = 4 THEN (stat.a).stavalues4 + WHEN (stat.a).stakind5 = 4 THEN (stat.a).stavalues5 + END) AS most_common_elems, + (CASE + WHEN (stat.a).stakind1 = 4 THEN (stat.a).stanumbers1 + WHEN (stat.a).stakind2 = 4 THEN (stat.a).stanumbers2 + WHEN (stat.a).stakind3 = 4 THEN (stat.a).stanumbers3 + WHEN (stat.a).stakind4 = 4 THEN (stat.a).stanumbers4 + WHEN (stat.a).stakind5 = 4 THEN (stat.a).stanumbers5 + END) AS most_common_elem_freqs, + (CASE + WHEN (stat.a).stakind1 = 5 THEN (stat.a).stanumbers1 + WHEN (stat.a).stakind2 = 5 THEN (stat.a).stanumbers2 + WHEN (stat.a).stakind3 = 5 THEN (stat.a).stanumbers3 + WHEN (stat.a).stakind4 = 5 THEN (stat.a).stanumbers4 + WHEN (stat.a).stakind5 = 5 THEN (stat.a).stanumbers5 + END) AS elem_count_histogram + FROM pg_statistic_ext s JOIN pg_class c ON (c.oid = s.stxrelid) + LEFT JOIN pg_statistic_ext_data sd ON (s.oid = sd.stxoid) + LEFT JOIN pg_namespace cn ON (cn.oid = c.relnamespace) + LEFT JOIN pg_namespace sn ON (sn.oid = s.stxnamespace) + JOIN LATERAL ( + SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr, + unnest(sd.stxdexpr)::pg_statistic AS a + ) stat ON (stat.expr IS NOT NULL) + WHERE pg_has_role(c.relowner, 'USAGE') + AND (c.relrowsecurity = false OR NOT row_security_active(c.oid)); diff --git a/src/backend/catalog/meson.build b/src/backend/catalog/meson.build index fa6609e577..793575e1e8 100644 --- a/src/backend/catalog/meson.build +++ b/src/backend/catalog/meson.build @@ -38,6 +38,7 @@ backend_sources += files( install_data( + 'fix-CVE-2024-4317.sql', 'information_schema.sql', 'sql_features.txt', 'system_functions.sql', diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index c18fea8362..1a52d03aa5 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -284,12 +284,7 @@ CREATE VIEW pg_stats_ext WITH (security_barrier) AS array_agg(base_frequency) AS most_common_base_freqs FROM pg_mcv_list_items(sd.stxdmcv) ) m ON sd.stxdmcv IS NOT NULL - WHERE NOT EXISTS - ( SELECT 1 - FROM unnest(stxkeys) k - JOIN pg_attribute a - ON (a.attrelid = s.stxrelid AND a.attnum = k) - WHERE NOT has_column_privilege(c.oid, a.attnum, 'select') ) + WHERE pg_has_role(c.relowner, 'USAGE') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid)); CREATE VIEW pg_stats_ext_exprs WITH (security_barrier) AS @@ -359,7 +354,9 @@ CREATE VIEW pg_stats_ext_exprs WITH (security_barrier) AS JOIN LATERAL ( SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr, unnest(sd.stxdexpr)::pg_statistic AS a - ) stat ON (stat.expr IS NOT NULL); + ) stat ON (stat.expr IS NOT NULL) + WHERE pg_has_role(c.relowner, 'USAGE') + AND (c.relrowsecurity = false OR NOT row_security_active(c.oid)); -- unprivileged users may read pg_statistic_ext but not pg_statistic_ext_data REVOKE ALL ON pg_statistic_ext_data FROM public; diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 7fd81e6a7d..09a255649b 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -2497,10 +2497,7 @@ pg_stats_ext| SELECT cn.nspname AS schemaname, array_agg(pg_mcv_list_items.frequency) AS most_common_freqs, array_agg(pg_mcv_list_items.base_frequency) AS most_common_base_freqs FROM pg_mcv_list_items(sd.stxdmcv) pg_mcv_list_items(index, "values", nulls, frequency, base_frequency)) m ON ((sd.stxdmcv IS NOT NULL))) - WHERE ((NOT (EXISTS ( SELECT 1 - FROM (unnest(s.stxkeys) k(k) - JOIN pg_attribute a ON (((a.attrelid = s.stxrelid) AND (a.attnum = k.k)))) - WHERE (NOT has_column_privilege(c.oid, a.attnum, 'select'::text))))) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid)))); + WHERE (pg_has_role(c.relowner, 'USAGE'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid)))); pg_stats_ext_exprs| SELECT cn.nspname AS schemaname, c.relname AS tablename, sn.nspname AS statistics_schemaname, @@ -2573,7 +2570,8 @@ pg_stats_ext_exprs| SELECT cn.nspname AS schemaname, LEFT JOIN pg_namespace cn ON ((cn.oid = c.relnamespace))) LEFT JOIN pg_namespace sn ON ((sn.oid = s.stxnamespace))) JOIN LATERAL ( SELECT unnest(pg_get_statisticsobjdef_expressions(s.oid)) AS expr, - unnest(sd.stxdexpr) AS a) stat ON ((stat.expr IS NOT NULL))); + unnest(sd.stxdexpr) AS a) stat ON ((stat.expr IS NOT NULL))) + WHERE (pg_has_role(c.relowner, 'USAGE'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid)))); pg_tables| SELECT n.nspname AS schemaname, c.relname AS tablename, pg_get_userbyid(c.relowner) AS tableowner, diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out index a430153b22..b4c85613de 100644 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -3281,10 +3281,53 @@ SELECT * FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not le (0 rows) DELETE FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak +-- privilege checks for pg_stats_ext and pg_stats_ext_exprs +RESET SESSION AUTHORIZATION; +CREATE TABLE stats_ext_tbl (id INT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY, col TEXT); +INSERT INTO stats_ext_tbl (col) VALUES ('secret'), ('secret'), ('very secret'); +CREATE STATISTICS s_col ON id, col FROM stats_ext_tbl; +CREATE STATISTICS s_expr ON mod(id, 2), lower(col) FROM stats_ext_tbl; +ANALYZE stats_ext_tbl; +-- unprivileged role should not have access +SET SESSION AUTHORIZATION regress_stats_user1; +SELECT statistics_name, most_common_vals FROM pg_stats_ext x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); + statistics_name | most_common_vals +-----------------+------------------ +(0 rows) + +SELECT statistics_name, most_common_vals FROM pg_stats_ext_exprs x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); + statistics_name | most_common_vals +-----------------+------------------ +(0 rows) + +-- give unprivileged role ownership of table +RESET SESSION AUTHORIZATION; +ALTER TABLE stats_ext_tbl OWNER TO regress_stats_user1; +-- unprivileged role should now have access +SET SESSION AUTHORIZATION regress_stats_user1; +SELECT statistics_name, most_common_vals FROM pg_stats_ext x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); + statistics_name | most_common_vals +-----------------+------------------------------------------- + s_col | {{1,secret},{2,secret},{3,"very secret"}} + s_expr | {{0,secret},{1,secret},{1,"very secret"}} +(2 rows) + +SELECT statistics_name, most_common_vals FROM pg_stats_ext_exprs x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); + statistics_name | most_common_vals +-----------------+------------------ + s_expr | {secret} + s_expr | {1} +(2 rows) + -- Tidy up DROP OPERATOR <<< (int, int); DROP FUNCTION op_leak(int, int); RESET SESSION AUTHORIZATION; +DROP TABLE stats_ext_tbl; DROP SCHEMA tststats CASCADE; NOTICE: drop cascades to 2 other objects DETAIL: drop cascades to table tststats.priv_test_tbl diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql index 90b625a5a2..1b80d3687b 100644 --- a/src/test/regress/sql/stats_ext.sql +++ b/src/test/regress/sql/stats_ext.sql @@ -1657,9 +1657,36 @@ SET SESSION AUTHORIZATION regress_stats_user1; SELECT * FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak DELETE FROM tststats.priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak +-- privilege checks for pg_stats_ext and pg_stats_ext_exprs +RESET SESSION AUTHORIZATION; +CREATE TABLE stats_ext_tbl (id INT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY, col TEXT); +INSERT INTO stats_ext_tbl (col) VALUES ('secret'), ('secret'), ('very secret'); +CREATE STATISTICS s_col ON id, col FROM stats_ext_tbl; +CREATE STATISTICS s_expr ON mod(id, 2), lower(col) FROM stats_ext_tbl; +ANALYZE stats_ext_tbl; + +-- unprivileged role should not have access +SET SESSION AUTHORIZATION regress_stats_user1; +SELECT statistics_name, most_common_vals FROM pg_stats_ext x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); +SELECT statistics_name, most_common_vals FROM pg_stats_ext_exprs x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); + +-- give unprivileged role ownership of table +RESET SESSION AUTHORIZATION; +ALTER TABLE stats_ext_tbl OWNER TO regress_stats_user1; + +-- unprivileged role should now have access +SET SESSION AUTHORIZATION regress_stats_user1; +SELECT statistics_name, most_common_vals FROM pg_stats_ext x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); +SELECT statistics_name, most_common_vals FROM pg_stats_ext_exprs x + WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*); + -- Tidy up DROP OPERATOR <<< (int, int); DROP FUNCTION op_leak(int, int); RESET SESSION AUTHORIZATION; +DROP TABLE stats_ext_tbl; DROP SCHEMA tststats CASCADE; DROP USER regress_stats_user1;