From 0823d061b0b7f1e20fbfd48bef3c2e093493dbd4 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Thu, 29 Sep 2022 15:05:40 +0900 Subject: [PATCH] Introduce SYSTEM_USER MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit SYSTEM_USER is a reserved keyword of the SQL specification that, roughly described, is aimed at reporting some information about the system user who has connected to the database server. It may include implementation-specific information about the means by the user connected, like an authentication method. This commit implements SYSTEM_USER as of auth_method:identity, where "auth_method" is a keyword about the authentication method used to log into the server (like peer, md5, scram-sha-256, gss, etc.) and "identity" is the authentication identity as introduced by 9afffcb (peer sets authn to the OS user name, gss to the user principal, etc.). This format has been suggested by Tom Lane. Note that thanks to d951052, SYSTEM_USER is available to parallel workers. Bump catalog version. Author: Bertrand Drouvot Reviewed-by: Jacob Champion, Joe Conway, Álvaro Herrera, Michael Paquier Discussion: https://postgr.es/m/7e692b8c-0b11-45db-1cad-3afc5b57409f@amazon.com --- doc/src/sgml/func.sgml | 19 +++++++++ src/backend/access/transam/parallel.c | 8 ++++ src/backend/parser/gram.y | 11 ++++- src/backend/utils/adt/ruleutils.c | 4 ++ src/backend/utils/init/miscinit.c | 50 +++++++++++++++++++++++ src/backend/utils/init/postinit.c | 4 ++ src/include/catalog/catversion.h | 2 +- src/include/catalog/pg_proc.dat | 3 ++ src/include/miscadmin.h | 3 ++ src/include/parser/kwlist.h | 1 + src/test/authentication/t/001_password.pl | 42 +++++++++++++++++++ src/test/kerberos/t/001_auth.pl | 28 ++++++++++++- src/test/regress/expected/create_view.out | 6 ++- src/test/regress/sql/create_view.sql | 3 +- 14 files changed, 177 insertions(+), 7 deletions(-) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 546213fa931..e82077292c6 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -22623,6 +22623,25 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n); + + + + system_user + + system_user + text + + + Returns the authentication method and the identity (if any) that the + user presented during the authentication cycle before they were + assigned a database role. It is represented as + auth_method:identity or + NULL if the user has not been authenticated (for + example if Trust authentication has + been used). + + + diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index 8cba8882239..ee0985c7edd 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -1496,6 +1496,14 @@ ParallelWorkerMain(Datum main_arg) false); RestoreClientConnectionInfo(clientconninfospace); + /* + * Initialize SystemUser now that MyClientConnectionInfo is restored. + * Also ensure that auth_method is actually valid, aka authn_id is not NULL. + */ + if (MyClientConnectionInfo.authn_id) + InitializeSystemUser(MyClientConnectionInfo.authn_id, + hba_authname(MyClientConnectionInfo.auth_method)); + /* Attach to the leader's serializable transaction, if SERIALIZABLE. */ AttachSerializableXact(fps->serializable_xact_handle); diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 0d8d2928509..94d5142a4a0 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -743,7 +743,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); SERIALIZABLE SERVER SESSION SESSION_USER SET SETS SETOF SHARE SHOW SIMILAR SIMPLE SKIP SMALLINT SNAPSHOT SOME SQL_P STABLE STANDALONE_P START STATEMENT STATISTICS STDIN STDOUT STORAGE STORED STRICT_P STRIP_P - SUBSCRIPTION SUBSTRING SUPPORT SYMMETRIC SYSID SYSTEM_P + SUBSCRIPTION SUBSTRING SUPPORT SYMMETRIC SYSID SYSTEM_P SYSTEM_USER TABLE TABLES TABLESAMPLE TABLESPACE TEMP TEMPLATE TEMPORARY TEXT_P THEN TIES TIME TIMESTAMP TO TRAILING TRANSACTION TRANSFORM @@ -15239,6 +15239,13 @@ func_expr_common_subexpr: { $$ = makeSQLValueFunction(SVFOP_SESSION_USER, -1, @1); } + | SYSTEM_USER + { + $$ = (Node *) makeFuncCall(SystemFuncName("system_user"), + NIL, + COERCE_SQL_SYNTAX, + @1); + } | USER { $$ = makeSQLValueFunction(SVFOP_USER, -1, @1); @@ -17120,6 +17127,7 @@ reserved_keyword: | SESSION_USER | SOME | SYMMETRIC + | SYSTEM_USER | TABLE | THEN | TO @@ -17500,6 +17508,7 @@ bare_label_keyword: | SYMMETRIC | SYSID | SYSTEM_P + | SYSTEM_USER | TABLE | TABLES | TABLESAMPLE diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 2b7b1b0c0f6..c4184035374 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -10317,6 +10317,10 @@ get_func_sql_syntax(FuncExpr *expr, deparse_context *context) appendStringInfoChar(buf, ')'); return true; + case F_SYSTEM_USER: + appendStringInfoString(buf, "SYSTEM_USER"); + return true; + case F_XMLEXISTS: /* XMLEXISTS ... extra parens because args are c_expr */ appendStringInfoString(buf, "XMLEXISTS(("); diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c index 4d341d3f7f1..dfdcd3d78eb 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -477,6 +477,7 @@ static Oid AuthenticatedUserId = InvalidOid; static Oid SessionUserId = InvalidOid; static Oid OuterUserId = InvalidOid; static Oid CurrentUserId = InvalidOid; +static const char *SystemUser = NULL; /* We also have to remember the superuser state of some of these levels */ static bool AuthenticatedUserIsSuperuser = false; @@ -548,6 +549,16 @@ SetSessionUserId(Oid userid, bool is_superuser) CurrentUserId = userid; } +/* + * Return the system user representing the authenticated identity. + * It is defined in InitializeSystemUser() as auth_method:authn_id. + */ +const char * +GetSystemUser(void) +{ + return SystemUser; +} + /* * GetAuthenticatedUserId - get the authenticated user ID */ @@ -818,6 +829,45 @@ InitializeSessionUserIdStandalone(void) SetSessionUserId(BOOTSTRAP_SUPERUSERID, true); } +/* + * Initialize the system user. + * + * This is built as auth_method:authn_id. + */ +void +InitializeSystemUser(const char *authn_id, const char *auth_method) +{ + char *system_user; + + /* call only once */ + Assert(SystemUser == NULL); + + /* + * InitializeSystemUser should be called only when authn_id is not NULL, + * meaning that auth_method is valid. + */ + Assert(authn_id != NULL); + + system_user = psprintf("%s:%s", auth_method, authn_id); + + /* Store SystemUser in long-lived storage */ + SystemUser = MemoryContextStrdup(TopMemoryContext, system_user); + pfree(system_user); +} + +/* + * SQL-function SYSTEM_USER + */ +Datum +system_user(PG_FUNCTION_ARGS) +{ + const char *sysuser = GetSystemUser(); + + if (sysuser) + PG_RETURN_DATUM(CStringGetTextDatum(sysuser)); + else + PG_RETURN_NULL(); +} /* * Change session auth ID while running diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 4a207a73917..31b7e1de5df 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -904,6 +904,10 @@ InitPostgres(const char *in_dbname, Oid dboid, Assert(MyProcPort != NULL); PerformAuthentication(MyProcPort); InitializeSessionUserId(username, useroid); + /* ensure that auth_method is actually valid, aka authn_id is not NULL */ + if (MyClientConnectionInfo.authn_id) + InitializeSystemUser(MyClientConnectionInfo.authn_id, + hba_authname(MyClientConnectionInfo.auth_method)); am_superuser = superuser(); } diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h index 95e7c249ed8..c1af6eaf5ff 100644 --- a/src/include/catalog/catversion.h +++ b/src/include/catalog/catversion.h @@ -57,6 +57,6 @@ */ /* yyyymmddN */ -#define CATALOG_VERSION_NO 202209261 +#define CATALOG_VERSION_NO 202209291 #endif diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index a07e737a337..68bb032d3ea 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -1508,6 +1508,9 @@ { oid => '746', descr => 'session user name', proname => 'session_user', provolatile => 's', prorettype => 'name', proargtypes => '', prosrc => 'session_user' }, +{ oid => '9977', descr => 'system user name', + proname => 'system_user', provolatile => 's', prorettype => 'text', + proargtypes => '', prosrc => 'system_user' }, { oid => '744', proname => 'array_eq', prorettype => 'bool', diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h index ee48e392ed7..e7ebea4ff44 100644 --- a/src/include/miscadmin.h +++ b/src/include/miscadmin.h @@ -357,6 +357,9 @@ extern void InitializeSessionUserIdStandalone(void); extern void SetSessionAuthorization(Oid userid, bool is_superuser); extern Oid GetCurrentRoleId(void); extern void SetCurrentRoleId(Oid roleid, bool is_superuser); +extern void InitializeSystemUser(const char *authn_id, + const char *auth_method); +extern const char *GetSystemUser(void); /* in utils/misc/superuser.c */ extern bool superuser(void); /* current user is superuser */ diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h index 9a7cc0c6bd1..ccc927851cb 100644 --- a/src/include/parser/kwlist.h +++ b/src/include/parser/kwlist.h @@ -409,6 +409,7 @@ PG_KEYWORD("support", SUPPORT, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("symmetric", SYMMETRIC, RESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("sysid", SYSID, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("system", SYSTEM_P, UNRESERVED_KEYWORD, BARE_LABEL) +PG_KEYWORD("system_user", SYSTEM_USER, RESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("table", TABLE, RESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("tables", TABLES, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("tablesample", TABLESAMPLE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL) diff --git a/src/test/authentication/t/001_password.pl b/src/test/authentication/t/001_password.pl index 3e3079c824a..58e4176e80d 100644 --- a/src/test/authentication/t/001_password.pl +++ b/src/test/authentication/t/001_password.pl @@ -72,6 +72,11 @@ $node->safe_psql('postgres', $node->safe_psql('postgres', "SET password_encryption='md5'; CREATE ROLE md5_role LOGIN PASSWORD 'pass';" ); +# Set up a table for tests of SYSTEM_USER. +$node->safe_psql( + 'postgres', + "CREATE TABLE sysuser_data (n) AS SELECT NULL FROM generate_series(1, 10); + GRANT ALL ON sysuser_data TO md5_role;"); $ENV{"PGPASSWORD"} = 'pass'; # For "trust" method, all users should be able to connect. These users are not @@ -82,6 +87,24 @@ test_role($node, 'scram_role', 'trust', 0, test_role($node, 'md5_role', 'trust', 0, log_unlike => [qr/connection authenticated:/]); +# SYSTEM_USER is null when not authenticated. +my $res = $node->safe_psql('postgres', "SELECT SYSTEM_USER IS NULL;"); +is($res, 't', "users with trust authentication use SYSTEM_USER = NULL"); + +# Test SYSTEM_USER with parallel workers when not authenticated. +$res = $node->safe_psql( + 'postgres', qq( + SET min_parallel_table_scan_size TO 0; + SET parallel_setup_cost TO 0; + SET parallel_tuple_cost TO 0; + SET max_parallel_workers_per_gather TO 2; + + SELECT bool_and(SYSTEM_USER IS NOT DISTINCT FROM n) FROM sysuser_data;), + connstr => "user=md5_role"); +is($res, 't', + "users with trust authentication use SYSTEM_USER = NULL in parallel workers" +); + # For plain "password" method, all users should also be able to connect. reset_pg_hba($node, 'password'); test_role($node, 'scram_role', 'password', 0, @@ -120,6 +143,25 @@ test_role($node, 'md5_role', 'md5', 0, log_like => [qr/connection authenticated: identity="md5_role" method=md5/]); +# Test SYSTEM_USER <> NULL with parallel workers. +$node->safe_psql( + 'postgres', + "TRUNCATE sysuser_data; +INSERT INTO sysuser_data SELECT 'md5:md5_role' FROM generate_series(1, 10);", + connstr => "user=md5_role"); +$res = $node->safe_psql( + 'postgres', qq( + SET min_parallel_table_scan_size TO 0; + SET parallel_setup_cost TO 0; + SET parallel_tuple_cost TO 0; + SET max_parallel_workers_per_gather TO 2; + + SELECT bool_and(SYSTEM_USER IS NOT DISTINCT FROM n) FROM sysuser_data;), + connstr => "user=md5_role"); +is($res, 't', + "users with md5 authentication use SYSTEM_USER = md5:role in parallel workers" +); + # Tests for channel binding without SSL. # Using the password authentication method; channel binding can't work reset_pg_hba($node, 'password'); diff --git a/src/test/kerberos/t/001_auth.pl b/src/test/kerberos/t/001_auth.pl index 47169a1d1eb..a2bc8a5351e 100644 --- a/src/test/kerberos/t/001_auth.pl +++ b/src/test/kerberos/t/001_auth.pl @@ -4,8 +4,8 @@ # Sets up a KDC and then runs a variety of tests to make sure that the # GSSAPI/Kerberos authentication and encryption are working properly, # that the options in pg_hba.conf and pg_ident.conf are handled correctly, -# and that the server-side pg_stat_gssapi view reports what we expect to -# see for each test. +# that the server-side pg_stat_gssapi view reports what we expect to +# see for each test and that SYSTEM_USER returns what we expect to see. # # Since this requires setting up a full KDC, it doesn't make much sense # to have multiple test scripts (since they'd have to also create their @@ -180,6 +180,13 @@ $node->start; $node->safe_psql('postgres', 'CREATE USER test1;'); +# Set up a table for SYSTEM_USER parallel worker testing. +$node->safe_psql('postgres', + "CREATE TABLE ids (id) AS SELECT 'gss:test1\@$realm' FROM generate_series(1, 10);" +); + +$node->safe_psql('postgres', 'GRANT SELECT ON ids TO public;'); + note "running tests"; # Test connection success or failure, and if success, that query returns true. @@ -311,6 +318,23 @@ test_query( 'gssencmode=require', 'sending 100K lines works'); +# Test that SYSTEM_USER works. +test_query($node, 'test1', 'SELECT SYSTEM_USER;', + qr/^gss:test1\@$realm$/s, 'gssencmode=require', 'testing system_user'); + +# Test that SYSTEM_USER works with parallel workers. +test_query( + $node, + 'test1', qq( + SET min_parallel_table_scan_size TO 0; + SET parallel_setup_cost TO 0; + SET parallel_tuple_cost TO 0; + SET max_parallel_workers_per_gather TO 2; + SELECT bool_and(SYSTEM_USER = id) FROM ids;), + qr/^t$/s, + 'gssencmode=require', + 'testing system_user with parallel workers'); + unlink($node->data_dir . '/pg_hba.conf'); $node->append_conf('pg_hba.conf', qq{hostgssenc all all $hostaddr/32 gss map=mymap}); diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out index a828b1f6de6..bf4ff30d86f 100644 --- a/src/test/regress/expected/create_view.out +++ b/src/test/regress/expected/create_view.out @@ -1940,7 +1940,8 @@ select trim(trailing ' foo ') as rt, trim(E'\\000'::bytea from E'\\000Tom\\000'::bytea) as btb, trim(leading E'\\000'::bytea from E'\\000Tom\\000'::bytea) as ltb, - trim(trailing E'\\000'::bytea from E'\\000Tom\\000'::bytea) as rtb; + trim(trailing E'\\000'::bytea from E'\\000Tom\\000'::bytea) as rtb, + SYSTEM_USER as su; select pg_get_viewdef('tt201v', true); pg_get_viewdef ----------------------------------------------------------------------------------------------- @@ -1961,7 +1962,8 @@ select pg_get_viewdef('tt201v', true); TRIM(TRAILING FROM ' foo '::text) AS rt, + TRIM(BOTH '\x00'::bytea FROM '\x00546f6d00'::bytea) AS btb, + TRIM(LEADING '\x00'::bytea FROM '\x00546f6d00'::bytea) AS ltb, + - TRIM(TRAILING '\x00'::bytea FROM '\x00546f6d00'::bytea) AS rtb; + TRIM(TRAILING '\x00'::bytea FROM '\x00546f6d00'::bytea) AS rtb, + + SYSTEM_USER AS su; (1 row) -- corner cases with empty join conditions diff --git a/src/test/regress/sql/create_view.sql b/src/test/regress/sql/create_view.sql index 44a6775f907..913b4ee4601 100644 --- a/src/test/regress/sql/create_view.sql +++ b/src/test/regress/sql/create_view.sql @@ -721,7 +721,8 @@ select trim(trailing ' foo ') as rt, trim(E'\\000'::bytea from E'\\000Tom\\000'::bytea) as btb, trim(leading E'\\000'::bytea from E'\\000Tom\\000'::bytea) as ltb, - trim(trailing E'\\000'::bytea from E'\\000Tom\\000'::bytea) as rtb; + trim(trailing E'\\000'::bytea from E'\\000Tom\\000'::bytea) as rtb, + SYSTEM_USER as su; select pg_get_viewdef('tt201v', true); -- corner cases with empty join conditions