On Fri, Aug 26, 2022 at 10:02:26AM +0900, Michael Paquier wrote: > FWIW, I was also wondering about the need for all this initialization > stanza and the extra SystemUser in TopMemoryContext. Now that we have > MyClientConnectionInfo, I was thinking to just build the string in the > SQL function as that's the only code path that needs to know about > it. True that this approach saves some extra palloc() calls each time > the function is called.
At the end, fine by me to keep this approach as that's more consistent. I have reviewed the patch, and a few things caught my attention: - I think that we'd better switch InitializeSystemUser() to have two const char * as arguments for authn_id and an auth_method, so as there is no need to use tweaks with UserAuth or ClientConnectionInfo in miscadmin.h to bypass an inclusion of libpq-be.h or hba.h. - The OID of the new function should be in the range 8000-9999, as taught by unused_oids. - Environments where the code is built without krb5 support would skip the test where SYSTEM_USER should be not NULL when authenticated, so I have added a test for that with MD5 in src/test/authentication/. - Docs have been reworded, and I have applied an indentation. - No need to use 200k rows in the table used to force the parallel scan, as long as the costs are set. It is a bit late here, so I may have missed something. For now, how does the attached look to you? -- Michael
From f8175b4887c03dc596483988e2171346480e2bda Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Wed, 7 Sep 2022 17:46:41 +0900
Subject: [PATCH v3] Add support for SYSTEM_USER
---
src/include/catalog/pg_proc.dat | 3 ++
src/include/miscadmin.h | 3 ++
src/include/nodes/primnodes.h | 1 +
src/include/parser/kwlist.h | 1 +
src/backend/access/transam/parallel.c | 4 ++
src/backend/executor/execExprInterp.c | 5 +++
src/backend/parser/gram.y | 8 +++-
src/backend/parser/parse_expr.c | 1 +
src/backend/parser/parse_target.c | 3 ++
src/backend/utils/adt/name.c | 1 -
src/backend/utils/adt/ruleutils.c | 3 ++
src/backend/utils/init/miscinit.c | 51 +++++++++++++++++++++++
src/backend/utils/init/postinit.c | 2 +
src/test/authentication/t/001_password.pl | 44 +++++++++++++++++++
src/test/kerberos/t/001_auth.pl | 28 ++++++++++++-
doc/src/sgml/func.sgml | 18 ++++++++
16 files changed, 172 insertions(+), 4 deletions(-)
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index a07e737a33..68bb032d3e 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 65cf4ba50f..0a034d2893 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/nodes/primnodes.h b/src/include/nodes/primnodes.h
index 40661334bb..74fbc6a4af 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -1318,6 +1318,7 @@ typedef enum SQLValueFunctionOp
SVFOP_CURRENT_USER,
SVFOP_USER,
SVFOP_SESSION_USER,
+ SVFOP_SYSTEM_USER,
SVFOP_CURRENT_CATALOG,
SVFOP_CURRENT_SCHEMA
} SQLValueFunctionOp;
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 9a7cc0c6bd..ccc927851c 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/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index bc93101ff7..0a8de9e6de 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -1496,6 +1496,10 @@ ParallelWorkerMain(Datum main_arg)
false);
RestoreClientConnectionInfo(clientconninfospace);
+ /* Initialize SystemUser now that MyClientConnectionInfo is restored. */
+ 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/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 9b9bbf00a9..c51578c0b9 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2537,6 +2537,11 @@ ExecEvalSQLValueFunction(ExprState *state, ExprEvalStep *op)
*op->resvalue = session_user(fcinfo);
*op->resnull = fcinfo->isnull;
break;
+ case SVFOP_SYSTEM_USER:
+ InitFunctionCallInfoData(*fcinfo, NULL, 0, InvalidOid, NULL, NULL);
+ *op->resvalue = system_user(fcinfo);
+ *op->resnull = fcinfo->isnull;
+ break;
case SVFOP_CURRENT_CATALOG:
InitFunctionCallInfoData(*fcinfo, NULL, 0, InvalidOid, NULL, NULL);
*op->resvalue = current_database(fcinfo);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0492ff9a66..1536f44170 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -747,7 +747,7 @@ 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
@@ -15242,6 +15242,10 @@ func_expr_common_subexpr:
{
$$ = makeSQLValueFunction(SVFOP_SESSION_USER, -1, @1);
}
+ | SYSTEM_USER
+ {
+ $$ = makeSQLValueFunction(SVFOP_SYSTEM_USER, -1, @1);
+ }
| USER
{
$$ = makeSQLValueFunction(SVFOP_USER, -1, @1);
@@ -17123,6 +17127,7 @@ reserved_keyword:
| SESSION_USER
| SOME
| SYMMETRIC
+ | SYSTEM_USER
| TABLE
| THEN
| TO
@@ -17503,6 +17508,7 @@ bare_label_keyword:
| SYMMETRIC
| SYSID
| SYSTEM_P
+ | SYSTEM_USER
| TABLE
| TABLES
| TABLESAMPLE
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 7aaf1c673f..96da28608f 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -2235,6 +2235,7 @@ transformSQLValueFunction(ParseState *pstate, SQLValueFunction *svf)
case SVFOP_CURRENT_USER:
case SVFOP_USER:
case SVFOP_SESSION_USER:
+ case SVFOP_SYSTEM_USER:
case SVFOP_CURRENT_CATALOG:
case SVFOP_CURRENT_SCHEMA:
svf->type = NAMEOID;
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index 4e1593d900..1e4bb10fd6 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -1916,6 +1916,9 @@ FigureColnameInternal(Node *node, char **name)
case SVFOP_SESSION_USER:
*name = "session_user";
return 2;
+ case SVFOP_SYSTEM_USER:
+ *name = "system_user";
+ return 2;
case SVFOP_CURRENT_CATALOG:
*name = "current_catalog";
return 2;
diff --git a/src/backend/utils/adt/name.c b/src/backend/utils/adt/name.c
index d22e1f277b..a1e71c7dc8 100644
--- a/src/backend/utils/adt/name.c
+++ b/src/backend/utils/adt/name.c
@@ -271,7 +271,6 @@ session_user(PG_FUNCTION_ARGS)
PG_RETURN_DATUM(DirectFunctionCall1(namein, CStringGetDatum(GetUserNameFromId(GetSessionUserId(), false))));
}
-
/*
* SQL-functions CURRENT_SCHEMA, CURRENT_SCHEMAS
*/
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 2b7b1b0c0f..c621b4328e 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -9210,6 +9210,9 @@ get_rule_expr(Node *node, deparse_context *context,
case SVFOP_SESSION_USER:
appendStringInfoString(buf, "SESSION_USER");
break;
+ case SVFOP_SYSTEM_USER:
+ appendStringInfoString(buf, "SYSTEM_USER");
+ break;
case SVFOP_CURRENT_CATALOG:
appendStringInfoString(buf, "CURRENT_CATALOG");
break;
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index 683f616b1a..2c5261d022 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 +829,46 @@ InitializeSessionUserIdStandalone(void)
SetSessionUserId(BOOTSTRAP_SUPERUSERID, true);
}
+/*
+ * Initialize the system user.
+ */
+void
+InitializeSystemUser(const char *authn_id, const char *auth_method)
+{
+ /* call only once */
+ Assert(SystemUser == NULL);
+
+ if (authn_id)
+ {
+ /* Build system user as auth_method:authn_id */
+ char *system_user;
+ Size authname_len = strlen(auth_method);
+ Size authn_id_len = strlen(authn_id);
+
+ system_user = palloc0(authname_len + authn_id_len + 2);
+ strcat(system_user, auth_method);
+ strcat(system_user, ":");
+ strcat(system_user, 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(CStringGetDatum(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 0d557a8684..d1eb5ed93a 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -855,6 +855,8 @@ InitPostgres(const char *in_dbname, Oid dboid,
Assert(MyProcPort != NULL);
PerformAuthentication(MyProcPort);
InitializeSessionUserId(username, useroid);
+ InitializeSystemUser(MyClientConnectionInfo.authn_id,
+ hba_authname(MyClientConnectionInfo.auth_method));
am_superuser = superuser();
}
diff --git a/src/test/authentication/t/001_password.pl b/src/test/authentication/t/001_password.pl
index 3e3079c824..b0b7aac4c0 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;");
$ENV{"PGPASSWORD"} = 'pass';
# For "trust" method, all users should be able to connect. These users are not
@@ -82,6 +87,25 @@ test_role($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 = $node->safe_psql(
+ 'postgres', "
+ SET min_parallel_table_scan_size TO 0;
+ SET parallel_setup_cost TO 0;
+ SET parallel_tuple_cost TO 0;
+ SET max_parallel_workers_per_gather TO 2;
+
+ SELECT bool_and(SYSTEM_USER IS NOT DISTINCT FROM n) FROM sysuser_data;
+ ",
+ connstr => "user=md5_role");
+is($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 +144,26 @@ 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 = $node->safe_psql(
+ 'postgres', "
+ SET min_parallel_table_scan_size TO 0;
+ SET parallel_setup_cost TO 0;
+ SET parallel_tuple_cost TO 0;
+ SET max_parallel_workers_per_gather TO 2;
+
+ SELECT bool_and(SYSTEM_USER IS NOT DISTINCT FROM n) FROM sysuser_data;
+ ",
+ connstr => "user=md5_role");
+is($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 62e0542639..f7d8228b24 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
@@ -176,6 +176,13 @@ $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.
@@ -307,6 +314,23 @@ 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(
+ $node,
+ 'test1',
+ "SET min_parallel_table_scan_size TO 0;\n"
+ . "SET parallel_setup_cost TO 0;\n"
+ . "SET parallel_tuple_cost TO 0;\n"
+ . "SET max_parallel_workers_per_gather TO 2;\n"
+ . "SELECT bool_and(SYSTEM_USER = id) FROM ids;",
+ qr/^t$/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/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 67eb380632..e7f4932a15 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23666,6 +23666,24 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>system_user</primary>
+ </indexterm>
+ <function>system_user</function>
+ <returnvalue>name</returnvalue>
+ </para>
+ <para>
+ 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
+ <literal>auth_method:identity</literal> or
+ <literal>NULL</literal> if the user has not been authenticated (for
+ example if <xref linkend="auth-trust"/> has been used).
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
--
2.37.2
signature.asc
Description: PGP signature
