Make standard maintenance operations (including VACUUM, ANALYZE, REINDEX,

and CLUSTER) execute as the table owner rather than the calling user, using
the same privilege-switching mechanism already used for SECURITY DEFINER
functions.  The purpose of this change is to ensure that user-defined
functions used in index definitions cannot acquire the privileges of a
superuser account that is performing routine maintenance.  While a function
used in an index is supposed to be IMMUTABLE and thus not able to do anything
very interesting, there are several easy ways around that restriction; and
even if we could plug them all, there would remain a risk of reading sensitive
information and broadcasting it through a covert channel such as CPU usage.

To prevent bypassing this security measure, execution of SET SESSION
AUTHORIZATION and SET ROLE is now forbidden within a SECURITY DEFINER context.

Thanks to Itagaki Takahiro for reporting this vulnerability.

Security: CVE-2007-6600

diff --git a/doc/src/sgml/ref/set_session_auth.sgml b/doc/src/sgml/ref/set_session_auth.sgml
index ba516c7bd09e2afc8468b937e9429a9f5c4cea7c..9a0beb96ad0498cfa3fc37e8c66af568e625499a 100644 (file)
--- a/doc/src/sgml/ref/set_session_auth.sgml
+++ b/doc/src/sgml/ref/set_session_auth.sgml
@@ -27,7 +27,7 @@ RESET SESSION AUTHORIZATION
 
   <para>
    This command sets the session user identifier and the current user
-   identifier of the current SQL-session context to be
+   identifier of the current SQL session to be
    <parameter>username</parameter>.  The user name may be written as
    either an identifier or a string literal.
    The session user identifier is valid for the duration of a
@@ -39,7 +39,7 @@ RESET SESSION AUTHORIZATION
    The session user identifier is initially set to be the (possibly
    authenticated) user name provided by the client.  The current user
    identifier is normally equal to the session user identifier, but
-   may change temporarily in the context of <quote>setuid</quote>
+   might change temporarily in the context of <literal>SECURITY DEFINER</>
    functions and similar mechanisms.  The current user identifier is
    relevant for permission checking.
   </para>
@@ -65,6 +65,15 @@ RESET SESSION AUTHORIZATION
 
  </refsect1>
 
+ <refsect1>
+  <title>Notes</title>
+
+  <para>
+   <command>SET SESSION AUTHORIZATION</> cannot be used within a
+   <literal>SECURITY DEFINER</> function.
+  </para>
+ </refsect1>
+
  <refsect1>
   <title>Examples</title>
 

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index a7ced751ab07df0878d88c4cbdc63c7c6eba8ba7..8e7d436b3f6445e7d2c6365d838266a90b3664d9 100644 (file)
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -215,6 +215,8 @@ static TransactionStateData CurrentTransactionStateData = {
 
 TransactionState CurrentTransactionState = &CurrentTransactionStateData;
 
+static Oid     prevUser;                       /* CurrentUserId at transaction start */
+
 /*
  * User-tweakable parameters
  */
@@ -960,6 +962,7 @@ static void
 CommitTransaction(void)
 {
        TransactionState s = CurrentTransactionState;
+       bool            prevSecDefCxt;
 
        /*
         * check the current transaction state
@@ -983,6 +986,10 @@ CommitTransaction(void)
         */
        s->state = TRANS_COMMIT;
 
+       GetUserIdAndContext(&prevUser, &prevSecDefCxt);
+       /* SecurityDefinerContext should never be set outside a transaction */
+       Assert(!prevSecDefCxt);
+
        /*
         * Do pre-commit processing (most of this stuff requires database
         * access, and in fact could still cause an error...)
@@ -1118,9 +1125,16 @@ AbortTransaction(void)
        AtAbort_Memory();
 
        /*
-        * Reset user id which might have been changed transiently
+        * Reset user ID which might have been changed transiently.  We need this
+        * to clean up in case control escaped out of a SECURITY DEFINER function
+        * or other local change of CurrentUserId; therefore, the prior value
+        * of SecurityDefinerContext also needs to be restored.
+        *
+        * (Note: it is not necessary to restore session authorization
+        * setting here because that can only be changed via GUC, and GUC will
+        * take care of rolling it back if need be.)
         */
-       SetUserId(GetSessionUserId());
+       SetUserIdAndContext(prevUser, false);
 
        /*
         * do abort processing

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 697cd05b8f4308711ccb4ddcb9acf42c94cb3d63..24df242a78ef087e2cce3b61351a8d5e9940a5cd 100644 (file)
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1439,6 +1439,8 @@ index_build(Relation heapRelation,
                        IndexInfo *indexInfo)
 {
        RegProcedure procedure;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /*
         * sanity checks
@@ -1449,6 +1451,13 @@ index_build(Relation heapRelation,
        procedure = indexRelation->rd_am->ambuild;
        Assert(RegProcedureIsValid(procedure));
 
+       /*
+        * Switch to the table owner's userid, so that any index functions are
+        * run as that user.
+        */
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+       SetUserIdAndContext(heapRelation->rd_rel->relowner, true);
+
        /*
         * Call the access method's build procedure
         */
@@ -1456,6 +1465,9 @@ index_build(Relation heapRelation,
                                         PointerGetDatum(heapRelation),
                                         PointerGetDatum(indexRelation),
                                         PointerGetDatum(indexInfo));
+
+       /* Restore userid */
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 }
 
 

diff --git a/src/backend/commands/schemacmds.c b/src/backend/commands/schemacmds.c
index 620eae5f07954ade4850663855b989eb990013d3..12c64077521db42b13abdd615679fa98b5644d2e 100644 (file)
--- a/src/backend/commands/schemacmds.c
+++ b/src/backend/commands/schemacmds.c
@@ -43,9 +43,10 @@ CreateSchemaCommand(CreateSchemaStmt *stmt)
        const char *owner_name;
        Oid                     owner_userid;
        Oid                     saved_userid;
+       bool            saved_secdefcxt;
        AclResult       aclresult;
 
-       saved_userid = GetUserId();
+       GetUserIdAndContext(&saved_userid, &saved_secdefcxt);
 
        /*
         * Figure out user identities.
@@ -68,7 +69,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt)
                 * (This will revert to session user on error or at the end of
                 * this routine.)
                 */
-               SetUserId(owner_userid);
+               SetUserIdAndContext(owner_userid, true);
        }
        else
 /* not superuser */
@@ -143,7 +144,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt)
        PopSpecialNamespace(namespaceId);
 
        /* Reset current user */
-       SetUserId(saved_userid);
+       SetUserIdAndContext(saved_userid, saved_secdefcxt);
 }
 
 

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 868b3de66e88897e5742f884e19043bab09a1cce..0be479c4ea9dabfa37a912488c4d59c9557feda1 100644 (file)
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -720,6 +720,8 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
        LockRelId       onerelid;
        Oid                     toast_relid;
        bool            result;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /* Begin a transaction for vacuuming this relation */
        StartTransactionCommand(true);
@@ -820,6 +822,14 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
         */
        toast_relid = onerel->rd_rel->reltoastrelid;
 
+       /*
+        * Switch to the table owner's userid, so that any index functions are
+        * run as that user.  (This is unnecessary, but harmless, for lazy
+        * VACUUM.)
+        */
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+       SetUserIdAndContext(onerel->rd_rel->relowner, true);
+
        /*
         * Do the actual work --- either FULL or "lazy" vacuum
         */
@@ -830,6 +840,9 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
 
        result = true;                          /* did the vacuum */
 
+       /* Restore userid */
+       SetUserIdAndContext(save_userid, save_secdefcxt);
+
        /* all done with this class, but hold lock until commit */
        relation_close(onerel, NoLock);
 

diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index 156fd5fdf2d5499de7ec63bab136c76237b5a844..6bba275e36b2d7bd8927f9fa77b345764d22cd73 100644 (file)
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -561,6 +561,20 @@ assign_session_authorization(const char *value, bool doit, bool interactive)
                /* not a saved ID, so look it up */
                HeapTuple       userTup;
 
+               if (InSecurityDefinerContext())
+               {
+                       /*
+                        * Disallow SET SESSION AUTHORIZATION inside a security definer
+                        * context.  We need to do this because when we exit the context,
+                        * GUC won't be notified, leaving things out of sync.  Note that
+                        * this test is positioned so that restoring a previously saved
+                        * setting isn't prevented.
+                        */
+                       if (interactive)
+                               elog(ERROR, "cannot set session authorization within security-definer function");
+                       return NULL;
+               }
+
                if (! IsTransactionState())
                {
                        /*

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index fa593a6852fffe095133f85fd1256894ac302d5b..0e1f8d660fda5ed7cffd1e6211e34c66503bceae 100644 (file)
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -178,9 +178,10 @@ RI_FKey_check(PG_FUNCTION_ARGS)
        bool            isnull;
        int                     i;
        int                     match_type;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
-       save_uid = GetUserId();
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
 
        ReferentialIntegritySnapshotOverride = true;
 
@@ -297,12 +298,12 @@ RI_FKey_check(PG_FUNCTION_ARGS)
                /*
                 * Execute the plan
                 */
-               SetUserId(RelationGetForm(pk_rel)->relowner);
+               SetUserIdAndContext(RelationGetForm(pk_rel)->relowner, true);
 
                if (SPI_execp(qplan, check_values, check_nulls, 1) != SPI_OK_SELECT)
                        elog(ERROR, "SPI_execp() failed in RI_FKey_check()");
 
-               SetUserId(save_uid);
+               SetUserIdAndContext(save_userid, save_secdefcxt);
 
                if (SPI_processed == 0)
                        elog(ERROR, "%s referential integrity violation - "
@@ -486,12 +487,12 @@ RI_FKey_check(PG_FUNCTION_ARGS)
         * Now check that foreign key exists in PK table
         */
 
-       SetUserId(RelationGetForm(pk_rel)->relowner);
+       SetUserIdAndContext(RelationGetForm(pk_rel)->relowner, true);
 
        if (SPI_execp(qplan, check_values, check_nulls, 1) != SPI_OK_SELECT)
                elog(ERROR, "SPI_execp() failed in RI_FKey_check()");
 
-       SetUserId(save_uid);
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 
        if (SPI_processed == 0)
                elog(ERROR, "%s referential integrity violation - "
@@ -558,10 +559,11 @@ ri_Check_Pk_Match(Relation pk_rel, HeapTuple old_row, Oid tgoid, int match_type,
        Datum           check_values[RI_MAX_NUMKEYS];
        char            check_nulls[RI_MAX_NUMKEYS + 1];
        int                     i;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        bool            result;
 
-       save_uid = GetUserId();
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
 
        ri_BuildQueryKeyPkCheck(&qkey, tgoid,
                                                        RI_PLAN_CHECK_LOOKUPPK, pk_rel,
@@ -681,12 +683,12 @@ ri_Check_Pk_Match(Relation pk_rel, HeapTuple old_row, Oid tgoid, int match_type,
         * Now check that foreign key exists in PK table
         */
 
-       SetUserId(RelationGetForm(pk_rel)->relowner);
+       SetUserIdAndContext(RelationGetForm(pk_rel)->relowner, true);
 
        if (SPI_execp(qplan, check_values, check_nulls, 1) != SPI_OK_SELECT)
                elog(ERROR, "SPI_execp() failed in ri_Check_Pk_Match()");
 
-       SetUserId(save_uid);
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 
        result = (SPI_processed != 0);
 
@@ -721,9 +723,10 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
        bool            isnull;
        int                     i;
        int                     match_type;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
-       save_uid = GetUserId();
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
 
        ReferentialIntegritySnapshotOverride = true;
 
@@ -886,12 +889,12 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
                        /*
                         * Now check for existing references
                         */
-                       SetUserId(RelationGetForm(pk_rel)->relowner);
+                       SetUserIdAndContext(RelationGetForm(pk_rel)->relowner, true);
 
                        if (SPI_execp(qplan, del_values, del_nulls, 1) != SPI_OK_SELECT)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_noaction_del()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_processed > 0)
                                elog(ERROR, "%s referential integrity violation - "
@@ -948,9 +951,10 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
        bool            isnull;
        int                     i;
        int                     match_type;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
-       save_uid = GetUserId();
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
 
        ReferentialIntegritySnapshotOverride = true;
 
@@ -1124,12 +1128,12 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
                        /*
                         * Now check for existing references
                         */
-                       SetUserId(RelationGetForm(pk_rel)->relowner);
+                       SetUserIdAndContext(RelationGetForm(pk_rel)->relowner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 1) != SPI_OK_SELECT)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_noaction_upd()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_processed > 0)
                                elog(ERROR, "%s referential integrity violation - "
@@ -1182,7 +1186,8 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
        char            del_nulls[RI_MAX_NUMKEYS + 1];
        bool            isnull;
        int                     i;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -1333,13 +1338,13 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
                        /*
                         * Now delete constraint
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, del_values, del_nulls, 0) != SPI_OK_DELETE)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_cascade_del()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_finish() != SPI_OK_FINISH)
                                elog(WARNING, "SPI_finish() failed in RI_FKey_cascade_del()");
@@ -1387,7 +1392,8 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
        bool            isnull;
        int                     i;
        int                     j;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -1569,13 +1575,13 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
                        /*
                         * Now update the existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 0) != SPI_OK_UPDATE)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_cascade_upd()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_finish() != SPI_OK_FINISH)
                                elog(WARNING, "SPI_finish() failed in RI_FKey_cascade_upd()");
@@ -1628,7 +1634,8 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
        char            del_nulls[RI_MAX_NUMKEYS + 1];
        bool            isnull;
        int                     i;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -1781,13 +1788,13 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
                        /*
                         * Now check for existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, del_values, del_nulls, 1) != SPI_OK_SELECT)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_restrict_del()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_processed > 0)
                                elog(ERROR, "%s referential integrity violation - "
@@ -1848,7 +1855,8 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
        char            upd_nulls[RI_MAX_NUMKEYS + 1];
        bool            isnull;
        int                     i;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -2012,15 +2020,13 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
                        /*
                         * Now check for existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
-
-                       SetUserId(RelationGetForm(pk_rel)->relowner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(RelationGetForm(pk_rel)->relowner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 1) != SPI_OK_SELECT)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_restrict_upd()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_processed > 0)
                                elog(ERROR, "%s referential integrity violation - "
@@ -2073,7 +2079,8 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
        char            upd_nulls[RI_MAX_NUMKEYS + 1];
        bool            isnull;
        int                     i;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -2234,13 +2241,13 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
                        /*
                         * Now update the existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 0) != SPI_OK_UPDATE)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_setnull_del()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_finish() != SPI_OK_FINISH)
                                elog(WARNING, "SPI_finish() failed in RI_FKey_setnull_del()");
@@ -2289,7 +2296,8 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
        int                     i;
        int                     match_type;
        bool            use_cached_query;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -2495,13 +2503,13 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
                        /*
                         * Now update the existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 0) != SPI_OK_UPDATE)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_setnull_upd()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_finish() != SPI_OK_FINISH)
                                elog(WARNING, "SPI_finish() failed in RI_FKey_setnull_upd()");
@@ -2547,7 +2555,8 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
        char            upd_nulls[RI_MAX_NUMKEYS + 1];
        bool            isnull;
        int                     i;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -2739,13 +2748,13 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
                        /*
                         * Now update the existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 0) != SPI_OK_UPDATE)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_setdefault_del()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_finish() != SPI_OK_FINISH)
                                elog(WARNING, "SPI_finish() failed in RI_FKey_setdefault_del()");
@@ -2803,7 +2812,8 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
        bool            isnull;
        int                     i;
        int                     match_type;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Oid                     fk_owner;
 
        ReferentialIntegritySnapshotOverride = true;
@@ -3018,13 +3028,13 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
                        /*
                         * Now update the existing references
                         */
-                       save_uid = GetUserId();
-                       SetUserId(fk_owner);
+                       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+                       SetUserIdAndContext(fk_owner, true);
 
                        if (SPI_execp(qplan, upd_values, upd_nulls, 0) != SPI_OK_UPDATE)
                                elog(ERROR, "SPI_execp() failed in RI_FKey_setdefault_upd()");
 
-                       SetUserId(save_uid);
+                       SetUserIdAndContext(save_userid, save_secdefcxt);
 
                        if (SPI_finish() != SPI_OK_FINISH)
                                elog(WARNING, "SPI_finish() failed in RI_FKey_setdefault_upd()");
@@ -3171,7 +3181,8 @@ ri_PlanCheck(char *querystr, int nargs, Oid *argtypes,
 {
        void       *qplan;
        Relation        query_rel;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /*
         * The query is always run against the FK table except
@@ -3185,14 +3196,14 @@ ri_PlanCheck(char *querystr, int nargs, Oid *argtypes,
                query_rel = fk_rel;
 
        /* Switch to proper UID to perform check as */
-       save_uid = GetUserId();
-       SetUserId(RelationGetForm(query_rel)->relowner);
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+       SetUserIdAndContext(RelationGetForm(query_rel)->relowner, true);
 
        /* Create the plan */
        qplan = SPI_prepare(querystr, nargs, argtypes);
 
        /* Restore UID */
-       SetUserId(save_uid);
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 
        /* Save the plan if requested */
        if (cache_plan)

diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c
index 04490562e61a04a25a512972d181c557b9ccbd72..7508b104fec48cc775abbb943ed19524959d1132 100644 (file)
--- a/src/backend/utils/fmgr/fmgr.c
+++ b/src/backend/utils/fmgr/fmgr.c
@@ -651,6 +651,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        FmgrInfo   *save_flinfo;
        struct fmgr_security_definer_cache *fcache;
        Oid                     save_userid;
+       bool            save_secdefcxt;
        HeapTuple       tuple;
 
        if (!fcinfo->flinfo->fn_extra)
@@ -673,16 +674,18 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        else
                fcache = fcinfo->flinfo->fn_extra;
 
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+       SetUserIdAndContext(fcache->userid, true);
+
        save_flinfo = fcinfo->flinfo;
        fcinfo->flinfo = &fcache->flinfo;
 
-       save_userid = GetUserId();
-       SetUserId(fcache->userid);
        result = FunctionCallInvoke(fcinfo);
-       SetUserId(save_userid);
 
        fcinfo->flinfo = save_flinfo;
 
+       SetUserIdAndContext(save_userid, save_secdefcxt);
+
        return result;
 }
 

diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index 7f7a18814f3209be454a5af5e3aed1cdb9610f94..1735243bff73ef6eeb4bab5ff1ba4e4fd5b2e09d 100644 (file)
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -483,6 +483,9 @@ GetCharSetByHost(char *TableName, int host, const char *DataDir)
  * are implemented.  Conceptually there is a stack, whose bottom
  * is the session user.  You are yourself responsible to save and
  * restore the current user id if you need to change it.
+ *
+ * SecurityDefinerContext is TRUE if we are within a SECURITY DEFINER function
+ * or another context that temporarily changes CurrentUserId.
  * ----------------------------------------------------------------
  */
 static Oid     AuthenticatedUserId = InvalidOid;
@@ -491,8 +494,13 @@ static Oid CurrentUserId = InvalidOid;
 
 static bool AuthenticatedUserIsSuperuser = false;
 
+static bool SecurityDefinerContext = false;
+
+
 /*
- * This function is relevant for all privilege checks.
+ * GetUserId - get the current effective user ID.
+ *
+ * Note: there's no SetUserId() anymore; use SetUserIdAndContext().
  */
 Oid
 GetUserId(void)
@@ -502,14 +510,6 @@ GetUserId(void)
 }
 
 
-void
-SetUserId(Oid newid)
-{
-       AssertArg(OidIsValid(newid));
-       CurrentUserId = newid;
-}
-
-
 /*
  * This value is only relevant for informational purposes.
  */
@@ -521,17 +521,57 @@ GetSessionUserId(void)
 }
 
 
-void
+static void
 SetSessionUserId(Oid newid)
 {
+       AssertState(!SecurityDefinerContext);
        AssertArg(OidIsValid(newid));
        SessionUserId = newid;
-       /* Current user defaults to session user. */
-       if (!OidIsValid(CurrentUserId))
-               CurrentUserId = newid;
+       CurrentUserId = newid;
 }
 
 
+/*
+ * GetUserIdAndContext/SetUserIdAndContext - get/set the current user ID
+ * and the SecurityDefinerContext flag.
+ *
+ * Unlike GetUserId, GetUserIdAndContext does *not* Assert that the current
+ * value of CurrentUserId is valid; nor does SetUserIdAndContext require
+ * the new value to be valid.  In fact, these routines had better not
+ * ever throw any kind of error.  This is because they are used by
+ * StartTransaction and AbortTransaction to save/restore the settings,
+ * and during the first transaction within a backend, the value to be saved
+ * and perhaps restored is indeed invalid.  We have to be able to get
+ * through AbortTransaction without asserting in case InitPostgres fails.
+ */
+void
+GetUserIdAndContext(Oid *userid, bool *sec_def_context)
+{
+       *userid = CurrentUserId;
+       *sec_def_context = SecurityDefinerContext;
+}
+
+void
+SetUserIdAndContext(Oid userid, bool sec_def_context)
+{
+       CurrentUserId = userid;
+       SecurityDefinerContext = sec_def_context;
+}
+
+
+/*
+ * InSecurityDefinerContext - are we inside a SECURITY DEFINER context?
+ */
+bool
+InSecurityDefinerContext(void)
+{
+       return SecurityDefinerContext;
+}
+
+
+/*
+ * Initialize user identity during normal backend startup
+ */
 void
 InitializeSessionUserId(const char *username)
 {
@@ -616,7 +656,6 @@ SetSessionAuthorization(Oid userid)
                elog(ERROR, "permission denied");
 
        SetSessionUserId(userid);
-       SetUserId(userid);
 }
 
 

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index be081e1d73c7a8788e9429d35baa038d7c2a22a0..614b4c9c9cb4a4553575e2f09ac85988f1dcca76 100644 (file)
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -203,9 +203,10 @@ extern void SetDatabasePath(const char *path);
 extern char *GetUserNameFromId(Oid userid);
 
 extern Oid     GetUserId(void);
-extern void SetUserId(Oid userid);
 extern Oid     GetSessionUserId(void);
-extern void SetSessionUserId(Oid userid);
+extern void GetUserIdAndContext(Oid *userid, bool *sec_def_context);
+extern void SetUserIdAndContext(Oid userid, bool sec_def_context);
+extern bool InSecurityDefinerContext(void);
 extern void InitializeSessionUserId(const char *username);
 extern void InitializeSessionUserIdStandalone(void);
 extern void SetSessionAuthorization(Oid userid);