OSDN Git Service

Make standard maintenance operations (including VACUUM, ANALYZE, REINDEX,
authorTom Lane <tgl@sss.pgh.pa.us>
Thu, 3 Jan 2008 21:23:15 +0000 (21:23 +0000)
committerTom Lane <tgl@sss.pgh.pa.us>
Thu, 3 Jan 2008 21:23:15 +0000 (21:23 +0000)
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

13 files changed:
doc/src/sgml/ref/set_role.sgml
doc/src/sgml/ref/set_session_auth.sgml
doc/src/sgml/ref/show.sgml
src/backend/access/transam/xact.c
src/backend/catalog/index.c
src/backend/commands/analyze.c
src/backend/commands/schemacmds.c
src/backend/commands/vacuum.c
src/backend/commands/variable.c
src/backend/utils/adt/ri_triggers.c
src/backend/utils/fmgr/fmgr.c
src/backend/utils/init/miscinit.c
src/include/miscadmin.h

index d58943f..5b8e1fd 100644 (file)
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/set_role.sgml,v 1.4 2007/01/31 23:26:04 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/set_role.sgml,v 1.5 2008/01/03 21:23:15 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -31,7 +31,7 @@ RESET ROLE
 
   <para>
    This command sets the current user
-   identifier of the current SQL-session context to be <replaceable
+   identifier of the current SQL session to be <replaceable
    class="parameter">rolename</replaceable>.  The role name can be
    written as either an identifier or a string literal.
    After <command>SET ROLE</>, permissions checking for SQL commands
@@ -89,6 +89,11 @@ RESET ROLE
    roles with <command>SET ROLE</> does not change the set of roles
    allowed to a later <command>SET ROLE</>.
   </para>
+
+  <para>
+   <command>SET ROLE</> cannot be used within a
+   <literal>SECURITY DEFINER</> function.
+  </para>
  </refsect1>
 
  <refsect1>
index 315aec1..f21c58f 100644 (file)
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.16 2007/01/31 23:26:04 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.17 2008/01/03 21:23:15 tgl Exp $ -->
 <refentry id="SQL-SET-SESSION-AUTHORIZATION">
  <refmeta>
   <refentrytitle id="sql-set-session-authorization-title">SET SESSION AUTHORIZATION</refentrytitle>
@@ -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 <replaceable
+   identifier of the current SQL session to be <replaceable
    class="parameter">username</replaceable>.  The user name can be
    written as either an identifier or a string literal.  Using this
    command, it is possible, for example, to temporarily become an
@@ -38,7 +38,7 @@ 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
-   might change temporarily in the context of <quote>setuid</quote>
+   might change temporarily in the context of <literal>SECURITY DEFINER</>
    functions and similar mechanisms; it can also be changed by
    <xref linkend="sql-set-role" endterm="sql-set-role-title">.
    The current user identifier is relevant for permission checking.
@@ -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>
 
 <programlisting>
index 14ddd67..ebd1ace 100644 (file)
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/show.sgml,v 1.44 2007/09/26 22:36:30 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/show.sgml,v 1.45 2008/01/03 21:23:15 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -104,8 +104,7 @@ SHOW ALL
         <term><literal>IS_SUPERUSER</literal></term>
         <listitem>
          <para>
-          True if the current session authorization identifier has
-          superuser privileges.
+          True if the current role has superuser privileges.
          </para>
         </listitem>
        </varlistentry>
index 4409f61..4cebea0 100644 (file)
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.255 2008/01/01 19:45:48 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.256 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -123,7 +123,8 @@ typedef struct TransactionStateData
        MemoryContext curTransactionContext;            /* my xact-lifetime context */
        ResourceOwner curTransactionOwner;      /* my query resources */
        List       *childXids;          /* subcommitted child XIDs */
-       Oid                     currentUser;    /* subxact start current_user */
+       Oid                     prevUser;               /* previous CurrentUserId setting */
+       bool            prevSecDefCxt;  /* previous SecurityDefinerContext setting */
        bool            prevXactReadOnly;               /* entry-time xact r/o state */
        struct TransactionStateData *parent;            /* back link to parent */
 } TransactionStateData;
@@ -148,7 +149,8 @@ static TransactionStateData TopTransactionStateData = {
        NULL,                                           /* cur transaction context */
        NULL,                                           /* cur transaction resource owner */
        NIL,                                            /* subcommitted child Xids */
-       0,                                                      /* entry-time current userid */
+       InvalidOid,                                     /* previous CurrentUserId setting */
+       false,                                          /* previous SecurityDefinerContext setting */
        false,                                          /* entry-time xact r/o state */
        NULL                                            /* link to parent state block */
 };
@@ -1490,19 +1492,15 @@ StartTransaction(void)
 
        /*
         * initialize current transaction state fields
+        *
+        * note: prevXactReadOnly is not used at the outermost level
         */
        s->nestingLevel = 1;
        s->gucNestLevel = 1;
        s->childXids = NIL;
-
-       /*
-        * You might expect to see "s->currentUser = GetUserId();" here, but you
-        * won't because it doesn't work during startup; the userid isn't set yet
-        * during a backend's first transaction start.  We only use the
-        * currentUser field in sub-transaction state structs.
-        *
-        * prevXactReadOnly is also valid only in sub-transactions.
-        */
+       GetUserIdAndContext(&s->prevUser, &s->prevSecDefCxt);
+       /* SecurityDefinerContext should never be set outside a transaction */
+       Assert(!s->prevSecDefCxt);
 
        /*
         * initialize other subsystems for new transaction
@@ -1963,17 +1961,16 @@ AbortTransaction(void)
        s->state = TRANS_ABORT;
 
        /*
-        * Reset user id which might have been changed transiently.  We cannot use
-        * s->currentUser, since it may not be set yet; instead rely on internal
-        * state of miscinit.c.
+        * 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 here
-        * because that can only be changed via GUC, and GUC will take care of
-        * rolling it back if need be.  However, an error within a SECURITY
-        * DEFINER function could send control here with the wrong current
-        * userid.)
+        * (Note: it is not necessary to restore session authorization or role
+        * settings here because those can only be changed via GUC, and GUC will
+        * take care of rolling them back if need be.)
         */
-       AtAbort_UserId();
+       SetUserIdAndContext(s->prevUser, s->prevSecDefCxt);
 
        /*
         * do abort processing
@@ -3807,6 +3804,12 @@ AbortSubTransaction(void)
        s->state = TRANS_ABORT;
 
        /*
+        * Reset user ID which might have been changed transiently.  (See notes
+        * in AbortTransaction.)
+        */
+       SetUserIdAndContext(s->prevUser, s->prevSecDefCxt);
+
+       /*
         * We can skip all this stuff if the subxact failed before creating a
         * ResourceOwner...
         */
@@ -3859,20 +3862,6 @@ AbortSubTransaction(void)
        }
 
        /*
-        * Reset user id which might have been changed transiently.  Here we want
-        * to restore to the userid that was current at subxact entry. (As in
-        * AbortTransaction, we need not worry about the session userid.)
-        *
-        * Must do this after AtEOXact_GUC to handle the case where we entered the
-        * subxact inside a SECURITY DEFINER function (hence current and session
-        * userids were different) and then session auth was changed inside the
-        * subxact.  GUC will reset both current and session userids to the
-        * entry-time session userid.  This is right in every other scenario so it
-        * seems simplest to let GUC do that and fix it here.
-        */
-       SetUserId(s->currentUser);
-
-       /*
         * Restore the upper transaction's read-only state, too.  This should be
         * redundant with GUC's cleanup but we may as well do it for consistency
         * with the commit case.
@@ -3926,13 +3915,6 @@ PushTransaction(void)
 {
        TransactionState p = CurrentTransactionState;
        TransactionState s;
-       Oid                     currentUser;
-
-       /*
-        * At present, GetUserId cannot fail, but let's not assume that.  Get the
-        * ID before entering the critical code sequence.
-        */
-       currentUser = GetUserId();
 
        /*
         * We keep subtransaction state nodes in TopTransactionContext.
@@ -3966,7 +3948,7 @@ PushTransaction(void)
        s->savepointLevel = p->savepointLevel;
        s->state = TRANS_DEFAULT;
        s->blockState = TBLOCK_SUBBEGIN;
-       s->currentUser = currentUser;
+       GetUserIdAndContext(&s->prevUser, &s->prevSecDefCxt);
        s->prevXactReadOnly = XactReadOnly;
 
        CurrentTransactionState = s;
index e3e3b5f..97904b7 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.289 2008/01/01 19:45:48 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.290 2008/01/03 21:23:15 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1339,6 +1339,8 @@ index_build(Relation heapRelation,
 {
        RegProcedure procedure;
        IndexBuildResult *stats;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /*
         * sanity checks
@@ -1350,6 +1352,13 @@ index_build(Relation heapRelation,
        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
         */
        stats = (IndexBuildResult *)
@@ -1359,6 +1368,9 @@ index_build(Relation heapRelation,
                                                                                 PointerGetDatum(indexInfo)));
        Assert(PointerIsValid(stats));
 
+       /* Restore userid */
+       SetUserIdAndContext(save_userid, save_secdefcxt);
+
        /*
         * If we found any potentially broken HOT chains, mark the index as not
         * being usable until the current transaction is below the event horizon.
@@ -1857,6 +1869,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
        IndexInfo  *indexInfo;
        IndexVacuumInfo ivinfo;
        v_i_state       state;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /* Open and lock the parent heap relation */
        heapRelation = heap_open(heapId, ShareUpdateExclusiveLock);
@@ -1874,6 +1888,13 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
        indexInfo->ii_Concurrent = true;
 
        /*
+        * 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);
+
+       /*
         * Scan the index and gather up all the TIDs into a tuplesort object.
         */
        ivinfo.index = indexRelation;
@@ -1910,6 +1931,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
                 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
                 state.htups, state.itups, state.tups_inserted);
 
+       /* Restore userid */
+       SetUserIdAndContext(save_userid, save_secdefcxt);
+
        /* Close rels, but keep locks */
        index_close(indexRelation, NoLock);
        heap_close(heapRelation, NoLock);
index f39a957..82bb020 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.113 2008/01/01 19:45:48 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.114 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -119,6 +119,8 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
        HeapTuple  *rows;
        PGRUsage        ru0;
        TimestampTz starttime = 0;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        if (vacstmt->verbose)
                elevel = INFO;
@@ -202,6 +204,18 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
                return;
        }
 
+       ereport(elevel,
+                       (errmsg("analyzing \"%s.%s\"",
+                                       get_namespace_name(RelationGetNamespace(onerel)),
+                                       RelationGetRelationName(onerel))));
+
+       /*
+        * Switch to the table owner's userid, so that any index functions are
+        * run as that user.
+        */
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+       SetUserIdAndContext(onerel->rd_rel->relowner, true);
+
        /* let others know what I'm doing */
        LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
        MyProc->vacuumFlags |= PROC_IN_ANALYZE;
@@ -215,11 +229,6 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
                        starttime = GetCurrentTimestamp();
        }
 
-       ereport(elevel,
-                       (errmsg("analyzing \"%s.%s\"",
-                                       get_namespace_name(RelationGetNamespace(onerel)),
-                                       RelationGetRelationName(onerel))));
-
        /*
         * Determine which columns to analyze
         *
@@ -344,9 +353,7 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
                                                                  onerel->rd_rel->relisshared,
                                                                  0, 0);
 
-               vac_close_indexes(nindexes, Irel, AccessShareLock);
-               relation_close(onerel, ShareUpdateExclusiveLock);
-               return;
+               goto cleanup;
        }
 
        /*
@@ -466,6 +473,9 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
                                                          totalrows, totaldeadrows);
        }
 
+       /* We skip to here if there were no analyzable columns */
+cleanup:
+
        /* Done with indexes */
        vac_close_indexes(nindexes, Irel, NoLock);
 
@@ -498,6 +508,9 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
        LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
        MyProc->vacuumFlags &= ~PROC_IN_ANALYZE;
        LWLockRelease(ProcArrayLock);
+
+       /* Restore userid */
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 }
 
 /*
index 91a7ce9..d77294c 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.48 2008/01/01 19:45:49 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.49 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,9 +48,10 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
        ListCell   *parsetree_item;
        Oid                     owner_uid;
        Oid                     saved_uid;
+       bool            saved_secdefcxt;
        AclResult       aclresult;
 
-       saved_uid = GetUserId();
+       GetUserIdAndContext(&saved_uid, &saved_secdefcxt);
 
        /*
         * Who is supposed to own the new schema?
@@ -86,11 +87,11 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
         * temporarily set the current user so that the object(s) will be created
         * with the correct ownership.
         *
-        * (The setting will revert to session user on error or at the end of this
-        * routine.)
+        * (The setting will be restored at the end of this routine, or in case
+        * of error, transaction abort will clean things up.)
         */
        if (saved_uid != owner_uid)
-               SetUserId(owner_uid);
+               SetUserIdAndContext(owner_uid, true);
 
        /* Create the schema's namespace */
        namespaceId = NamespaceCreate(schemaName, owner_uid);
@@ -142,7 +143,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
        PopOverrideSearchPath();
 
        /* Reset current user */
-       SetUserId(saved_uid);
+       SetUserIdAndContext(saved_uid, saved_secdefcxt);
 }
 
 
index 389141c..6b2b70d 100644 (file)
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.362 2008/01/01 19:45:49 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.363 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -971,6 +971,8 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
        Relation        onerel;
        LockRelId       onerelid;
        Oid                     toast_relid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /* Begin a transaction for vacuuming this relation */
        StartTransactionCommand();
@@ -1101,6 +1103,14 @@ 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
         */
        if (vacstmt->full)
@@ -1108,6 +1118,9 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
        else
                lazy_vacuum_rel(onerel, vacstmt, vac_strategy);
 
+       /* Restore userid */
+       SetUserIdAndContext(save_userid, save_secdefcxt);
+
        /* all done with this class, but hold lock until commit */
        relation_close(onerel, NoLock);
 
index d0f1168..2c23407 100644 (file)
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.124 2008/01/01 19:45:49 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.125 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -717,6 +717,21 @@ assign_session_authorization(const char *value, bool doit, GucSource source)
                /* not a saved ID, so look it up */
                HeapTuple       roleTup;
 
+               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.
+                        */
+                       ereport(GUC_complaint_elevel(source),
+                                       (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                                        errmsg("cannot set session authorization within security-definer function")));
+                       return NULL;
+               }
+
                if (!IsTransactionState())
                {
                        /*
@@ -823,6 +838,24 @@ assign_role(const char *value, bool doit, GucSource source)
                }
        }
 
+       if (roleid == InvalidOid && InSecurityDefinerContext())
+       {
+               /*
+                * Disallow SET ROLE 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 arranged so
+                * that restoring a previously saved setting isn't prevented.
+                *
+                * XXX it would be nice to allow this case in future, with the
+                * behavior being that the SET ROLE's effects end when the security
+                * definer context is exited.
+                */
+               ereport(GUC_complaint_elevel(source),
+                               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                                errmsg("cannot set role within security-definer function")));
+               return NULL;
+       }
+
        if (roleid == InvalidOid &&
                strcmp(actual_rolename, "none") != 0)
        {
index cd6e396..50f4b4c 100644 (file)
@@ -15,7 +15,7 @@
  *
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.100 2008/01/01 19:45:52 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.101 2008/01/03 21:23:15 tgl Exp $
  *
  * ----------
  */
@@ -3173,7 +3173,8 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
 {
        SPIPlanPtr      qplan;
        Relation        query_rel;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
 
        /*
         * The query is always run against the FK table except when this is an
@@ -3187,8 +3188,8 @@ ri_PlanCheck(const 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);
@@ -3197,7 +3198,7 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
                elog(ERROR, "SPI_prepare returned %d for %s", SPI_result, querystr);
 
        /* Restore UID */
-       SetUserId(save_uid);
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 
        /* Save the plan if requested */
        if (cache_plan)
@@ -3226,7 +3227,8 @@ ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
        Snapshot        crosscheck_snapshot;
        int                     limit;
        int                     spi_result;
-       Oid                     save_uid;
+       Oid                     save_userid;
+       bool            save_secdefcxt;
        Datum           vals[RI_MAX_NUMKEYS * 2];
        char            nulls[RI_MAX_NUMKEYS * 2];
 
@@ -3304,8 +3306,8 @@ ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
        limit = (expect_OK == SPI_OK_SELECT) ? 1 : 0;
 
        /* 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);
 
        /* Finally we can run the query. */
        spi_result = SPI_execute_snapshot(qplan,
@@ -3314,7 +3316,7 @@ ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
                                                                          false, false, limit);
 
        /* Restore UID */
-       SetUserId(save_uid);
+       SetUserIdAndContext(save_userid, save_secdefcxt);
 
        /* Check result */
        if (spi_result < 0)
index b2254ba..19216b4 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.112 2008/01/01 19:45:53 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.113 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -864,6 +864,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        struct fmgr_security_definer_cache *volatile fcache;
        FmgrInfo   *save_flinfo;
        Oid                     save_userid;
+       bool            save_secdefcxt;
        volatile int save_nestlevel;
 
        if (!fcinfo->flinfo->fn_extra)
@@ -908,46 +909,50 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        else
                fcache = fcinfo->flinfo->fn_extra;
 
-       save_flinfo = fcinfo->flinfo;
-       /* GetUserId is cheap enough that no harm in a wasted call */
-       save_userid = GetUserId();
+       /* GetUserIdAndContext is cheap enough that no harm in a wasted call */
+       GetUserIdAndContext(&save_userid, &save_secdefcxt);
        if (fcache->proconfig)          /* Need a new GUC nesting level */
                save_nestlevel = NewGUCNestLevel();
        else
                save_nestlevel = 0;             /* keep compiler quiet */
 
-       PG_TRY();
+       if (OidIsValid(fcache->userid))
+               SetUserIdAndContext(fcache->userid, true);
+
+       if (fcache->proconfig)
        {
-               fcinfo->flinfo = &fcache->flinfo;
+               ProcessGUCArray(fcache->proconfig,
+                                               (superuser() ? PGC_SUSET : PGC_USERSET),
+                                               PGC_S_SESSION,
+                                               GUC_ACTION_SAVE);
+       }
 
-               if (OidIsValid(fcache->userid))
-                       SetUserId(fcache->userid);
+       /*
+        * We don't need to restore GUC or userid settings on error, because the
+        * ensuing xact or subxact abort will do that.  The PG_TRY block is only
+        * needed to clean up the flinfo link.
+        */
+       save_flinfo = fcinfo->flinfo;
 
-               if (fcache->proconfig)
-               {
-                       ProcessGUCArray(fcache->proconfig,
-                                                       (superuser() ? PGC_SUSET : PGC_USERSET),
-                                                       PGC_S_SESSION,
-                                                       GUC_ACTION_SAVE);
-               }
+       PG_TRY();
+       {
+               fcinfo->flinfo = &fcache->flinfo;
 
                result = FunctionCallInvoke(fcinfo);
        }
        PG_CATCH();
        {
                fcinfo->flinfo = save_flinfo;
-               /* We don't need to restore GUC settings, outer xact abort will */
-               if (OidIsValid(fcache->userid))
-                       SetUserId(save_userid);
                PG_RE_THROW();
        }
        PG_END_TRY();
 
        fcinfo->flinfo = save_flinfo;
+
        if (fcache->proconfig)
                AtEOXact_GUC(true, save_nestlevel);
        if (OidIsValid(fcache->userid))
-               SetUserId(save_userid);
+               SetUserIdAndContext(save_userid, save_secdefcxt);
 
        return result;
 }
index 888d5fa..5a42a89 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.165 2008/01/01 19:45:53 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.166 2008/01/03 21:23:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -264,13 +264,15 @@ make_absolute_path(const char *path)
  * OuterUserId is the current user ID in effect at the "outer level" (outside
  * any transaction or function).  This is initially the same as SessionUserId,
  * but can be changed by SET ROLE to any role that SessionUserId is a
- * member of.  We store this mainly so that AtAbort_UserId knows what to
- * reset CurrentUserId to.
+ * member of.  (XXX rename to something like CurrentRoleId?)
  *
  * CurrentUserId is the current effective user ID; this is the one to use
  * for all normal permissions-checking purposes.  At outer level this will
  * be the same as OuterUserId, but it changes during calls to SECURITY
  * DEFINER functions, as well as locally in some specialized commands.
+ *
+ * SecurityDefinerContext is TRUE if we are within a SECURITY DEFINER function
+ * or another context that temporarily changes CurrentUserId.
  * ----------------------------------------------------------------
  */
 static Oid     AuthenticatedUserId = InvalidOid;
@@ -282,12 +284,16 @@ static Oid        CurrentUserId = InvalidOid;
 static bool AuthenticatedUserIsSuperuser = false;
 static bool SessionUserIsSuperuser = false;
 
+static bool SecurityDefinerContext = false;
+
 /* We also remember if a SET ROLE is currently active */
 static bool SetRoleIsActive = false;
 
 
 /*
- * GetUserId/SetUserId - get/set the current effective user ID.
+ * GetUserId - get the current effective user ID.
+ *
+ * Note: there's no SetUserId() anymore; use SetUserIdAndContext().
  */
 Oid
 GetUserId(void)
@@ -297,14 +303,6 @@ GetUserId(void)
 }
 
 
-void
-SetUserId(Oid userid)
-{
-       AssertArg(OidIsValid(userid));
-       CurrentUserId = userid;
-}
-
-
 /*
  * GetOuterUserId/SetOuterUserId - get/set the outer-level user ID.
  */
@@ -319,6 +317,7 @@ GetOuterUserId(void)
 static void
 SetOuterUserId(Oid userid)
 {
+       AssertState(!SecurityDefinerContext);
        AssertArg(OidIsValid(userid));
        OuterUserId = userid;
 
@@ -341,6 +340,7 @@ GetSessionUserId(void)
 static void
 SetSessionUserId(Oid userid, bool is_superuser)
 {
+       AssertState(!SecurityDefinerContext);
        AssertArg(OidIsValid(userid));
        SessionUserId = userid;
        SessionUserIsSuperuser = is_superuser;
@@ -353,6 +353,44 @@ SetSessionUserId(Oid userid, bool is_superuser)
 
 
 /*
+ * 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
@@ -480,21 +518,6 @@ InitializeSessionUserIdStandalone(void)
 
 
 /*
- * Reset effective userid during AbortTransaction
- *
- * This is essentially SetUserId(GetOuterUserId()), but without the Asserts.
- * The reason is that if a backend's InitPostgres transaction fails (eg,
- * because an invalid user name was given), we have to be able to get through
- * AbortTransaction without asserting.
- */
-void
-AtAbort_UserId(void)
-{
-       CurrentUserId = OuterUserId;
-}
-
-
-/*
  * Change session auth ID while running
  *
  * Only a superuser may set auth ID to something other than himself.  Note
index f7260ec..6ded4c9 100644 (file)
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.198 2008/01/01 19:45:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.199 2008/01/03 21:23:15 tgl Exp $
  *
  * NOTES
  *       some of the information in this file should be moved to other files.
@@ -234,12 +234,13 @@ extern void SetDatabasePath(const char *path);
 
 extern char *GetUserNameFromId(Oid roleid);
 extern Oid     GetUserId(void);
-extern void SetUserId(Oid userid);
 extern Oid     GetOuterUserId(void);
 extern Oid     GetSessionUserId(void);
+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 *rolename);
 extern void InitializeSessionUserIdStandalone(void);
-extern void AtAbort_UserId(void);
 extern void SetSessionAuthorization(Oid userid, bool is_superuser);
 extern Oid     GetCurrentRoleId(void);
 extern void SetCurrentRoleId(Oid roleid, bool is_superuser);