]> granicus.if.org Git - postgresql/commitdiff
Prevent indirect security attacks via changing session-local state within
authorTom Lane <tgl@sss.pgh.pa.us>
Wed, 9 Dec 2009 21:58:04 +0000 (21:58 +0000)
committerTom Lane <tgl@sss.pgh.pa.us>
Wed, 9 Dec 2009 21:58:04 +0000 (21:58 +0000)
an allegedly immutable index function.  It was previously recognized that
we had to prevent such a function from executing SET/RESET ROLE/SESSION
AUTHORIZATION, or it could trivially obtain the privileges of the session
user.  However, since there is in general no privilege checking for changes
of session-local state, it is also possible for such a function to change
settings in a way that might subvert later operations in the same session.
Examples include changing search_path to cause an unexpected function to
be called, or replacing an existing prepared statement with another one
that will execute a function of the attacker's choosing.

The present patch secures VACUUM, ANALYZE, and CREATE INDEX/REINDEX against
these threats, which are the same places previously deemed to need protection
against the SET ROLE issue.  GUC changes are still allowed, since there are
many useful cases for that, but we prevent security problems by forcing a
rollback of any GUC change after completing the operation.  Other cases are
handled by throwing an error if any change is attempted; these include temp
table creation, closing a cursor, and creating or deleting a prepared
statement.  (In 7.4, the infrastructure to roll back GUC changes doesn't
exist, so we settle for rejecting changes of "search_path" in these contexts.)

Original report and patch by Gurjeet Singh, additional analysis by
Tom Lane.

Security: CVE-2009-4136

14 files changed:
src/backend/access/transam/xact.c
src/backend/catalog/index.c
src/backend/commands/analyze.c
src/backend/commands/schemacmds.c
src/backend/commands/tablecmds.c
src/backend/commands/vacuum.c
src/backend/executor/execMain.c
src/backend/tcop/utility.c
src/backend/utils/adt/ri_triggers.c
src/backend/utils/fmgr/fmgr.c
src/backend/utils/init/miscinit.c
src/backend/utils/misc/guc.c
src/include/miscadmin.h
src/include/utils/guc.h

index 941b4e3815fed776af4b43450f908f2a13435124..068bc4e1eb32b4558d7bc33756518bbd54778b9c 100644 (file)
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.274.2.1 2009/11/23 09:58:51 heikki Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.274.2.2 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -138,7 +138,7 @@ typedef struct TransactionStateData
        int                     nChildXids;             /* # of subcommitted child XIDs */
        int                     maxChildXids;   /* allocated size of childXids[] */
        Oid                     prevUser;               /* previous CurrentUserId setting */
-       bool            prevSecDefCxt;  /* previous SecurityDefinerContext setting */
+       int                     prevSecContext; /* previous SecurityRestrictionContext */
        bool            prevXactReadOnly;               /* entry-time xact r/o state */
        struct TransactionStateData *parent;            /* back link to parent */
 } TransactionStateData;
@@ -166,7 +166,7 @@ static TransactionStateData TopTransactionStateData = {
        0,                                                      /* # of subcommitted child Xids */
        0,                                                      /* allocated size of childXids[] */
        InvalidOid,                                     /* previous CurrentUserId setting */
-       false,                                          /* previous SecurityDefinerContext setting */
+       0,                                                      /* previous SecurityRestrictionContext */
        false,                                          /* entry-time xact r/o state */
        NULL                                            /* link to parent state block */
 };
@@ -1523,9 +1523,9 @@ StartTransaction(void)
        s->childXids = NULL;
        s->nChildXids = 0;
        s->maxChildXids = 0;
-       GetUserIdAndContext(&s->prevUser, &s->prevSecDefCxt);
-       /* SecurityDefinerContext should never be set outside a transaction */
-       Assert(!s->prevSecDefCxt);
+       GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
+       /* SecurityRestrictionContext should never be set outside a transaction */
+       Assert(s->prevSecContext == 0);
 
        /*
         * initialize other subsystems for new transaction
@@ -2022,13 +2022,13 @@ AbortTransaction(void)
         * 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.
+        * SecurityRestrictionContext also needs to be restored.
         *
         * (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.)
         */
-       SetUserIdAndContext(s->prevUser, s->prevSecDefCxt);
+       SetUserIdAndSecContext(s->prevUser, s->prevSecContext);
 
        /*
         * do abort processing
@@ -3871,7 +3871,7 @@ AbortSubTransaction(void)
         * Reset user ID which might have been changed transiently.  (See notes in
         * AbortTransaction.)
         */
-       SetUserIdAndContext(s->prevUser, s->prevSecDefCxt);
+       SetUserIdAndSecContext(s->prevUser, s->prevSecContext);
 
        /*
         * We can skip all this stuff if the subxact failed before creating a
@@ -4013,7 +4013,7 @@ PushTransaction(void)
        s->savepointLevel = p->savepointLevel;
        s->state = TRANS_DEFAULT;
        s->blockState = TBLOCK_SUBBEGIN;
-       GetUserIdAndContext(&s->prevUser, &s->prevSecDefCxt);
+       GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
        s->prevXactReadOnly = XactReadOnly;
 
        CurrentTransactionState = s;
index b75aac04e172d02f8a86b266f61001d8d41a8c7e..93b7171963b0224cc7a5c07aa189baa561caaffa 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.318 2009/06/11 14:48:55 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.318.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -54,6 +54,7 @@
 #include "storage/smgr.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
+#include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -1371,7 +1372,8 @@ index_build(Relation heapRelation,
        RegProcedure procedure;
        IndexBuildResult *stats;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
+       int                     save_nestlevel;
 
        /*
         * sanity checks
@@ -1384,10 +1386,13 @@ index_build(Relation heapRelation,
 
        /*
         * Switch to the table owner's userid, so that any index functions are run
-        * as that user.
+        * as that user.  Also lock down security-restricted operations and
+        * arrange to make GUC variable changes local to this command.
         */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
-       SetUserIdAndContext(heapRelation->rd_rel->relowner, true);
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
+       SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
+                                                  save_sec_context | SECURITY_RESTRICTED_OPERATION);
+       save_nestlevel = NewGUCNestLevel();
 
        /*
         * Call the access method's build procedure
@@ -1399,8 +1404,11 @@ index_build(Relation heapRelation,
                                                                                 PointerGetDatum(indexInfo)));
        Assert(PointerIsValid(stats));
 
-       /* Restore userid */
-       SetUserIdAndContext(save_userid, save_secdefcxt);
+       /* Roll back any GUC changes executed by index functions */
+       AtEOXact_GUC(false, save_nestlevel);
+
+       /* Restore userid and security context */
+       SetUserIdAndSecContext(save_userid, save_sec_context);
 
        /*
         * If we found any potentially broken HOT chains, mark the index as not
@@ -1908,7 +1916,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
        IndexVacuumInfo ivinfo;
        v_i_state       state;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
+       int                     save_nestlevel;
 
        /* Open and lock the parent heap relation */
        heapRelation = heap_open(heapId, ShareUpdateExclusiveLock);
@@ -1927,10 +1936,13 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 
        /*
         * Switch to the table owner's userid, so that any index functions are run
-        * as that user.
+        * as that user.  Also lock down security-restricted operations and
+        * arrange to make GUC variable changes local to this command.
         */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
-       SetUserIdAndContext(heapRelation->rd_rel->relowner, true);
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
+       SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
+                                                  save_sec_context | SECURITY_RESTRICTED_OPERATION);
+       save_nestlevel = NewGUCNestLevel();
 
        /*
         * Scan the index and gather up all the TIDs into a tuplesort object.
@@ -1971,8 +1983,11 @@ 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);
+       /* Roll back any GUC changes executed by index functions */
+       AtEOXact_GUC(false, save_nestlevel);
+
+       /* Restore userid and security context */
+       SetUserIdAndSecContext(save_userid, save_sec_context);
 
        /* Close rels, but keep locks */
        index_close(indexRelation, NoLock);
index 181083fe39288623a4f26b54de7d506a90c2005e..baddc650a62c7b05bfc3ac344f9500df36a5092c 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.139.2.1 2009/08/12 18:23:55 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.139.2.2 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,6 +38,7 @@
 #include "storage/procarray.h"
 #include "utils/acl.h"
 #include "utils/datum.h"
+#include "utils/guc.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/pg_rusage.h"
@@ -133,7 +134,8 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
        PGRUsage        ru0;
        TimestampTz starttime = 0;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
+       int                     save_nestlevel;
 
        if (vacstmt->verbose)
                elevel = INFO;
@@ -235,10 +237,13 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt,
 
        /*
         * Switch to the table owner's userid, so that any index functions are run
-        * as that user.
+        * as that user.  Also lock down security-restricted operations and
+        * arrange to make GUC variable changes local to this command.
         */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
-       SetUserIdAndContext(onerel->rd_rel->relowner, true);
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
+       SetUserIdAndSecContext(onerel->rd_rel->relowner,
+                                                  save_sec_context | SECURITY_RESTRICTED_OPERATION);
+       save_nestlevel = NewGUCNestLevel();
 
        /* let others know what I'm doing */
        LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
@@ -543,8 +548,11 @@ cleanup:
        MyProc->vacuumFlags &= ~PROC_IN_ANALYZE;
        LWLockRelease(ProcArrayLock);
 
-       /* Restore userid */
-       SetUserIdAndContext(save_userid, save_secdefcxt);
+       /* Roll back any GUC changes executed by index functions */
+       AtEOXact_GUC(false, save_nestlevel);
+
+       /* Restore userid and security context */
+       SetUserIdAndSecContext(save_userid, save_sec_context);
 }
 
 /*
index 5680da36579a774e43244f60d0aa8088c20cfee8..4cc83eb018dda5c0f7dfcd6f80eb66af96d5034b 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.53 2009/06/11 14:48:56 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.53.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,10 +48,10 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
        ListCell   *parsetree_item;
        Oid                     owner_uid;
        Oid                     saved_uid;
-       bool            saved_secdefcxt;
+       int                     save_sec_context;
        AclResult       aclresult;
 
-       GetUserIdAndContext(&saved_uid, &saved_secdefcxt);
+       GetUserIdAndSecContext(&saved_uid, &save_sec_context);
 
        /*
         * Who is supposed to own the new schema?
@@ -91,7 +91,8 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
         * error, transaction abort will clean things up.)
         */
        if (saved_uid != owner_uid)
-               SetUserIdAndContext(owner_uid, true);
+               SetUserIdAndSecContext(owner_uid,
+                                                          save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
 
        /* Create the schema's namespace */
        namespaceId = NamespaceCreate(schemaName, owner_uid);
@@ -142,8 +143,8 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString)
        /* Reset search path to normal state */
        PopOverrideSearchPath();
 
-       /* Reset current user */
-       SetUserIdAndContext(saved_uid, saved_secdefcxt);
+       /* Reset current user and security context */
+       SetUserIdAndSecContext(saved_uid, save_sec_context);
 }
 
 
index a2bd54c183a67507dac5dc70f20a678821dc6f75..632c9d8d388e77cd985ff768a39b6db9683c6843 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.288.2.2 2009/10/06 00:55:34 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.288.2.3 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -369,6 +369,16 @@ DefineRelation(CreateStmt *stmt, char relkind)
                                (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                                 errmsg("ON COMMIT can only be used on temporary tables")));
 
+       /*
+        * Security check: disallow creating temp tables from security-restricted
+        * code.  This is needed because calling code might not expect untrusted
+        * tables to appear in pg_temp at the front of its search path.
+        */
+       if (stmt->relation->istemp && InSecurityRestrictedOperation())
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                errmsg("cannot create temporary table within security-restricted operation")));
+
        /*
         * Look up the namespace in which we are supposed to create the relation.
         * Check we have permission to create there. Skip check if bootstrapping,
index 215c77bc985118e6e58b8ae520f6b753b8131f63..9d2c7234b7e4142fb27d172871f632a5b850a520 100644 (file)
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.389.2.2 2009/11/10 18:00:26 alvherre Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.389.2.3 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,6 +48,7 @@
 #include "utils/builtins.h"
 #include "utils/flatfiles.h"
 #include "utils/fmgroids.h"
+#include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -1022,7 +1023,8 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound,
        LockRelId       onerelid;
        Oid                     toast_relid;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
+       int                     save_nestlevel;
        bool            heldoff;
 
        if (scanned_all)
@@ -1181,10 +1183,14 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound,
 
        /*
         * 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.)
+        * as that user.  Also lock down security-restricted operations and
+        * arrange to make GUC variable changes local to this command.
+        * (This is unnecessary, but harmless, for lazy VACUUM.)
         */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
-       SetUserIdAndContext(onerel->rd_rel->relowner, true);
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
+       SetUserIdAndSecContext(onerel->rd_rel->relowner,
+                                                  save_sec_context | SECURITY_RESTRICTED_OPERATION);
+       save_nestlevel = NewGUCNestLevel();
 
        /*
         * Do the actual work --- either FULL or "lazy" vacuum
@@ -1194,8 +1200,11 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound,
        else
                heldoff = lazy_vacuum_rel(onerel, vacstmt, vac_strategy, scanned_all);
 
-       /* Restore userid */
-       SetUserIdAndContext(save_userid, save_secdefcxt);
+       /* Roll back any GUC changes executed by index functions */
+       AtEOXact_GUC(false, save_nestlevel);
+
+       /* Restore userid and security context */
+       SetUserIdAndSecContext(save_userid, save_sec_context);
 
        /* all done with this class, but hold lock until commit */
        relation_close(onerel, NoLock);
index 1fddf10bc9a353002a666767e94153d35de9d001..fb8dea18ee68988c7c152d2fdb1fde6312615f55 100644 (file)
@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.326 2009/06/11 20:46:11 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.326.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2851,6 +2851,11 @@ OpenIntoRel(QueryDesc *queryDesc)
 
        Assert(into);
 
+       /*
+        * XXX This code needs to be kept in sync with DefineRelation().
+        * Maybe we should try to use that function instead.
+        */
+
        /*
         * Check consistency of arguments
         */
@@ -2859,6 +2864,16 @@ OpenIntoRel(QueryDesc *queryDesc)
                                (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
                                 errmsg("ON COMMIT can only be used on temporary tables")));
 
+       /*
+        * Security check: disallow creating temp tables from security-restricted
+        * code.  This is needed because calling code might not expect untrusted
+        * tables to appear in pg_temp at the front of its search path.
+        */
+       if (into->rel->istemp && InSecurityRestrictedOperation())
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                errmsg("cannot create temporary table within security-restricted operation")));
+
        /*
         * Find namespace to create in, check its permissions
         */
index f51f90f86b4a296b3c43a7126f5a0052c3c276b9..bd91162cec38143ea9e27fd8f20dab88af00d3f9 100644 (file)
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.309 2009/06/11 20:46:11 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.309.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -224,6 +224,25 @@ check_xact_readonly(Node *parsetree)
 }
 
 
+/*
+ * CheckRestrictedOperation: throw error for hazardous command if we're
+ * inside a security restriction context.
+ *
+ * This is needed to protect session-local state for which there is not any
+ * better-defined protection mechanism, such as ownership.
+ */
+static void
+CheckRestrictedOperation(const char *cmdname)
+{
+       if (InSecurityRestrictedOperation())
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                /* translator: %s is name of a SQL command, eg PREPARE */
+                                errmsg("cannot execute %s within security-restricted operation",
+                                               cmdname)));
+}
+
+
 /*
  * ProcessUtility
  *             general utility function invoker
@@ -389,6 +408,7 @@ ProcessUtility(Node *parsetree,
                        {
                                ClosePortalStmt *stmt = (ClosePortalStmt *) parsetree;
 
+                               CheckRestrictedOperation("CLOSE");
                                PerformPortalClose(stmt->portalname);
                        }
                        break;
@@ -585,6 +605,7 @@ ProcessUtility(Node *parsetree,
                        break;
 
                case T_PrepareStmt:
+                       CheckRestrictedOperation("PREPARE");
                        PrepareQuery((PrepareStmt *) parsetree, queryString);
                        break;
 
@@ -594,6 +615,7 @@ ProcessUtility(Node *parsetree,
                        break;
 
                case T_DeallocateStmt:
+                       CheckRestrictedOperation("DEALLOCATE");
                        DeallocateQuery((DeallocateStmt *) parsetree);
                        break;
 
@@ -873,6 +895,7 @@ ProcessUtility(Node *parsetree,
                        {
                                ListenStmt *stmt = (ListenStmt *) parsetree;
 
+                               CheckRestrictedOperation("LISTEN");
                                Async_Listen(stmt->conditionname);
                        }
                        break;
@@ -881,6 +904,7 @@ ProcessUtility(Node *parsetree,
                        {
                                UnlistenStmt *stmt = (UnlistenStmt *) parsetree;
 
+                               CheckRestrictedOperation("UNLISTEN");
                                if (stmt->conditionname)
                                        Async_Unlisten(stmt->conditionname);
                                else
@@ -924,6 +948,8 @@ ProcessUtility(Node *parsetree,
                        break;
 
                case T_DiscardStmt:
+                       /* should we allow DISCARD PLANS? */
+                       CheckRestrictedOperation("DISCARD");
                        DiscardCommand((DiscardStmt *) parsetree, isTopLevel);
                        break;
 
index 05e840dae5f9e0c52b24204730e4be8edcc687ad..ec0eeddc263973ffc1d020b7147e28bea138244f 100644 (file)
@@ -15,7 +15,7 @@
  *
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.113.2.1 2009/11/05 04:38:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.113.2.2 2009/12/09 21:58:04 tgl Exp $
  *
  * ----------
  */
@@ -3209,7 +3209,7 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
        SPIPlanPtr      qplan;
        Relation        query_rel;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
 
        /*
         * The query is always run against the FK table except when this is an
@@ -3223,8 +3223,9 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
                query_rel = fk_rel;
 
        /* Switch to proper UID to perform check as */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
-       SetUserIdAndContext(RelationGetForm(query_rel)->relowner, true);
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
+       SetUserIdAndSecContext(RelationGetForm(query_rel)->relowner,
+                                                  save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
 
        /* Create the plan */
        qplan = SPI_prepare(querystr, nargs, argtypes);
@@ -3232,8 +3233,8 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
        if (qplan == NULL)
                elog(ERROR, "SPI_prepare returned %d for %s", SPI_result, querystr);
 
-       /* Restore UID */
-       SetUserIdAndContext(save_userid, save_secdefcxt);
+       /* Restore UID and security context */
+       SetUserIdAndSecContext(save_userid, save_sec_context);
 
        /* Save the plan if requested */
        if (cache_plan)
@@ -3263,7 +3264,7 @@ ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
        int                     limit;
        int                     spi_result;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
        Datum           vals[RI_MAX_NUMKEYS * 2];
        char            nulls[RI_MAX_NUMKEYS * 2];
 
@@ -3343,8 +3344,9 @@ ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
        limit = (expect_OK == SPI_OK_SELECT) ? 1 : 0;
 
        /* Switch to proper UID to perform check as */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
-       SetUserIdAndContext(RelationGetForm(query_rel)->relowner, true);
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
+       SetUserIdAndSecContext(RelationGetForm(query_rel)->relowner,
+                                                  save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
 
        /* Finally we can run the query. */
        spi_result = SPI_execute_snapshot(qplan,
@@ -3352,8 +3354,8 @@ ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
                                                                          test_snapshot, crosscheck_snapshot,
                                                                          false, false, limit);
 
-       /* Restore UID */
-       SetUserIdAndContext(save_userid, save_secdefcxt);
+       /* Restore UID and security context */
+       SetUserIdAndSecContext(save_userid, save_sec_context);
 
        /* Check result */
        if (spi_result < 0)
index 1256e7c88d070d678314abcff861a52ddd814a3d..308d7a0a2399b2db65083c0dd6b84e8be3979722 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.126 2009/06/11 14:49:05 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.126.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -880,7 +880,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        struct fmgr_security_definer_cache *volatile fcache;
        FmgrInfo   *save_flinfo;
        Oid                     save_userid;
-       bool            save_secdefcxt;
+       int                     save_sec_context;
        volatile int save_nestlevel;
        PgStat_FunctionCallUsage fcusage;
 
@@ -926,15 +926,16 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        else
                fcache = fcinfo->flinfo->fn_extra;
 
-       /* GetUserIdAndContext is cheap enough that no harm in a wasted call */
-       GetUserIdAndContext(&save_userid, &save_secdefcxt);
+       /* GetUserIdAndSecContext is cheap enough that no harm in a wasted call */
+       GetUserIdAndSecContext(&save_userid, &save_sec_context);
        if (fcache->proconfig)          /* Need a new GUC nesting level */
                save_nestlevel = NewGUCNestLevel();
        else
                save_nestlevel = 0;             /* keep compiler quiet */
 
        if (OidIsValid(fcache->userid))
-               SetUserIdAndContext(fcache->userid, true);
+               SetUserIdAndSecContext(fcache->userid,
+                                                          save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
 
        if (fcache->proconfig)
        {
@@ -981,7 +982,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS)
        if (fcache->proconfig)
                AtEOXact_GUC(true, save_nestlevel);
        if (OidIsValid(fcache->userid))
-               SetUserIdAndContext(save_userid, save_secdefcxt);
+               SetUserIdAndSecContext(save_userid, save_sec_context);
 
        return result;
 }
index 7bdfb67204e02f7efda8bd10d4b922d23296e055..55b395f9a2b0fbc79952d7864265d50ed86b93f1 100644 (file)
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.175 2009/06/11 14:49:05 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.175.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -272,8 +272,10 @@ make_absolute_path(const char *path)
  * 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.
+ * SecurityRestrictionContext holds flags indicating reason(s) for changing
+ * CurrentUserId.  In some cases we need to lock down operations that are
+ * not directly controlled by privilege settings, and this provides a
+ * convenient way to do it.
  * ----------------------------------------------------------------
  */
 static Oid     AuthenticatedUserId = InvalidOid;
@@ -285,7 +287,7 @@ static Oid  CurrentUserId = InvalidOid;
 static bool AuthenticatedUserIsSuperuser = false;
 static bool SessionUserIsSuperuser = false;
 
-static bool SecurityDefinerContext = false;
+static int     SecurityRestrictionContext = 0;
 
 /* We also remember if a SET ROLE is currently active */
 static bool SetRoleIsActive = false;
@@ -294,7 +296,7 @@ static bool SetRoleIsActive = false;
 /*
  * GetUserId - get the current effective user ID.
  *
- * Note: there's no SetUserId() anymore; use SetUserIdAndContext().
+ * Note: there's no SetUserId() anymore; use SetUserIdAndSecContext().
  */
 Oid
 GetUserId(void)
@@ -318,7 +320,7 @@ GetOuterUserId(void)
 static void
 SetOuterUserId(Oid userid)
 {
-       AssertState(!SecurityDefinerContext);
+       AssertState(SecurityRestrictionContext == 0);
        AssertArg(OidIsValid(userid));
        OuterUserId = userid;
 
@@ -341,7 +343,7 @@ GetSessionUserId(void)
 static void
 SetSessionUserId(Oid userid, bool is_superuser)
 {
-       AssertState(!SecurityDefinerContext);
+       AssertState(SecurityRestrictionContext == 0);
        AssertArg(OidIsValid(userid));
        SessionUserId = userid;
        SessionUserIsSuperuser = is_superuser;
@@ -354,11 +356,29 @@ SetSessionUserId(Oid userid, bool is_superuser)
 
 
 /*
- * GetUserIdAndContext/SetUserIdAndContext - get/set the current user ID
- * and the SecurityDefinerContext flag.
+ * GetUserIdAndSecContext/SetUserIdAndSecContext - get/set the current user ID
+ * and the SecurityRestrictionContext flags.
  *
- * Unlike GetUserId, GetUserIdAndContext does *not* Assert that the current
- * value of CurrentUserId is valid; nor does SetUserIdAndContext require
+ * Currently there are two valid bits in SecurityRestrictionContext:
+ *
+ * SECURITY_LOCAL_USERID_CHANGE indicates that we are inside an operation
+ * that is temporarily changing CurrentUserId via these functions.  This is
+ * needed to indicate that the actual value of CurrentUserId is not in sync
+ * with guc.c's internal state, so SET ROLE has to be disallowed.
+ *
+ * SECURITY_RESTRICTED_OPERATION indicates that we are inside an operation
+ * that does not wish to trust called user-defined functions at all.  This
+ * bit prevents not only SET ROLE, but various other changes of session state
+ * that normally is unprotected but might possibly be used to subvert the
+ * calling session later.  An example is replacing an existing prepared
+ * statement with new code, which will then be executed with the outer
+ * session's permissions when the prepared statement is next used.  Since
+ * these restrictions are fairly draconian, we apply them only in contexts
+ * where the called functions are really supposed to be side-effect-free
+ * anyway, such as VACUUM/ANALYZE/REINDEX.
+ *
+ * Unlike GetUserId, GetUserIdAndSecContext does *not* Assert that the current
+ * value of CurrentUserId is valid; nor does SetUserIdAndSecContext 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,
@@ -367,27 +387,66 @@ SetSessionUserId(Oid userid, bool is_superuser)
  * through AbortTransaction without asserting in case InitPostgres fails.
  */
 void
-GetUserIdAndContext(Oid *userid, bool *sec_def_context)
+GetUserIdAndSecContext(Oid *userid, int *sec_context)
 {
        *userid = CurrentUserId;
-       *sec_def_context = SecurityDefinerContext;
+       *sec_context = SecurityRestrictionContext;
 }
 
 void
-SetUserIdAndContext(Oid userid, bool sec_def_context)
+SetUserIdAndSecContext(Oid userid, int sec_context)
 {
        CurrentUserId = userid;
-       SecurityDefinerContext = sec_def_context;
+       SecurityRestrictionContext = sec_context;
 }
 
 
 /*
- * InSecurityDefinerContext - are we inside a SECURITY DEFINER context?
+ * InLocalUserIdChange - are we inside a local change of CurrentUserId?
  */
 bool
-InSecurityDefinerContext(void)
+InLocalUserIdChange(void)
 {
-       return SecurityDefinerContext;
+       return (SecurityRestrictionContext & SECURITY_LOCAL_USERID_CHANGE) != 0;
+}
+
+/*
+ * InSecurityRestrictedOperation - are we inside a security-restricted command?
+ */
+bool
+InSecurityRestrictedOperation(void)
+{
+       return (SecurityRestrictionContext & SECURITY_RESTRICTED_OPERATION) != 0;
+}
+
+
+/*
+ * These are obsolete versions of Get/SetUserIdAndSecContext that are
+ * only provided for bug-compatibility with some rather dubious code in
+ * pljava.  We allow the userid to be set, but only when not inside a
+ * security restriction context.
+ */
+void
+GetUserIdAndContext(Oid *userid, bool *sec_def_context)
+{
+       *userid = CurrentUserId;
+       *sec_def_context = InLocalUserIdChange();
+}
+
+void
+SetUserIdAndContext(Oid userid, bool sec_def_context)
+{
+       /* We throw the same error SET ROLE would. */
+       if (InSecurityRestrictedOperation())
+               ereport(ERROR,
+                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                errmsg("cannot set parameter \"%s\" within security-restricted operation",
+                                               "role")));
+       CurrentUserId = userid;
+       if (sec_def_context)
+               SecurityRestrictionContext |= SECURITY_LOCAL_USERID_CHANGE;
+       else
+               SecurityRestrictionContext &= ~SECURITY_LOCAL_USERID_CHANGE;
 }
 
 
index fc7c2e5e1ce5366d6679d541e0b81060ef9687be..8f9a96722e99fe83ebbd7d84721292df7e45e9d5 100644 (file)
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.505.2.2 2009/09/03 22:08:14 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.505.2.3 2009/12/09 21:58:04 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -2305,7 +2305,7 @@ static struct config_string ConfigureNamesString[] =
                {"role", PGC_USERSET, UNGROUPED,
                        gettext_noop("Sets the current role."),
                        NULL,
-                       GUC_IS_NAME | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_DEF
+                       GUC_IS_NAME | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_REST
                },
                &role_string,
                "none", assign_role, show_role
@@ -2316,7 +2316,7 @@ static struct config_string ConfigureNamesString[] =
                {"session_authorization", PGC_USERSET, UNGROUPED,
                        gettext_noop("Sets the session user name."),
                        NULL,
-                       GUC_IS_NAME | GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_DEF
+                       GUC_IS_NAME | GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_REST
                },
                &session_authorization_string,
                NULL, assign_session_authorization, show_session_authorization
@@ -4636,29 +4636,45 @@ set_config_option(const char *name, const char *value,
        }
 
        /*
-        * Disallow changing GUC_NOT_WHILE_SEC_DEF values if we are inside a
-        * security-definer function.  We can reject this regardless of
-        * the context or source, mainly because sources that it might be
+        * Disallow changing GUC_NOT_WHILE_SEC_REST values if we are inside a
+        * security restriction context.  We can reject this regardless of
+        * the GUC context or source, mainly because sources that it might be
         * reasonable to override for won't be seen while inside a function.
         *
-        * Note: variables marked GUC_NOT_WHILE_SEC_DEF should probably be marked
+        * Note: variables marked GUC_NOT_WHILE_SEC_REST should usually be marked
         * GUC_NO_RESET_ALL as well, because ResetAllOptions() doesn't check this.
+        * An exception might be made if the reset value is assumed to be "safe".
         *
         * Note: this flag is currently used for "session_authorization" and
-        * "role".  We need to prohibit this because when we exit the sec-def
-        * context, GUC won't be notified, leaving things out of sync.
-        *
-        * XXX it would be nice to allow these cases in future, with the behavior
-        * being that the SET's effects end when the security definer context is
-        * exited.
+        * "role".  We need to prohibit changing these inside a local userid
+        * context because when we exit it, GUC won't be notified, leaving things
+        * out of sync.  (This could be fixed by forcing a new GUC nesting level,
+        * but that would change behavior in possibly-undesirable ways.)  Also,
+        * we prohibit changing these in a security-restricted operation because
+        * otherwise RESET could be used to regain the session user's privileges.
         */
-       if ((record->flags & GUC_NOT_WHILE_SEC_DEF) && InSecurityDefinerContext())
+       if (record->flags & GUC_NOT_WHILE_SEC_REST)
        {
-               ereport(elevel,
-                               (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-                                errmsg("cannot set parameter \"%s\" within security-definer function",
-                                               name)));
-               return false;
+               if (InLocalUserIdChange())
+               {
+                       /*
+                        * Phrasing of this error message is historical, but it's the
+                        * most common case.
+                        */
+                       ereport(elevel,
+                                       (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                        errmsg("cannot set parameter \"%s\" within security-definer function",
+                                                       name)));
+                       return false;
+               }
+               if (InSecurityRestrictedOperation())
+               {
+                       ereport(elevel,
+                                       (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+                                        errmsg("cannot set parameter \"%s\" within security-restricted operation",
+                                                       name)));
+                       return false;
+               }
        }
 
        /*
index e4c5d66475db52bbf73ac98d6b3f0d9f763dca65..87d01305b3cd26d366522bf9d3369f5366c1da4f 100644 (file)
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.211 2009/06/11 14:49:08 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.211.2.1 2009/12/09 21:58:04 tgl Exp $
  *
  * NOTES
  *       some of the information in this file should be moved to other files.
@@ -242,6 +242,10 @@ extern void check_stack_depth(void);
  *                     POSTGRES directory path definitions.                                                     *
  *****************************************************************************/
 
+/* flags to be OR'd to form sec_context */
+#define SECURITY_LOCAL_USERID_CHANGE   0x0001
+#define SECURITY_RESTRICTED_OPERATION  0x0002
+
 extern char *DatabasePath;
 
 /* now in utils/init/miscinit.c */
@@ -251,9 +255,12 @@ extern char *GetUserNameFromId(Oid roleid);
 extern Oid     GetUserId(void);
 extern Oid     GetOuterUserId(void);
 extern Oid     GetSessionUserId(void);
+extern void GetUserIdAndSecContext(Oid *userid, int *sec_context);
+extern void SetUserIdAndSecContext(Oid userid, int sec_context);
+extern bool InLocalUserIdChange(void);
+extern bool InSecurityRestrictedOperation(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 SetSessionAuthorization(Oid userid, bool is_superuser);
index 24111dca68ef7d5fe4faceac348eb8c27af17692..4b3dc315c6030489b850f23b9e48087ea432b06b 100644 (file)
@@ -7,7 +7,7 @@
  * Copyright (c) 2000-2009, PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
- * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.102.2.1 2009/09/03 22:08:14 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.102.2.2 2009/12/09 21:58:04 tgl Exp $
  *--------------------------------------------------------------------
  */
 #ifndef GUC_H
@@ -146,7 +146,7 @@ typedef enum
 #define GUC_UNIT_MIN                   0x4000  /* value is in minutes */
 #define GUC_UNIT_TIME                  0x7000  /* mask for MS, S, MIN */
 
-#define GUC_NOT_WHILE_SEC_DEF  0x8000  /* can't change inside sec-def func */
+#define GUC_NOT_WHILE_SEC_REST 0x8000  /* can't set if security restricted */
 
 /* GUC vars that are actually declared in guc.c, rather than elsewhere */
 extern bool log_duration;