From 613981be04d59ccac56ee578bee1bd01c3ce68bd Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 9 Dec 2009 21:58:44 +0000 Subject: [PATCH] Prevent indirect security attacks via changing session-local state within 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 --- src/backend/access/transam/xact.c | 42 ++++++---- src/backend/catalog/index.c | 24 ++++-- src/backend/commands/analyze.c | 24 ++++-- src/backend/commands/schemacmds.c | 13 +-- src/backend/commands/tablecmds.c | 12 ++- src/backend/commands/vacuum.c | 26 +++--- src/backend/executor/execMain.c | 13 ++- src/backend/tcop/utility.c | 26 +++++- src/backend/utils/adt/ri_triggers.c | 24 +++--- src/backend/utils/fmgr/fmgr.c | 11 +-- src/backend/utils/init/miscinit.c | 105 ++++++++++++++++++------ src/backend/utils/misc/guc.c | 119 ++++++++++++++++++++-------- src/include/miscadmin.h | 11 ++- src/include/utils/guc.h | 6 +- src/include/utils/guc_tables.h | 4 +- 15 files changed, 331 insertions(+), 129 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index 36070484ca3..55a46cef668 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.215.2.5 2009/11/23 09:59:21 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.215.2.6 2009/12/09 21:58:41 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -116,12 +116,13 @@ typedef struct TransactionStateData int savepointLevel; /* savepoint level */ TransState state; /* low-level state */ TBlockState blockState; /* high-level state */ - int nestingLevel; /* nest depth */ + int nestingLevel; /* transaction nesting depth */ + int gucNestLevel; /* GUC context nesting depth */ MemoryContext curTransactionContext; /* my xact-lifetime context */ ResourceOwner curTransactionOwner; /* my query resources */ List *childXids; /* subcommitted child XIDs */ 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; @@ -149,12 +150,13 @@ static TransactionStateData TopTransactionStateData = { TRANS_DEFAULT, /* transaction state */ TBLOCK_DEFAULT, /* transaction block state from the client * perspective */ - 0, /* nesting level */ + 0, /* transaction nesting depth */ + 0, /* GUC context nesting depth */ NULL, /* cur transaction context */ NULL, /* cur transaction resource owner */ NIL, /* subcommitted child Xids */ InvalidOid, /* previous CurrentUserId setting */ - false, /* previous SecurityDefinerContext setting */ + 0, /* previous SecurityRestrictionContext */ false, /* entry-time xact r/o state */ NULL /* link to parent state block */ }; @@ -1379,14 +1381,16 @@ StartTransaction(void) * note: prevXactReadOnly is not used at the outermost level */ s->nestingLevel = 1; + s->gucNestLevel = 1; s->childXids = NIL; - 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 */ + AtStart_GUC(); AtStart_Inval(); AtStart_Cache(); AfterTriggerBeginXact(); @@ -1570,7 +1574,7 @@ CommitTransaction(void) /* Check we've released all catcache entries */ AtEOXact_CatCache(true); - AtEOXact_GUC(true, false); + AtEOXact_GUC(true, 1); AtEOXact_SPI(true); AtEOXact_on_commit_actions(true); AtEOXact_Namespace(true); @@ -1590,6 +1594,7 @@ CommitTransaction(void) s->transactionId = InvalidTransactionId; s->subTransactionId = InvalidSubTransactionId; s->nestingLevel = 0; + s->gucNestLevel = 0; s->childXids = NIL; /* @@ -1786,7 +1791,7 @@ PrepareTransaction(void) AtEOXact_CatCache(true); /* PREPARE acts the same as COMMIT as far as GUC is concerned */ - AtEOXact_GUC(true, false); + AtEOXact_GUC(true, 1); AtEOXact_SPI(true); AtEOXact_on_commit_actions(true); AtEOXact_Namespace(true); @@ -1805,6 +1810,7 @@ PrepareTransaction(void) s->transactionId = InvalidTransactionId; s->subTransactionId = InvalidSubTransactionId; s->nestingLevel = 0; + s->gucNestLevel = 0; s->childXids = NIL; /* @@ -1868,13 +1874,13 @@ 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. + * of 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 @@ -1934,7 +1940,7 @@ AbortTransaction(void) false, true); AtEOXact_CatCache(false); - AtEOXact_GUC(false, false); + AtEOXact_GUC(false, 1); AtEOXact_SPI(false); AtEOXact_on_commit_actions(false); AtEOXact_Namespace(false); @@ -1981,6 +1987,7 @@ CleanupTransaction(void) s->transactionId = InvalidTransactionId; s->subTransactionId = InvalidSubTransactionId; s->nestingLevel = 0; + s->gucNestLevel = 0; s->childXids = NIL; /* @@ -3645,7 +3652,7 @@ CommitSubTransaction(void) RESOURCE_RELEASE_AFTER_LOCKS, true, false); - AtEOXact_GUC(true, true); + AtEOXact_GUC(true, s->gucNestLevel); AtEOSubXact_SPI(true, s->subTransactionId); AtEOSubXact_on_commit_actions(true, s->subTransactionId, s->parent->subTransactionId); @@ -3718,7 +3725,7 @@ 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 @@ -3761,7 +3768,7 @@ AbortSubTransaction(void) RESOURCE_RELEASE_AFTER_LOCKS, false, false); - AtEOXact_GUC(false, true); + AtEOXact_GUC(false, s->gucNestLevel); AtEOSubXact_SPI(false, s->subTransactionId); AtEOSubXact_on_commit_actions(false, s->subTransactionId, s->parent->subTransactionId); @@ -3855,10 +3862,11 @@ PushTransaction(void) s->subTransactionId = currentSubTransactionId; s->parent = p; s->nestingLevel = p->nestingLevel + 1; + s->gucNestLevel = NewGUCNestLevel(); 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; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 343779cfad1..557dd82985d 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.261.2.5 2008/05/27 21:13:39 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.261.2.6 2009/12/09 21:58:42 tgl Exp $ * * * INTERFACE ROUTINES @@ -45,6 +45,7 @@ #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" @@ -1364,7 +1365,8 @@ index_build(Relation heapRelation, { RegProcedure procedure; Oid save_userid; - bool save_secdefcxt; + int save_sec_context; + int save_nestlevel; /* * sanity checks @@ -1376,11 +1378,14 @@ index_build(Relation heapRelation, Assert(RegProcedureIsValid(procedure)); /* - * Switch to the table owner's userid, so that any index functions are - * run as that user. + * Switch to the table owner's userid, so that any index functions are run + * 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 @@ -1390,8 +1395,11 @@ index_build(Relation heapRelation, PointerGetDatum(indexRelation), PointerGetDatum(indexInfo)); - /* 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); } diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c index 04ac6b92c84..9291b03c29f 100644 --- a/src/backend/commands/analyze.c +++ b/src/backend/commands/analyze.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.89.2.3 2009/05/19 08:30:24 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.89.2.4 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -34,6 +34,7 @@ #include "utils/builtins.h" #include "utils/datum.h" #include "utils/fmgroids.h" +#include "utils/guc.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/syscache.h" @@ -113,7 +114,8 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt) totaldeadrows; HeapTuple *rows; Oid save_userid; - bool save_secdefcxt; + int save_sec_context; + int save_nestlevel; if (vacstmt->verbose) elevel = INFO; @@ -202,11 +204,14 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt) RelationGetRelationName(onerel)))); /* - * Switch to the table owner's userid, so that any index functions are - * run as that user. + * Switch to the table owner's userid, so that any index functions are run + * 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(); /* * Determine which columns to analyze @@ -447,8 +452,11 @@ cleanup: */ relation_close(onerel, NoLock); - /* 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); } /* diff --git a/src/backend/commands/schemacmds.c b/src/backend/commands/schemacmds.c index 957d50d7fa7..a7636c922a5 100644 --- a/src/backend/commands/schemacmds.c +++ b/src/backend/commands/schemacmds.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.35.2.1 2008/01/03 21:24:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/schemacmds.c,v 1.35.2.2 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -44,10 +44,10 @@ CreateSchemaCommand(CreateSchemaStmt *stmt) 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? @@ -87,7 +87,8 @@ CreateSchemaCommand(CreateSchemaStmt *stmt) * of 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); @@ -138,8 +139,8 @@ CreateSchemaCommand(CreateSchemaStmt *stmt) /* Reset search path to normal state */ PopSpecialNamespace(namespaceId); - /* Reset current user */ - SetUserIdAndContext(saved_uid, saved_secdefcxt); + /* Reset current user and security context */ + SetUserIdAndSecContext(saved_uid, save_sec_context); } diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index f54902f5daa..e4bcff6c38a 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.174.2.8 2008/10/07 11:16:01 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.174.2.9 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -295,6 +295,16 @@ 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, diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index f9fce596a36..eb0ba4afef2 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -13,7 +13,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.317.2.8 2009/11/10 18:01:11 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.317.2.9 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -44,6 +44,7 @@ #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" @@ -962,7 +963,8 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind) Oid toast_relid; bool result; Oid save_userid; - bool save_secdefcxt; + int save_sec_context; + int save_nestlevel; bool heldoff; /* Begin a transaction for vacuuming this relation */ @@ -1075,12 +1077,15 @@ 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.) + * Switch to the table owner's userid, so that any index functions are run + * 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 @@ -1092,8 +1097,11 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind) result = true; /* did the vacuum */ - /* 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); diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 643714a948c..923ac2c7d05 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -26,7 +26,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.256.2.7 2008/08/08 17:01:34 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.256.2.8 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -763,6 +763,17 @@ InitPlan(QueryDesc *queryDesc, bool explainOnly) Oid intoRelationId; TupleDesc tupdesc; + /* + * 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 (parseTree->into->istemp && InSecurityRestrictedOperation()) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("cannot create temporary table within security-restricted operation"))); + /* * find namespace to create in, check permissions */ diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c index 8e3c900053c..38452672a14 100644 --- a/src/backend/tcop/utility.c +++ b/src/backend/tcop/utility.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.245 2005/10/15 02:49:27 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.245.2.1 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -330,6 +330,25 @@ 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 @@ -474,6 +493,7 @@ ProcessUtility(Node *parsetree, { ClosePortalStmt *stmt = (ClosePortalStmt *) parsetree; + CheckRestrictedOperation("CLOSE"); PerformPortalClose(stmt->portalname); } break; @@ -606,6 +626,7 @@ ProcessUtility(Node *parsetree, break; case T_PrepareStmt: + CheckRestrictedOperation("PREPARE"); PrepareQuery((PrepareStmt *) parsetree); break; @@ -614,6 +635,7 @@ ProcessUtility(Node *parsetree, break; case T_DeallocateStmt: + CheckRestrictedOperation("DEALLOCATE"); DeallocateQuery((DeallocateStmt *) parsetree); break; @@ -820,6 +842,7 @@ ProcessUtility(Node *parsetree, { ListenStmt *stmt = (ListenStmt *) parsetree; + CheckRestrictedOperation("LISTEN"); Async_Listen(stmt->relation->relname); } break; @@ -828,6 +851,7 @@ ProcessUtility(Node *parsetree, { UnlistenStmt *stmt = (UnlistenStmt *) parsetree; + CheckRestrictedOperation("UNLISTEN"); Async_Unlisten(stmt->relation->relname); } break; diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c index 7cbac5eab82..45f19eaf561 100644 --- a/src/backend/utils/adt/ri_triggers.c +++ b/src/backend/utils/adt/ri_triggers.c @@ -17,7 +17,7 @@ * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.82.2.3 2008/01/03 21:24:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.82.2.4 2009/12/09 21:58:42 tgl Exp $ * * ---------- */ @@ -3004,7 +3004,7 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes, void *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 @@ -3018,8 +3018,9 @@ 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); @@ -3027,8 +3028,8 @@ 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) @@ -3058,7 +3059,7 @@ ri_PerformCheck(RI_QueryKey *qkey, void *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]; @@ -3136,8 +3137,9 @@ ri_PerformCheck(RI_QueryKey *qkey, void *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, @@ -3145,8 +3147,8 @@ ri_PerformCheck(RI_QueryKey *qkey, void *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) diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c index 48a5b0bf654..1c85102002b 100644 --- a/src/backend/utils/fmgr/fmgr.c +++ b/src/backend/utils/fmgr/fmgr.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.97.2.3 2008/01/03 21:24:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/fmgr/fmgr.c,v 1.97.2.4 2009/12/09 21:58:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -784,7 +784,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS) FmgrInfo *save_flinfo; struct fmgr_security_definer_cache *volatile fcache; Oid save_userid; - bool save_secdefcxt; + int save_sec_context; HeapTuple tuple; if (!fcinfo->flinfo->fn_extra) @@ -810,8 +810,9 @@ fmgr_security_definer(PG_FUNCTION_ARGS) else fcache = fcinfo->flinfo->fn_extra; - GetUserIdAndContext(&save_userid, &save_secdefcxt); - SetUserIdAndContext(fcache->userid, true); + GetUserIdAndSecContext(&save_userid, &save_sec_context); + SetUserIdAndSecContext(fcache->userid, + save_sec_context | SECURITY_LOCAL_USERID_CHANGE); /* * We don't need to restore the userid settings on error, because the @@ -835,7 +836,7 @@ fmgr_security_definer(PG_FUNCTION_ARGS) fcinfo->flinfo = save_flinfo; - SetUserIdAndContext(save_userid, save_secdefcxt); + SetUserIdAndSecContext(save_userid, save_sec_context); return result; } diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c index 7a81fabb8fb..34dfe670e43 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.150.2.2 2008/01/03 21:24:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.150.2.3 2009/12/09 21:58:43 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -293,8 +293,10 @@ 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; @@ -306,7 +308,7 @@ 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; @@ -315,7 +317,7 @@ 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) @@ -339,7 +341,7 @@ GetOuterUserId(void) static void SetOuterUserId(Oid userid) { - AssertState(!SecurityDefinerContext); + AssertState(SecurityRestrictionContext == 0); AssertArg(OidIsValid(userid)); OuterUserId = userid; @@ -362,7 +364,7 @@ GetSessionUserId(void) static void SetSessionUserId(Oid userid, bool is_superuser) { - AssertState(!SecurityDefinerContext); + AssertState(SecurityRestrictionContext == 0); AssertArg(OidIsValid(userid)); SessionUserId = userid; SessionUserIsSuperuser = is_superuser; @@ -375,11 +377,29 @@ 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, @@ -388,27 +408,66 @@ SetSessionUserId(Oid userid, bool is_superuser) * through AbortTransaction without asserting in case InitPostgres fails. */ void +GetUserIdAndSecContext(Oid *userid, int *sec_context) +{ + *userid = CurrentUserId; + *sec_context = SecurityRestrictionContext; +} + +void +SetUserIdAndSecContext(Oid userid, int sec_context) +{ + CurrentUserId = userid; + SecurityRestrictionContext = sec_context; +} + + +/* + * InLocalUserIdChange - are we inside a local change of CurrentUserId? + */ +bool +InLocalUserIdChange(void) +{ + 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 = SecurityDefinerContext; + *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; - SecurityDefinerContext = sec_def_context; -} - - -/* - * InSecurityDefinerContext - are we inside a SECURITY DEFINER context? - */ -bool -InSecurityDefinerContext(void) -{ - return SecurityDefinerContext; + if (sec_def_context) + SecurityRestrictionContext |= SECURITY_LOCAL_USERID_CHANGE; + else + SecurityRestrictionContext &= ~SECURITY_LOCAL_USERID_CHANGE; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 06dce7c4053..751e7921512 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -10,7 +10,7 @@ * Written by Peter Eisentraut . * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.299.2.5 2009/09/03 22:08:45 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.299.2.6 2009/12/09 21:58:43 tgl Exp $ * *-------------------------------------------------------------------- */ @@ -1936,7 +1936,7 @@ 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 @@ -1947,7 +1947,7 @@ 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 @@ -2162,6 +2162,8 @@ static bool guc_dirty; /* TRUE if need to do commit/abort work */ static bool reporting_enabled; /* TRUE to enable GUC_REPORT */ +static int GUCNestLevel = 0; /* 1 when in main transaction */ + static int guc_var_compare(const void *a, const void *b); static int guc_name_compare(const char *namea, const char *nameb); @@ -3000,17 +3002,16 @@ ResetAllOptions(void) static void push_old_value(struct config_generic * gconf) { - int my_level = GetCurrentTransactionNestLevel(); GucStack *stack; /* If we're not inside a transaction, do nothing */ - if (my_level == 0) + if (GUCNestLevel == 0) return; for (;;) { /* Done if we already pushed it at this nesting depth */ - if (gconf->stack && gconf->stack->nest_level >= my_level) + if (gconf->stack && gconf->stack->nest_level >= GUCNestLevel) return; /* @@ -3069,20 +3070,53 @@ push_old_value(struct config_generic * gconf) } /* - * Do GUC processing at transaction or subtransaction commit or abort. + * Do GUC processing at main transaction start. */ void -AtEOXact_GUC(bool isCommit, bool isSubXact) +AtStart_GUC(void) +{ + /* + * The nest level should be 0 between transactions; if it isn't, + * somebody didn't call AtEOXact_GUC, or called it with the wrong + * nestLevel. We throw a warning but make no other effort to clean up. + */ + if (GUCNestLevel != 0) + elog(WARNING, "GUC nest level = %d at transaction start", + GUCNestLevel); + GUCNestLevel = 1; +} + +/* + * Enter a new nesting level for GUC values. This is called at subtransaction + * start and when entering a function that has proconfig settings. NOTE that + * we must not risk error here, else subtransaction start will be unhappy. + */ +int +NewGUCNestLevel(void) +{ + return ++GUCNestLevel; +} + +/* + * Do GUC processing at transaction or subtransaction commit or abort, or + * when exiting a function that has proconfig settings. (The name is thus + * a bit of a misnomer; perhaps it should be ExitGUCNestLevel or some such.) + * During abort, we discard all GUC settings that were applied at nesting + * levels >= nestLevel. nestLevel == 1 corresponds to the main transaction. + */ +void +AtEOXact_GUC(bool isCommit, int nestLevel) { - int my_level; int i; + Assert(nestLevel > 0 && nestLevel <= GUCNestLevel); + /* Quick exit if nothing's changed in this transaction */ if (!guc_dirty) + { + GUCNestLevel = nestLevel - 1; return; - - my_level = GetCurrentTransactionNestLevel(); - Assert(isSubXact ? (my_level > 1) : (my_level == 1)); + } for (i = 0; i < num_guc_variables; i++) { @@ -3103,9 +3137,9 @@ AtEOXact_GUC(bool isCommit, bool isSubXact) /* Assert that we stacked old value before changing it */ Assert(stack != NULL && (my_status & GUC_HAVE_STACK)); /* However, the last change may have been at an outer xact level */ - if (stack->nest_level < my_level) + if (stack->nest_level < nestLevel) continue; - Assert(stack->nest_level == my_level); + Assert(stack->nest_level == nestLevel); /* * We will pop the stack entry. Start by restoring outer xact status @@ -3289,7 +3323,7 @@ AtEOXact_GUC(bool isCommit, bool isSubXact) set_string_field(conf, &stack->tentative_val.stringval, NULL); /* Don't store tentative value separately after commit */ - if (!isSubXact) + if (nestLevel == 1) set_string_field(conf, &conf->tentative_val, NULL); break; } @@ -3303,7 +3337,7 @@ AtEOXact_GUC(bool isCommit, bool isSubXact) * If we're now out of all xact levels, forget TENTATIVE status bit; * there's nothing tentative about the value anymore. */ - if (!isSubXact) + if (nestLevel == 1) { Assert(gconf->stack == NULL); gconf->status = 0; @@ -3320,8 +3354,11 @@ AtEOXact_GUC(bool isCommit, bool isSubXact) * that all outer transaction levels will have stacked values to deal * with.) */ - if (!isSubXact) + if (nestLevel == 1) guc_dirty = false; + + /* Update nesting level */ + GUCNestLevel = nestLevel - 1; } @@ -3666,29 +3703,45 @@ 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; + } } /* diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h index 7a9a5690265..6414427cc3d 100644 --- a/src/include/miscadmin.h +++ b/src/include/miscadmin.h @@ -13,7 +13,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.183.2.2 2008/01/03 21:24:26 tgl Exp $ + * $PostgreSQL: pgsql/src/include/miscadmin.h,v 1.183.2.3 2009/12/09 21:58:44 tgl Exp $ * * NOTES * some of the information in this file should be moved to other files. @@ -222,6 +222,10 @@ 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 */ @@ -231,9 +235,12 @@ 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); diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h index dfeb2bc2644..fd1b226a754 100644 --- a/src/include/utils/guc.h +++ b/src/include/utils/guc.h @@ -7,7 +7,7 @@ * Copyright (c) 2000-2005, PostgreSQL Global Development Group * Written by Peter Eisentraut . * - * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.63.2.1 2006/05/21 20:11:02 tgl Exp $ + * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.63.2.2 2009/12/09 21:58:44 tgl Exp $ *-------------------------------------------------------------------- */ #ifndef GUC_H @@ -189,7 +189,9 @@ extern void ProcessConfigFile(GucContext context); extern void InitializeGUCOptions(void); extern bool SelectConfigFiles(const char *userDoption, const char *progname); extern void ResetAllOptions(void); -extern void AtEOXact_GUC(bool isCommit, bool isSubXact); +extern void AtStart_GUC(void); +extern int NewGUCNestLevel(void); +extern void AtEOXact_GUC(bool isCommit, int nestLevel); extern void BeginReportingGUCOptions(void); extern void ParseLongOption(const char *string, char **name, char **value); extern bool set_config_option(const char *name, const char *value, diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h index 05b1dc48cf2..7d41103749b 100644 --- a/src/include/utils/guc_tables.h +++ b/src/include/utils/guc_tables.h @@ -7,7 +7,7 @@ * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.20.2.2 2009/09/03 22:08:45 tgl Exp $ + * $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.20.2.3 2009/12/09 21:58:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -128,7 +128,7 @@ struct config_generic #define GUC_SUPERUSER_ONLY 0x0100 /* show only to superusers */ #define GUC_IS_NAME 0x0200 /* limit string to NAMEDATALEN-1 */ -#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 */ /* bit values in status field */ #define GUC_HAVE_TENTATIVE 0x0001 /* tentative value is defined */