Fix column-privilege leak in error-message paths

While building error messages to return to the user,
BuildIndexValueDescription, ExecBuildSlotValueDescription and
ri_ReportViolation would happily include the entire key or entire row in
the result returned to the user, even if the user didn't have access to
view all of the columns being included.

Instead, include only those columns which the user is providing or which
the user has select rights on.  If the user does not have any rights
to view the table or any of the columns involved then no detail is
provided and a NULL value is returned from BuildIndexValueDescription
and ExecBuildSlotValueDescription.  Note that, for key cases, the user
must have access to all of the columns for the key to be shown; a
partial key will not be returned.

Further, in master only, do not return any data for cases where row
security is enabled on the relation and row security should be applied
for the user.  This required a bit of refactoring and moving of things
around related to RLS- note the addition of utils/misc/rls.c.

Back-patch all the way, as column-level privileges are now in all
supported versions.

This has been assigned CVE-2014-8161, but since the issue and the patch
have already been publicized on pgsql-hackers, there's no point in trying
to hide this commit.

src/backend/commands/copy.c

@@ -40,7 +40,6 @@
 #include "parser/parse_relation.h"
 #include "nodes/makefuncs.h"
 #include "rewrite/rewriteHandler.h"
-#include "rewrite/rowsecurity.h"
 #include "storage/fd.h"
 #include "tcop/tcopprot.h"
 #include "utils/acl.h"
@@ -49,6 +48,7 @@
 #include "utils/memutils.h"
 #include "utils/portal.h"
 #include "utils/rel.h"
+#include "utils/rls.h"
 #include "utils/snapmgr.h"
 
 
@@ -163,6 +163,7 @@ typedef struct CopyStateData
 	int		   *defmap;			/* array of default att numbers */
 	ExprState **defexprs;		/* array of default att expressions */
 	bool		volatile_defexprs;		/* is any of defexprs volatile? */
+	List	   *range_table;
 
 	/*
 	 * These variables are used to reduce overhead in textual COPY FROM.
@@ -789,6 +790,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed)
 	Relation	rel;
 	Oid			relid;
 	Node	   *query = NULL;
+	RangeTblEntry *rte;
 
 	/* Disallow COPY to/from file or program except to superusers. */
 	if (!pipe && !superuser())
@@ -811,7 +813,6 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed)
 	{
 		TupleDesc	tupDesc;
 		AclMode		required_access = (is_from ? ACL_INSERT : ACL_SELECT);
-		RangeTblEntry *rte;
 		List	   *attnums;
 		ListCell   *cur;
 
@@ -857,7 +858,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed)
 		 * If RLS is not enabled for this, then just fall through to the
 		 * normal non-filtering relation handling.
 		 */
-		if (check_enable_rls(rte->relid, InvalidOid) == RLS_ENABLED)
+		if (check_enable_rls(rte->relid, InvalidOid, false) == RLS_ENABLED)
 		{
 			SelectStmt *select;
 			ColumnRef  *cr;
@@ -920,6 +921,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed)
 
 		cstate = BeginCopyFrom(rel, stmt->filename, stmt->is_program,
 							   stmt->attlist, stmt->options);
+		cstate->range_table = list_make1(rte);
 		*processed = CopyFrom(cstate);	/* copy from file to database */
 		EndCopyFrom(cstate);
 	}
@@ -928,6 +930,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed)
 		cstate = BeginCopyTo(rel, query, queryString, relid,
 							 stmt->filename, stmt->is_program,
 							 stmt->attlist, stmt->options);
+		cstate->range_table = list_make1(rte);
 		*processed = DoCopyTo(cstate);	/* copy from database to file */
 		EndCopyTo(cstate);
 	}
@@ -2277,6 +2280,7 @@ CopyFrom(CopyState cstate)
 	estate->es_result_relations = resultRelInfo;
 	estate->es_num_result_relations = 1;
 	estate->es_result_relation_info = resultRelInfo;
+	estate->es_range_table = cstate->range_table;
 
 	/* Set up a tuple slot too */
 	myslot = ExecInitExtraTupleSlot(estate);

src/backend/commands/createas.c

@@ -38,12 +38,12 @@
 #include "miscadmin.h"
 #include "parser/parse_clause.h"
 #include "rewrite/rewriteHandler.h"
-#include "rewrite/rowsecurity.h"
 #include "storage/smgr.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/rls.h"
 #include "utils/snapmgr.h"
 
 
@@ -446,7 +446,7 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
 	 * be enabled here.  We don't actually support that currently, so throw
 	 * our own ereport(ERROR) if that happens.
 	 */
-	if (check_enable_rls(intoRelationId, InvalidOid) == RLS_ENABLED)
+	if (check_enable_rls(intoRelationId, InvalidOid, false) == RLS_ENABLED)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 (errmsg("policies not yet implemented for this command"))));

src/backend/commands/matview.c

@@ -596,6 +596,13 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
 	if (SPI_processed > 0)
 	{
+		/*
+		 * Note that this ereport() is returning data to the user.  Generally,
+		 * we would want to make sure that the user has been granted access to
+		 * this data.  However, REFRESH MAT VIEW is only able to be run by the
+		 * owner of the mat view (or a superuser) and therefore there is no
+		 * need to check for access to data in the mat view.
+		 */
 		ereport(ERROR,
 				(errcode(ERRCODE_CARDINALITY_VIOLATION),
 				 errmsg("new data for \"%s\" contains duplicate rows without any null columns",

src/backend/commands/trigger.c

@@ -65,6 +65,12 @@ int			SessionReplicationRole = SESSION_REPLICATION_ROLE_ORIGIN;
 /* How many levels deep into trigger execution are we? */
 static int	MyTriggerDepth = 0;
 
+/*
+ * Note that this macro also exists in executor/execMain.c.  There does not
+ * appear to be any good header to put it into, given the structures that
+ * it uses, so we let them be duplicated.  Be sure to update both if one needs
+ * to be changed, however.
+ */
 #define GetModifiedColumns(relinfo, estate) \
 	(rt_fetch((relinfo)->ri_RangeTableIndex, (estate)->es_range_table)->modifiedCols)