Avoid fetching past the end of the indoption array.

pg_get_indexdef_worker carelessly fetched indoption entries even for
non-key index columns that don't have one.  99.999% of the time this
would be harmless, since the code wouldn't examine the value ... but
some fine day this will be a fetch off the end of memory, resulting
in SIGSEGV.

Detected through valgrind testing.  Odd that the buildfarm's valgrind
critters haven't noticed.

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 7b142e3b188dee63458c30222a6a4cd53e80b0c9..0c7a533e6972ee1c5d1cd38d99a5a17681f5ed76 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -1308,7 +1308,6 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
        for (keyno = 0; keyno < idxrec->indnatts; keyno++)
        {
                AttrNumber      attnum = idxrec->indkey.values[keyno];
-               int16           opt = indoption->values[keyno];
                Oid                     keycoltype;
                Oid                     keycolcollation;
 
@@ -1370,10 +1369,10 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
                if (!attrsOnly && keyno < idxrec->indnkeyatts &&
                        (!colno || colno == keyno + 1))
                {
-                       Oid                     indcoll;
+                       int16           opt = indoption->values[keyno];
+                       Oid                     indcoll = indcollation->values[keyno];
 
                        /* Add collation, if not default for column */
-                       indcoll = indcollation->values[keyno];
                        if (OidIsValid(indcoll) && indcoll != keycolcollation)
                                appendStringInfo(&buf, " COLLATE %s",
                                                                 generate_collation_name((indcoll)));