Fix "path" infrastructure bug affecting jsonb_set()

jsonb_set() and other clients of the setPathArray() utility function
could get spurious results when an array integer subscript is provided
that is not within the range of int.

To fix, ensure that the value returned by strtol() within setPathArray()
is within the range of int;  when it isn't, assume an invalid input in
line with existing, similar cases.  The path-orientated operators that
appeared in PostgreSQL 9.3 and 9.4 do not call setPathArray(), and
already independently take this precaution, so no change there.

Peter Geoghegan

1 files changed, 5 insertions, 2 deletions

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index c14d3f73fca..13d5b7af2f4 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -3814,11 +3814,14 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 	if (level < path_len && !path_nulls[level])
 	{
 		char	   *c = VARDATA_ANY(path_elems[level]);
+		long		lindex;
 
 		errno = 0;
-		idx = (int) strtol(c, &badp, 10);
-		if (errno != 0 || badp == c)
+		lindex = strtol(c, &badp, 10);
+		if (errno != 0 || badp == c || lindex > INT_MAX || lindex < INT_MIN)
 			idx = nelems;
+		else
+			idx = lindex;
 	}
 	else
 		idx = nelems;