From: Arran Cudbard-Bell <a.cudbardb@freeradius.org>
Date: Thu, 2 Apr 2020 16:34:31 +0000 (-0600)
Subject: cursor: Add note and guard for fr_cursor_intersect_* functions
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b12940a1ae6ba22f7836c4e4e4b0b2d00325f9ef;p=thirdparty%2Ffreeradius-server.git

cursor: Add note and guard for fr_cursor_intersect_* functions
---

diff --git a/src/lib/util/cursor.c b/src/lib/util/cursor.c
index 5be7d695a50..585c2ec777d 100644
--- a/src/lib/util/cursor.c
+++ b/src/lib/util/cursor.c
@@ -403,6 +403,8 @@ void fr_cursor_merge(fr_cursor_t *cursor, fr_cursor_t *to_append)
 }
 
 /** Return the first item matching the iterator in cursor a and cursor b
+ *
+ * @note Both cursors must operate on the same list of items.
  *
  * @param[in] a		First cursor.
  * @param[in] b		Second cursor.
@@ -412,6 +414,8 @@ void *fr_cursor_intersect_head(fr_cursor_t *a, fr_cursor_t *b)
 {
 	void *a_item, *b_item;
 
+	if (unlikely(a->head != b->head)) return NULL;
+
 	a_item = fr_cursor_head(a);
 	b_item = fr_cursor_head(b);
 
@@ -421,6 +425,8 @@ void *fr_cursor_intersect_head(fr_cursor_t *a, fr_cursor_t *b)
 }
 
 /** Return the next item matching the iterator in cursor a and cursor b
+ *
+ * @note Both cursors must operate on the same list of items.
  *
  * @param[in] a		First cursor.
  * @param[in] b		Second cursor.
@@ -430,6 +436,8 @@ void *fr_cursor_intersect_next(fr_cursor_t *a, fr_cursor_t *b)
 {
 	fr_cursor_iter_t b_iter;
 
+	if (unlikely(a->head != b->head)) return NULL;
+
 	/*
 	 *	If either of the iterators lack an iterator
 	 *	just use cursor_next...