From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Thu, 17 Nov 2022 19:32:36 +0000 (-0500)
Subject: maple_tree: Reduce user error potential
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=b723e7bc9bc5b2044f456cd0407b9f91c89346fa;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Reduce user error potential

When iterating, a user may modify the tree and cause the iterator to be
out of range.  Detect this scenario and walk to the limit, then return
NULL

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 0da105a6d8a7..b617a5f57ab6 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4732,6 +4732,11 @@ static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit)
 	unsigned long last;
 	enum maple_type mt;
 
+	if (mas->index > limit) {
+		mas_set(mas, limit);
+		mas_walk(mas);
+		return NULL;
+	}
 	last = mas->last;
 retry:
 	offset = mas->offset;
@@ -4838,6 +4843,11 @@ static inline void *mas_prev_entry(struct ma_state *mas, unsigned long min)
 {
 	void *entry;
 
+	if (mas->index < min) {
+		mas_set(mas, min);
+		mas_walk(mas);
+		return NULL;
+	}
 retry:
 	while (likely(!mas_is_none(mas))) {
 		entry = mas_prev_nentry(mas, min, mas->index);